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Study implicates circular RNAs in leukemia, other cancers
Image courtesy of The Armed
Forces Institute of Pathology
A class of circular RNAs may play a key role in the development and progression of certain leukemias and other cancers, according to research published in Cell.
Investigators found that cancer-associated chromosomal translocations give rise to fusion circular RNAs (f-circRNAs).
And these f-circRNAs aid cellular transformation, promote cell viability, confer treatment resistance, and exhibit tumor-promoting properties in vivo.
“Cancer is essentially a disease of mutated or broken genes, so that motivated us to examine whether circular RNAs, like proteins, can be affected by these chromosomal breaks,” said study author Pier Paolo Pandolfi, MD, PhD, of Beth Israel Deaconess Medical Center in Boston, Massachusetts.
“Our work paves the way to discovering many more of these unusual RNAs and how they contribute to cancer, which could reveal new mechanisms and druggable pathways involved in tumor progression.”
Curious about the possibility of circular RNAs contributing to cancer, Dr Pandolfi and his colleagues set out to see if they could detect relevant changes in tumors known to harbor distinct fusion proteins.
The team examined acute promyelocytic leukemia, which often carries a translocation between the PML and RARα genes, and acute myeloid leukemia, which can harbor a translocation between the MLL and AF9 genes.
The investigators found f-circRNAs corresponding to different exons associated with the PML-RARα gene fusion and the MLL-AF9 gene fusion. Normally, multiple circular RNAs can be generated from a single gene, so the team was not surprised to find different f-circRNAs emerging from the same fusion gene.
Dr Pandolfi and his colleagues also uncovered f-circRNAs in solid tumors—in Ewing sarcoma and lung cancer.
The team identified the f-circRNAs using 2 distinct methods—PCR-based amplification and sequencing-based approaches. They said this suggests f-circRNAs are bona fide biological entities, rather than experimental artifacts.
“Our ability to readily detect these fusion-circular RNAs—and their normal, non-fused counterparts—will be enhanced by advances in sequencing technology and analytic methods,” said study author Jlenia Guarnerio, PhD, also of Beth Israel Deaconess Medical Center.
“Indeed, as we look ahead to cataloguing them comprehensively across all cancers and to deeply understanding their mechanisms of action, we will need to propel these new methodologies even further.”
To determine whether f-circRNAs play a functional role in cancer, the investigators introduced the RNAs into cells. This caused the cells to increase their proliferation and tendency to overgrow—features shared by tumor cells.
On the other hand, when the team blocked f-circRNA activity, the cells’ normal behaviors were restored.
Dr Pandolfi and his colleagues also conducted experiments using a mouse model of leukemia. They focused on a specific f-circRNA associated with the MLL-AF9 fusion gene, called f-circM9.
Although f-circM9 could not trigger leukemia on its own, it appeared to work with other cancer-promoting signals—such as the MLL-AF9 fusion protein—to cause leukemia.
Additional experiments suggested that f-circM9 may also help tumor cells persist despite treatment with anticancer drugs.
“These results are particularly exciting because they suggest that drugs directed at fusion-circular RNAs could be a powerful strategy to pursue for future therapeutic development in cancer,” Dr Pandolfi said.
“[However,] our knowledge of circular RNAs is really in its infancy. We know that, normally, they can bind proteins as well as DNA and microRNAs, but much more needs to be done to understand how fusion-circular RNAs work. We have only scratched the surface of these RNAs and their roles in cancer and other diseases.” 
Image courtesy of The Armed
Forces Institute of Pathology
A class of circular RNAs may play a key role in the development and progression of certain leukemias and other cancers, according to research published in Cell.
Investigators found that cancer-associated chromosomal translocations give rise to fusion circular RNAs (f-circRNAs).
And these f-circRNAs aid cellular transformation, promote cell viability, confer treatment resistance, and exhibit tumor-promoting properties in vivo.
“Cancer is essentially a disease of mutated or broken genes, so that motivated us to examine whether circular RNAs, like proteins, can be affected by these chromosomal breaks,” said study author Pier Paolo Pandolfi, MD, PhD, of Beth Israel Deaconess Medical Center in Boston, Massachusetts.
“Our work paves the way to discovering many more of these unusual RNAs and how they contribute to cancer, which could reveal new mechanisms and druggable pathways involved in tumor progression.”
Curious about the possibility of circular RNAs contributing to cancer, Dr Pandolfi and his colleagues set out to see if they could detect relevant changes in tumors known to harbor distinct fusion proteins.
The team examined acute promyelocytic leukemia, which often carries a translocation between the PML and RARα genes, and acute myeloid leukemia, which can harbor a translocation between the MLL and AF9 genes.
The investigators found f-circRNAs corresponding to different exons associated with the PML-RARα gene fusion and the MLL-AF9 gene fusion. Normally, multiple circular RNAs can be generated from a single gene, so the team was not surprised to find different f-circRNAs emerging from the same fusion gene.
Dr Pandolfi and his colleagues also uncovered f-circRNAs in solid tumors—in Ewing sarcoma and lung cancer.
The team identified the f-circRNAs using 2 distinct methods—PCR-based amplification and sequencing-based approaches. They said this suggests f-circRNAs are bona fide biological entities, rather than experimental artifacts.
“Our ability to readily detect these fusion-circular RNAs—and their normal, non-fused counterparts—will be enhanced by advances in sequencing technology and analytic methods,” said study author Jlenia Guarnerio, PhD, also of Beth Israel Deaconess Medical Center.
“Indeed, as we look ahead to cataloguing them comprehensively across all cancers and to deeply understanding their mechanisms of action, we will need to propel these new methodologies even further.”
To determine whether f-circRNAs play a functional role in cancer, the investigators introduced the RNAs into cells. This caused the cells to increase their proliferation and tendency to overgrow—features shared by tumor cells.
On the other hand, when the team blocked f-circRNA activity, the cells’ normal behaviors were restored.
Dr Pandolfi and his colleagues also conducted experiments using a mouse model of leukemia. They focused on a specific f-circRNA associated with the MLL-AF9 fusion gene, called f-circM9.
Although f-circM9 could not trigger leukemia on its own, it appeared to work with other cancer-promoting signals—such as the MLL-AF9 fusion protein—to cause leukemia.
Additional experiments suggested that f-circM9 may also help tumor cells persist despite treatment with anticancer drugs.
“These results are particularly exciting because they suggest that drugs directed at fusion-circular RNAs could be a powerful strategy to pursue for future therapeutic development in cancer,” Dr Pandolfi said.
“[However,] our knowledge of circular RNAs is really in its infancy. We know that, normally, they can bind proteins as well as DNA and microRNAs, but much more needs to be done to understand how fusion-circular RNAs work. We have only scratched the surface of these RNAs and their roles in cancer and other diseases.”
Image courtesy of The Armed
Forces Institute of Pathology
A class of circular RNAs may play a key role in the development and progression of certain leukemias and other cancers, according to research published in Cell.
Investigators found that cancer-associated chromosomal translocations give rise to fusion circular RNAs (f-circRNAs).
And these f-circRNAs aid cellular transformation, promote cell viability, confer treatment resistance, and exhibit tumor-promoting properties in vivo.
“Cancer is essentially a disease of mutated or broken genes, so that motivated us to examine whether circular RNAs, like proteins, can be affected by these chromosomal breaks,” said study author Pier Paolo Pandolfi, MD, PhD, of Beth Israel Deaconess Medical Center in Boston, Massachusetts.
“Our work paves the way to discovering many more of these unusual RNAs and how they contribute to cancer, which could reveal new mechanisms and druggable pathways involved in tumor progression.”
