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Most patients with chronic myeloid leukemia (CML) have a normal life expectancy thanks to dramatic improvements in treatments and outcomes over the past few decades, but new treatment approaches are needed for the subset who fail to respond or who develop resistance to existing treatments, according to Jorge Cortes, MD, director of the Georgia Cancer Center, Augusta.
Several novel tyrosine kinase inhibitors (TKIs) and combination therapies show promise in early studies, he said at the Society of Hematologic Oncology virtual meeting.
Asciminib
The allosteric inhibitor asciminib (ABL-001), for example, has completed phase 1/2 trials evaluating its use as a single agent and in combination with other therapies in the first-line setting, and a pivotal phase 3 study comparing it with bosutinib in the third-line setting is underway, Dr. Cortes said.
The rate of major cytogenetic response (MCyr) to asciminib in heavily pretreated patients in a phase 1/2 study published the New England Journal of Medicine was “very good” at 77%.
“And almost half [48%] of the patients had a major molecular response by 12 months,” he said, noting that even after excluding those who had a prior response but were enrolled because they couldn’t tolerate prior treatments, the MCyr and major molecular response (MMR) rates were 60% and 36%, respectively.
Asciminib also showed activity in patients with T315I mutations: The MCyr rate was 55% and the MMR rate at 12 months was 24%.
“Now, it is important to recognize that the doses that are required for inhibition – for getting these responses in [patients with] T315I – are higher than we need for the patients that do not have T315I, so it needs higher concentrations in vitro and it needs higher doses in vivo,” he said.
Also of note, the response rates were good both in those with two or fewer prior lines of therapy and in those with three or more (12-month MMR rates were 47% and 34%, respectively). For the latter, that’s “a very good rate, even though we’re only talking about 12 months of therapy,” Dr. Cortes said.
“And even in the patients who had been resistant or intolerant to ponatinib, 40% achieved a major molecular response, so very good results regardless of the number or type of tyrosine kinase inhibitors the patient had received, ” he added. The numbers in the group with T315I mutations are small, so further exploration is needed in subsequent studies, he noted.
The emergence of resistance is a concern with asciminib, but in a xenograft model, combining it with nilotinib appeared to prevent resistance. Therefore, the combination of asciminib and various TKIs has been explored in the clinic.
In a phase 1 study of asciminib and imatinib presented by Dr. Cortes at the European Hematology Association meeting in 2019, the complete cytogenetic response and MMR rates at 48 weeks were 50% and 42%, respectively.
“Now, this is a different type of population – perhaps a little more heavily pretreated than the ones who received single-agent asciminib, but it does show the potential for synergy, and importantly it was not associated with increased toxicity,” he said.
PF-114
Another agent in development is PF-114, a third-generation BCR-ABL inhibitor. It is a structural analogue of ponatinib that is modified to avoid inhibiting the VEGFR receptor in an effort to prevent “arterial occlusive and particularly hypertension, adverse events that we see with ponatinib,” he said.
In a phase 1 study of 51 patients with CML who failed at least two prior TKIs or had T315I mutation, the MCyr rate was 50% and the MMR rate was 36%. The drug was very well tolerated: The dose-limiting toxicity was skin toxicity involving psoriasiform lesions, which were manageable, he noted.
“Importantly ... there was no cardiovascular toxicity,” he added.
Those findings were presented at ASH 2018. The drug is now moving to a phase 2 study.
HQP1351 (GZD824)
The orally active, small-molecule BCR-ABL inhibitor HQP1351 is a third-generation TKI with activity against a broad spectrum of BCR-ABL mutations.
A phase 1 study of patients who were resistant to prior TKIs is complete, and results presented at ASH 2019 showed that most patients (67%) had only one or two prior therapies and 63% had T315I mutation. Response rates were better in the patients with T315I mutations (MCyr, 78% vs. 34%; MMR, 52% vs. 15% in 101 chronic phase patients).
The treatment was well tolerated, with grade 3 toxicity involving only hypertriglyceridemia, pyrexia, and proteinuria. No arterial occlusive events were reported.
K0706
K0706 is a selective inhibitor of BCR-ABL1 designed to inhibit enzymatic activity of BCR-ABL. The agent was efficacious and well tolerated with limited off-target activity in preclinical models. It can inhibit wild-type and mutant forms of BCR-ABL, but does not have activity against T315I.
Results of a phase 1 study presented at ASH in 2019 by Dr. Cortes showed that all the patients who received a dose of 174 mg or greater achieved or maintained a cytogenetic response at 6 months, and 50% achieved or maintained an MMR.
“This is a very good response rate in this heavily pretreated population,” he said.
Patients who received prior ponatinib had a somewhat lower response, but still, nearly 45% achieved an MCyr.
“So very good response rates, no arterial occlusive events, and phase 2 studies will be starting at the dose of 174 mg,” he said.
