AAML1831: A Phase III Trial Comparing Standard Induction Therapy With CPX-351 in De Novo Pediatric AML: A Report From...

The Children's Oncology Group phase III clinical trial AAML1831 (ClinicalTrials.gov identifier: NCT04293562) evaluated liposomal daunorubicin and cytarabine (CPX-351) versus standard daunorubicin/cytarabine (DA) induction therapy in children and young adults with newly diagnosed AML. We hypothesized that CPX-351 given during induction 1 and 2 would improve outcomes compared with DA.

Patients (21 years and younger) were randomly assigned to two cycles of DA induction (arm A = DA) or CPX-351 (arm B = CPX-351). All patients also received gemtuzumab ozogamicin in induction 1. Postinduction chemotherapy was according to risk assignment made at the end of induction 1 (EOI1). Those with high-risk (HR) AML received consolidation with allogeneic hematopoietic stem-cell transplantation (HSCT), whereas low-risk (LR) patients received chemotherapy alone. Protocol-specified interim analysis monitored efficacy and futility of CPX-351 induction with respect to the primary end point, event-free survival (EFS) from study entry. Disease-free survival (DFS) was calculated to determine the impact of EOI1 risk assignment.

Seven hundred twenty-one eligible patients with FLT3 wild-type AML were randomly assigned to DA (n = 358) or CPX-351 (n = 363). Interim analysis determined that the futility monitoring rule was crossed because of inferior EFS in the CPX-351 arm and the random assignment was stopped. The two-year EFS from study entry was 62.2% for DA versus 51.2% for CPX-351 (P = .011). DFS for patients with HR AML was comparable for both arms. However, DFS was significantly lower and cumulative incidence of relapse (CIR) was higher for LR patients assigned to CPX-351 versus DA (2-year DFS from EOI1: DA: 73.8% v CPX-351 57.5% [P = .001]; 2-year CIR Arm DA: 23.6% v CPX-351: 39.9% [P = .001]).

CPX-351 was inferior to DA induction in the AAML1831 trial with differential EFS largely driven by events in LR patients.