Curious about the possibility of circular RNAs contributing to cancer, Dr Pandolfi and his colleagues set out to see if they could detect relevant changes in tumors known to harbor distinct fusion proteins.
The team examined acute promyelocytic leukemia, which often carries a translocation between the PML and RARα genes, and acute myeloid leukemia, which can harbor a translocation between the MLL and AF9 genes.
The investigators found f-circRNAs corresponding to different exons associated with the PML-RARα gene fusion and the MLL-AF9 gene fusion. Normally, multiple circular RNAs can be generated from a single gene, so the team was not surprised to find different f-circRNAs emerging from the same fusion gene.
Dr Pandolfi and his colleagues also uncovered f-circRNAs in solid tumors—in Ewing sarcoma and lung cancer.
The team identified the f-circRNAs using 2 distinct methods—PCR-based amplification and sequencing-based approaches. They said this suggests f-circRNAs are bona fide biological entities, rather than experimental artifacts.
“Our ability to readily detect these fusion-circular RNAs—and their normal, non-fused counterparts—will be enhanced by advances in sequencing technology and analytic methods,” said study author Jlenia Guarnerio, PhD, also of Beth Israel Deaconess Medical Center.
“Indeed, as we look ahead to cataloguing them comprehensively across all cancers and to deeply understanding their mechanisms of action, we will need to propel these new methodologies even further.”
To determine whether f-circRNAs play a functional role in cancer, the investigators introduced the RNAs into cells. This caused the cells to increase their proliferation and tendency to overgrow—features shared by tumor cells.
On the other hand, when the team blocked f-circRNA activity, the cells’ normal behaviors were restored.
Dr Pandolfi and his colleagues also conducted experiments using a mouse model of leukemia. They focused on a specific f-circRNA associated with the MLL-AF9 fusion gene, called f-circM9.
Although f-circM9 could not trigger leukemia on its own, it appeared to work with other cancer-promoting signals—such as the MLL-AF9 fusion protein—to cause leukemia.
Additional experiments suggested that f-circM9 may also help tumor cells persist despite treatment with anticancer drugs.
“These results are particularly exciting because they suggest that drugs directed at fusion-circular RNAs could be a powerful strategy to pursue for future therapeutic development in cancer,” Dr Pandolfi said.
“[However,] our knowledge of circular RNAs is really in its infancy. We know that, normally, they can bind proteins as well as DNA and microRNAs, but much more needs to be done to understand how fusion-circular RNAs work. We have only scratched the surface of these RNAs and their roles in cancer and other diseases.”
FDA grants product orphan designation for AML
Image by Lance Liotta
The US Food and Drug Administration (FDA) has granted orphan designation for the radioimmunoconjugate Iomab-B to be used as a conditioning agent for patients with relapsed or refractory acute myeloid leukemia (AML) who are undergoing hematopoietic stem cell transplant (HSCT).
Iomab-B is a radioimmunoconjugate consisting of BC8, a novel murine monoclonal antibody, and the radioisotope iodine-131.
BC8 targets CD45, a pan-leukocytic antigen widely expressed on white blood cells. This makes BC8 potentially useful in targeting white blood cells in preparation for HSCT.
When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow, while avoiding the effects of radiation on most healthy tissues, according to Actinium Pharmaceuticals, Inc., the company developing Iomab-B.
Actinium said Iomab-B has been tested as a myeloconditioning/myeloablative agent in more than 250 patients with incurable hematologic malignancies.
The company has released data from a phase 1/2 trial of Iomab-B in patients with relapsed/refractory AML who are older than 50.
The data show that patients who received Iomab-B before HSCT (n=27) had higher rates of survival at 1 and 2 years than patients who underwent HSCT with conventional myeloablative conditioning (n=10) or chemotherapy (n=61).
One-year survival rates were 30% in the Iomab-B arm and 10% each in the conventional conditioning and chemotherapy arms. Two-year survival rates were 19%, 0%, and 0%, respectively.
Now, Actinium is planning a phase 3 trial of Iomab-B in relapsed/refractory AML patients over the age of 55.
About orphan designation
The FDA grants orphan designation to drugs intended to treat diseases or conditions affecting fewer than 200,000 patients in the US.
The designation provides the drug’s sponsor with various development incentives, including opportunities to apply for research-related tax credits and grant funding, assistance in designing clinical trials, and 7 years of US market exclusivity if the drug is approved.
Image by Lance Liotta
The US Food and Drug Administration (FDA) has granted orphan designation for the radioimmunoconjugate Iomab-B to be used as a conditioning agent for patients with relapsed or refractory acute myeloid leukemia (AML) who are undergoing hematopoietic stem cell transplant (HSCT).
Iomab-B is a radioimmunoconjugate consisting of BC8, a novel murine monoclonal antibody, and the radioisotope iodine-131.
BC8 targets CD45, a pan-leukocytic antigen widely expressed on white blood cells. This makes BC8 potentially useful in targeting white blood cells in preparation for HSCT.
When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow, while avoiding the effects of radiation on most healthy tissues, according to Actinium Pharmaceuticals, Inc., the company developing Iomab-B.
Actinium said Iomab-B has been tested as a myeloconditioning/myeloablative agent in more than 250 patients with incurable hematologic malignancies.
The company has released data from a phase 1/2 trial of Iomab-B in patients with relapsed/refractory AML who are older than 50.
The data show that patients who received Iomab-B before HSCT (n=27) had higher rates of survival at 1 and 2 years than patients who underwent HSCT with conventional myeloablative conditioning (n=10) or chemotherapy (n=61).
One-year survival rates were 30% in the Iomab-B arm and 10% each in the conventional conditioning and chemotherapy arms. Two-year survival rates were 19%, 0%, and 0%, respectively.
Now, Actinium is planning a phase 3 trial of Iomab-B in relapsed/refractory AML patients over the age of 55.
About orphan designation
The FDA grants orphan designation to drugs intended to treat diseases or conditions affecting fewer than 200,000 patients in the US.
The designation provides the drug’s sponsor with various development incentives, including opportunities to apply for research-related tax credits and grant funding, assistance in designing clinical trials, and 7 years of US market exclusivity if the drug is approved.
Image by Lance Liotta
The US Food and Drug Administration (FDA) has granted orphan designation for the radioimmunoconjugate Iomab-B to be used as a conditioning agent for patients with relapsed or refractory acute myeloid leukemia (AML) who are undergoing hematopoietic stem cell transplant (HSCT).
Iomab-B is a radioimmunoconjugate consisting of BC8, a novel murine monoclonal antibody, and the radioisotope iodine-131.
BC8 targets CD45, a pan-leukocytic antigen widely expressed on white blood cells. This makes BC8 potentially useful in targeting white blood cells in preparation for HSCT.
When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow, while avoiding the effects of radiation on most healthy tissues, according to Actinium Pharmaceuticals, Inc., the company developing Iomab-B.
Actinium said Iomab-B has been tested as a myeloconditioning/myeloablative agent in more than 250 patients with incurable hematologic malignancies.
The company has released data from a phase 1/2 trial of Iomab-B in patients with relapsed/refractory AML who are older than 50.
The data show that patients who received Iomab-B before HSCT (n=27) had higher rates of survival at 1 and 2 years than patients who underwent HSCT with conventional myeloablative conditioning (n=10) or chemotherapy (n=61).
One-year survival rates were 30% in the Iomab-B arm and 10% each in the conventional conditioning and chemotherapy arms. Two-year survival rates were 19%, 0%, and 0%, respectively.
