GI and Hepatology News

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO – Patients carrying at least one of the four key genes show a significantly increased risk for disease recurrence and mortality in gastric cancer, according to new research that potentially paves the way for precision oncology and improved targeting of therapies.

“About a third of patients with gastric cancer in our study had somatic mutations or variants of uncertain significance in [one of] four key genes,” lead author Ulysses Ribeiro, MD, PhD, a professor of digestive system surgery at the University of São Paulo School of Medicine in São Paulo, Brazil, said in a press briefing for the study, presented at Digestive Disease Week® (DDW) 2025.

“These patients were more likely to have their cancer come back or to die from the disease, even after surgery and the best chemotherapy and immunotherapy regimens,” said Ribeiro. While treatment strategies in gastric cancer have improved in recent years, resistance to multiple drugs continues, and the 5-year overall survival rate remains low — about 36% — underscoring the critical need for targeted therapies.

In an effort to identify genetic alterations that could have prognostic value, Ribeiro and his colleagues used next-generation DNA sequencing to analyze 21 genes in the tumor samples of 87 patients with gastric cancer who had undergone curative surgery and chemotherapy at the Sao Paulo Cancer Institute, São Paulo, Brazil.

Using Cox regression analysis, they found pathogenic variants or variants of uncertain significance in the following four genes: BRCA2, CDH1, RHOA, and TP53. “We found that 33% of patients carried at least one of these four genes,” Ribeiro told GI & Hepatology News.

Individually, each of the four genes with pathogenic variants or variants of uncertain significance had significantly or near-significantly higher risks in a survival analysis vs wild-type or benign variants, including BRCA2 (hazard ratio [HR], 4.33; P = .030); CDH1 (HR, 7.54; P = .004); RHOA (HR, 29.24; P < .001); and TP53 (HR, 2.82; P = .07).

A further multivariate analysis adjusting for key confounders showed that, when combined, carriers of the genes had lower disease-free survival (P = .005) and worse overall survival (P = .009) than those with none of the mutations.

“Individually, all four genes were related to prognosis in our gastric cancer patients, and when combined, the genes had even a higher difference in prognosis, varying from 2 to 28 times higher,” Ribeiro said.

Overall, factors such as having a more advanced tumor, node, metastasis stage, pathological stage, and the presence of a pathogenic mutation or a variant of uncertain significance in the four genes in the model were independently associated with worse disease-free survival.

 

Familiar Genes

Some of these genes are highly familiar. BRCA2 is well-known for its role in increasing the risk for breast and ovarian cancers, and CDH1 is known to be associated with hereditary diffuse gastric cancer, which is the most common hereditary cancer syndrome linked to gastric cancer.

TP53, also known as the “guardian of the genome,” is the most commonly altered gene in human cancers, while RHOA is known to be involved in encoding the GTPase protein RhoA, which is key in the regulation of cell shape, motility, and other essential cellular processes.

“This is the first time that these four genes have been shown to strongly relate to these gastric cancer outcomes,” said Ribeiro. This suggests that there’s more than one pathway by which stomach cancer forms and that some stomach cancers are much more aggressive than others.

He noted that “patients without these high-risk mutations” could be given “less aggressive treatment, in some cases sparing them from unnecessary side effects.”

Speaking during the press briefing, Loren A. Laine, MD, AGAF, who is a professor of medicine and chief of the Section of Digestive Diseases at the Yale School of Medicine in New Haven, Connecticut, and council chair of DDW 2025, agreed that “certainly, if these genetic factors, along with other factors, predict risk, this also has implications in practice with respect to the level of monitoring during the follow-up and determining the need for therapy.”

In addition, “it will be interesting to see how much this adds to other known risk factors, such as pathologic stage,” said Laine.

A strength of this study, “which I think is unique, is that it looks at a Western population,” whereas data on gastric as well as esophageal cancer is heavily biased to Eastern regions like China and East Asia, where the rates are much higher than in the West, Alia Qureshi, MD, an associate professor of esophageal and gastric cancer surgery at Oregon Health & Science University in Portland, Oregon, told GI & Hepatology News.

While noting the limitation of the relatively small sample size, Qureshi said the study is nevertheless “exciting and moving the direction we want to go, specifically towards precision medicine [and] precision oncology.”

The study “builds on existing understanding, especially with regard to TP53 and CDH1, and it points to the opportunity to use this data in a way to direct patient care or possibly therapeutic intervention,” she said.

Laine’s disclosures include consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept Pharmaceuticals, Merck, and Pfizer. Qureshi had no disclosures to report.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

SAN DIEGO — A 20-year initiative by Kaiser Permanente Northern California that assessed colorectal cancer (CRC) screening status and offered flexible options for screening has made a huge difference in CRC incidence, deaths, and racial disparities, an analysis showed.

“The program promptly doubled the proportion of people up to date with screening,” reported lead investigator Douglas A. Corley, MD, PhD, AGAF, a research scientist with Kaiser’s Division of Research, at a press briefing held on April 24, ahead of a presentation at the Digestive Disease Week® (DDW) 2025.

Additionally, within about 10 years, cancer rates were cut by a third, deaths were halved for the second most common cause of cancer deaths in the United States, and the differences that had previously been seen by race or ethnicity were largely eliminated, he said.

“Ten years ago, there were big gaps in cancer risk and death, especially among our Black patients. Now, those differences are nearly gone,” Corley said.

 

Closing the Gap

A systematic CRC screening program was implemented across Kaiser Permanente Northern California. The program included proactive outreach to members who were overdue for screening and mailing them fecal immunochemical test (FIT) kits for at-home use.

Corley and colleagues tracked screening status and CRC incidence and mortality annually from 2000 to 2019 among about 1.1 million members aged 50-75 years across 22 medical centers of the integrated healthcare system. The cohort included American Indian or Alaska Native, Asian, Black, Hispanic, Native Hawaiian or Pacific Islander, and White members.

Screening rates via FIT, colonoscopy, or sigmoidoscopy more than doubled after starting the program, from about 37% in the early years to about 80% within a few years, and it stayed that high through 2019, Corley reported. 

“Importantly, these large increases occurred across the whole population with only small differences,” he said. 

For example, about 76% of Hispanic members, 77% of Black members, 82% of White members, and 83% of Asian members were up to date in the later years and through 2019.

“This shows that systematic, comparable outreach can provide a level playing field for completion of preventive care,” Corley said.

After an expected early uptick in CRC incidence due to early detection, incidence later declined and by 2019 had dropped approximately 30% across the groups.

 

Long-Standing Disparities Erased

CRC deaths also fell by about 50% across all groups, with the largest decline among Black members, Corley noted.

Racial and ethnic disparities in both CRC incidence and mortality have long existed, with Black patients in particular experiencing higher risks and worse outcomes, likely from a mixture of risk factors and healthcare utilization, Corley said.

Offering outreach and equal access to screening in the Kaiser program erased those long-standing disparities.

“It’s remarkable that some of these large differences in mortality by race and ethnicity that we saw two decades ago, and which are found throughout the United States, are now similar to small chance variation in the population,” Corley said.

Flexibility was key to getting more people screened, he noted. “It’s about reaching people at their homes and offering a choice to patients. It’s an astonishingly simple concept.”

It’s important to note that these findings stem from a large, integrated healthcare system, which may differ from other settings, although similar outreach strategies have succeeded in safety net clinics and smaller practices, Corley added.

By boosting screening rates to 80%, the health system reached the level that’s essentially been defined in the past as our goal of screening programs, said Loren Laine, MD, AGAF, professor of medicine (digestive diseases) at Yale School of Medicine, New Haven, Connecticut, and chair of this year’s DDW. 

“It shows that if health systems institute programmatic screening for all their covered individuals, they could markedly increase screening, said Laine, who also served as moderator of the press briefing.

“Most importantly, of course, [screening] was associated with a reduction in colorectal cancer incidence and deaths,” he said.

The study had no commercial funding. Corley reported having no relevant conflicts of interest.

Laine’s disclosures included consulting and/or relationships with Medtronic, Phathom Pharmaceuticals, Biohaven, Celgene, Intercept, Merck, and Pfizer.

A version of this article appeared on Medscape.com.

Both endoscopic ultrasound–guided rendezvous (EUS-RV) and precut sphincterotomy are equally effective salvage techniques for patients with benign biliary obstruction and difficult bile duct cannulation, new data suggest.

Selective deep cannulation of the common bile duct remains the key rate-limiting step in successful endoscopic retrograde cholangiopancreatography (ERCP), especially in benign biliary disease.

In cases of difficult cannulation, the traditional fallback has been precut sphincterotomy. Recently, EUS-RV has emerged as an alternative. However, head-to-head comparisons of these salvage techniques in homogeneous patient populations have been lacking, until now. 

A team led by Arup Choudhury, MD, DM, with Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India, compared the two salvage techniques in a single-center, randomized controlled trial of 100 patients with benign biliary disease and difficult bile duct cannulation.

There were 50 patients in each group. When one technique failed, patients were crossed over to the other technique.

The technical success rate for achieving deep biliary, the primary outcome measure, was similar with EUS-RV and precut sphincterotomy (92% and 90%, respectively; P = 1.00; relative risk [RR], 1.02), the authors reported in Annals of Internal Medicine.

Median procedure time was also comparable (10.1 minutes with EUS-RV and 9.75 minutes with precut sphincterotomy). As expected, radiation exposure was notably higher in the EUS-RV group (median, 200.2 vs 67.8 mGy).

There was no difference in overall complication rates (12% and 10%, respectively; RR, 1.20).

Five patients in each group (10%) developed post-ERCP pancreatitis (PEP); one patient in the EUS-RV had moderately severe pancreatitis, whereas the rest had mild pancreatitis.

