BCL-2 inhibitor shows potential for treating MM

The patients’ median age was 66 (range, 42-79), and they had received a median of 6 prior therapies (range, 1-13). Fifteen patients were bortezomib-refractory, 12 were refractory to lenalidomide, and 10 patients were refractory to both drugs.

After a 2-week lead-in period, patients received venetoclax daily on a 21-day cycle, ranging from 300 mg to 1200 mg on a 3+3 design. They also received prophylaxis for tumor lysis syndrome. Patients who progressed during treatment were allowed to receive dexamethasone as well and continue the study.

Twenty-three patients (79%) discontinued treatment, 18 due to disease progression, 4 due to AEs, and 1 due to patient decision.

The ORR was 7% (n=2). Both patients achieved a CR, and both were t(11;14)-positive. One of the patients is in the 600 mg cohort and is still responding to treatment. The duration of response, thus far, is 2.1 months.

The other patient with a CR is in the 900 mg dose cohort. This patient is still responding as well, and the response duration, thus far, is 2.8 months.

Common AEs—occurring in at least 20% of patients—were diarrhea (41%), nausea (41%),  fatigue (24%), vomiting (21%), asthenia (21%), and neutropenia (21%).

Grade 3/4 AEs—occurring in at least 10% of patients—were thrombocytopenia (24%), neutropenia (14%), and anemia (10%). Serious AEs—each occurring in 7% of patients—were pyrexia, malignant neoplasm progression, and cough.

Two patients had dose-limiting toxicities at the 600 mg dose of venetoclax. However, the researchers said the maximum tolerated dose was not reached, and the recommended phase 2 dose is 1200 mg.

*Information in the abstract differs from that presented at the meeting.