Now, Actinium is planning a phase 3 trial of Iomab-B in relapsed/refractory AML patients over the age of 55.
About orphan designation
The FDA grants orphan designation to drugs intended to treat diseases or conditions affecting fewer than 200,000 patients in the US.
The designation provides the drug’s sponsor with various development incentives, including opportunities to apply for research-related tax credits and grant funding, assistance in designing clinical trials, and 7 years of US market exclusivity if the drug is approved.
Drug for conditioning AML patients for transplant gets orphan drug designation
A radioimmunotherapeutic drug for conditioning relapsed and refractory acute myeloid leukemia (AML) patients for a hematopoietic stem cell transplant has been granted orphan drug designation by the Food and Drug Administration.
Iomab-B is a radioimmunoconjugate consisting of the murine monoclonal antibody BC8 and an iodine-131 radioisotope. The Fred Hutchinson Cancer Research Center developed BC8 to target CD45, a panleukocytic antigen widely expressed on white blood cells. “When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow while avoiding effects of radiation on most healthy tissues,” says a statement from Actinium Pharmaceuticals, which would market the drug.
Iomab-B will be tested in a multicenter trial that will include 150 patients over age 55 with refractory and relapsed AML. “There has not been a new drug approved for relapsed and refractory AML patients over the age of 55 in decades and with Iomab-B being the only therapy of its kind, we are pleased to have achieved this important milestone,” Sandesh Seth, executive chairman of Actinium, said in the statement.
A radioimmunotherapeutic drug for conditioning relapsed and refractory acute myeloid leukemia (AML) patients for a hematopoietic stem cell transplant has been granted orphan drug designation by the Food and Drug Administration.
Iomab-B is a radioimmunoconjugate consisting of the murine monoclonal antibody BC8 and an iodine-131 radioisotope. The Fred Hutchinson Cancer Research Center developed BC8 to target CD45, a panleukocytic antigen widely expressed on white blood cells. “When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow while avoiding effects of radiation on most healthy tissues,” says a statement from Actinium Pharmaceuticals, which would market the drug.
Iomab-B will be tested in a multicenter trial that will include 150 patients over age 55 with refractory and relapsed AML. “There has not been a new drug approved for relapsed and refractory AML patients over the age of 55 in decades and with Iomab-B being the only therapy of its kind, we are pleased to have achieved this important milestone,” Sandesh Seth, executive chairman of Actinium, said in the statement.
A radioimmunotherapeutic drug for conditioning relapsed and refractory acute myeloid leukemia (AML) patients for a hematopoietic stem cell transplant has been granted orphan drug designation by the Food and Drug Administration.
Iomab-B is a radioimmunoconjugate consisting of the murine monoclonal antibody BC8 and an iodine-131 radioisotope. The Fred Hutchinson Cancer Research Center developed BC8 to target CD45, a panleukocytic antigen widely expressed on white blood cells. “When labeled with radioactive isotopes, BC8 carries radioactivity directly to the site of cancerous growth and bone marrow while avoiding effects of radiation on most healthy tissues,” says a statement from Actinium Pharmaceuticals, which would market the drug.
Iomab-B will be tested in a multicenter trial that will include 150 patients over age 55 with refractory and relapsed AML. “There has not been a new drug approved for relapsed and refractory AML patients over the age of 55 in decades and with Iomab-B being the only therapy of its kind, we are pleased to have achieved this important milestone,” Sandesh Seth, executive chairman of Actinium, said in the statement.
New drug approved for hepatic veno-occlusive disease
Defibrotide sodium has been approved to treat hepatic veno-occlusive disease (VOD) in patients with renal or pulmonary dysfunction following a hematopoietic stem cell transplantation, the Food and Drug Administration has announced.
The drug, which will be marketed as Defitelio by Jazz Pharmaceuticals, was tested in two prospective clinical trials and an expanded access study that included a total of 528 patients with hepatic VOD and multiorgan dysfunction following a transplantation. All patients received 6.25 mg/kg doses of the drug intravenously, every 6 hours until resolution of VOD. The percentages of patients surviving more than 100 days after receiving a stem cell transplantation in each of the studies were 38%, 44%, and 45%, respectively, according to a statement from the FDA.
Contraindications for taking the drug are concurrent use of anticoagulants or fibrinolytic therapies.
Hypotension, diarrhea, vomiting, nausea, and epistaxis are the most common adverse reactions to the drug.
Full prescribing information is available at the FDA website.
Defibrotide sodium has been approved to treat hepatic veno-occlusive disease (VOD) in patients with renal or pulmonary dysfunction following a hematopoietic stem cell transplantation, the Food and Drug Administration has announced.
The drug, which will be marketed as Defitelio by Jazz Pharmaceuticals, was tested in two prospective clinical trials and an expanded access study that included a total of 528 patients with hepatic VOD and multiorgan dysfunction following a transplantation. All patients received 6.25 mg/kg doses of the drug intravenously, every 6 hours until resolution of VOD. The percentages of patients surviving more than 100 days after receiving a stem cell transplantation in each of the studies were 38%, 44%, and 45%, respectively, according to a statement from the FDA.
Contraindications for taking the drug are concurrent use of anticoagulants or fibrinolytic therapies.
Hypotension, diarrhea, vomiting, nausea, and epistaxis are the most common adverse reactions to the drug.
Full prescribing information is available at the FDA website.
Defibrotide sodium has been approved to treat hepatic veno-occlusive disease (VOD) in patients with renal or pulmonary dysfunction following a hematopoietic stem cell transplantation, the Food and Drug Administration has announced.
The drug, which will be marketed as Defitelio by Jazz Pharmaceuticals, was tested in two prospective clinical trials and an expanded access study that included a total of 528 patients with hepatic VOD and multiorgan dysfunction following a transplantation. All patients received 6.25 mg/kg doses of the drug intravenously, every 6 hours until resolution of VOD. The percentages of patients surviving more than 100 days after receiving a stem cell transplantation in each of the studies were 38%, 44%, and 45%, respectively, according to a statement from the FDA.
Contraindications for taking the drug are concurrent use of anticoagulants or fibrinolytic therapies.
Hypotension, diarrhea, vomiting, nausea, and epistaxis are the most common adverse reactions to the drug.
Full prescribing information is available at the FDA website.
Mouse model replicates aggressive AML subtype
Researchers have developed a mouse model of an aggressive type of acute myeloid leukemia (AML) that, they believe, accurately replicates the human form of the disease.
The model replicates AML with co-occurring mutations in FLT3 and DNMT3A.
The researchers said they found that mice with Flt3-ITD and inducible deletion of Dnmt3a developed a rapidly lethal, completely penetrant, and transplantable AML of normal karyotype.
The team described this work in Cancer Discovery.
“Our goal was to create a model that was faithful to the human form of the disease that can be used for preclinical testing of potential cures,” said study author H. Leighton Grimes, PhD, of Cincinnati Children’s Hospital Medical Center in Ohio.
“Previous models were slow, difficult to analyze, and did not accurately represent the human disease. This model is rapid, fully penetrant, and completely spontaneous. We hope that it will open the way for other researchers to join us in attacking this particularly lethal AML subtype.”
Dr Grimes and his colleagues said they were able to look at the disease in a new way with the help of a powerful new core facility utilizing analytical tools related to single-cell RNA sequencing. The team used complementary single-cell analyses to identify the core leukemia-causing stem cells of the tumor.
“Before, researchers were comparing the gene expression patterns of one AML subtype to either normal cells or other AML subtypes,” said study author Sara Meyer, PhD, a fellow in the Grimes lab.
