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Geography hampers access to lung cancer screening
a recent analysis shows.
That percentage, although quite small, still translates to more than 750,000 individuals who are eligible to receive lung cancer screening but live at least 40 miles from a facility.
Overall, a larger proportion of eligible individuals in rural areas had no access to a facility, but a greater number of people in urban areas had no access, especially at shorter distances.
Understanding access issues is important given that “lung cancer screening with low-dose computed tomography scanning (LDCT) reduces mortality among high-risk adults, ... [but] annual screening rates remain low,” write study authors Liora Sahar, PhD, of the American Cancer Society in Atlanta, and colleagues.
The study was published online Feb. 15 in the journal Cancer.
It expands on a previous report, which found that “less than 6% of those 55 to 79 years of age do not have access to registry screening facilities”.
The new analysis incorporates the most recent guidelines from the U.S. Preventive Services Task Force, which lowered the screening age to 50 years and compares access across urban and rural areas.
Dr. Sahar and colleagues calculated the distances from population centers to screening facilities and estimated the number of individuals living within different distances of those facilities – 10, 20, 40, 50, and 100 miles. Geographical subdivisions, or census tracts, were also classified along a spectrum of rural to urban.
The authors found that, overall, about 14.8 million people aged 50-80 years are eligible for lung cancer screening, and 5.1% of that population – or 753,038 individuals – do not live within 40 miles of a facility and have no access to screening.
The proportion of people affected by access issues varies by geographic location. For eligible people living 40 miles or more from a facility, almost 25% (n = 287,803) in rural counties had no access, compared with 1.6% (n = 195,120) in metropolitan areas.
At greater distances to facilities (50 and 100 miles), these proportions diminish. In rural counties, for instance, 16% of eligible individuals (n = 186,401) living 50 or more miles away and 2.8% (n = 33,504) living 100 or more miles away had no access to a facility.
Not surprisingly, across all distances, “there is a significantly higher percentage of rural residents who do not have access to facilities in comparison with those in urban settings,” the authors write. “There are fewer facilities in rural areas, so residents need to travel longer distances to reach a facility.”
Notably, however, distance to a facility was not necessarily the greatest barrier to screening. The authors found a greater number of eligible individuals living in or close to urban areas were not getting screening when facilities were 10 miles away – more than 2.8 million in metropolitan areas versus just over 1 million in rural areas.
“The total number of individuals with no access in urban areas exceeds that of rural individuals, particularly at shorter distances ... [which] reveals an additional underserved population.”
Identifying geographic areas with greater access issues can help researchers address barriers to screening and improve uptake.
“Areas and local pockets with persistently low or no access across short and long distances should be considered for tailored interventions, such as implementing mobile units, repurposing existing imaging or health facilities, and adding appropriate navigation, radiology, and screening program staff to better support the communities,” the authors conclude.
The study was supported in part by the National Lung Cancer Roundtable. Coauthor Debra S. Dyer, MD, serves on the clinical advisory board for computer software company Imidex and on the GO2 Foundation scientific advisory board; she also serves as a consultant for Lung Ambition Alliance. Coauthor Ella A. Kazerooni, MD, reports past participation on the Bristol Myers Squibb Foundation advisory board. The other authors have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
a recent analysis shows.
That percentage, although quite small, still translates to more than 750,000 individuals who are eligible to receive lung cancer screening but live at least 40 miles from a facility.
Overall, a larger proportion of eligible individuals in rural areas had no access to a facility, but a greater number of people in urban areas had no access, especially at shorter distances.
Understanding access issues is important given that “lung cancer screening with low-dose computed tomography scanning (LDCT) reduces mortality among high-risk adults, ... [but] annual screening rates remain low,” write study authors Liora Sahar, PhD, of the American Cancer Society in Atlanta, and colleagues.
The study was published online Feb. 15 in the journal Cancer.
It expands on a previous report, which found that “less than 6% of those 55 to 79 years of age do not have access to registry screening facilities”.
The new analysis incorporates the most recent guidelines from the U.S. Preventive Services Task Force, which lowered the screening age to 50 years and compares access across urban and rural areas.
Dr. Sahar and colleagues calculated the distances from population centers to screening facilities and estimated the number of individuals living within different distances of those facilities – 10, 20, 40, 50, and 100 miles. Geographical subdivisions, or census tracts, were also classified along a spectrum of rural to urban.
The authors found that, overall, about 14.8 million people aged 50-80 years are eligible for lung cancer screening, and 5.1% of that population – or 753,038 individuals – do not live within 40 miles of a facility and have no access to screening.
The proportion of people affected by access issues varies by geographic location. For eligible people living 40 miles or more from a facility, almost 25% (n = 287,803) in rural counties had no access, compared with 1.6% (n = 195,120) in metropolitan areas.
At greater distances to facilities (50 and 100 miles), these proportions diminish. In rural counties, for instance, 16% of eligible individuals (n = 186,401) living 50 or more miles away and 2.8% (n = 33,504) living 100 or more miles away had no access to a facility.