In an exploratory analysis of the subcohort of 72 patients who did not have 1 or more inadvertent pancreatic duct cannulation, two (5.6%) patients in the precut sphincterotomy group had PEP, whereas none of the patients in the EUS-RV had PEP (RR, 0.21). The investigators caution that a larger, multicenter, randomized controlled trial would be required to evaluate the “probable benefit” of lower PEP in the EUS-RV approach.

None of the patients had bleeding or perforation, but two (4%) patients in the EUS-RV group had an infection after the intervention. One required repeated ERCP due to post procedure cholangitis, whereas the other developed lower respiratory tract infection with transient acute lung injury and sputum showing gram-negative organism. None of the patients required surgical intervention.

“Interestingly,” said the investigators, on crossover from one salvage technique to the other, all of the cases could be successfully cannulated, suggesting the two salvage techniques are “complementary to each other and can help achieve successful cannulation in all cases when used in any sequence.”

Summing up, they said it appears from this head-to-head comparison that both EUS-RV and precut sphincterotomy can be considered effective salvage techniques in expert centers with similar safety and success profiles.

Limitations included the single-center design with both procedures performed by expert operators. EUS-RV entailed additional cost of needle and use of a separate scope, and a cost-efficacy analysis was not done.

This study had no specific funding. Disclosures for the authors are available with the original article.

A version of this article appeared on Medscape.com.

Both endoscopic ultrasound–guided rendezvous (EUS-RV) and precut sphincterotomy are equally effective salvage techniques for patients with benign biliary obstruction and difficult bile duct cannulation, new data suggest.

Selective deep cannulation of the common bile duct remains the key rate-limiting step in successful endoscopic retrograde cholangiopancreatography (ERCP), especially in benign biliary disease.

In cases of difficult cannulation, the traditional fallback has been precut sphincterotomy. Recently, EUS-RV has emerged as an alternative. However, head-to-head comparisons of these salvage techniques in homogeneous patient populations have been lacking, until now. 

A team led by Arup Choudhury, MD, DM, with Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India, compared the two salvage techniques in a single-center, randomized controlled trial of 100 patients with benign biliary disease and difficult bile duct cannulation.

There were 50 patients in each group. When one technique failed, patients were crossed over to the other technique.

The technical success rate for achieving deep biliary, the primary outcome measure, was similar with EUS-RV and precut sphincterotomy (92% and 90%, respectively; P = 1.00; relative risk [RR], 1.02), the authors reported in Annals of Internal Medicine.

Median procedure time was also comparable (10.1 minutes with EUS-RV and 9.75 minutes with precut sphincterotomy). As expected, radiation exposure was notably higher in the EUS-RV group (median, 200.2 vs 67.8 mGy).

There was no difference in overall complication rates (12% and 10%, respectively; RR, 1.20).

Five patients in each group (10%) developed post-ERCP pancreatitis (PEP); one patient in the EUS-RV had moderately severe pancreatitis, whereas the rest had mild pancreatitis.

In an exploratory analysis of the subcohort of 72 patients who did not have 1 or more inadvertent pancreatic duct cannulation, two (5.6%) patients in the precut sphincterotomy group had PEP, whereas none of the patients in the EUS-RV had PEP (RR, 0.21). The investigators caution that a larger, multicenter, randomized controlled trial would be required to evaluate the “probable benefit” of lower PEP in the EUS-RV approach.

None of the patients had bleeding or perforation, but two (4%) patients in the EUS-RV group had an infection after the intervention. One required repeated ERCP due to post procedure cholangitis, whereas the other developed lower respiratory tract infection with transient acute lung injury and sputum showing gram-negative organism. None of the patients required surgical intervention.

“Interestingly,” said the investigators, on crossover from one salvage technique to the other, all of the cases could be successfully cannulated, suggesting the two salvage techniques are “complementary to each other and can help achieve successful cannulation in all cases when used in any sequence.”

Summing up, they said it appears from this head-to-head comparison that both EUS-RV and precut sphincterotomy can be considered effective salvage techniques in expert centers with similar safety and success profiles.

Limitations included the single-center design with both procedures performed by expert operators. EUS-RV entailed additional cost of needle and use of a separate scope, and a cost-efficacy analysis was not done.

This study had no specific funding. Disclosures for the authors are available with the original article.

A version of this article appeared on Medscape.com.

Both endoscopic ultrasound–guided rendezvous (EUS-RV) and precut sphincterotomy are equally effective salvage techniques for patients with benign biliary obstruction and difficult bile duct cannulation, new data suggest.

Selective deep cannulation of the common bile duct remains the key rate-limiting step in successful endoscopic retrograde cholangiopancreatography (ERCP), especially in benign biliary disease.

In cases of difficult cannulation, the traditional fallback has been precut sphincterotomy. Recently, EUS-RV has emerged as an alternative. However, head-to-head comparisons of these salvage techniques in homogeneous patient populations have been lacking, until now. 

A team led by Arup Choudhury, MD, DM, with Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India, compared the two salvage techniques in a single-center, randomized controlled trial of 100 patients with benign biliary disease and difficult bile duct cannulation.

There were 50 patients in each group. When one technique failed, patients were crossed over to the other technique.

The technical success rate for achieving deep biliary, the primary outcome measure, was similar with EUS-RV and precut sphincterotomy (92% and 90%, respectively; P = 1.00; relative risk [RR], 1.02), the authors reported in Annals of Internal Medicine.

Median procedure time was also comparable (10.1 minutes with EUS-RV and 9.75 minutes with precut sphincterotomy). As expected, radiation exposure was notably higher in the EUS-RV group (median, 200.2 vs 67.8 mGy).

There was no difference in overall complication rates (12% and 10%, respectively; RR, 1.20).

Five patients in each group (10%) developed post-ERCP pancreatitis (PEP); one patient in the EUS-RV had moderately severe pancreatitis, whereas the rest had mild pancreatitis.

In an exploratory analysis of the subcohort of 72 patients who did not have 1 or more inadvertent pancreatic duct cannulation, two (5.6%) patients in the precut sphincterotomy group had PEP, whereas none of the patients in the EUS-RV had PEP (RR, 0.21). The investigators caution that a larger, multicenter, randomized controlled trial would be required to evaluate the “probable benefit” of lower PEP in the EUS-RV approach.

None of the patients had bleeding or perforation, but two (4%) patients in the EUS-RV group had an infection after the intervention. One required repeated ERCP due to post procedure cholangitis, whereas the other developed lower respiratory tract infection with transient acute lung injury and sputum showing gram-negative organism. None of the patients required surgical intervention.

“Interestingly,” said the investigators, on crossover from one salvage technique to the other, all of the cases could be successfully cannulated, suggesting the two salvage techniques are “complementary to each other and can help achieve successful cannulation in all cases when used in any sequence.”

Summing up, they said it appears from this head-to-head comparison that both EUS-RV and precut sphincterotomy can be considered effective salvage techniques in expert centers with similar safety and success profiles.

Limitations included the single-center design with both procedures performed by expert operators. EUS-RV entailed additional cost of needle and use of a separate scope, and a cost-efficacy analysis was not done.

This study had no specific funding. Disclosures for the authors are available with the original article.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

WASHINGTON — When a published case of auto-brewery syndrome (ABS) in China — caused by Klebsiella pneumoniae — received widespread publicity in 2019, patients reacted, sending emails to lead author Jing Yuan, in Beijing, China. Many of these inquiries were from patients in the United States who believed they might have ABS.

“Can you check to see if I have ABS?” patients asked Yuan.

For help, Yuan contacted Bernd Schnabl, MD, AGAF, at the University of California, San Diego, whose research was addressing alcohol-associated liver disease and who was also interested in the gut-liver axis and the role of gut microbiome–derived ethanol in metabolic dysfunction–associated steatotic liver disease (MASLD).

“She asked me, ‘Are you interested in looking into ABS?” Schnabl recalled at the Gut Microbiota for Health (GMFH) World Summit 2025. He dug in and formed what may be the largest research cohort thus far of patients with ABS — a group of 22 patients with their diagnosis confirmed through observed glucose challenge.

His soon-to-be-published research on this cohort has confirmed excess ethanol production — and elevations of both proteobacteria and fermentation pathways — in patients whose ABS symptoms had flared.

ABS is considered a rare condition, but “I’d argue that it’s rarely diagnosed because many physicians don’t know of the diagnosis, and many are actually very skeptical about the disease,” Schnabl said at the meeting, convened by AGA and the European Society of Neurogastroenterology and Motility.

Patients experience symptoms of intoxication when ethanol produced by dysregulated gut microbiota exceeds the capacity of the liver to metabolize it and accumulates in the blood, he explained.

“Patients constantly talk about brain fog; they can’t concentrate, and it can be very severe,” he said. “They don’t get a firm diagnosis and go from one medical center to another, and they also suffer from complications of alcohol use disorder including serious family, social, and legal problems.”

 

Advancing Knowledge, Findings From the Cohort

The phenomenon of ethanol production by gut microbiota has been known for over a century, Schnabl wrote with two co-authors in a 2024 review in Nature Reviews Gastroenterology & Hepatology of “endogenous ethanol production in health and disease.”

And in recent decades, he said at the meeting, research has linked endogenous ethanol production to MASLD, positioning it as a potential contributor to disease pathogenesis. In one of the most recently published studies, patients with MASLD had higher concentrations of ethanol in their systemic circulation after a mixed meal test than did healthy controls — and even higher ethanol concentrations in their portal vein blood, “suggesting that this ethanol is coming from the gut microbiome,” Schnabl said.

The paper from China that led Schnabl to establish his cohort was spurred on by a patient with both ABS and MASLD cirrhosis. The patient was found to have strains of high alcohol–producing K pneumoniae in the gut microbiome. When the researchers transplanted these strains into mice via fecal microbiota transplantation (FMT), the mice developed MASLD.

Schnabl’s study focused just on ABS, which is alternatively sometimes called gut fermentation syndrome. The 22 patients in his ABS cohort — each of whom provided stool samples corresponding to remission or flare of ABS symptoms — had a median age of 45 years and were predominantly men, slightly overweight and not obese, and without liver disease. (About 48 patients with suspected ABS were screened, and 20 were excluded after an observed glucose challenge failed to establish a diagnosis; 6 withdrew from the study.)