“That approach made it difficult to tease out the specific impact of Dnmt3a mutation. Instead, we isolated the variables and studied only human and murine AML with Flt3 mutation. Comparing Flt3-mutant AML with and without Dnmt3a mutation allowed us to more finely identify those patterns that were specific to the Dnmt3a mutation.”
With that more detailed understanding, the researchers gained new insights into the contributions of the Dnmt3a mutation to the disease.
First, their work confirms suspicions that low-level Dnmt3a activity is cancer-causing. Moreover, they discovered that reduced Dnmt3a function allows genes that are normally expressed only at early development stages of blood cell formation to continue expression at later stages, leading to the development of AML.
The researchers also found that, in mouse tumor cells, rescuing expression of Dnmt3a reversed the leukemia phenotypes and gene expression. But they said more research is warranted to determine if rescuing normal levels of DNMT3A function is a viable method for treating human AML.
The team also identified several potential treatment targets that are unique to this type of AML. In future studies, they plan to proceed with testing potential therapies.
Researchers have developed a mouse model of an aggressive type of acute myeloid leukemia (AML) that, they believe, accurately replicates the human form of the disease.
The model replicates AML with co-occurring mutations in FLT3 and DNMT3A.
The researchers said they found that mice with Flt3-ITD and inducible deletion of Dnmt3a developed a rapidly lethal, completely penetrant, and transplantable AML of normal karyotype.
The team described this work in Cancer Discovery.
“Our goal was to create a model that was faithful to the human form of the disease that can be used for preclinical testing of potential cures,” said study author H. Leighton Grimes, PhD, of Cincinnati Children’s Hospital Medical Center in Ohio.
“Previous models were slow, difficult to analyze, and did not accurately represent the human disease. This model is rapid, fully penetrant, and completely spontaneous. We hope that it will open the way for other researchers to join us in attacking this particularly lethal AML subtype.”
Dr Grimes and his colleagues said they were able to look at the disease in a new way with the help of a powerful new core facility utilizing analytical tools related to single-cell RNA sequencing. The team used complementary single-cell analyses to identify the core leukemia-causing stem cells of the tumor.
“Before, researchers were comparing the gene expression patterns of one AML subtype to either normal cells or other AML subtypes,” said study author Sara Meyer, PhD, a fellow in the Grimes lab.
“That approach made it difficult to tease out the specific impact of Dnmt3a mutation. Instead, we isolated the variables and studied only human and murine AML with Flt3 mutation. Comparing Flt3-mutant AML with and without Dnmt3a mutation allowed us to more finely identify those patterns that were specific to the Dnmt3a mutation.”
With that more detailed understanding, the researchers gained new insights into the contributions of the Dnmt3a mutation to the disease.
First, their work confirms suspicions that low-level Dnmt3a activity is cancer-causing. Moreover, they discovered that reduced Dnmt3a function allows genes that are normally expressed only at early development stages of blood cell formation to continue expression at later stages, leading to the development of AML.
The researchers also found that, in mouse tumor cells, rescuing expression of Dnmt3a reversed the leukemia phenotypes and gene expression. But they said more research is warranted to determine if rescuing normal levels of DNMT3A function is a viable method for treating human AML.
The team also identified several potential treatment targets that are unique to this type of AML. In future studies, they plan to proceed with testing potential therapies.
Researchers have developed a mouse model of an aggressive type of acute myeloid leukemia (AML) that, they believe, accurately replicates the human form of the disease.
The model replicates AML with co-occurring mutations in FLT3 and DNMT3A.
The researchers said they found that mice with Flt3-ITD and inducible deletion of Dnmt3a developed a rapidly lethal, completely penetrant, and transplantable AML of normal karyotype.
The team described this work in Cancer Discovery.
“Our goal was to create a model that was faithful to the human form of the disease that can be used for preclinical testing of potential cures,” said study author H. Leighton Grimes, PhD, of Cincinnati Children’s Hospital Medical Center in Ohio.
“Previous models were slow, difficult to analyze, and did not accurately represent the human disease. This model is rapid, fully penetrant, and completely spontaneous. We hope that it will open the way for other researchers to join us in attacking this particularly lethal AML subtype.”
Dr Grimes and his colleagues said they were able to look at the disease in a new way with the help of a powerful new core facility utilizing analytical tools related to single-cell RNA sequencing. The team used complementary single-cell analyses to identify the core leukemia-causing stem cells of the tumor.
“Before, researchers were comparing the gene expression patterns of one AML subtype to either normal cells or other AML subtypes,” said study author Sara Meyer, PhD, a fellow in the Grimes lab.
“That approach made it difficult to tease out the specific impact of Dnmt3a mutation. Instead, we isolated the variables and studied only human and murine AML with Flt3 mutation. Comparing Flt3-mutant AML with and without Dnmt3a mutation allowed us to more finely identify those patterns that were specific to the Dnmt3a mutation.”
With that more detailed understanding, the researchers gained new insights into the contributions of the Dnmt3a mutation to the disease.
First, their work confirms suspicions that low-level Dnmt3a activity is cancer-causing. Moreover, they discovered that reduced Dnmt3a function allows genes that are normally expressed only at early development stages of blood cell formation to continue expression at later stages, leading to the development of AML.
The researchers also found that, in mouse tumor cells, rescuing expression of Dnmt3a reversed the leukemia phenotypes and gene expression. But they said more research is warranted to determine if rescuing normal levels of DNMT3A function is a viable method for treating human AML.
The team also identified several potential treatment targets that are unique to this type of AML. In future studies, they plan to proceed with testing potential therapies.
PET probe could aid treatment for leukemia
Image by Jens Langner
A PET probe known as [18F]CFA could be used to aid the treatment of leukemias and other cancers, according to research published in PNAS.
Investigators say [18F]CFA can detect the activity of deoxycytidine kinase (dCK) in humans more effectively than existing probes.
dCK is a rate-limiting enzyme in the cytosolic deoxyribonucleoside salvage pathway and is considered an important therapeutic and PET-imaging target in certain cancers.
Research has shown that dCK is highly expressed in acute leukemia cells and activated lymphocytes. And the enzyme plays an integral role in allowing drugs such as clofarabine, cytarabine, and fludarabine to treat certain leukemias.
“This enzyme is essential for the therapeutic activity of an entire class of anticancer drugs and even for some antiviral drugs,” said study author Caius Radu, MD, of the University of California, Los Angeles.
“It can take an inactive drug and activate it. If you trick a cancer cell or virus to activate the drug, it would be toxic for the cancer cell or viral genome.”
Until recently, PET technology was only able to clearly detect dCK in mice due to the metabolic instability of the available probes and cross-reactivity with a dCK-related enzyme in humans.
However, Dr Radu and his colleagues showed that [18F]CFA can clearly detect dCK in humans.
The team found that [18F]CFA accumulation in leukemia cells correlated with dCK expression, and they were able to inhibit [18F]CFA accumulation with a dCK inhibitor.
Experiments with [18F]CFA PET/CT in humans showed probe accumulation in tissues with high dCK expression, such as hematopoietic bone marrow and secondary lymphoid organs.
“We are able to clearly see tissues, including tumor tissues, with high dCK activity that we haven’t seen before in humans using any of the other probes previously developed for this enzyme,” Dr Radu said.
He added that, since activated immune cells increase their expression of dCK, [18F]CFA could also be used to monitor the effectiveness of immunotherapeutic interventions.
The investigators hope to begin clinical trials with [18F]CFA in the near future.
Dr Radu and his team invented [18F]CFA and its analogs, which were patented by the University of California and have been licensed to Sofie Biosciences, a company founded by Dr Radu and his team. The University of California also patented additional intellectual property for small-molecule dCK inhibitors.