Not surprisingly, across all distances, “there is a significantly higher percentage of rural residents who do not have access to facilities in comparison with those in urban settings,” the authors write. “There are fewer facilities in rural areas, so residents need to travel longer distances to reach a facility.”
Notably, however, distance to a facility was not necessarily the greatest barrier to screening. The authors found a greater number of eligible individuals living in or close to urban areas were not getting screening when facilities were 10 miles away – more than 2.8 million in metropolitan areas versus just over 1 million in rural areas.
“The total number of individuals with no access in urban areas exceeds that of rural individuals, particularly at shorter distances ... [which] reveals an additional underserved population.”
Identifying geographic areas with greater access issues can help researchers address barriers to screening and improve uptake.
“Areas and local pockets with persistently low or no access across short and long distances should be considered for tailored interventions, such as implementing mobile units, repurposing existing imaging or health facilities, and adding appropriate navigation, radiology, and screening program staff to better support the communities,” the authors conclude.
The study was supported in part by the National Lung Cancer Roundtable. Coauthor Debra S. Dyer, MD, serves on the clinical advisory board for computer software company Imidex and on the GO2 Foundation scientific advisory board; she also serves as a consultant for Lung Ambition Alliance. Coauthor Ella A. Kazerooni, MD, reports past participation on the Bristol Myers Squibb Foundation advisory board. The other authors have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
a recent analysis shows.
That percentage, although quite small, still translates to more than 750,000 individuals who are eligible to receive lung cancer screening but live at least 40 miles from a facility.
Overall, a larger proportion of eligible individuals in rural areas had no access to a facility, but a greater number of people in urban areas had no access, especially at shorter distances.
Understanding access issues is important given that “lung cancer screening with low-dose computed tomography scanning (LDCT) reduces mortality among high-risk adults, ... [but] annual screening rates remain low,” write study authors Liora Sahar, PhD, of the American Cancer Society in Atlanta, and colleagues.
The study was published online Feb. 15 in the journal Cancer.
It expands on a previous report, which found that “less than 6% of those 55 to 79 years of age do not have access to registry screening facilities”.
The new analysis incorporates the most recent guidelines from the U.S. Preventive Services Task Force, which lowered the screening age to 50 years and compares access across urban and rural areas.
Dr. Sahar and colleagues calculated the distances from population centers to screening facilities and estimated the number of individuals living within different distances of those facilities – 10, 20, 40, 50, and 100 miles. Geographical subdivisions, or census tracts, were also classified along a spectrum of rural to urban.
The authors found that, overall, about 14.8 million people aged 50-80 years are eligible for lung cancer screening, and 5.1% of that population – or 753,038 individuals – do not live within 40 miles of a facility and have no access to screening.
The proportion of people affected by access issues varies by geographic location. For eligible people living 40 miles or more from a facility, almost 25% (n = 287,803) in rural counties had no access, compared with 1.6% (n = 195,120) in metropolitan areas.
At greater distances to facilities (50 and 100 miles), these proportions diminish. In rural counties, for instance, 16% of eligible individuals (n = 186,401) living 50 or more miles away and 2.8% (n = 33,504) living 100 or more miles away had no access to a facility.
Not surprisingly, across all distances, “there is a significantly higher percentage of rural residents who do not have access to facilities in comparison with those in urban settings,” the authors write. “There are fewer facilities in rural areas, so residents need to travel longer distances to reach a facility.”
Notably, however, distance to a facility was not necessarily the greatest barrier to screening. The authors found a greater number of eligible individuals living in or close to urban areas were not getting screening when facilities were 10 miles away – more than 2.8 million in metropolitan areas versus just over 1 million in rural areas.
“The total number of individuals with no access in urban areas exceeds that of rural individuals, particularly at shorter distances ... [which] reveals an additional underserved population.”
Identifying geographic areas with greater access issues can help researchers address barriers to screening and improve uptake.
“Areas and local pockets with persistently low or no access across short and long distances should be considered for tailored interventions, such as implementing mobile units, repurposing existing imaging or health facilities, and adding appropriate navigation, radiology, and screening program staff to better support the communities,” the authors conclude.
The study was supported in part by the National Lung Cancer Roundtable. Coauthor Debra S. Dyer, MD, serves on the clinical advisory board for computer software company Imidex and on the GO2 Foundation scientific advisory board; she also serves as a consultant for Lung Ambition Alliance. Coauthor Ella A. Kazerooni, MD, reports past participation on the Bristol Myers Squibb Foundation advisory board. The other authors have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.
FROM CANCER
FDA investigates possible increased risk of death with lymphoma drug
The FDA granted accelerated approval to umbralisib in February 2021 for patients with two types of lymphoma: Adults with relapsed or refractory marginal zone lymphoma who received at least one prior therapy, and those with relapsed or refractory follicular lymphoma who received at least three prior therapies.
According to the FDA, the possible increased risk of death arose from early findings in a phase 3 trial evaluating the drug in a related type of cancer: chronic lymphocytic leukemia.