During remission (no symptoms), patients’ mean blood alcohol content (BAC) level was zero, but during a flare, the mean BAC level was 136 mg/dL. “To put it into perspective, the legal limit for driving in the US is 80 mg/dL,” Schnabl said. Within a mean of 4 hours after the oral glucose load used for diagnosis, patients’ mean BAC level was 73 mg/dL, he noted.

To assess ethanol production by the patients’ microbiota, Schnabl and his team cultured the stool samples — anaerobically adding glucose and measuring ethanol production — and compared the results with findings from stool samples collected from household partners who generally were of the opposite sex. Among their findings: cultures of stool from patients experiencing a flare produced significantly more ethanol than stool from household partners and samples from patients in remission.

To assess whether ethanol was produced by bacteria or fungi, the researchers measured ethanol production in cultures treated with either the antifungal amphotericin B or the antibiotic chloramphenicol. “Chloramphenicol clearly decreased the ethanol production,” Schnabl said. “So at least in this culture test, bacteria produced most of the alcohol in our patients.”

Taxonomic profiling, moreover, revealed “significantly elevated levels” of proteobacteria — with relative abundance of Escherichia coli and K pneumoniae — in patients who were flaring, he said. And functional profiling of the fecal microbiota showed much higher activity of fermentation pathways during patients’ flares than in household partners or healthy controls. (Healthy controls were incorporated into the taxonomic and functional profiling parts of the research.)

 

A Clinical Approach to ABS

Schnabl said at the meeting that stool cultures of both household partners and patients in long-term remission “all produced some low amount of ethanol, which was initially puzzling to us” but became less surprising as he and his colleagues reviewed more of the literature.

Asked during a discussion period whether ABS could explain chronic fatigue, a commonly reported chronic symptom in populations, Schnabl said it’s possible. And in an interview after the meeting, he elaborated. “The literature clearly says ABS is a rare disease, but I argue that more patients may have ABS; they just don’t know it. And I suspect some may have mild symptoms, like brain fog, feeling tired,” he said. “But at this point, this is complete speculation.”

Physicians should “be aware that if a patient has unexplained symptoms that could be aligned with ABS, checking the blood alcohol level” may be warranted, he said in the interview. A PEth (phosphatidylethanol) test — a biomarker test used to check for longer-term alcohol consumption — is an option, but it is important to appreciate it will not discriminate between exogenous alcohol drinking and endogenous ethanol production.

There are no standardized diagnostic tests for ABS, but at the meeting, Schnabl outlined a clinical approach, starting with a standardized oral glucose tolerance challenge test to detect elevated ethanol concentrations.

A fecal yeast test is warranted for diagnosed patients on the basis of some case reports in which ABS symptoms have improved with antifungal treatments. When the fecal yeast test is negative, “ideally you want to identify the ethanol-producing intestinal bacteria in the patient,” he said, using cultures and fecal metagenomics sequencing.

Treatment could then be tailored to the identified microbial strain, with options being selective antibiotics, probiotics and/or prebiotics, and — likely in the future — phages or FMT, he said. (These options, all aimed at restoring gut homeostasis, are also discussed in his 2024 review.)

Schnabl and his team recently performed FMT in a patient with ABS in whom E coli was determined to be producing excessive ethanol. The FMT, performed after antibiotic pretreatment, resulted in decreases in the relative abundance of proteobacteria and E coli levels, lower blood alcohol levels and fermentation enrichment pathways, and normalized liver enzymes.

After 6 months, however, the patient relapsed, and the measurements reversed. “We decided to do FMT every month, and we treated the patient for 6 months,” Schnabl said, noting that ABS had rendered the patient dysfunctional and unable to work. “He has been out of treatment for over a year now and is not flaring any longer.”

Schnabl and Elizabeth Hohmann, MD, at Massachusetts General Hospital, Boston, are currently recruiting patients with confirmed ABS for a National Institutes of Health–funded phase 1 safety and tolerability study of FMT for ABS.

Schnabl disclosed serving as an external scientific advisor/consultant to Ambys Medicines, Boehringer Ingelheim, Gelesis, Mabwell Therapeutics, Surrozen, and Takeda; and as the founder/BOD/BEO of Nterica Bio.

A version of this article appeared on Medscape.com.

An AGA multidisciplinary panel has reached the conclusion that no recommendation can be made for or against the use of computer-aided detection (CADe)–assisted colonoscopy for colorectal cancer (CRC), the third most common cause of cancer mortality in the United States.

The systematic data review is a collaboration between AGA and The BMJ’s MAGIC Rapid Recommendations. The BMJ issued a separate recommendation against CADe shortly after the AGA guideline was published.

Led by Shahnaz S. Sultan, MD, MHSc, AGAF, of the Division of Gastroenterology, Hepatology, and Nutrition at University of Minnesota, Minneapolis, and recently published in Gastroenterology, found only very low certainty of GRADE-based evidence for several critical long-term outcomes, both desirable and undesirable. These included the following: 11 fewer CRCs per 10,000 individuals and two fewer CRC deaths per 10,000 individuals, an increased burden of more intensive surveillance colonoscopies (635 more per 10,000 individuals), and cost and resource implications.

This technology did, however, yield an 8% (95% CI, 6-10) absolute increase in the adenoma detection rate (ADR) and a 2% (95% CI, 0-4) increase in the detection rate of advanced adenomas and/or sessile serrated lesions. “How this translates into a reduction in CRC incidence or death is where we were uncertain,” Sultan said. “Our best effort at trying to translate the ADR and other endoscopy outcomes to CRC incidence and CRC death relied on the modeling study, which included a lot of assumptions, which also contributed to our overall lower certainty.”

The systematic and meta-analysis included 41 randomized controlled trials with more than 32,108 participants who underwent CADe-assisted colonoscopy. This technology was associated with a higher polyp detection rate than standard colonoscopy: 56.1% vs 47.9% (relative risk [RR], 1.22, 95% CI, 1.15-1.28). It also had a higher ADR: 44.8% vs 37.4% (RR, 1.22; 95% CI, 1.16-1.29).

But although CADe-assisted colonoscopy may increase ADR, it carries a risk for overdiagnosis, as most polyps detected during colonoscopy are diminutive (< 5 mm) and of low malignant potential, the panel noted. Approximately 25% of lesions are missed at colonoscopy. More than 15 million colonoscopies are performed annually in the United States, but studies have demonstrated variable quality of colonoscopies across key quality indicators.

“Artificial intelligence [AI] is revolutionizing medicine and healthcare in the field of GI [gastroenterology], and CADe in colonoscopy has been brought to commercialization,” Sultan told GI & Hepatology News. “Unlike many areas of endoscopic research where we often have a finite number of clinical trial data, CADe-assisted colonoscopy intervention has been studied in over 44 randomized controlled trials and numerous nonrandomized, real-world studies. The question of whether or not to adopt this intervention at a health system or practice level is an important question that was prioritized to be addressed as guidance was needed.”

Commenting on the guideline but not involved in its formulation, Larry S. Kim, MD, MBA, AGAF, a gastroenterologist at South Denver Gastroenterology in Denver, Colorado, said his practice group has used the GI Genius AI system in its affiliated hospitals but has so far chosen not to implement the technology at its endoscopy centers. “At the hospital, our physicians have the ability to utilize the system for select patients or not at all,” he told GI & Hepatology News.

The fact that The BMJ reached a different conclusion based on the same data, evidence-grading system, and microsimulation, Kim added, “highlights the point that when evidence for benefit is uncertain, underlying values are critical.” In declining to make a recommendation, the AGA panel balanced the benefit of improved detection of potentially precancerous adenomas vs increased resource utilization in the face of unclear benefit. “With different priorities, other bodies could reasonably decide to recommend either for or against CADe.”

 

The Future

According to Sultan, gastroenterologists need a better understanding of patient values and preferences and the value placed on increased adenoma detection, which may also lead to more lifetime colonoscopies without reducing the risk for CRC. “We need better intermediate- and long-term data on the impact of adenoma detection on interval cancers and CRC incidence,” she said. “We need data on detection of polyps that are more clinically significant such as those 6-10 mm in size, as well as serrated sessile lesions. We also need to understand at the population or health system level what the impact is on resources, cost, and access.”

Ultimately, the living guideline underscores the trade-off between desirable and undesirable effects and the limitations of current evidence to support a recommendation, but CADe has to improve as an iterative AI application with further validation and better training.

With the anticipated improvement in software accuracy as AI machine learning reads increasing numbers of images, Sultan added, “the next version of the software may perform better, especially for polyps that are more clinically significant or for flat sessile serrated polyps, which are harder to detect. We plan to revisit the question in the next year or two and potentially revise the guideline.”

These guidelines were fully funded by the AGA Institute with no funding from any outside agency or industry.

Sultan is supported by the US Food and Drug Administration. Co-authors Shazia Mehmood Siddique, Dennis L. Shung, and Benjamin Lebwohl are supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases. Theodore R. Levin is supported by the Permanente Medical Group Delivery Science and Applied Research Program. Cesare Hassan is a consultant for Fujifilm and Olympus. Peter S. Liang reported doing research work for Freenome and advisory board work for Guardant Health and Natera.

Kim is the AGA president-elect. He disclosed no competing interests relevant to his comments.

A version of this article appeared on Medscape.com.

An AGA multidisciplinary panel has reached the conclusion that no recommendation can be made for or against the use of computer-aided detection (CADe)–assisted colonoscopy for colorectal cancer (CRC), the third most common cause of cancer mortality in the United States.

The systematic data review is a collaboration between AGA and The BMJ’s MAGIC Rapid Recommendations. The BMJ issued a separate recommendation against CADe shortly after the AGA guideline was published.