Image by Jens Langner
A PET probe known as [18F]CFA could be used to aid the treatment of leukemias and other cancers, according to research published in PNAS.
Investigators say [18F]CFA can detect the activity of deoxycytidine kinase (dCK) in humans more effectively than existing probes.
dCK is a rate-limiting enzyme in the cytosolic deoxyribonucleoside salvage pathway and is considered an important therapeutic and PET-imaging target in certain cancers.
Research has shown that dCK is highly expressed in acute leukemia cells and activated lymphocytes. And the enzyme plays an integral role in allowing drugs such as clofarabine, cytarabine, and fludarabine to treat certain leukemias.
“This enzyme is essential for the therapeutic activity of an entire class of anticancer drugs and even for some antiviral drugs,” said study author Caius Radu, MD, of the University of California, Los Angeles.
“It can take an inactive drug and activate it. If you trick a cancer cell or virus to activate the drug, it would be toxic for the cancer cell or viral genome.”
Until recently, PET technology was only able to clearly detect dCK in mice due to the metabolic instability of the available probes and cross-reactivity with a dCK-related enzyme in humans.
However, Dr Radu and his colleagues showed that [18F]CFA can clearly detect dCK in humans.
The team found that [18F]CFA accumulation in leukemia cells correlated with dCK expression, and they were able to inhibit [18F]CFA accumulation with a dCK inhibitor.
Experiments with [18F]CFA PET/CT in humans showed probe accumulation in tissues with high dCK expression, such as hematopoietic bone marrow and secondary lymphoid organs.
“We are able to clearly see tissues, including tumor tissues, with high dCK activity that we haven’t seen before in humans using any of the other probes previously developed for this enzyme,” Dr Radu said.
He added that, since activated immune cells increase their expression of dCK, [18F]CFA could also be used to monitor the effectiveness of immunotherapeutic interventions.
The investigators hope to begin clinical trials with [18F]CFA in the near future.
Dr Radu and his team invented [18F]CFA and its analogs, which were patented by the University of California and have been licensed to Sofie Biosciences, a company founded by Dr Radu and his team. The University of California also patented additional intellectual property for small-molecule dCK inhibitors.
Image by Jens Langner
A PET probe known as [18F]CFA could be used to aid the treatment of leukemias and other cancers, according to research published in PNAS.
Investigators say [18F]CFA can detect the activity of deoxycytidine kinase (dCK) in humans more effectively than existing probes.
dCK is a rate-limiting enzyme in the cytosolic deoxyribonucleoside salvage pathway and is considered an important therapeutic and PET-imaging target in certain cancers.
Research has shown that dCK is highly expressed in acute leukemia cells and activated lymphocytes. And the enzyme plays an integral role in allowing drugs such as clofarabine, cytarabine, and fludarabine to treat certain leukemias.
“This enzyme is essential for the therapeutic activity of an entire class of anticancer drugs and even for some antiviral drugs,” said study author Caius Radu, MD, of the University of California, Los Angeles.
“It can take an inactive drug and activate it. If you trick a cancer cell or virus to activate the drug, it would be toxic for the cancer cell or viral genome.”
Until recently, PET technology was only able to clearly detect dCK in mice due to the metabolic instability of the available probes and cross-reactivity with a dCK-related enzyme in humans.
However, Dr Radu and his colleagues showed that [18F]CFA can clearly detect dCK in humans.
The team found that [18F]CFA accumulation in leukemia cells correlated with dCK expression, and they were able to inhibit [18F]CFA accumulation with a dCK inhibitor.
Experiments with [18F]CFA PET/CT in humans showed probe accumulation in tissues with high dCK expression, such as hematopoietic bone marrow and secondary lymphoid organs.
“We are able to clearly see tissues, including tumor tissues, with high dCK activity that we haven’t seen before in humans using any of the other probes previously developed for this enzyme,” Dr Radu said.
He added that, since activated immune cells increase their expression of dCK, [18F]CFA could also be used to monitor the effectiveness of immunotherapeutic interventions.
The investigators hope to begin clinical trials with [18F]CFA in the near future.
Dr Radu and his team invented [18F]CFA and its analogs, which were patented by the University of California and have been licensed to Sofie Biosciences, a company founded by Dr Radu and his team. The University of California also patented additional intellectual property for small-molecule dCK inhibitors.
High costs limit CML patients’ access to TKIs
Photo courtesy of the CDC
A new study suggests that cost-sharing policies in the US create a barrier to the treatment of chronic myeloid leukemia (CML).
Researchers examined Medicare claims data and found that “Part D” (prescription drug plan) co-insurance policies for “specialty drugs” seem to be reducing or delaying the use of tyrosine kinase inhibitors (TKIs) in patients with CML.
The team reported these findings in the American Journal of Managed Care.
“High out-of-pocket costs for specialty drugs appear to pose a very real barrier to treatment,” said study author Jalpa A. Doshi, PhD, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.
While there is no standard definition for specialty drugs, the term typically refers to medications requiring special handling, administration, or monitoring. Most are aimed at treating chronic or life-threatening diseases.
Although specialty drugs typically tend to offer significant medical advances over non-specialty drugs, they are correspondingly more expensive. In 2014, such drugs accounted for less than 1% of prescriptions in the US but nearly a third of total prescription spending.
While insurers have been imposing higher cost-sharing requirements as part of their efforts to manage specialty drug spending, there has been limited information about the corresponding impact on patients.
“[I]t was particularly important to examine the extent to which the aggressive cost-sharing policies for specialty drugs seen under Medicare Part D, which are increasingly making their way into the private insurance market, adversely impact access to these treatments even for a condition like cancer,” Dr Doshi said.
So she and her colleagues examined the impact of specialty drug cost-sharing under the Medicare Part D prescription drug benefit on patients with CML. The team analyzed Medicare data on patients who were newly diagnosed with CML to examine whether and how quickly they initiated TKI treatment.
The researchers compared patients who were eligible for low-income subsidies and therefore faced nominal out-of-pocket costs to patients who faced average out-of-pocket costs of $2600 or more for their first 30-day TKI prescription fill.
Results showed that patients in the high-cost group were significantly less likely than the low-cost group to have a Part D claim for a TKI prescription within 6 months of their CML diagnosis. The rates were 45.3% and 66.9%, respectively (P<0.001).
Patients in the high cost-sharing group also took twice as long, on average, to initiate TKI treatment. The mean time to fill a TKI prescription was 50.9 days in the high-cost group and 23.7 days in the low-cost group (P<0.001).
“Medicare Part D was created to increase access to prescription drug treatment among beneficiaries, but our data suggest that current policies are interfering with that goal when it comes to specialty drugs,” Dr Doshi said.
She added that making Part D out-of-pocket costs more consistent and limiting them to more reasonable sums would help mitigate this negative impact.
Dr Doshi and her colleagues are now pursuing further studies of the impact of Part D cost-sharing policies in different disease areas. They hope to gain a better understanding of changes in drug access and of the long-range clinical outcomes and costs associated with any delays or interruptions in treatment.
“We need to know if the current aggressive cost-sharing arrangements have adverse long-term impacts on health and perhaps, paradoxically, increase overall spending due to complications of poorly controlled disease,” Dr Doshi said.
Photo courtesy of the CDC
A new study suggests that cost-sharing policies in the US create a barrier to the treatment of chronic myeloid leukemia (CML).
Researchers examined Medicare claims data and found that “Part D” (prescription drug plan) co-insurance policies for “specialty drugs” seem to be reducing or delaying the use of tyrosine kinase inhibitors (TKIs) in patients with CML.