“Because of the seriousness of this safety concern and the similarities between the two types of cancer for which this drug is approved and the type of cancer that was studied in the clinical trial, we are alerting patients and health care professionals that we are reevaluating this risk against the benefits of Ukoniq [umbralisib] for its approved uses,” the FDA safety communication states.
The FDA said it performed an initial review of data from the phase 3, randomized controlled UNITY trial, which is evaluating the efficacy of umbralisib plus a monoclonal antibody in patients with chronic lymphocytic leukemia.
“The results showed a possible increased risk of death in patients receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody compared to the control arm,” according to the FDA. “Those receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody also experienced more serious adverse events than those in the control arm.”
Although the drug has not been approved for patients with chronic lymphocytic leukemia, the FDA believes the findings could “have implications for its approved uses” in marginal zone lymphoma and follicular lymphoma.
However, the phase 2 trial that led to February 2021 approvals found the drug’s safety profile to be “manageable,” with serious adverse reactions reported in 18% of patients receiving the dual oral inhibitor of phosphoinositide 3 kinase delta and casein kinase 1 epsilon. These adverse reactions included diarrhea-colitis (4%), pneumonia (3%), sepsis (2%), and urinary tract infection (2%); however, no elevated risk of death was indicated in that analysis.
The FDA noted it will continue to evaluate the results from the phase 3 UNITY trial in chronic lymphocytic leukemia and has suspended enrollment of new patients in other ongoing clinical trials of the drug.
The FDA stated that it would communicate its “final conclusions and recommendations when we have completed our review.” In the meantime, the agency asks health care professionals to review how patients receiving umbralisib are faring and discuss “the risks and benefits of continuing” versus switching to other treatments.
The FDA also asks clinicians and patients to report side effects involving the drug to the FDA MedWatch program.
A version of this article first appeared on Medscape.com.
The FDA granted accelerated approval to umbralisib in February 2021 for patients with two types of lymphoma: Adults with relapsed or refractory marginal zone lymphoma who received at least one prior therapy, and those with relapsed or refractory follicular lymphoma who received at least three prior therapies.
According to the FDA, the possible increased risk of death arose from early findings in a phase 3 trial evaluating the drug in a related type of cancer: chronic lymphocytic leukemia.
“Because of the seriousness of this safety concern and the similarities between the two types of cancer for which this drug is approved and the type of cancer that was studied in the clinical trial, we are alerting patients and health care professionals that we are reevaluating this risk against the benefits of Ukoniq [umbralisib] for its approved uses,” the FDA safety communication states.
The FDA said it performed an initial review of data from the phase 3, randomized controlled UNITY trial, which is evaluating the efficacy of umbralisib plus a monoclonal antibody in patients with chronic lymphocytic leukemia.
“The results showed a possible increased risk of death in patients receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody compared to the control arm,” according to the FDA. “Those receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody also experienced more serious adverse events than those in the control arm.”
Although the drug has not been approved for patients with chronic lymphocytic leukemia, the FDA believes the findings could “have implications for its approved uses” in marginal zone lymphoma and follicular lymphoma.
However, the phase 2 trial that led to February 2021 approvals found the drug’s safety profile to be “manageable,” with serious adverse reactions reported in 18% of patients receiving the dual oral inhibitor of phosphoinositide 3 kinase delta and casein kinase 1 epsilon. These adverse reactions included diarrhea-colitis (4%), pneumonia (3%), sepsis (2%), and urinary tract infection (2%); however, no elevated risk of death was indicated in that analysis.
The FDA noted it will continue to evaluate the results from the phase 3 UNITY trial in chronic lymphocytic leukemia and has suspended enrollment of new patients in other ongoing clinical trials of the drug.
The FDA stated that it would communicate its “final conclusions and recommendations when we have completed our review.” In the meantime, the agency asks health care professionals to review how patients receiving umbralisib are faring and discuss “the risks and benefits of continuing” versus switching to other treatments.
The FDA also asks clinicians and patients to report side effects involving the drug to the FDA MedWatch program.
A version of this article first appeared on Medscape.com.
The FDA granted accelerated approval to umbralisib in February 2021 for patients with two types of lymphoma: Adults with relapsed or refractory marginal zone lymphoma who received at least one prior therapy, and those with relapsed or refractory follicular lymphoma who received at least three prior therapies.
According to the FDA, the possible increased risk of death arose from early findings in a phase 3 trial evaluating the drug in a related type of cancer: chronic lymphocytic leukemia.
“Because of the seriousness of this safety concern and the similarities between the two types of cancer for which this drug is approved and the type of cancer that was studied in the clinical trial, we are alerting patients and health care professionals that we are reevaluating this risk against the benefits of Ukoniq [umbralisib] for its approved uses,” the FDA safety communication states.
The FDA said it performed an initial review of data from the phase 3, randomized controlled UNITY trial, which is evaluating the efficacy of umbralisib plus a monoclonal antibody in patients with chronic lymphocytic leukemia.