Led by Shahnaz S. Sultan, MD, MHSc, AGAF, of the Division of Gastroenterology, Hepatology, and Nutrition at University of Minnesota, Minneapolis, and recently published in Gastroenterology, found only very low certainty of GRADE-based evidence for several critical long-term outcomes, both desirable and undesirable. These included the following: 11 fewer CRCs per 10,000 individuals and two fewer CRC deaths per 10,000 individuals, an increased burden of more intensive surveillance colonoscopies (635 more per 10,000 individuals), and cost and resource implications.

This technology did, however, yield an 8% (95% CI, 6-10) absolute increase in the adenoma detection rate (ADR) and a 2% (95% CI, 0-4) increase in the detection rate of advanced adenomas and/or sessile serrated lesions. “How this translates into a reduction in CRC incidence or death is where we were uncertain,” Sultan said. “Our best effort at trying to translate the ADR and other endoscopy outcomes to CRC incidence and CRC death relied on the modeling study, which included a lot of assumptions, which also contributed to our overall lower certainty.”

The systematic and meta-analysis included 41 randomized controlled trials with more than 32,108 participants who underwent CADe-assisted colonoscopy. This technology was associated with a higher polyp detection rate than standard colonoscopy: 56.1% vs 47.9% (relative risk [RR], 1.22, 95% CI, 1.15-1.28). It also had a higher ADR: 44.8% vs 37.4% (RR, 1.22; 95% CI, 1.16-1.29).

But although CADe-assisted colonoscopy may increase ADR, it carries a risk for overdiagnosis, as most polyps detected during colonoscopy are diminutive (< 5 mm) and of low malignant potential, the panel noted. Approximately 25% of lesions are missed at colonoscopy. More than 15 million colonoscopies are performed annually in the United States, but studies have demonstrated variable quality of colonoscopies across key quality indicators.

“Artificial intelligence [AI] is revolutionizing medicine and healthcare in the field of GI [gastroenterology], and CADe in colonoscopy has been brought to commercialization,” Sultan told GI & Hepatology News. “Unlike many areas of endoscopic research where we often have a finite number of clinical trial data, CADe-assisted colonoscopy intervention has been studied in over 44 randomized controlled trials and numerous nonrandomized, real-world studies. The question of whether or not to adopt this intervention at a health system or practice level is an important question that was prioritized to be addressed as guidance was needed.”

Commenting on the guideline but not involved in its formulation, Larry S. Kim, MD, MBA, AGAF, a gastroenterologist at South Denver Gastroenterology in Denver, Colorado, said his practice group has used the GI Genius AI system in its affiliated hospitals but has so far chosen not to implement the technology at its endoscopy centers. “At the hospital, our physicians have the ability to utilize the system for select patients or not at all,” he told GI & Hepatology News.

The fact that The BMJ reached a different conclusion based on the same data, evidence-grading system, and microsimulation, Kim added, “highlights the point that when evidence for benefit is uncertain, underlying values are critical.” In declining to make a recommendation, the AGA panel balanced the benefit of improved detection of potentially precancerous adenomas vs increased resource utilization in the face of unclear benefit. “With different priorities, other bodies could reasonably decide to recommend either for or against CADe.”

 

The Future

According to Sultan, gastroenterologists need a better understanding of patient values and preferences and the value placed on increased adenoma detection, which may also lead to more lifetime colonoscopies without reducing the risk for CRC. “We need better intermediate- and long-term data on the impact of adenoma detection on interval cancers and CRC incidence,” she said. “We need data on detection of polyps that are more clinically significant such as those 6-10 mm in size, as well as serrated sessile lesions. We also need to understand at the population or health system level what the impact is on resources, cost, and access.”

Ultimately, the living guideline underscores the trade-off between desirable and undesirable effects and the limitations of current evidence to support a recommendation, but CADe has to improve as an iterative AI application with further validation and better training.

With the anticipated improvement in software accuracy as AI machine learning reads increasing numbers of images, Sultan added, “the next version of the software may perform better, especially for polyps that are more clinically significant or for flat sessile serrated polyps, which are harder to detect. We plan to revisit the question in the next year or two and potentially revise the guideline.”

These guidelines were fully funded by the AGA Institute with no funding from any outside agency or industry.

Sultan is supported by the US Food and Drug Administration. Co-authors Shazia Mehmood Siddique, Dennis L. Shung, and Benjamin Lebwohl are supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases. Theodore R. Levin is supported by the Permanente Medical Group Delivery Science and Applied Research Program. Cesare Hassan is a consultant for Fujifilm and Olympus. Peter S. Liang reported doing research work for Freenome and advisory board work for Guardant Health and Natera.

Kim is the AGA president-elect. He disclosed no competing interests relevant to his comments.

A version of this article appeared on Medscape.com.

An AGA multidisciplinary panel has reached the conclusion that no recommendation can be made for or against the use of computer-aided detection (CADe)–assisted colonoscopy for colorectal cancer (CRC), the third most common cause of cancer mortality in the United States.

The systematic data review is a collaboration between AGA and The BMJ’s MAGIC Rapid Recommendations. The BMJ issued a separate recommendation against CADe shortly after the AGA guideline was published.

Led by Shahnaz S. Sultan, MD, MHSc, AGAF, of the Division of Gastroenterology, Hepatology, and Nutrition at University of Minnesota, Minneapolis, and recently published in Gastroenterology, found only very low certainty of GRADE-based evidence for several critical long-term outcomes, both desirable and undesirable. These included the following: 11 fewer CRCs per 10,000 individuals and two fewer CRC deaths per 10,000 individuals, an increased burden of more intensive surveillance colonoscopies (635 more per 10,000 individuals), and cost and resource implications.

This technology did, however, yield an 8% (95% CI, 6-10) absolute increase in the adenoma detection rate (ADR) and a 2% (95% CI, 0-4) increase in the detection rate of advanced adenomas and/or sessile serrated lesions. “How this translates into a reduction in CRC incidence or death is where we were uncertain,” Sultan said. “Our best effort at trying to translate the ADR and other endoscopy outcomes to CRC incidence and CRC death relied on the modeling study, which included a lot of assumptions, which also contributed to our overall lower certainty.”

The systematic and meta-analysis included 41 randomized controlled trials with more than 32,108 participants who underwent CADe-assisted colonoscopy. This technology was associated with a higher polyp detection rate than standard colonoscopy: 56.1% vs 47.9% (relative risk [RR], 1.22, 95% CI, 1.15-1.28). It also had a higher ADR: 44.8% vs 37.4% (RR, 1.22; 95% CI, 1.16-1.29).

But although CADe-assisted colonoscopy may increase ADR, it carries a risk for overdiagnosis, as most polyps detected during colonoscopy are diminutive (< 5 mm) and of low malignant potential, the panel noted. Approximately 25% of lesions are missed at colonoscopy. More than 15 million colonoscopies are performed annually in the United States, but studies have demonstrated variable quality of colonoscopies across key quality indicators.

“Artificial intelligence [AI] is revolutionizing medicine and healthcare in the field of GI [gastroenterology], and CADe in colonoscopy has been brought to commercialization,” Sultan told GI & Hepatology News. “Unlike many areas of endoscopic research where we often have a finite number of clinical trial data, CADe-assisted colonoscopy intervention has been studied in over 44 randomized controlled trials and numerous nonrandomized, real-world studies. The question of whether or not to adopt this intervention at a health system or practice level is an important question that was prioritized to be addressed as guidance was needed.”

Commenting on the guideline but not involved in its formulation, Larry S. Kim, MD, MBA, AGAF, a gastroenterologist at South Denver Gastroenterology in Denver, Colorado, said his practice group has used the GI Genius AI system in its affiliated hospitals but has so far chosen not to implement the technology at its endoscopy centers. “At the hospital, our physicians have the ability to utilize the system for select patients or not at all,” he told GI & Hepatology News.

The fact that The BMJ reached a different conclusion based on the same data, evidence-grading system, and microsimulation, Kim added, “highlights the point that when evidence for benefit is uncertain, underlying values are critical.” In declining to make a recommendation, the AGA panel balanced the benefit of improved detection of potentially precancerous adenomas vs increased resource utilization in the face of unclear benefit. “With different priorities, other bodies could reasonably decide to recommend either for or against CADe.”

 

The Future

According to Sultan, gastroenterologists need a better understanding of patient values and preferences and the value placed on increased adenoma detection, which may also lead to more lifetime colonoscopies without reducing the risk for CRC. “We need better intermediate- and long-term data on the impact of adenoma detection on interval cancers and CRC incidence,” she said. “We need data on detection of polyps that are more clinically significant such as those 6-10 mm in size, as well as serrated sessile lesions. We also need to understand at the population or health system level what the impact is on resources, cost, and access.”

Ultimately, the living guideline underscores the trade-off between desirable and undesirable effects and the limitations of current evidence to support a recommendation, but CADe has to improve as an iterative AI application with further validation and better training.

With the anticipated improvement in software accuracy as AI machine learning reads increasing numbers of images, Sultan added, “the next version of the software may perform better, especially for polyps that are more clinically significant or for flat sessile serrated polyps, which are harder to detect. We plan to revisit the question in the next year or two and potentially revise the guideline.”

These guidelines were fully funded by the AGA Institute with no funding from any outside agency or industry.

Sultan is supported by the US Food and Drug Administration. Co-authors Shazia Mehmood Siddique, Dennis L. Shung, and Benjamin Lebwohl are supported by grants from the National Institute of Diabetes and Digestive and Kidney Diseases. Theodore R. Levin is supported by the Permanente Medical Group Delivery Science and Applied Research Program. Cesare Hassan is a consultant for Fujifilm and Olympus. Peter S. Liang reported doing research work for Freenome and advisory board work for Guardant Health and Natera.

Kim is the AGA president-elect. He disclosed no competing interests relevant to his comments.

A version of this article appeared on Medscape.com.