The team reported these findings in the American Journal of Managed Care.
“High out-of-pocket costs for specialty drugs appear to pose a very real barrier to treatment,” said study author Jalpa A. Doshi, PhD, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.
While there is no standard definition for specialty drugs, the term typically refers to medications requiring special handling, administration, or monitoring. Most are aimed at treating chronic or life-threatening diseases.
Although specialty drugs typically tend to offer significant medical advances over non-specialty drugs, they are correspondingly more expensive. In 2014, such drugs accounted for less than 1% of prescriptions in the US but nearly a third of total prescription spending.
While insurers have been imposing higher cost-sharing requirements as part of their efforts to manage specialty drug spending, there has been limited information about the corresponding impact on patients.
“[I]t was particularly important to examine the extent to which the aggressive cost-sharing policies for specialty drugs seen under Medicare Part D, which are increasingly making their way into the private insurance market, adversely impact access to these treatments even for a condition like cancer,” Dr Doshi said.
So she and her colleagues examined the impact of specialty drug cost-sharing under the Medicare Part D prescription drug benefit on patients with CML. The team analyzed Medicare data on patients who were newly diagnosed with CML to examine whether and how quickly they initiated TKI treatment.
The researchers compared patients who were eligible for low-income subsidies and therefore faced nominal out-of-pocket costs to patients who faced average out-of-pocket costs of $2600 or more for their first 30-day TKI prescription fill.
Results showed that patients in the high-cost group were significantly less likely than the low-cost group to have a Part D claim for a TKI prescription within 6 months of their CML diagnosis. The rates were 45.3% and 66.9%, respectively (P<0.001).
Patients in the high cost-sharing group also took twice as long, on average, to initiate TKI treatment. The mean time to fill a TKI prescription was 50.9 days in the high-cost group and 23.7 days in the low-cost group (P<0.001).
“Medicare Part D was created to increase access to prescription drug treatment among beneficiaries, but our data suggest that current policies are interfering with that goal when it comes to specialty drugs,” Dr Doshi said.
She added that making Part D out-of-pocket costs more consistent and limiting them to more reasonable sums would help mitigate this negative impact.
Dr Doshi and her colleagues are now pursuing further studies of the impact of Part D cost-sharing policies in different disease areas. They hope to gain a better understanding of changes in drug access and of the long-range clinical outcomes and costs associated with any delays or interruptions in treatment.
“We need to know if the current aggressive cost-sharing arrangements have adverse long-term impacts on health and perhaps, paradoxically, increase overall spending due to complications of poorly controlled disease,” Dr Doshi said.
Photo courtesy of the CDC
A new study suggests that cost-sharing policies in the US create a barrier to the treatment of chronic myeloid leukemia (CML).
Researchers examined Medicare claims data and found that “Part D” (prescription drug plan) co-insurance policies for “specialty drugs” seem to be reducing or delaying the use of tyrosine kinase inhibitors (TKIs) in patients with CML.
The team reported these findings in the American Journal of Managed Care.
“High out-of-pocket costs for specialty drugs appear to pose a very real barrier to treatment,” said study author Jalpa A. Doshi, PhD, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia.
While there is no standard definition for specialty drugs, the term typically refers to medications requiring special handling, administration, or monitoring. Most are aimed at treating chronic or life-threatening diseases.
Although specialty drugs typically tend to offer significant medical advances over non-specialty drugs, they are correspondingly more expensive. In 2014, such drugs accounted for less than 1% of prescriptions in the US but nearly a third of total prescription spending.
While insurers have been imposing higher cost-sharing requirements as part of their efforts to manage specialty drug spending, there has been limited information about the corresponding impact on patients.
“[I]t was particularly important to examine the extent to which the aggressive cost-sharing policies for specialty drugs seen under Medicare Part D, which are increasingly making their way into the private insurance market, adversely impact access to these treatments even for a condition like cancer,” Dr Doshi said.
So she and her colleagues examined the impact of specialty drug cost-sharing under the Medicare Part D prescription drug benefit on patients with CML. The team analyzed Medicare data on patients who were newly diagnosed with CML to examine whether and how quickly they initiated TKI treatment.
The researchers compared patients who were eligible for low-income subsidies and therefore faced nominal out-of-pocket costs to patients who faced average out-of-pocket costs of $2600 or more for their first 30-day TKI prescription fill.
Results showed that patients in the high-cost group were significantly less likely than the low-cost group to have a Part D claim for a TKI prescription within 6 months of their CML diagnosis. The rates were 45.3% and 66.9%, respectively (P<0.001).
Patients in the high cost-sharing group also took twice as long, on average, to initiate TKI treatment. The mean time to fill a TKI prescription was 50.9 days in the high-cost group and 23.7 days in the low-cost group (P<0.001).
“Medicare Part D was created to increase access to prescription drug treatment among beneficiaries, but our data suggest that current policies are interfering with that goal when it comes to specialty drugs,” Dr Doshi said.
She added that making Part D out-of-pocket costs more consistent and limiting them to more reasonable sums would help mitigate this negative impact.
Dr Doshi and her colleagues are now pursuing further studies of the impact of Part D cost-sharing policies in different disease areas. They hope to gain a better understanding of changes in drug access and of the long-range clinical outcomes and costs associated with any delays or interruptions in treatment.
“We need to know if the current aggressive cost-sharing arrangements have adverse long-term impacts on health and perhaps, paradoxically, increase overall spending due to complications of poorly controlled disease,” Dr Doshi said.
Study: Dying at home doesn’t mean dying sooner
patient’s hand
Choosing to die at home does not hasten death for patients with terminal cancer, according to a study published in Cancer.
The research showed that cancer patients who died at home lived at least as long as patients who spent their last days in hospitals.
Investigators say these results suggest oncologists should not hesitate to refer patients for home-based palliative care simply because less medical treatment may be provided.
“The cancer patient and family tend to be concerned that the quality of medical treatment provided at home will be inferior to that given in a hospital and that survival might be shortened,” said study author Jun Hamano, MD, of the University of Tsukuba in Japan.
“However, our finding—that home death does not actually have a negative influence on the survival of cancer patients at all and, rather, may have a positive influence—could suggest that the patient and family can choose the place of death in terms of their preference and values.”
Dr Hamano and his colleagues conducted this research by prospectively studying 2069 patients—1582 receiving hospital-based palliative care and 487 receiving home-based palliative care.
In all, 1607 patients died in the hospital, and 462 died at home.
Among patients thought to have only days to live, the survival of those who died at home was significantly longer than the survival of those who died in a hospital. The estimated median survival times were 13 days and 9 days, respectively (P<0.006).
Similarly, survival was significantly longer in the home group than the hospital group among patients thought to have weeks to live. The estimated median survival times were 36 days and 29 days, respectively (P<0.007).
There was no significant difference between the home and hospital groups among patients thought to have months to live. The estimated median survival times were 59 days and 62 days, respectively (P=0.925).
Finally, analyses suggested the place of death had a significant influence on the survival time in both unadjusted and adjusted models. The hazard ratios were 0.86 (P<0.01) and 0.87 (P=0.01), respectively.
Based on these findings, Dr Hamano concluded that, “Patients, families, and clinicians should be reassured that good home hospice care does not shorten patient life and even may achieve longer survival.”
patient’s hand
Choosing to die at home does not hasten death for patients with terminal cancer, according to a study published in Cancer.
The research showed that cancer patients who died at home lived at least as long as patients who spent their last days in hospitals.