“The results showed a possible increased risk of death in patients receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody compared to the control arm,” according to the FDA. “Those receiving the combination of Ukoniq [umbralisib] and the monoclonal antibody also experienced more serious adverse events than those in the control arm.”
Although the drug has not been approved for patients with chronic lymphocytic leukemia, the FDA believes the findings could “have implications for its approved uses” in marginal zone lymphoma and follicular lymphoma.
However, the phase 2 trial that led to February 2021 approvals found the drug’s safety profile to be “manageable,” with serious adverse reactions reported in 18% of patients receiving the dual oral inhibitor of phosphoinositide 3 kinase delta and casein kinase 1 epsilon. These adverse reactions included diarrhea-colitis (4%), pneumonia (3%), sepsis (2%), and urinary tract infection (2%); however, no elevated risk of death was indicated in that analysis.
The FDA noted it will continue to evaluate the results from the phase 3 UNITY trial in chronic lymphocytic leukemia and has suspended enrollment of new patients in other ongoing clinical trials of the drug.
The FDA stated that it would communicate its “final conclusions and recommendations when we have completed our review.” In the meantime, the agency asks health care professionals to review how patients receiving umbralisib are faring and discuss “the risks and benefits of continuing” versus switching to other treatments.
The FDA also asks clinicians and patients to report side effects involving the drug to the FDA MedWatch program.
A version of this article first appeared on Medscape.com.
Treating metastatic TNBC: Where are we now?
Treating triple-negative breast cancer (TNBC), one of the more lethal breast cancer subtypes, remains a challenge. By definition, TNBC lacks the three telltale molecular signatures known to spur tumor growth: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). A growing amount of literature shows that these frequently aggressive tumors harbor a rich array of molecular characteristics but no clear oncogenic driver.
“TNBC is incredibly heterogeneous, which makes it challenging to treat,” said Rita Nanda, MD, director of the breast oncology program and associate professor of medicine at the University of Chicago. “We have subsets of TNBC that don’t respond to currently available therapies and, as of yet, have no identifiable therapeutic targets.”
Overall, about 40% of patients with TNBC show a pathologic complete response after first-line neoadjuvant chemotherapy – typically anthracycline and taxane-based agents. But for 50% of patients, chemotherapy leaves behind substantial residual cancer tissue. These patients subsequently face a 40%-80% risk for recurrence and progression to advanced disease.
When triple-negative disease metastasizes, survival rates plummet. The most recent data from the National Cancer Institute, which tracked patients by stage of diagnosis between 2010 and 2016, showed steep declines in 5-year survival as TNBC progressed from local (91.2%) to regional (65%) to advanced-stage disease (11.5%).
Experts have started to make headway identifying and targeting different molecular features of advanced TNBC. These approaches often focus on three key areas: targeting cell surface proteins or oncogenes, stimulating an anticancer immune response, or inhibiting an overactive signaling pathway.
“For a patient with metastatic breast cancer, finding a molecular target or an oncogenic driver is essential,” said Kelly McCann, MD, PhD, a hematologist/oncologist in the department of medicine at the University of California, Los Angeles. “Because TNBC encompasses many different molecular subsets of breast cancer, the development of effective new therapeutics is going to depend on subdividing TNBC into categories with more clear targets.”
A targeted strategy
The Food and Drug Administration’s approval of sacituzumab govitecan, the first antibody-drug conjugate to treat metastatic TNBC, marked an important addition to the TNBC drug armamentarium. “Sacituzumab govitecan is one of the most exciting drugs available for the treatment of metastatic disease,” Dr. Nanda said.
Sacituzumab govitecan, approved as third-line therapy for metastatic TNBC, works by targeting the cell surface protein TROP2, expressed in about 88% of TNBC tumors but rarely in healthy cells.
In the phase 1/2 ASCENT trial, the median progression-free survival was 5.5 months and overall survival was 13.0 months in 108 patients with metastatic TNBC who had received at least two therapies prior to sacituzumab govitecan.
A subsequent phase 3 trial showed progression-free survival of 5.6 months with sacituzumab govitecan and 1.7 months with physician’s choice of chemotherapy. The median overall survival was 12.1 months and 6.7 months, respectively.
But, according to the analysis, TROP2 expression did not necessarily predict who would benefit from sacituzumab govitecan. A biomarker study revealed that although patients with moderate to high TROP2 expression exhibited the strongest treatment response, those with low TROP2 expression also survived longer when given sacituzumab govitecan, compared with chemotherapy alone.
In other words, “patients did better on sacituzumab govitecan regardless of TROP2 expression, which suggests we do not have a good biomarker for identifying who will benefit,” Dr. Nanda said.
Two other investigational antibody-drug conjugates, trastuzumab deruxtecan and ladiratuzumab vedotin, show promise in the metastatic space as well. For instance, the recent phase 2 trial evaluating trastuzumab deruxtecan in patients with HER2-positive breast cancer reported treatment response in 44% of patients with HER2-low tumors.