Short-term adherence to a palatable elemental diet (PED) significantly improved symptoms and the gut microbiota in adults with microbiome-driven gastrointestinal disorders, according to a new study.

“Elemental diets have long shown promise for treating gastrointestinal disorders like Crohn’s disease, eosinophilic esophagitis, SIBO (small intestinal bacterial overgrowth), and IMO (intestinal methanogen overgrowth), but poor palatability has limited their use,” lead author Ali Rezaie, MD, medical director of the Gastrointestinal (GI) Motility Program and director of Bioinformatics at Cedars-Sinai Medical Center, Los Angeles, told GI & Hepatology News.

Elemental diets are specialized formulas tailored to meet an individual’s specific nutritional needs and daily requirements for vitamins, minerals, fat, free amino acids, and carbohydrates.

In SIBO and IMO specifically, only about half the patients respond to antibiotics, and many require repeat treatments, which underscores the need for effective nonantibiotic alternatives, said Rezaie. “This is the first prospective trial using a PED, aiming to make this approach both viable and accessible for patients,” he noted.

 

Assessing a Novel Diet in IMO and SIBO

In the study, which was recently published in Clinical Gastroenterology and Hepatology, Rezaie and colleagues enrolled 30 adults with IMO (40%), SIBO (20%), or both (40%). The mean participant age was 45 years, and 63% were women.

All participants completed 2 weeks of a PED, transitioned to 2-3 days of a bland diet, and then resumed their regular diets for 2 weeks.

The diet consisted of multiple 300-calorie packets, adjusted for individual caloric needs. Participants could consume additional packets for hunger but were prohibited from eating other foods. There was no restriction on water intake.

The primary endpoint was changes in stool microbiome after the PED and reintroduction of regular food. Secondary endpoints included lactose breath test normalization to determine bacterial overgrowth in the gut, symptom response, and adverse events.

Researchers collected 29 stool samples at baseline, 27 post-PED, and 27 at study conclusion (2 weeks post-diet).

 

Key Outcomes

Although the stool samples’ alpha diversity decreased after the PED, the difference was not statistically significant at the end of the study. However, 30 bacterial families showed significant differences in relative abundance post-PED.

Daily symptom severity improved significantly during the second week of the diet compared with baseline, with reduction in abdominal discomfort, bloating, distention, constipation, and flatulence. Further significant improvements in measures such as abdominal pain, diarrhea, fatigue, urgency, and brain fog were observed after reintroducing regular food.

“We observed 73% breath test normalization and 83% global symptom relief — with 100% adherence and tolerance to 2 weeks of exclusive PED,” Rezaie told GI & Hepatology News. No serious adverse events occurred during the study, he added.

Lactose breath test normalization rates post-PED were 58% in patients with IMO, 100% in patients with SIBO, and 75% in those with both conditions.

The extent of patient response to PED was notable, given that 83% had failed prior treatments, Rezaie said.

“While we expected benefit based on palatability improvements and prior retrospective data, the rapid reduction in methane and hydrogen gas — and the sustained microbiome modulation even after reintroducing a regular diet — exceeded expectations,” he said. A significant reduction in visceral fat was another novel finding.

“This study reinforces the power of diet as a therapeutic tool,” Rezaie said, adding that the results show that elemental diets can be palatable, thereby improving patient adherence, tolerance, and, eventually, effectiveness. This is particularly valuable for patients with SIBO and IMO who do not tolerate or respond to antibiotics, prefer nonpharmacologic options, or experience recurrent symptoms after antibiotic treatment.

 

Limitations and Next Steps

Study limitations included the lack of a placebo group with a sham diet, the short follow-up after reintroducing a regular diet, and the inability to assess microbial gene function.

However, the results support the safety, tolerance, and benefit of a PED in patients with IMO/SIBO. Personalized dietary interventions that support the growth of beneficial bacteria may be an effective approach to treating these disorders, Rezaie and colleagues noted in their publication.

Although the current study is a promising first step, longer-term studies are needed to evaluate the durability of microbiome and symptom improvements, Rezaie said.

 

Making the Most of Microbiome Manipulation

Elemental diets may help modulate the gut microbiome while reducing immune activation, making them attractive for microbiome-targeted gastrointestinal therapies, Jatin Roper, MD, a gastroenterologist at Duke University, Durham, North Carolina, told GI & Hepatology News.

“Antibiotics are only effective in half of SIBO cases and often require retreatment, so better therapies are needed,” said Roper, who was not affiliated with the study. He added that its findings confirmed the researchers’ hypothesis that a PED can be both safe and effective in patients with SIBO.

Roper noted the 83% symptom improvement as the study’s most unexpected and encouraging finding, as it represents a substantial improvement compared with standard antibiotic therapy. “It is also surprising that the tolerance rate of the elemental diet in this study was 100%,” he said.

However, diet palatability remains a major barrier in real-world practice.

“Adherence rates are likely to be far lower than in trials in which patients are closely monitored, and this challenge will not be easily overcome,” he added.

The study’s limitations, including the lack of metagenomic analysis and a placebo group, are important to address in future research, Roper said. In particular, controlled trials of elemental diets are needed to determine whether microbiome changes are directly responsible for symptom improvement.

The study was supported in part by Good LFE and the John and Geraldine Cusenza Foundation. Rezaie disclosed serving as a consultant/speaker for Bausch Health and having equity in Dieta Health, Gemelli Biotech, and Good LFE. Roper had no financial conflicts to disclose.

A version of this article first appeared on Medscape.com.

Short-term adherence to a palatable elemental diet (PED) significantly improved symptoms and the gut microbiota in adults with microbiome-driven gastrointestinal disorders, according to a new study.

“Elemental diets have long shown promise for treating gastrointestinal disorders like Crohn’s disease, eosinophilic esophagitis, SIBO (small intestinal bacterial overgrowth), and IMO (intestinal methanogen overgrowth), but poor palatability has limited their use,” lead author Ali Rezaie, MD, medical director of the Gastrointestinal (GI) Motility Program and director of Bioinformatics at Cedars-Sinai Medical Center, Los Angeles, told GI & Hepatology News.

Elemental diets are specialized formulas tailored to meet an individual’s specific nutritional needs and daily requirements for vitamins, minerals, fat, free amino acids, and carbohydrates.

In SIBO and IMO specifically, only about half the patients respond to antibiotics, and many require repeat treatments, which underscores the need for effective nonantibiotic alternatives, said Rezaie. “This is the first prospective trial using a PED, aiming to make this approach both viable and accessible for patients,” he noted.

 

Assessing a Novel Diet in IMO and SIBO

In the study, which was recently published in Clinical Gastroenterology and Hepatology, Rezaie and colleagues enrolled 30 adults with IMO (40%), SIBO (20%), or both (40%). The mean participant age was 45 years, and 63% were women.

All participants completed 2 weeks of a PED, transitioned to 2-3 days of a bland diet, and then resumed their regular diets for 2 weeks.

The diet consisted of multiple 300-calorie packets, adjusted for individual caloric needs. Participants could consume additional packets for hunger but were prohibited from eating other foods. There was no restriction on water intake.

The primary endpoint was changes in stool microbiome after the PED and reintroduction of regular food. Secondary endpoints included lactose breath test normalization to determine bacterial overgrowth in the gut, symptom response, and adverse events.

Researchers collected 29 stool samples at baseline, 27 post-PED, and 27 at study conclusion (2 weeks post-diet).

 

Key Outcomes

Although the stool samples’ alpha diversity decreased after the PED, the difference was not statistically significant at the end of the study. However, 30 bacterial families showed significant differences in relative abundance post-PED.

Daily symptom severity improved significantly during the second week of the diet compared with baseline, with reduction in abdominal discomfort, bloating, distention, constipation, and flatulence. Further significant improvements in measures such as abdominal pain, diarrhea, fatigue, urgency, and brain fog were observed after reintroducing regular food.

“We observed 73% breath test normalization and 83% global symptom relief — with 100% adherence and tolerance to 2 weeks of exclusive PED,” Rezaie told GI & Hepatology News. No serious adverse events occurred during the study, he added.

Lactose breath test normalization rates post-PED were 58% in patients with IMO, 100% in patients with SIBO, and 75% in those with both conditions.

The extent of patient response to PED was notable, given that 83% had failed prior treatments, Rezaie said.

“While we expected benefit based on palatability improvements and prior retrospective data, the rapid reduction in methane and hydrogen gas — and the sustained microbiome modulation even after reintroducing a regular diet — exceeded expectations,” he said. A significant reduction in visceral fat was another novel finding.

“This study reinforces the power of diet as a therapeutic tool,” Rezaie said, adding that the results show that elemental diets can be palatable, thereby improving patient adherence, tolerance, and, eventually, effectiveness. This is particularly valuable for patients with SIBO and IMO who do not tolerate or respond to antibiotics, prefer nonpharmacologic options, or experience recurrent symptoms after antibiotic treatment.

 

Limitations and Next Steps

Study limitations included the lack of a placebo group with a sham diet, the short follow-up after reintroducing a regular diet, and the inability to assess microbial gene function.

However, the results support the safety, tolerance, and benefit of a PED in patients with IMO/SIBO. Personalized dietary interventions that support the growth of beneficial bacteria may be an effective approach to treating these disorders, Rezaie and colleagues noted in their publication.

Although the current study is a promising first step, longer-term studies are needed to evaluate the durability of microbiome and symptom improvements, Rezaie said.

 

Making the Most of Microbiome Manipulation

Elemental diets may help modulate the gut microbiome while reducing immune activation, making them attractive for microbiome-targeted gastrointestinal therapies, Jatin Roper, MD, a gastroenterologist at Duke University, Durham, North Carolina, told GI & Hepatology News.

“Antibiotics are only effective in half of SIBO cases and often require retreatment, so better therapies are needed,” said Roper, who was not affiliated with the study. He added that its findings confirmed the researchers’ hypothesis that a PED can be both safe and effective in patients with SIBO.

