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Venetoclax (Venclexta®)
The U.S. Food and Drug Administration (FDA) has granted accelerated approval to venetoclax (Venclexta®) for use in acute myeloid leukemia (AML).
The BCL-2 inhibitor is now approved for use in combination with azacitidine, decitabine, or low-dose cytarabine to treat adults with newly diagnosed AML who are age 75 and older or who are ineligible for intensive chemotherapy.
The FDA grants accelerated approval based on a surrogate or intermediate endpoint that is reasonably likely to predict clinical benefit.
Therefore, continued approval of venetoclax in AML may be contingent upon verification of clinical benefit in confirmatory trials.
The approval is based on data from two studies—the phase 1 b M14-358 trial (NCT02203773) and the phase 1/2 M14-387 trial (NCT02287233).
M14-358 trial
In M14-358, newly diagnosed AML patients received venetoclax in combination with azacitidine (n=84) or decitabine (n=31). There were 67 patients in the azacitidine arm and 13 in the decitabine arm who were 75 or older or were ineligible for intensive induction chemotherapy.
Patients received venetoclax via a daily ramp-up to a final dose of 400 mg once daily. They received prophylaxis for tumor lysis syndrome and were hospitalized for monitoring during the ramp-up.
They received azacitidine at 75 mg/m2 on days 1-7 of each 28-day cycle or decitabine at 20 mg/m2 on days 1-5 of each cycle. Patients continued treatment until disease progression or unacceptable toxicity.
The median follow-up was 7.9 months for the azacitidine arm and 11 months for the decitabine arm.
The complete response (CR) rate was 37% (25/67) in the azacitidine arm and 54% (7/13) in the decitabine arm. The rates of CR with partial hematologic recovery were 24% (16/67) and 7.7% (1/13), respectively.
The most common adverse events (AEs)—occurring in at least 30% of patients in both arms—were nausea, diarrhea, constipation, neutropenia, thrombocytopenia, hemorrhage, peripheral edema, vomiting, fatigue, febrile neutropenia, rash, and anemia.
The incidence of serious AEs was 75% overall. The most frequent serious AEs (occurring in at least 5% of patients) were febrile neutropenia, pneumonia (excluding fungal), sepsis (excluding fungal), respiratory failure, and multiple organ dysfunction syndrome.
The incidence of fatal AEs was 1.5% within 30 days of treatment initiation.
M14-387 trial
The M14-387 trial included 82 AML patients who received venetoclax plus low-dose cytarabine. Patients were newly diagnosed with AML, but some had previous exposure to a hypomethylating agent for an antecedent hematologic disorder.
There were 61 patients who were 75 or older or were ineligible for intensive induction chemotherapy.
Patients received venetoclax via daily ramp-up to a final dose of 600 mg once daily. They received prophylaxis for tumor lysis syndrome and were hospitalized for monitoring during the ramp-up.
Cytarabine was given at 20 mg/m2 on days 1-10 of each 28-day cycle. Patients continued to receive treatment until disease progression or unacceptable toxicity.
At a median follow-up of 6.5 months, the CR rate was 21% (13/61), and the rate of CR with partial hematologic recovery was 21% (13/61).
The most common AEs (occurring in at least 30% of patients) were nausea, thrombocytopenia, hemorrhage, febrile neutropenia, neutropenia, diarrhea, fatigue, constipation, and dyspnea.
The incidence of serious AEs was 95%. The most frequent serious AEs (occurring in at least 5% of patients) were febrile neutropenia, sepsis (excluding fungal), hemorrhage, pneumonia (excluding fungal), and device-related infection.
The incidence of fatal AEs was 4.9% within 30 days of treatment initiation.
Additional details from the M14-358 and M14-387 trials are available in the prescribing information for venetoclax.
Venetoclax is being developed by AbbVie and Roche. It is jointly commercialized by AbbVie and Genentech, a member of the Roche Group, in the United States and by AbbVie elsewhere.