Given that about 36.6% of TNBC tumors exhibit low levels of HER2 expression, “trastuzumab deruxtecan represents potential in treating HER2-low TNBC,” said Yuan Yuan, MD, PhD, medical oncologist at City of Hope, a comprehensive cancer center in Los Angeles County.
Early results from a phase 1b study showed that trastuzumab deruxtecan produced a response rate of 37% in patients with HER2-low breast cancer.
Investigators are now recruiting for an open-label phase 3 trial to determine whether trastuzumab deruxtecan extends survival in patients with HER2-low metastatic breast cancers.
Immunotherapy advances
Immune checkpoint inhibitors represent another promising treatment avenue for metastatic TNBC. Pembrolizumab and atezolizumab, recently approved by the FDA, show moderate progression-free and overall survival benefits in patients with metastatic TNBC expressing PD-L1. Estimates of PD-L1 immune cells present in TNBC tumors vary widely, from about 20% to 65%.
Yet, data on which patients will benefit are not so clear-cut. “These drugs give us more choices and represent the fast-evolving therapeutic landscape in TNBC, but they also leave a lot of unanswered questions about PD-L1 as a biomarker,” Dr. Yuan said.
Take two recent phase 3 trials evaluating atezolizumab: IMpassion130 and IMpassion131. In IMpassion130, patients with PDL1–positive tumors exhibited significantly longer median overall survival on atezolizumab plus nab-paclitaxel (25.0 months) compared with nab-paclitaxel alone (15.5 months). As with the trend observed in the TROP2 data for sacituzumab govitecan, all patients survived longer on atezolizumab plus nab-paclitaxel regardless of PD-L1 status: 21.3 months vs. 17.6 months with nab-paclitaxel alone.
However, in IMpassion131, neither progression-free survival nor overall survival significantly improved in the PD-L1–positive group receiving atezolizumab plus paclitaxel compared with paclitaxel alone: Progression-free survival was 5.7 months vs. 6 months, respectively, and overall survival was 28.3 months vs. 22.1 months.
“It is unclear why this study failed to demonstrate a significant improvement in progression-free survival with the addition of atezolizumab to paclitaxel,” Dr. Nanda said. “Perhaps the negative finding has to do with how the trial was conducted, or perhaps the PD-L1 assay used is an unreliable biomarker of immunotherapy benefit.”
Continued efforts to understand TNBC
Given the diversity of metastatic TNBC and the absence of clear molecular targets, researchers are exploring a host of therapeutic strategies in addition to antibody-drug conjugates and immunotherapies.
On the oncogene front, researchers are investigating common mutations in TNBC. About 11% of TNBC tumors, for instance, carry germline mutations in BRCA1 and BRCA2. These tumors may be more likely to respond to platinum agents and PARP inhibitors, such as FDA-approved olaparib. In a phase 3 trial, patients with metastatic HER2-negative breast cancer and a germline BRCA mutation who received olaparib exhibited a 2.8-month longer median progression-free survival and a 42% reduced risk for disease progression or death compared with those on standard chemotherapy.
When considering signaling pathways, the PI3K/AKT/mTOR pathway has been the target of numerous clinical trials. Dysregulation of signaling through the PI3K and AKT signaling pathway occurs in 25%-30% of patients with advanced TNBC, and AKT inhibitors have been shown to extend survival in these patients. Data show, for instance, that adding capivasertib to first-line paclitaxel therapy in patients with metastatic TNBC led to longer overall survival – 19.1 months vs. 12.6 with placebo plus paclitaxel – with better survival results in patients with PIK3CA/AKT1/PTEN altered tumors.
But there’s more to learn about treating metastatic TNBC. “Relapses tend to occur early in TNBC, and some tumors are inherently resistant to chemotherapy from the get-go,” said Charles Shapiro, MD, medical oncologist, Icahn School of Medicine at Mount Sinai, New York. “Understanding the causes of drug response and resistance in patients with metastatic TNBC represents the holy grail.”
Dr. Nanda agreed, noting that advancing treatments for TNBC will hinge on identifying the key factors driving metastasis. “For TNBC, we are still trying to elucidate the best molecular targets, while at the same time trying to identify robust biomarkers to predict benefit from therapies we already have available,” she said.
A version of this article first appeared on Medscape.com.
Treating triple-negative breast cancer (TNBC), one of the more lethal breast cancer subtypes, remains a challenge. By definition, TNBC lacks the three telltale molecular signatures known to spur tumor growth: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). A growing amount of literature shows that these frequently aggressive tumors harbor a rich array of molecular characteristics but no clear oncogenic driver.
“TNBC is incredibly heterogeneous, which makes it challenging to treat,” said Rita Nanda, MD, director of the breast oncology program and associate professor of medicine at the University of Chicago. “We have subsets of TNBC that don’t respond to currently available therapies and, as of yet, have no identifiable therapeutic targets.”