Additional combinations
As for combining TKIs with other agents, efforts are underway around the world to find ways to eradicate minimal residual disease. Examples include TKIs and imatinib, TKIs and azacitidine, and asciminib plus another TKI, to name a few.
One study from Germany showed that adding interferon leads to earlier achievement of MMR, but ultimately the responses were similar, Dr. Cortes said.
Adding venetoclax has shown some activity in the preclinical setting, and studies of that combination will be starting soon in the clinic, he noted.
Implications
The current survival probability in CML patients is 92% when considering CML-related deaths (68% when considering all-cause mortality), compared with 8% in the 1980s and 35%-43% in the early 1990s.
But the current benefits don’t extend to all patients, Dr. Cortes said.
“There are patients who actually end up having worse prognosis than we would expect,” he said, explaining that some CML-related deaths are attributable to lack of access to therapy and good care, but some are related to true poor prognosis, often caused by resistance or inability to tolerate treatments.
In fact, data from studies of various treatments show that almost 40% of patients on dasatinib or nilotinib change therapy by 5 years, and by 10 years, half of those randomized to nilotinib have changed therapy.
“So it is not uncommon that patients have to change therapy for one reason or another,” he said, adding that, as resistance persists through additional treatment options, the prognosis worsens significantly.
“It is important that we have new therapeutic options to be able to help these patients who are going to be in need of additional therapies,” he said.
Dr. Cortes has received grant or research support from Novartis, Pfizer, Takeda, and Sun Pharma, and he is a paid consultant for Pfizer, Novartis, and Takeda.
Most patients with chronic myeloid leukemia (CML) have a normal life expectancy thanks to dramatic improvements in treatments and outcomes over the past few decades, but new treatment approaches are needed for the subset who fail to respond or who develop resistance to existing treatments, according to Jorge Cortes, MD, director of the Georgia Cancer Center, Augusta.
Several novel tyrosine kinase inhibitors (TKIs) and combination therapies show promise in early studies, he said at the Society of Hematologic Oncology virtual meeting.
Asciminib
The allosteric inhibitor asciminib (ABL-001), for example, has completed phase 1/2 trials evaluating its use as a single agent and in combination with other therapies in the first-line setting, and a pivotal phase 3 study comparing it with bosutinib in the third-line setting is underway, Dr. Cortes said.
The rate of major cytogenetic response (MCyr) to asciminib in heavily pretreated patients in a phase 1/2 study published the New England Journal of Medicine was “very good” at 77%.
“And almost half [48%] of the patients had a major molecular response by 12 months,” he said, noting that even after excluding those who had a prior response but were enrolled because they couldn’t tolerate prior treatments, the MCyr and major molecular response (MMR) rates were 60% and 36%, respectively.
Asciminib also showed activity in patients with T315I mutations: The MCyr rate was 55% and the MMR rate at 12 months was 24%.
“Now, it is important to recognize that the doses that are required for inhibition – for getting these responses in [patients with] T315I – are higher than we need for the patients that do not have T315I, so it needs higher concentrations in vitro and it needs higher doses in vivo,” he said.
Also of note, the response rates were good both in those with two or fewer prior lines of therapy and in those with three or more (12-month MMR rates were 47% and 34%, respectively). For the latter, that’s “a very good rate, even though we’re only talking about 12 months of therapy,” Dr. Cortes said.
“And even in the patients who had been resistant or intolerant to ponatinib, 40% achieved a major molecular response, so very good results regardless of the number or type of tyrosine kinase inhibitors the patient had received, ” he added. The numbers in the group with T315I mutations are small, so further exploration is needed in subsequent studies, he noted.
The emergence of resistance is a concern with asciminib, but in a xenograft model, combining it with nilotinib appeared to prevent resistance. Therefore, the combination of asciminib and various TKIs has been explored in the clinic.
In a phase 1 study of asciminib and imatinib presented by Dr. Cortes at the European Hematology Association meeting in 2019, the complete cytogenetic response and MMR rates at 48 weeks were 50% and 42%, respectively.
“Now, this is a different type of population – perhaps a little more heavily pretreated than the ones who received single-agent asciminib, but it does show the potential for synergy, and importantly it was not associated with increased toxicity,” he said.
PF-114
Another agent in development is PF-114, a third-generation BCR-ABL inhibitor. It is a structural analogue of ponatinib that is modified to avoid inhibiting the VEGFR receptor in an effort to prevent “arterial occlusive and particularly hypertension, adverse events that we see with ponatinib,” he said.
In a phase 1 study of 51 patients with CML who failed at least two prior TKIs or had T315I mutation, the MCyr rate was 50% and the MMR rate was 36%. The drug was very well tolerated: The dose-limiting toxicity was skin toxicity involving psoriasiform lesions, which were manageable, he noted.
