Lower-intensity CPX-351 plus venetoclax induction for adults with newly diagnosed AML unfit for intensive chemotherapy

Preclinical data suggest a rationale for combining CPX-351, a dual-drug liposomal encapsulation of daunorubicin and cytarabine, with venetoclax, a B-cell lymphoma-2 inhibitor. This phase 1b study evaluated lower-intensity CPX-351 combined with venetoclax in adults with acute myeloid leukemia (AML) considered unfit/ineligible for intensive chemotherapy. In a dose-exploration phase using a 3+3 design, patients received stepwise dosing of CPX-351 IV on days 1 and 3 plus venetoclax 400 mg orally on days 2 to 21 per cycle to determine the recommended phase 2 dose (RP2D) for this combination. During the expansion phase, additional patients received CPX-351 plus venetoclax at the identified RP2D. The primary end points were the RP2D and safety of CPX-351 combined with venetoclax. Secondary end points included preliminary efficacy and pharmacokinetics. Overall, 35 patients were enrolled in the study. A RP2D of CPX-351 30 units/m2 (daunorubicin 13.2 mg/m2 and cytarabine 30 mg/m2) plus venetoclax 400 mg was established. The safety profile of the combination was consistent with the known safety profiles of CPX-351 and venetoclax. Complete remission (CR)/CR with incomplete hematologic recovery (CRi) was achieved by 17 of 35 patients (49%), all after cycle 1; of these, 14 were negative for measurable residual disease. CR was achieved by 1 of 8 patients (13%) with a mutation in TP53, and CR/CRi was achieved by 15 of 26 patients (58%) with wild-type TP53. This study highlights that lower-intensity therapy of CPX-351 plus venetoclax as induction therapy provides a well-tolerated treatment option in adults with AML deemed unfit for intensive chemotherapy. This trial was registered at www.ClinicalTrials.gov as #NCT04038437.