Investigators say these results suggest oncologists should not hesitate to refer patients for home-based palliative care simply because less medical treatment may be provided.
“The cancer patient and family tend to be concerned that the quality of medical treatment provided at home will be inferior to that given in a hospital and that survival might be shortened,” said study author Jun Hamano, MD, of the University of Tsukuba in Japan.
“However, our finding—that home death does not actually have a negative influence on the survival of cancer patients at all and, rather, may have a positive influence—could suggest that the patient and family can choose the place of death in terms of their preference and values.”
Dr Hamano and his colleagues conducted this research by prospectively studying 2069 patients—1582 receiving hospital-based palliative care and 487 receiving home-based palliative care.
In all, 1607 patients died in the hospital, and 462 died at home.
Among patients thought to have only days to live, the survival of those who died at home was significantly longer than the survival of those who died in a hospital. The estimated median survival times were 13 days and 9 days, respectively (P<0.006).
Similarly, survival was significantly longer in the home group than the hospital group among patients thought to have weeks to live. The estimated median survival times were 36 days and 29 days, respectively (P<0.007).
There was no significant difference between the home and hospital groups among patients thought to have months to live. The estimated median survival times were 59 days and 62 days, respectively (P=0.925).
Finally, analyses suggested the place of death had a significant influence on the survival time in both unadjusted and adjusted models. The hazard ratios were 0.86 (P<0.01) and 0.87 (P=0.01), respectively.
Based on these findings, Dr Hamano concluded that, “Patients, families, and clinicians should be reassured that good home hospice care does not shorten patient life and even may achieve longer survival.”
patient’s hand
Choosing to die at home does not hasten death for patients with terminal cancer, according to a study published in Cancer.
The research showed that cancer patients who died at home lived at least as long as patients who spent their last days in hospitals.
Investigators say these results suggest oncologists should not hesitate to refer patients for home-based palliative care simply because less medical treatment may be provided.
“The cancer patient and family tend to be concerned that the quality of medical treatment provided at home will be inferior to that given in a hospital and that survival might be shortened,” said study author Jun Hamano, MD, of the University of Tsukuba in Japan.
“However, our finding—that home death does not actually have a negative influence on the survival of cancer patients at all and, rather, may have a positive influence—could suggest that the patient and family can choose the place of death in terms of their preference and values.”
Dr Hamano and his colleagues conducted this research by prospectively studying 2069 patients—1582 receiving hospital-based palliative care and 487 receiving home-based palliative care.
In all, 1607 patients died in the hospital, and 462 died at home.
Among patients thought to have only days to live, the survival of those who died at home was significantly longer than the survival of those who died in a hospital. The estimated median survival times were 13 days and 9 days, respectively (P<0.006).
Similarly, survival was significantly longer in the home group than the hospital group among patients thought to have weeks to live. The estimated median survival times were 36 days and 29 days, respectively (P<0.007).
There was no significant difference between the home and hospital groups among patients thought to have months to live. The estimated median survival times were 59 days and 62 days, respectively (P=0.925).
Finally, analyses suggested the place of death had a significant influence on the survival time in both unadjusted and adjusted models. The hazard ratios were 0.86 (P<0.01) and 0.87 (P=0.01), respectively.
Based on these findings, Dr Hamano concluded that, “Patients, families, and clinicians should be reassured that good home hospice care does not shorten patient life and even may achieve longer survival.”
Drug exhibits preclinical activity against MDS
Researchers have found the fusion protein APG101 can rescue erythropoiesis in bone marrow samples from patients with lower-risk myelodysplastic syndromes (MDS).
Previous research suggested that CD95—a receptor that can induce apoptosis when triggered by the CD95 ligand—is overexpressed in two-thirds of patients with lower-risk MDS, and overexpression of CD95 is predictive of a lower response to erythropoiesis-stimulating agents (ESAs).
APG101, which consists of the extracellular domain of the CD95 receptor and the Fc domain of an IgG antibody, is designed to block the CD95 ligand.
The new study showed that APG101 can inhibit apoptosis in erythrocyte precursor cells and improve their overall proliferation rate. The drug increased the number of burst-forming unit-erythroid (BFU-E) progenitors in samples from MDS patients with low BFU-E numbers at baseline.
“APG101 added to cellular assays efficiently rescued the growth of erythroid progenitors in MDS patients harboring a profound defect of erythropoiesis, independent of the expression level of CD95 or CD95 ligand,” said Michaela Fontenay, MD, PhD, of the Institut Cochin in Paris, France.
Dr Fontenay and her colleagues described these results in Oncotarget. The research was funded by Apogenix, the company developing APG101.
By comparing bone marrow samples from MDS patients and healthy control subjects, the researchers found that CD95, but not CD95 ligand, was overexpressed in patients with lower-risk MDS.
Further analysis revealed that a patient’s CD95 expression level at diagnosis could predict response to an ESA. Specifically, CD95 overexpression was predictive of a lower response rate to ESAs in patients with low- or intermediate-1-risk MDS.
Next, the researchers tested bone marrow erythroid progenitors from 3 control subjects and 5 patients with MDS and found that CD95 expression increased during MDS erythroid progenitor amplification but remained lower in control cultures.
On day 5 of culture, the mean number of BFU-Es was significantly lower in MDS patient samples than in controls. And treatment with APG101 prompted a dose-dependent increase in BFU-E growth in MDS samples but not in controls.
When the researchers added APG101 (at 10 μg/mL) to the cultures over 7 days, they observed an improvement in the proliferation of erythroblasts but no significant effect on the kinetics of differentiation.
They also found that APG101 reduced apoptosis in immature precursors by 30% but had no effect on apoptosis in mature precursors.
Baseline BFU-E number affects response
The researchers then assessed the effects of APG101 in samples from 5 control subjects and 20 MDS patients with varying responses to ESAs and varying baseline levels of BFU-Es.
Fifteen of the MDS patients had a significantly lower number of baseline BFU-Es than controls (P=0.005), but 5 MDS patients had a mean number of BFU-Es that was comparable to controls (P=0.429). There was no significant difference in WHO classification or CD95 expression between the 2 groups of MDS patients (P=0.612).
However, 11 of the 15 patients with low erythropoiesis had received an ESA, and all of them were resistant to this treatment. In all, 15 of the MDS patients had received an ESA, and 14 were resistant to it (6 primary and 8 secondary).
The researchers found that APG101 induced a dose-dependent increase of BFU-Es in samples from the 15 MDS patients with low erythropoiesis but not in samples from the 5 patients with normal erythropoiesis or in the control samples (P<0.001).
The team said that a low BFU-E number at baseline was significantly associated with in vitro response to APG101 among the 20 MDS patients (P=0.031) and the 14 ESA-resistant patients (P=0.027).
Further investigation confirmed that a low clonogenic progenitor number at baseline, but not the level of CD95 or CD95 ligand expression, was predictive of the response to APG101.
“This study provides a rationale for further clinical investigation of this potential new therapeutic option in patients with severely impaired erythropoiesis who are resistant to erythropoiesis-stimulating agents,” Dr Fontenay said.
Apogenix has conducted a phase 1 trial of APG101 in transfusion-dependent patients with low- to intermediate-1-risk MDS. The company expects the results of this trial will be available in the coming months.
Researchers have found the fusion protein APG101 can rescue erythropoiesis in bone marrow samples from patients with lower-risk myelodysplastic syndromes (MDS).
Previous research suggested that CD95—a receptor that can induce apoptosis when triggered by the CD95 ligand—is overexpressed in two-thirds of patients with lower-risk MDS, and overexpression of CD95 is predictive of a lower response to erythropoiesis-stimulating agents (ESAs).