Roper noted the 83% symptom improvement as the study’s most unexpected and encouraging finding, as it represents a substantial improvement compared with standard antibiotic therapy. “It is also surprising that the tolerance rate of the elemental diet in this study was 100%,” he said.

However, diet palatability remains a major barrier in real-world practice.

“Adherence rates are likely to be far lower than in trials in which patients are closely monitored, and this challenge will not be easily overcome,” he added.

The study’s limitations, including the lack of metagenomic analysis and a placebo group, are important to address in future research, Roper said. In particular, controlled trials of elemental diets are needed to determine whether microbiome changes are directly responsible for symptom improvement.

The study was supported in part by Good LFE and the John and Geraldine Cusenza Foundation. Rezaie disclosed serving as a consultant/speaker for Bausch Health and having equity in Dieta Health, Gemelli Biotech, and Good LFE. Roper had no financial conflicts to disclose.

A version of this article first appeared on Medscape.com.

Short-term adherence to a palatable elemental diet (PED) significantly improved symptoms and the gut microbiota in adults with microbiome-driven gastrointestinal disorders, according to a new study.

“Elemental diets have long shown promise for treating gastrointestinal disorders like Crohn’s disease, eosinophilic esophagitis, SIBO (small intestinal bacterial overgrowth), and IMO (intestinal methanogen overgrowth), but poor palatability has limited their use,” lead author Ali Rezaie, MD, medical director of the Gastrointestinal (GI) Motility Program and director of Bioinformatics at Cedars-Sinai Medical Center, Los Angeles, told GI & Hepatology News.

Elemental diets are specialized formulas tailored to meet an individual’s specific nutritional needs and daily requirements for vitamins, minerals, fat, free amino acids, and carbohydrates.

In SIBO and IMO specifically, only about half the patients respond to antibiotics, and many require repeat treatments, which underscores the need for effective nonantibiotic alternatives, said Rezaie. “This is the first prospective trial using a PED, aiming to make this approach both viable and accessible for patients,” he noted.

 

Assessing a Novel Diet in IMO and SIBO

In the study, which was recently published in Clinical Gastroenterology and Hepatology, Rezaie and colleagues enrolled 30 adults with IMO (40%), SIBO (20%), or both (40%). The mean participant age was 45 years, and 63% were women.

All participants completed 2 weeks of a PED, transitioned to 2-3 days of a bland diet, and then resumed their regular diets for 2 weeks.

The diet consisted of multiple 300-calorie packets, adjusted for individual caloric needs. Participants could consume additional packets for hunger but were prohibited from eating other foods. There was no restriction on water intake.

The primary endpoint was changes in stool microbiome after the PED and reintroduction of regular food. Secondary endpoints included lactose breath test normalization to determine bacterial overgrowth in the gut, symptom response, and adverse events.

Researchers collected 29 stool samples at baseline, 27 post-PED, and 27 at study conclusion (2 weeks post-diet).

 

Key Outcomes

Although the stool samples’ alpha diversity decreased after the PED, the difference was not statistically significant at the end of the study. However, 30 bacterial families showed significant differences in relative abundance post-PED.

Daily symptom severity improved significantly during the second week of the diet compared with baseline, with reduction in abdominal discomfort, bloating, distention, constipation, and flatulence. Further significant improvements in measures such as abdominal pain, diarrhea, fatigue, urgency, and brain fog were observed after reintroducing regular food.

“We observed 73% breath test normalization and 83% global symptom relief — with 100% adherence and tolerance to 2 weeks of exclusive PED,” Rezaie told GI & Hepatology News. No serious adverse events occurred during the study, he added.

Lactose breath test normalization rates post-PED were 58% in patients with IMO, 100% in patients with SIBO, and 75% in those with both conditions.

The extent of patient response to PED was notable, given that 83% had failed prior treatments, Rezaie said.

“While we expected benefit based on palatability improvements and prior retrospective data, the rapid reduction in methane and hydrogen gas — and the sustained microbiome modulation even after reintroducing a regular diet — exceeded expectations,” he said. A significant reduction in visceral fat was another novel finding.

“This study reinforces the power of diet as a therapeutic tool,” Rezaie said, adding that the results show that elemental diets can be palatable, thereby improving patient adherence, tolerance, and, eventually, effectiveness. This is particularly valuable for patients with SIBO and IMO who do not tolerate or respond to antibiotics, prefer nonpharmacologic options, or experience recurrent symptoms after antibiotic treatment.

 

Limitations and Next Steps

Study limitations included the lack of a placebo group with a sham diet, the short follow-up after reintroducing a regular diet, and the inability to assess microbial gene function.

However, the results support the safety, tolerance, and benefit of a PED in patients with IMO/SIBO. Personalized dietary interventions that support the growth of beneficial bacteria may be an effective approach to treating these disorders, Rezaie and colleagues noted in their publication.

Although the current study is a promising first step, longer-term studies are needed to evaluate the durability of microbiome and symptom improvements, Rezaie said.

 

Making the Most of Microbiome Manipulation

Elemental diets may help modulate the gut microbiome while reducing immune activation, making them attractive for microbiome-targeted gastrointestinal therapies, Jatin Roper, MD, a gastroenterologist at Duke University, Durham, North Carolina, told GI & Hepatology News.

“Antibiotics are only effective in half of SIBO cases and often require retreatment, so better therapies are needed,” said Roper, who was not affiliated with the study. He added that its findings confirmed the researchers’ hypothesis that a PED can be both safe and effective in patients with SIBO.

Roper noted the 83% symptom improvement as the study’s most unexpected and encouraging finding, as it represents a substantial improvement compared with standard antibiotic therapy. “It is also surprising that the tolerance rate of the elemental diet in this study was 100%,” he said.

However, diet palatability remains a major barrier in real-world practice.

“Adherence rates are likely to be far lower than in trials in which patients are closely monitored, and this challenge will not be easily overcome,” he added.

The study’s limitations, including the lack of metagenomic analysis and a placebo group, are important to address in future research, Roper said. In particular, controlled trials of elemental diets are needed to determine whether microbiome changes are directly responsible for symptom improvement.

The study was supported in part by Good LFE and the John and Geraldine Cusenza Foundation. Rezaie disclosed serving as a consultant/speaker for Bausch Health and having equity in Dieta Health, Gemelli Biotech, and Good LFE. Roper had no financial conflicts to disclose.

A version of this article first appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

WASHINGTON, DC — Research on the gut microbiome — and clinical attention to it — has focused mainly on bacteria, but bacteriophages and fungi play critical roles as well, with significant influences on health and disease, experts said at the Gut Microbiota for Health (GMFH) World Summit 2025.

Fungi account for < 1% of the total genetic material in the microbiome but 1%-2% of its total biomass. “Despite their relative rarity, they have an important and outsized influence on gut health” — an impact that results from their unique interface with the immune system, said Kyla Ost, PhD, of the Anschutz Medical Campus, University of Colorado, in Denver, whose research focuses on this interface.

And bacteriophages — viruses that infect and kill bacteria — are highly abundant in the gut. “Bacteriophages begin to colonize our GI [gastrointestinal] tract at the same time we develop our own microbiome shortly after birth, and from that time on, they interact with the bacteria in our GI tract, shaping [and being shaped by] the bacterial species we carry with us,” said Robert (Chip) Schooley, MD, distinguished professor of medicine at the University of California San Diego School of Medicine.

“We’ve been talking about things that affect the gut microbiome — diet, genetics, immune response — but probably the biggest influence on what grows in the GI tract are bacteriophages,” said Schooley, co-director of the Center for Innovative Phage Applications and Therapeutics, in a session on the extra-bacterial gut ecosystem.

Among the current questions: How can phages be used to manipulate the gut microbiome and influence GI-related diseases? And how can the pathogenic potential of commensal fungi be limited?

 

‘New life’ for Phage Therapy

Bacteriophages represent a promising approach for the treatment of multidrug resistant bacterial pathogens in an era of increasing resistance and a dried-up antibiotic discovery pipeline, Schooley said. (In 2019, an estimated 4.95 million deaths around the world were associated with bacterial antimicrobial resistance, and by 2050, it has been forecast that this number will rise to an estimated 8.22 million deaths.)

But in addition to suppressing bacterial pathogens causing direct morbidity, phage therapy has the potential to suppress bacteria believed to contribute to chronic diseases, he said. “We have proof-of-concept studies about the ability of phage to modulate bacteria in the digestive tract,” and an increasing number of clinical trials of the use of phages in GI and other diseases are underway, he said.

Phages were discovered just over a century ago, but phage therapy was widely abandoned once antibiotics were developed, except for in Russia and the former Eastern Bloc countries, where phage therapy continued to be used.

Phage therapy “got new life” in the West, Schooley said, about 10-15 years ago with an increasing number of detailed and high-profile case reports, including one in which a UC San Diego colleague, Tom Patterson, PhD, contracted a deadly multidrug resistant bacterial infection in Egypt and was eventually saved with bacteriophage therapy. (The case was the subject of the book The Perfect Predator).

Since then, as described in case reports and studies in the literature, “hundreds of people have been treated with bacteriophages here and in Europe,” most commonly for pulmonary infections and infections in implanted vascular and orthopedic devices, said Schooley, who coauthored a review in Cell in 2023 that describes phage biology and advances and future directions in phage therapy.

The use of bacteriophages to prevent systemic infections during high-risk periods — such as during chemotherapeutic regimens for hematological regimens — is an area of interest, he said at the meeting.

In research that is making its way to a clinical trial of patients undergoing allogeneic hematopoietic stem cell transplant (HSCT), researchers screened a library of phages to identify those with broad coverage of Escherichia coli. Using tail fiber engineering and CRISPR technology, they then engineered a combination of the four most complementary bacteriophages to selectively kill E coli — including fluoroquinolone-resistant strains that, in patients whose GI tracts are colonized with these strains, can translocate from the gut into the bloodstream, causing sepsis, during chemotherapeutic regimens for HSCT.

