Phase II trial of CPX-351 in patients with acute myeloid leukemia at high risk for induction mortality

CPX-351 is a liposomal formulation of cytarabine/daunorubicin with a 5:1 fixed molar ratio. We investigated the safety and efficacy of escalating doses of CPX-351 in patients with acute myeloid leukemia (AML) at high risk of induction mortality with standard chemotherapy determined through assessment of leukemia and patient-related risk factors for intensive chemotherapy in an open-label, phase II trial. Patients were randomized to receive 50 or 75 units/m2 on days 1, 3, and 5. Once safety was established, a 100 units/m2 arm was opened. Fifty-six patients were enrolled, 16, 24, and 16 in the 50, 75, and 100 units/m2 arms, respectively. The composite complete remission rate (complete remission + complete remission with incomplete blood count recovery) was lowest with 50 units/m2 (19%) compared with 75 units/m2 (38%) and 100 units/m2 (44%) (P = 0.35). The 50 units/m2 arm had a median OS of 4.3 months, compared with 8.6 and 6.2 months for the 75 and 100 units/m2 respectively (P = 0.04). Nonhematologic grade 3/4 treatment-emergent adverse events included febrile neutropenia (34%), pneumonia (23%), and sepsis (16%). CPX-351 at 75 units/m2 has favorable safety and efficacy for AML patients at high risk of induction mortality with some tolerating the standard dose of 100 units/m2.