APG101, which consists of the extracellular domain of the CD95 receptor and the Fc domain of an IgG antibody, is designed to block the CD95 ligand.
The new study showed that APG101 can inhibit apoptosis in erythrocyte precursor cells and improve their overall proliferation rate. The drug increased the number of burst-forming unit-erythroid (BFU-E) progenitors in samples from MDS patients with low BFU-E numbers at baseline.
“APG101 added to cellular assays efficiently rescued the growth of erythroid progenitors in MDS patients harboring a profound defect of erythropoiesis, independent of the expression level of CD95 or CD95 ligand,” said Michaela Fontenay, MD, PhD, of the Institut Cochin in Paris, France.
Dr Fontenay and her colleagues described these results in Oncotarget. The research was funded by Apogenix, the company developing APG101.
By comparing bone marrow samples from MDS patients and healthy control subjects, the researchers found that CD95, but not CD95 ligand, was overexpressed in patients with lower-risk MDS.
Further analysis revealed that a patient’s CD95 expression level at diagnosis could predict response to an ESA. Specifically, CD95 overexpression was predictive of a lower response rate to ESAs in patients with low- or intermediate-1-risk MDS.
Next, the researchers tested bone marrow erythroid progenitors from 3 control subjects and 5 patients with MDS and found that CD95 expression increased during MDS erythroid progenitor amplification but remained lower in control cultures.
On day 5 of culture, the mean number of BFU-Es was significantly lower in MDS patient samples than in controls. And treatment with APG101 prompted a dose-dependent increase in BFU-E growth in MDS samples but not in controls.
When the researchers added APG101 (at 10 μg/mL) to the cultures over 7 days, they observed an improvement in the proliferation of erythroblasts but no significant effect on the kinetics of differentiation.
They also found that APG101 reduced apoptosis in immature precursors by 30% but had no effect on apoptosis in mature precursors.
Baseline BFU-E number affects response
The researchers then assessed the effects of APG101 in samples from 5 control subjects and 20 MDS patients with varying responses to ESAs and varying baseline levels of BFU-Es.
Fifteen of the MDS patients had a significantly lower number of baseline BFU-Es than controls (P=0.005), but 5 MDS patients had a mean number of BFU-Es that was comparable to controls (P=0.429). There was no significant difference in WHO classification or CD95 expression between the 2 groups of MDS patients (P=0.612).
However, 11 of the 15 patients with low erythropoiesis had received an ESA, and all of them were resistant to this treatment. In all, 15 of the MDS patients had received an ESA, and 14 were resistant to it (6 primary and 8 secondary).
The researchers found that APG101 induced a dose-dependent increase of BFU-Es in samples from the 15 MDS patients with low erythropoiesis but not in samples from the 5 patients with normal erythropoiesis or in the control samples (P<0.001).
The team said that a low BFU-E number at baseline was significantly associated with in vitro response to APG101 among the 20 MDS patients (P=0.031) and the 14 ESA-resistant patients (P=0.027).
Further investigation confirmed that a low clonogenic progenitor number at baseline, but not the level of CD95 or CD95 ligand expression, was predictive of the response to APG101.
“This study provides a rationale for further clinical investigation of this potential new therapeutic option in patients with severely impaired erythropoiesis who are resistant to erythropoiesis-stimulating agents,” Dr Fontenay said.
Apogenix has conducted a phase 1 trial of APG101 in transfusion-dependent patients with low- to intermediate-1-risk MDS. The company expects the results of this trial will be available in the coming months.
Researchers have found the fusion protein APG101 can rescue erythropoiesis in bone marrow samples from patients with lower-risk myelodysplastic syndromes (MDS).
Previous research suggested that CD95—a receptor that can induce apoptosis when triggered by the CD95 ligand—is overexpressed in two-thirds of patients with lower-risk MDS, and overexpression of CD95 is predictive of a lower response to erythropoiesis-stimulating agents (ESAs).
APG101, which consists of the extracellular domain of the CD95 receptor and the Fc domain of an IgG antibody, is designed to block the CD95 ligand.
The new study showed that APG101 can inhibit apoptosis in erythrocyte precursor cells and improve their overall proliferation rate. The drug increased the number of burst-forming unit-erythroid (BFU-E) progenitors in samples from MDS patients with low BFU-E numbers at baseline.
“APG101 added to cellular assays efficiently rescued the growth of erythroid progenitors in MDS patients harboring a profound defect of erythropoiesis, independent of the expression level of CD95 or CD95 ligand,” said Michaela Fontenay, MD, PhD, of the Institut Cochin in Paris, France.
Dr Fontenay and her colleagues described these results in Oncotarget. The research was funded by Apogenix, the company developing APG101.
By comparing bone marrow samples from MDS patients and healthy control subjects, the researchers found that CD95, but not CD95 ligand, was overexpressed in patients with lower-risk MDS.
Further analysis revealed that a patient’s CD95 expression level at diagnosis could predict response to an ESA. Specifically, CD95 overexpression was predictive of a lower response rate to ESAs in patients with low- or intermediate-1-risk MDS.
Next, the researchers tested bone marrow erythroid progenitors from 3 control subjects and 5 patients with MDS and found that CD95 expression increased during MDS erythroid progenitor amplification but remained lower in control cultures.
On day 5 of culture, the mean number of BFU-Es was significantly lower in MDS patient samples than in controls. And treatment with APG101 prompted a dose-dependent increase in BFU-E growth in MDS samples but not in controls.
When the researchers added APG101 (at 10 μg/mL) to the cultures over 7 days, they observed an improvement in the proliferation of erythroblasts but no significant effect on the kinetics of differentiation.
They also found that APG101 reduced apoptosis in immature precursors by 30% but had no effect on apoptosis in mature precursors.
Baseline BFU-E number affects response
The researchers then assessed the effects of APG101 in samples from 5 control subjects and 20 MDS patients with varying responses to ESAs and varying baseline levels of BFU-Es.
Fifteen of the MDS patients had a significantly lower number of baseline BFU-Es than controls (P=0.005), but 5 MDS patients had a mean number of BFU-Es that was comparable to controls (P=0.429). There was no significant difference in WHO classification or CD95 expression between the 2 groups of MDS patients (P=0.612).
However, 11 of the 15 patients with low erythropoiesis had received an ESA, and all of them were resistant to this treatment. In all, 15 of the MDS patients had received an ESA, and 14 were resistant to it (6 primary and 8 secondary).
The researchers found that APG101 induced a dose-dependent increase of BFU-Es in samples from the 15 MDS patients with low erythropoiesis but not in samples from the 5 patients with normal erythropoiesis or in the control samples (P<0.001).
The team said that a low BFU-E number at baseline was significantly associated with in vitro response to APG101 among the 20 MDS patients (P=0.031) and the 14 ESA-resistant patients (P=0.027).
Further investigation confirmed that a low clonogenic progenitor number at baseline, but not the level of CD95 or CD95 ligand expression, was predictive of the response to APG101.
“This study provides a rationale for further clinical investigation of this potential new therapeutic option in patients with severely impaired erythropoiesis who are resistant to erythropoiesis-stimulating agents,” Dr Fontenay said.
Apogenix has conducted a phase 1 trial of APG101 in transfusion-dependent patients with low- to intermediate-1-risk MDS. The company expects the results of this trial will be available in the coming months.
A line-up of new therapies and expanded combinations
Click on the PDF icon at the top of this introduction to read the full article.
Click on the PDF icon at the top of this introduction to read the full article.
Click on the PDF icon at the top of this introduction to read the full article.