In a mouse model, the CRISPR-enhanced four-phage cocktail (SNIPR001) led to a steady reduction in the E coli colony counts in stool, “showing you can modulate these bacteria in the gut by using bacteriophages to kill them,” Schooley said. Moreover, the CRISPR enhancement strengthened the phages’ ability to break up biofilms, he said, showing “that you can engineer bacteriophages to make them better killers.” A phase 1b/2a study is being planned.

 

Other Niches for Therapeutic Phages, Challenges

Bacteriophages also could be used to target a gut bacterium that has been shown to attenuate alcoholic liver disease. Patients with alcoholic hepatitis “have a gut microbiome that is different in distribution,” Schooley said, often with increased numbers of Enterococcus faecalis that produce cytolysin, an exotoxin that exacerbates liver injury and is associated with increased mortality.

In published research led by investigators at UC San Diego, stool from cytolysin-positive patients with alcoholic hepatitis was found to exacerbate ethanol-induced liver disease in gnotobiotic mice, and phage therapy against cytolytic E faecalis was found to abolish it, Schooley shared.

Research is also exploring the potential of phage therapy to selectively target adherent invasive E coli in Crohn’s disease, and Klebsiella pneumoniae in the gut microbiome as an exacerbator of inflammatory bowel disease (IBD), he said.

And investigators in Japan, he noted, have reported that bacteriophage therapy against K pneumoniae can ameliorate liver inflammation and disease severity in primary sclerosing cholangitis.

Challenges in the therapeutic use of phages include the narrow host range of phages and an uncertain predictive value of in vitro phage susceptibility testing. “We don’t know yet how to do resistance testing as well as we do with antibiotics,” he said.

In addition, most phages tend to be acid labile, requiring strategies to mitigate inactivation by gastric acid, and there are “major knowledge gaps” relating to phage pharmacology. “We also know that adaptive immune responses to phages can but often doesn’t impact therapy, and we want to understand that better in clinical trials,” Schooley said.

Phages that have a “lysogenic” lifestyle — as opposed to lytic phages which are used therapeutically — can contribute to antibiotic resistance by facilitating the interchange of bacterial resistance genes, he noted.

 

A Window Into the Mycobiome

The human gut mycobiome is primarily composed of fungi in the Saccharomyces, Candida, and Malassezia genera, with Candida species dominating. Fungal cells harbor distinct immune-stimulatory molecules and activate distinct immune pathways compared with bacteria and other members of the microbiome, said Ost, assistant professor in the immunology and microbiology department of CU Anschutz.

Some fungi, including those in the Candida genus, activate adaptive and innate immune responses that promote metabolic health and protect against infection. A recently published study in Science, for instance, demonstrated that colonization with C dubliniensis in very young mice who had been exposed to broad-spectrum antibiotics promoted “the expansion and development of beta cells in the pancreas” in a macrophage dependent manner, improving metabolic health and reducing diabetes incidence, she shared.

On the one hand, fungi can “exacerbate and perpetuate the pathogenic inflammation that’s found in a growing list of inflammatory diseases” such as IBD. And “in fact, a lot of the benefits and detriments are driven by the exact same species of fungi,” said Ost. “This is particularly true of Candida,” which is a “lifelong colonizer of intestinal microbiota that rarely causes disease but can be quite pathogenic when it does.”

A 2023 review in Nature Reviews Gastroenterology & Hepatology coauthored by Ost describes the role of commensal fungi in intestinal diseases, including IBD, colorectal cancer, and pancreatic cancer.

The pathogenic potential of commensal fungi is largely dependent on its strain, its morphology and its expression of virulence factors, researchers are learning. Ost has studied C albicans, which has been associated with intestinal inflammation and IBD. Like some other Candida species, C albicans are “fascinating shape shifters,” she said, transitioning between a less pathogenic “yeast” morphology and an elongated, adhesive “hyphae” shape that is more pathogenic.

It turns out, according to research by Ost and others, that the C albicans hyphal morphotype — and the adhesins (sticky proteins that facilitate adherence to epithelial cells) and a cytolytic toxin it produces — are preferentially targeted and suppressed by immunoglobulin A (IgA) in the gut.

“Our gut is protected by a large quantity of IgA antibodies…and these IgA interact with the microbiota and play a big role in what microbes are there and the biology of the microbes,” Ost said. Indeed, symptomatic IgA deficiency in humans has been shown to be associated with C albicans overgrowth.

Leveraging the hyphal-specific IgA response to protect against disease seems possible, she said, referring to an experimental anti-Candida fungal vaccine (NDV-3A) designed to induce an adhesin-specific immune response. In a mouse model of colitis, the vaccine protected against C albicans-associated damage. “We saw an immediate IgA response that targeted C albicans in the intestinal contents,” Ost said.

C glabrata, which has also been associated with intestinal inflammation and IBD, does not form hyphae but — depending on the strain — may also induce intestinal IgA responses, she said in describing her recent research.

Ost reported having no disclosures. Schooley disclosed being a consultant for SNIPR Biome, BiomX, Locus, MicrobiotiX, Amazon Data Monitoring Committee: Merck.

A version of this article appeared on Medscape.com.

Patient navigation was more effective than usual care in increasing follow-up colonoscopy rates after an abnormal stool test result, a new randomized controlled trial revealed.

The intervention led to a significant 13-point increase in follow-up colonoscopy completion at 1 year, compared with usual care (55.1% vs 42.1%), according the study, which was published online in Annals of Internal Medicine.

 

“Patients with an abnormal fecal test results have about a 1 in 20 chance of having colorectal cancer found, and many more will be found to have advanced adenomas that can be removed to prevent cancer,” Gloria Coronado, PhD, of Kaiser Permanente Center for Health Research, Portland, Oregon, and University of Arizona Cancer Center, Tucson, said in an interview.

“It is critical that these patients get a follow-up colonoscopy,” she said. “Patient navigation can accomplish this goal.”

 

‘Highly Effective’ Intervention

Researchers compared the effectiveness of a patient navigation program with that of usual care outreach in increasing follow-up colonoscopy completion after an abnormal stool test. They also developed a risk-prediction model that calculated a patient’s probability of obtaining a follow-up colonoscopy without navigation to determine if the addition of this intervention had a greater impact on those determined to be less likely to follow through.

The study included 967 patients from a community health center in Washington State who received an abnormal fecal test result within the prior month. The mean age of participants was 61 years, approximately 45% were women and 77% were White, and 18% preferred a Spanish-language intervention. In total, 479 patients received the intervention and 488 received usual care.

The intervention was delivered by a patient navigator who mailed introductory letters, sent text messages, and made live phone calls. In the calls, the navigators addressed the topics of barrier assessment and resolution, bowel preparation instruction and reminders, colonoscopy check-in, and understanding colonoscopy results and retesting intervals.

Patients in the usual-care group were contacted by a referral coordinator to schedule a follow-up colonoscopy appointment. If they couldn’t be reached initially, up to two follow-up attempts were made at 30 and 45 days after the referral date.

Patient navigation resulted in a significant 13% increase in follow-up, and those in this group completed a colonoscopy 27 days sooner than those in the usual care group (mean, 229 days vs 256 days).

Contrary to the authors’ expectation, the effectiveness of the intervention did not vary by patients’ predicted likelihood of obtaining a colonoscopy without navigation.

Notably, 20.3% of patients were unreachable or lost to follow-up, and 29.7% did not receive navigation. Among the 479 patients assigned to navigation, 79 (16.5%) declined participation and 56 (11.7%) were never reached.

The study was primarily conducted during the height of the COVID-19 pandemic, which created additional systemic and individual barriers to completing colonoscopies.

Nevertheless, the authors wrote, “our findings suggest that patient navigation is highly effective for patients eligible for colonoscopy.”

“Most patients who were reached were contacted with six or fewer phone attempts,” Coronado noted. “Further efforts are needed to determine how to reach and motivate patients [who did not participate] to get a follow-up colonoscopy.”

Coronado and colleagues are exploring ways to leverage artificial intelligence and virtual approaches to augment patient navigation programs — for example, by using a virtual navigator or low-cost automated tools to provide education to build patient confidence in getting a colonoscopy.

 

‘A Promising Tool’

“Colonoscopy completion after positive stool-based testing is critical to mitigating the impact of colon cancer,” commented Rajiv Bhuta, MD, assistant professor of clinical gastroenterology & hepatology, Lewis Katz School of Medicine, Temple University, Philadelphia, who was not involved in the study. “While prior studies assessing navigation have demonstrated improvements, none were as large enrollment-wise or as generalizable as the current study.”

That said, Bhuta said in an interview that the study could have provided more detail about coordination and communication with local gastrointestinal practices.

“Local ordering and prescribing practices vary and can significantly impact compliance rates. Were colonoscopies completed via an open access pathway or were the patients required to see a gastroenterologist first? How long was the average wait time for colonoscopy once scheduled? What were the local policies on requiring an escort after the procedure?”

He also noted that some aspects of the study — such as access to reduced-cost specialty care and free ride-share services — may limit generalizable to settings without such resources.

He added: “Although patient navigators for cancer treatment have mandated reimbursement, there is no current reimbursement for navigators for abnormal screening tests, another barrier to wide-spread implementation.”

Bhuta said that the dropout rate in the study mirrors that of his own real-world practice, which serves a high-risk, low-resource community. “I would specifically like to see research that provides behavioral insights on why patients respond positively to navigation — whether it is due to reminders, emotional support, or logistical assistance. Is it systemic barriers or patient disinterest or both that drives noncompliance?”

Despite these uncertainties and the need to refine implementation logistics, Bhuta concluded, “this strategy is a promising tool to reduce disparities and improve colorectal cancer outcomes. Clinicians should advocate for or implement structured follow-up systems, particularly in high-risk populations.”