“Importantly ... there was no cardiovascular toxicity,” he added.
Those findings were presented at ASH 2018. The drug is now moving to a phase 2 study.
HQP1351 (GZD824)
The orally active, small-molecule BCR-ABL inhibitor HQP1351 is a third-generation TKI with activity against a broad spectrum of BCR-ABL mutations.
A phase 1 study of patients who were resistant to prior TKIs is complete, and results presented at ASH 2019 showed that most patients (67%) had only one or two prior therapies and 63% had T315I mutation. Response rates were better in the patients with T315I mutations (MCyr, 78% vs. 34%; MMR, 52% vs. 15% in 101 chronic phase patients).
The treatment was well tolerated, with grade 3 toxicity involving only hypertriglyceridemia, pyrexia, and proteinuria. No arterial occlusive events were reported.
K0706
K0706 is a selective inhibitor of BCR-ABL1 designed to inhibit enzymatic activity of BCR-ABL. The agent was efficacious and well tolerated with limited off-target activity in preclinical models. It can inhibit wild-type and mutant forms of BCR-ABL, but does not have activity against T315I.
Results of a phase 1 study presented at ASH in 2019 by Dr. Cortes showed that all the patients who received a dose of 174 mg or greater achieved or maintained a cytogenetic response at 6 months, and 50% achieved or maintained an MMR.
“This is a very good response rate in this heavily pretreated population,” he said.
Patients who received prior ponatinib had a somewhat lower response, but still, nearly 45% achieved an MCyr.
“So very good response rates, no arterial occlusive events, and phase 2 studies will be starting at the dose of 174 mg,” he said.
Additional combinations
As for combining TKIs with other agents, efforts are underway around the world to find ways to eradicate minimal residual disease. Examples include TKIs and imatinib, TKIs and azacitidine, and asciminib plus another TKI, to name a few.
One study from Germany showed that adding interferon leads to earlier achievement of MMR, but ultimately the responses were similar, Dr. Cortes said.
Adding venetoclax has shown some activity in the preclinical setting, and studies of that combination will be starting soon in the clinic, he noted.
Implications
The current survival probability in CML patients is 92% when considering CML-related deaths (68% when considering all-cause mortality), compared with 8% in the 1980s and 35%-43% in the early 1990s.
But the current benefits don’t extend to all patients, Dr. Cortes said.
“There are patients who actually end up having worse prognosis than we would expect,” he said, explaining that some CML-related deaths are attributable to lack of access to therapy and good care, but some are related to true poor prognosis, often caused by resistance or inability to tolerate treatments.
In fact, data from studies of various treatments show that almost 40% of patients on dasatinib or nilotinib change therapy by 5 years, and by 10 years, half of those randomized to nilotinib have changed therapy.
“So it is not uncommon that patients have to change therapy for one reason or another,” he said, adding that, as resistance persists through additional treatment options, the prognosis worsens significantly.
“It is important that we have new therapeutic options to be able to help these patients who are going to be in need of additional therapies,” he said.
Dr. Cortes has received grant or research support from Novartis, Pfizer, Takeda, and Sun Pharma, and he is a paid consultant for Pfizer, Novartis, and Takeda.
Most patients with chronic myeloid leukemia (CML) have a normal life expectancy thanks to dramatic improvements in treatments and outcomes over the past few decades, but new treatment approaches are needed for the subset who fail to respond or who develop resistance to existing treatments, according to Jorge Cortes, MD, director of the Georgia Cancer Center, Augusta.
Several novel tyrosine kinase inhibitors (TKIs) and combination therapies show promise in early studies, he said at the Society of Hematologic Oncology virtual meeting.
Asciminib
The allosteric inhibitor asciminib (ABL-001), for example, has completed phase 1/2 trials evaluating its use as a single agent and in combination with other therapies in the first-line setting, and a pivotal phase 3 study comparing it with bosutinib in the third-line setting is underway, Dr. Cortes said.
The rate of major cytogenetic response (MCyr) to asciminib in heavily pretreated patients in a phase 1/2 study published the New England Journal of Medicine was “very good” at 77%.
“And almost half [48%] of the patients had a major molecular response by 12 months,” he said, noting that even after excluding those who had a prior response but were enrolled because they couldn’t tolerate prior treatments, the MCyr and major molecular response (MMR) rates were 60% and 36%, respectively.
Asciminib also showed activity in patients with T315I mutations: The MCyr rate was 55% and the MMR rate at 12 months was 24%.
“Now, it is important to recognize that the doses that are required for inhibition – for getting these responses in [patients with] T315I – are higher than we need for the patients that do not have T315I, so it needs higher concentrations in vitro and it needs higher doses in vivo,” he said.