Overall, about 40% of patients with TNBC show a pathologic complete response after first-line neoadjuvant chemotherapy – typically anthracycline and taxane-based agents. But for 50% of patients, chemotherapy leaves behind substantial residual cancer tissue. These patients subsequently face a 40%-80% risk for recurrence and progression to advanced disease.
When triple-negative disease metastasizes, survival rates plummet. The most recent data from the National Cancer Institute, which tracked patients by stage of diagnosis between 2010 and 2016, showed steep declines in 5-year survival as TNBC progressed from local (91.2%) to regional (65%) to advanced-stage disease (11.5%).
Experts have started to make headway identifying and targeting different molecular features of advanced TNBC. These approaches often focus on three key areas: targeting cell surface proteins or oncogenes, stimulating an anticancer immune response, or inhibiting an overactive signaling pathway.
“For a patient with metastatic breast cancer, finding a molecular target or an oncogenic driver is essential,” said Kelly McCann, MD, PhD, a hematologist/oncologist in the department of medicine at the University of California, Los Angeles. “Because TNBC encompasses many different molecular subsets of breast cancer, the development of effective new therapeutics is going to depend on subdividing TNBC into categories with more clear targets.”
A targeted strategy
The Food and Drug Administration’s approval of sacituzumab govitecan, the first antibody-drug conjugate to treat metastatic TNBC, marked an important addition to the TNBC drug armamentarium. “Sacituzumab govitecan is one of the most exciting drugs available for the treatment of metastatic disease,” Dr. Nanda said.
Sacituzumab govitecan, approved as third-line therapy for metastatic TNBC, works by targeting the cell surface protein TROP2, expressed in about 88% of TNBC tumors but rarely in healthy cells.
In the phase 1/2 ASCENT trial, the median progression-free survival was 5.5 months and overall survival was 13.0 months in 108 patients with metastatic TNBC who had received at least two therapies prior to sacituzumab govitecan.
A subsequent phase 3 trial showed progression-free survival of 5.6 months with sacituzumab govitecan and 1.7 months with physician’s choice of chemotherapy. The median overall survival was 12.1 months and 6.7 months, respectively.
But, according to the analysis, TROP2 expression did not necessarily predict who would benefit from sacituzumab govitecan. A biomarker study revealed that although patients with moderate to high TROP2 expression exhibited the strongest treatment response, those with low TROP2 expression also survived longer when given sacituzumab govitecan, compared with chemotherapy alone.
In other words, “patients did better on sacituzumab govitecan regardless of TROP2 expression, which suggests we do not have a good biomarker for identifying who will benefit,” Dr. Nanda said.
Two other investigational antibody-drug conjugates, trastuzumab deruxtecan and ladiratuzumab vedotin, show promise in the metastatic space as well. For instance, the recent phase 2 trial evaluating trastuzumab deruxtecan in patients with HER2-positive breast cancer reported treatment response in 44% of patients with HER2-low tumors.
Given that about 36.6% of TNBC tumors exhibit low levels of HER2 expression, “trastuzumab deruxtecan represents potential in treating HER2-low TNBC,” said Yuan Yuan, MD, PhD, medical oncologist at City of Hope, a comprehensive cancer center in Los Angeles County.
Early results from a phase 1b study showed that trastuzumab deruxtecan produced a response rate of 37% in patients with HER2-low breast cancer.
Investigators are now recruiting for an open-label phase 3 trial to determine whether trastuzumab deruxtecan extends survival in patients with HER2-low metastatic breast cancers.
Immunotherapy advances
Immune checkpoint inhibitors represent another promising treatment avenue for metastatic TNBC. Pembrolizumab and atezolizumab, recently approved by the FDA, show moderate progression-free and overall survival benefits in patients with metastatic TNBC expressing PD-L1. Estimates of PD-L1 immune cells present in TNBC tumors vary widely, from about 20% to 65%.
Yet, data on which patients will benefit are not so clear-cut. “These drugs give us more choices and represent the fast-evolving therapeutic landscape in TNBC, but they also leave a lot of unanswered questions about PD-L1 as a biomarker,” Dr. Yuan said.
Take two recent phase 3 trials evaluating atezolizumab: IMpassion130 and IMpassion131. In IMpassion130, patients with PDL1–positive tumors exhibited significantly longer median overall survival on atezolizumab plus nab-paclitaxel (25.0 months) compared with nab-paclitaxel alone (15.5 months). As with the trend observed in the TROP2 data for sacituzumab govitecan, all patients survived longer on atezolizumab plus nab-paclitaxel regardless of PD-L1 status: 21.3 months vs. 17.6 months with nab-paclitaxel alone.
However, in IMpassion131, neither progression-free survival nor overall survival significantly improved in the PD-L1–positive group receiving atezolizumab plus paclitaxel compared with paclitaxel alone: Progression-free survival was 5.7 months vs. 6 months, respectively, and overall survival was 28.3 months vs. 22.1 months.