The study was funded by the US National Cancer Institute. Coronado received a grant/contract from Guardant Health. Bhuta declared no relevant conflicts of interest.

A version of this article appeared on Medscape.com.

Patient navigation was more effective than usual care in increasing follow-up colonoscopy rates after an abnormal stool test result, a new randomized controlled trial revealed.

The intervention led to a significant 13-point increase in follow-up colonoscopy completion at 1 year, compared with usual care (55.1% vs 42.1%), according the study, which was published online in Annals of Internal Medicine.

 

“Patients with an abnormal fecal test results have about a 1 in 20 chance of having colorectal cancer found, and many more will be found to have advanced adenomas that can be removed to prevent cancer,” Gloria Coronado, PhD, of Kaiser Permanente Center for Health Research, Portland, Oregon, and University of Arizona Cancer Center, Tucson, said in an interview.

“It is critical that these patients get a follow-up colonoscopy,” she said. “Patient navigation can accomplish this goal.”

 

‘Highly Effective’ Intervention

Researchers compared the effectiveness of a patient navigation program with that of usual care outreach in increasing follow-up colonoscopy completion after an abnormal stool test. They also developed a risk-prediction model that calculated a patient’s probability of obtaining a follow-up colonoscopy without navigation to determine if the addition of this intervention had a greater impact on those determined to be less likely to follow through.

The study included 967 patients from a community health center in Washington State who received an abnormal fecal test result within the prior month. The mean age of participants was 61 years, approximately 45% were women and 77% were White, and 18% preferred a Spanish-language intervention. In total, 479 patients received the intervention and 488 received usual care.

The intervention was delivered by a patient navigator who mailed introductory letters, sent text messages, and made live phone calls. In the calls, the navigators addressed the topics of barrier assessment and resolution, bowel preparation instruction and reminders, colonoscopy check-in, and understanding colonoscopy results and retesting intervals.

Patients in the usual-care group were contacted by a referral coordinator to schedule a follow-up colonoscopy appointment. If they couldn’t be reached initially, up to two follow-up attempts were made at 30 and 45 days after the referral date.

Patient navigation resulted in a significant 13% increase in follow-up, and those in this group completed a colonoscopy 27 days sooner than those in the usual care group (mean, 229 days vs 256 days).

Contrary to the authors’ expectation, the effectiveness of the intervention did not vary by patients’ predicted likelihood of obtaining a colonoscopy without navigation.

Notably, 20.3% of patients were unreachable or lost to follow-up, and 29.7% did not receive navigation. Among the 479 patients assigned to navigation, 79 (16.5%) declined participation and 56 (11.7%) were never reached.

The study was primarily conducted during the height of the COVID-19 pandemic, which created additional systemic and individual barriers to completing colonoscopies.

Nevertheless, the authors wrote, “our findings suggest that patient navigation is highly effective for patients eligible for colonoscopy.”

“Most patients who were reached were contacted with six or fewer phone attempts,” Coronado noted. “Further efforts are needed to determine how to reach and motivate patients [who did not participate] to get a follow-up colonoscopy.”

Coronado and colleagues are exploring ways to leverage artificial intelligence and virtual approaches to augment patient navigation programs — for example, by using a virtual navigator or low-cost automated tools to provide education to build patient confidence in getting a colonoscopy.

 

‘A Promising Tool’

“Colonoscopy completion after positive stool-based testing is critical to mitigating the impact of colon cancer,” commented Rajiv Bhuta, MD, assistant professor of clinical gastroenterology & hepatology, Lewis Katz School of Medicine, Temple University, Philadelphia, who was not involved in the study. “While prior studies assessing navigation have demonstrated improvements, none were as large enrollment-wise or as generalizable as the current study.”

That said, Bhuta said in an interview that the study could have provided more detail about coordination and communication with local gastrointestinal practices.

“Local ordering and prescribing practices vary and can significantly impact compliance rates. Were colonoscopies completed via an open access pathway or were the patients required to see a gastroenterologist first? How long was the average wait time for colonoscopy once scheduled? What were the local policies on requiring an escort after the procedure?”

He also noted that some aspects of the study — such as access to reduced-cost specialty care and free ride-share services — may limit generalizable to settings without such resources.

He added: “Although patient navigators for cancer treatment have mandated reimbursement, there is no current reimbursement for navigators for abnormal screening tests, another barrier to wide-spread implementation.”

Bhuta said that the dropout rate in the study mirrors that of his own real-world practice, which serves a high-risk, low-resource community. “I would specifically like to see research that provides behavioral insights on why patients respond positively to navigation — whether it is due to reminders, emotional support, or logistical assistance. Is it systemic barriers or patient disinterest or both that drives noncompliance?”

Despite these uncertainties and the need to refine implementation logistics, Bhuta concluded, “this strategy is a promising tool to reduce disparities and improve colorectal cancer outcomes. Clinicians should advocate for or implement structured follow-up systems, particularly in high-risk populations.”

The study was funded by the US National Cancer Institute. Coronado received a grant/contract from Guardant Health. Bhuta declared no relevant conflicts of interest.

A version of this article appeared on Medscape.com.

Patient navigation was more effective than usual care in increasing follow-up colonoscopy rates after an abnormal stool test result, a new randomized controlled trial revealed.

The intervention led to a significant 13-point increase in follow-up colonoscopy completion at 1 year, compared with usual care (55.1% vs 42.1%), according the study, which was published online in Annals of Internal Medicine.

 

“Patients with an abnormal fecal test results have about a 1 in 20 chance of having colorectal cancer found, and many more will be found to have advanced adenomas that can be removed to prevent cancer,” Gloria Coronado, PhD, of Kaiser Permanente Center for Health Research, Portland, Oregon, and University of Arizona Cancer Center, Tucson, said in an interview.

“It is critical that these patients get a follow-up colonoscopy,” she said. “Patient navigation can accomplish this goal.”

 

‘Highly Effective’ Intervention

Researchers compared the effectiveness of a patient navigation program with that of usual care outreach in increasing follow-up colonoscopy completion after an abnormal stool test. They also developed a risk-prediction model that calculated a patient’s probability of obtaining a follow-up colonoscopy without navigation to determine if the addition of this intervention had a greater impact on those determined to be less likely to follow through.

The study included 967 patients from a community health center in Washington State who received an abnormal fecal test result within the prior month. The mean age of participants was 61 years, approximately 45% were women and 77% were White, and 18% preferred a Spanish-language intervention. In total, 479 patients received the intervention and 488 received usual care.

The intervention was delivered by a patient navigator who mailed introductory letters, sent text messages, and made live phone calls. In the calls, the navigators addressed the topics of barrier assessment and resolution, bowel preparation instruction and reminders, colonoscopy check-in, and understanding colonoscopy results and retesting intervals.

Patients in the usual-care group were contacted by a referral coordinator to schedule a follow-up colonoscopy appointment. If they couldn’t be reached initially, up to two follow-up attempts were made at 30 and 45 days after the referral date.

Patient navigation resulted in a significant 13% increase in follow-up, and those in this group completed a colonoscopy 27 days sooner than those in the usual care group (mean, 229 days vs 256 days).

Contrary to the authors’ expectation, the effectiveness of the intervention did not vary by patients’ predicted likelihood of obtaining a colonoscopy without navigation.

Notably, 20.3% of patients were unreachable or lost to follow-up, and 29.7% did not receive navigation. Among the 479 patients assigned to navigation, 79 (16.5%) declined participation and 56 (11.7%) were never reached.

The study was primarily conducted during the height of the COVID-19 pandemic, which created additional systemic and individual barriers to completing colonoscopies.

Nevertheless, the authors wrote, “our findings suggest that patient navigation is highly effective for patients eligible for colonoscopy.”

“Most patients who were reached were contacted with six or fewer phone attempts,” Coronado noted. “Further efforts are needed to determine how to reach and motivate patients [who did not participate] to get a follow-up colonoscopy.”

Coronado and colleagues are exploring ways to leverage artificial intelligence and virtual approaches to augment patient navigation programs — for example, by using a virtual navigator or low-cost automated tools to provide education to build patient confidence in getting a colonoscopy.

 

‘A Promising Tool’

“Colonoscopy completion after positive stool-based testing is critical to mitigating the impact of colon cancer,” commented Rajiv Bhuta, MD, assistant professor of clinical gastroenterology & hepatology, Lewis Katz School of Medicine, Temple University, Philadelphia, who was not involved in the study. “While prior studies assessing navigation have demonstrated improvements, none were as large enrollment-wise or as generalizable as the current study.”

That said, Bhuta said in an interview that the study could have provided more detail about coordination and communication with local gastrointestinal practices.

“Local ordering and prescribing practices vary and can significantly impact compliance rates. Were colonoscopies completed via an open access pathway or were the patients required to see a gastroenterologist first? How long was the average wait time for colonoscopy once scheduled? What were the local policies on requiring an escort after the procedure?”

He also noted that some aspects of the study — such as access to reduced-cost specialty care and free ride-share services — may limit generalizable to settings without such resources.

He added: “Although patient navigators for cancer treatment have mandated reimbursement, there is no current reimbursement for navigators for abnormal screening tests, another barrier to wide-spread implementation.”

Bhuta said that the dropout rate in the study mirrors that of his own real-world practice, which serves a high-risk, low-resource community. “I would specifically like to see research that provides behavioral insights on why patients respond positively to navigation — whether it is due to reminders, emotional support, or logistical assistance. Is it systemic barriers or patient disinterest or both that drives noncompliance?”

Despite these uncertainties and the need to refine implementation logistics, Bhuta concluded, “this strategy is a promising tool to reduce disparities and improve colorectal cancer outcomes. Clinicians should advocate for or implement structured follow-up systems, particularly in high-risk populations.”

The study was funded by the US National Cancer Institute. Coronado received a grant/contract from Guardant Health. Bhuta declared no relevant conflicts of interest.

A version of this article appeared on Medscape.com.