Also of note, the response rates were good both in those with two or fewer prior lines of therapy and in those with three or more (12-month MMR rates were 47% and 34%, respectively). For the latter, that’s “a very good rate, even though we’re only talking about 12 months of therapy,” Dr. Cortes said.
“And even in the patients who had been resistant or intolerant to ponatinib, 40% achieved a major molecular response, so very good results regardless of the number or type of tyrosine kinase inhibitors the patient had received, ” he added. The numbers in the group with T315I mutations are small, so further exploration is needed in subsequent studies, he noted.
The emergence of resistance is a concern with asciminib, but in a xenograft model, combining it with nilotinib appeared to prevent resistance. Therefore, the combination of asciminib and various TKIs has been explored in the clinic.
In a phase 1 study of asciminib and imatinib presented by Dr. Cortes at the European Hematology Association meeting in 2019, the complete cytogenetic response and MMR rates at 48 weeks were 50% and 42%, respectively.
“Now, this is a different type of population – perhaps a little more heavily pretreated than the ones who received single-agent asciminib, but it does show the potential for synergy, and importantly it was not associated with increased toxicity,” he said.
PF-114
Another agent in development is PF-114, a third-generation BCR-ABL inhibitor. It is a structural analogue of ponatinib that is modified to avoid inhibiting the VEGFR receptor in an effort to prevent “arterial occlusive and particularly hypertension, adverse events that we see with ponatinib,” he said.
In a phase 1 study of 51 patients with CML who failed at least two prior TKIs or had T315I mutation, the MCyr rate was 50% and the MMR rate was 36%. The drug was very well tolerated: The dose-limiting toxicity was skin toxicity involving psoriasiform lesions, which were manageable, he noted.
“Importantly ... there was no cardiovascular toxicity,” he added.
Those findings were presented at ASH 2018. The drug is now moving to a phase 2 study.
HQP1351 (GZD824)
The orally active, small-molecule BCR-ABL inhibitor HQP1351 is a third-generation TKI with activity against a broad spectrum of BCR-ABL mutations.
A phase 1 study of patients who were resistant to prior TKIs is complete, and results presented at ASH 2019 showed that most patients (67%) had only one or two prior therapies and 63% had T315I mutation. Response rates were better in the patients with T315I mutations (MCyr, 78% vs. 34%; MMR, 52% vs. 15% in 101 chronic phase patients).
The treatment was well tolerated, with grade 3 toxicity involving only hypertriglyceridemia, pyrexia, and proteinuria. No arterial occlusive events were reported.
K0706
K0706 is a selective inhibitor of BCR-ABL1 designed to inhibit enzymatic activity of BCR-ABL. The agent was efficacious and well tolerated with limited off-target activity in preclinical models. It can inhibit wild-type and mutant forms of BCR-ABL, but does not have activity against T315I.
Results of a phase 1 study presented at ASH in 2019 by Dr. Cortes showed that all the patients who received a dose of 174 mg or greater achieved or maintained a cytogenetic response at 6 months, and 50% achieved or maintained an MMR.
“This is a very good response rate in this heavily pretreated population,” he said.
Patients who received prior ponatinib had a somewhat lower response, but still, nearly 45% achieved an MCyr.
“So very good response rates, no arterial occlusive events, and phase 2 studies will be starting at the dose of 174 mg,” he said.
Additional combinations
As for combining TKIs with other agents, efforts are underway around the world to find ways to eradicate minimal residual disease. Examples include TKIs and imatinib, TKIs and azacitidine, and asciminib plus another TKI, to name a few.
One study from Germany showed that adding interferon leads to earlier achievement of MMR, but ultimately the responses were similar, Dr. Cortes said.
Adding venetoclax has shown some activity in the preclinical setting, and studies of that combination will be starting soon in the clinic, he noted.
Implications
The current survival probability in CML patients is 92% when considering CML-related deaths (68% when considering all-cause mortality), compared with 8% in the 1980s and 35%-43% in the early 1990s.
But the current benefits don’t extend to all patients, Dr. Cortes said.
“There are patients who actually end up having worse prognosis than we would expect,” he said, explaining that some CML-related deaths are attributable to lack of access to therapy and good care, but some are related to true poor prognosis, often caused by resistance or inability to tolerate treatments.
In fact, data from studies of various treatments show that almost 40% of patients on dasatinib or nilotinib change therapy by 5 years, and by 10 years, half of those randomized to nilotinib have changed therapy.
“So it is not uncommon that patients have to change therapy for one reason or another,” he said, adding that, as resistance persists through additional treatment options, the prognosis worsens significantly.
“It is important that we have new therapeutic options to be able to help these patients who are going to be in need of additional therapies,” he said.
Dr. Cortes has received grant or research support from Novartis, Pfizer, Takeda, and Sun Pharma, and he is a paid consultant for Pfizer, Novartis, and Takeda.
FROM SOHO 2020