“It is unclear why this study failed to demonstrate a significant improvement in progression-free survival with the addition of atezolizumab to paclitaxel,” Dr. Nanda said. “Perhaps the negative finding has to do with how the trial was conducted, or perhaps the PD-L1 assay used is an unreliable biomarker of immunotherapy benefit.”
Continued efforts to understand TNBC
Given the diversity of metastatic TNBC and the absence of clear molecular targets, researchers are exploring a host of therapeutic strategies in addition to antibody-drug conjugates and immunotherapies.
On the oncogene front, researchers are investigating common mutations in TNBC. About 11% of TNBC tumors, for instance, carry germline mutations in BRCA1 and BRCA2. These tumors may be more likely to respond to platinum agents and PARP inhibitors, such as FDA-approved olaparib. In a phase 3 trial, patients with metastatic HER2-negative breast cancer and a germline BRCA mutation who received olaparib exhibited a 2.8-month longer median progression-free survival and a 42% reduced risk for disease progression or death compared with those on standard chemotherapy.
When considering signaling pathways, the PI3K/AKT/mTOR pathway has been the target of numerous clinical trials. Dysregulation of signaling through the PI3K and AKT signaling pathway occurs in 25%-30% of patients with advanced TNBC, and AKT inhibitors have been shown to extend survival in these patients. Data show, for instance, that adding capivasertib to first-line paclitaxel therapy in patients with metastatic TNBC led to longer overall survival – 19.1 months vs. 12.6 with placebo plus paclitaxel – with better survival results in patients with PIK3CA/AKT1/PTEN altered tumors.
But there’s more to learn about treating metastatic TNBC. “Relapses tend to occur early in TNBC, and some tumors are inherently resistant to chemotherapy from the get-go,” said Charles Shapiro, MD, medical oncologist, Icahn School of Medicine at Mount Sinai, New York. “Understanding the causes of drug response and resistance in patients with metastatic TNBC represents the holy grail.”
Dr. Nanda agreed, noting that advancing treatments for TNBC will hinge on identifying the key factors driving metastasis. “For TNBC, we are still trying to elucidate the best molecular targets, while at the same time trying to identify robust biomarkers to predict benefit from therapies we already have available,” she said.
A version of this article first appeared on Medscape.com.
Treating triple-negative breast cancer (TNBC), one of the more lethal breast cancer subtypes, remains a challenge. By definition, TNBC lacks the three telltale molecular signatures known to spur tumor growth: estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). A growing amount of literature shows that these frequently aggressive tumors harbor a rich array of molecular characteristics but no clear oncogenic driver.
“TNBC is incredibly heterogeneous, which makes it challenging to treat,” said Rita Nanda, MD, director of the breast oncology program and associate professor of medicine at the University of Chicago. “We have subsets of TNBC that don’t respond to currently available therapies and, as of yet, have no identifiable therapeutic targets.”
Overall, about 40% of patients with TNBC show a pathologic complete response after first-line neoadjuvant chemotherapy – typically anthracycline and taxane-based agents. But for 50% of patients, chemotherapy leaves behind substantial residual cancer tissue. These patients subsequently face a 40%-80% risk for recurrence and progression to advanced disease.
When triple-negative disease metastasizes, survival rates plummet. The most recent data from the National Cancer Institute, which tracked patients by stage of diagnosis between 2010 and 2016, showed steep declines in 5-year survival as TNBC progressed from local (91.2%) to regional (65%) to advanced-stage disease (11.5%).
Experts have started to make headway identifying and targeting different molecular features of advanced TNBC. These approaches often focus on three key areas: targeting cell surface proteins or oncogenes, stimulating an anticancer immune response, or inhibiting an overactive signaling pathway.
“For a patient with metastatic breast cancer, finding a molecular target or an oncogenic driver is essential,” said Kelly McCann, MD, PhD, a hematologist/oncologist in the department of medicine at the University of California, Los Angeles. “Because TNBC encompasses many different molecular subsets of breast cancer, the development of effective new therapeutics is going to depend on subdividing TNBC into categories with more clear targets.”
A targeted strategy
The Food and Drug Administration’s approval of sacituzumab govitecan, the first antibody-drug conjugate to treat metastatic TNBC, marked an important addition to the TNBC drug armamentarium. “Sacituzumab govitecan is one of the most exciting drugs available for the treatment of metastatic disease,” Dr. Nanda said.
Sacituzumab govitecan, approved as third-line therapy for metastatic TNBC, works by targeting the cell surface protein TROP2, expressed in about 88% of TNBC tumors but rarely in healthy cells.
In the phase 1/2 ASCENT trial, the median progression-free survival was 5.5 months and overall survival was 13.0 months in 108 patients with metastatic TNBC who had received at least two therapies prior to sacituzumab govitecan.
A subsequent phase 3 trial showed progression-free survival of 5.6 months with sacituzumab govitecan and 1.7 months with physician’s choice of chemotherapy. The median overall survival was 12.1 months and 6.7 months, respectively.
But, according to the analysis, TROP2 expression did not necessarily predict who would benefit from sacituzumab govitecan. A biomarker study revealed that although patients with moderate to high TROP2 expression exhibited the strongest treatment response, those with low TROP2 expression also survived longer when given sacituzumab govitecan, compared with chemotherapy alone.
In other words, “patients did better on sacituzumab govitecan regardless of TROP2 expression, which suggests we do not have a good biomarker for identifying who will benefit,” Dr. Nanda said.
Two other investigational antibody-drug conjugates, trastuzumab deruxtecan and ladiratuzumab vedotin, show promise in the metastatic space as well. For instance, the recent phase 2 trial evaluating trastuzumab deruxtecan in patients with HER2-positive breast cancer reported treatment response in 44% of patients with HER2-low tumors.
Given that about 36.6% of TNBC tumors exhibit low levels of HER2 expression, “trastuzumab deruxtecan represents potential in treating HER2-low TNBC,” said Yuan Yuan, MD, PhD, medical oncologist at City of Hope, a comprehensive cancer center in Los Angeles County.
Early results from a phase 1b study showed that trastuzumab deruxtecan produced a response rate of 37% in patients with HER2-low breast cancer.
Investigators are now recruiting for an open-label phase 3 trial to determine whether trastuzumab deruxtecan extends survival in patients with HER2-low metastatic breast cancers.
Immunotherapy advances
Immune checkpoint inhibitors represent another promising treatment avenue for metastatic TNBC. Pembrolizumab and atezolizumab, recently approved by the FDA, show moderate progression-free and overall survival benefits in patients with metastatic TNBC expressing PD-L1. Estimates of PD-L1 immune cells present in TNBC tumors vary widely, from about 20% to 65%.
Yet, data on which patients will benefit are not so clear-cut. “These drugs give us more choices and represent the fast-evolving therapeutic landscape in TNBC, but they also leave a lot of unanswered questions about PD-L1 as a biomarker,” Dr. Yuan said.
Take two recent phase 3 trials evaluating atezolizumab: IMpassion130 and IMpassion131. In IMpassion130, patients with PDL1–positive tumors exhibited significantly longer median overall survival on atezolizumab plus nab-paclitaxel (25.0 months) compared with nab-paclitaxel alone (15.5 months). As with the trend observed in the TROP2 data for sacituzumab govitecan, all patients survived longer on atezolizumab plus nab-paclitaxel regardless of PD-L1 status: 21.3 months vs. 17.6 months with nab-paclitaxel alone.
However, in IMpassion131, neither progression-free survival nor overall survival significantly improved in the PD-L1–positive group receiving atezolizumab plus paclitaxel compared with paclitaxel alone: Progression-free survival was 5.7 months vs. 6 months, respectively, and overall survival was 28.3 months vs. 22.1 months.
“It is unclear why this study failed to demonstrate a significant improvement in progression-free survival with the addition of atezolizumab to paclitaxel,” Dr. Nanda said. “Perhaps the negative finding has to do with how the trial was conducted, or perhaps the PD-L1 assay used is an unreliable biomarker of immunotherapy benefit.”
Continued efforts to understand TNBC
Given the diversity of metastatic TNBC and the absence of clear molecular targets, researchers are exploring a host of therapeutic strategies in addition to antibody-drug conjugates and immunotherapies.
On the oncogene front, researchers are investigating common mutations in TNBC. About 11% of TNBC tumors, for instance, carry germline mutations in BRCA1 and BRCA2. These tumors may be more likely to respond to platinum agents and PARP inhibitors, such as FDA-approved olaparib. In a phase 3 trial, patients with metastatic HER2-negative breast cancer and a germline BRCA mutation who received olaparib exhibited a 2.8-month longer median progression-free survival and a 42% reduced risk for disease progression or death compared with those on standard chemotherapy.
When considering signaling pathways, the PI3K/AKT/mTOR pathway has been the target of numerous clinical trials. Dysregulation of signaling through the PI3K and AKT signaling pathway occurs in 25%-30% of patients with advanced TNBC, and AKT inhibitors have been shown to extend survival in these patients. Data show, for instance, that adding capivasertib to first-line paclitaxel therapy in patients with metastatic TNBC led to longer overall survival – 19.1 months vs. 12.6 with placebo plus paclitaxel – with better survival results in patients with PIK3CA/AKT1/PTEN altered tumors.
But there’s more to learn about treating metastatic TNBC. “Relapses tend to occur early in TNBC, and some tumors are inherently resistant to chemotherapy from the get-go,” said Charles Shapiro, MD, medical oncologist, Icahn School of Medicine at Mount Sinai, New York. “Understanding the causes of drug response and resistance in patients with metastatic TNBC represents the holy grail.”
Dr. Nanda agreed, noting that advancing treatments for TNBC will hinge on identifying the key factors driving metastasis. “For TNBC, we are still trying to elucidate the best molecular targets, while at the same time trying to identify robust biomarkers to predict benefit from therapies we already have available,” she said.
A version of this article first appeared on Medscape.com.