Randomized phase 2 study to assess the role of single-agent nivolumab to maintain remission in acute myeloid leukemia.

We conducted a multicenter, open-label, randomized phase 2 study to assess the efficacy of nivolumab (Nivo) as maintenance therapy for patients with acute myeloid leukemia (AML) in first complete remission (CR) or CR with incomplete hematologic recovery who were not candidates for stem cell transplant. Patients were stratified and randomized to observation (Obs) or Nivo (3 mg/kg IV every 2 weeks for 46 doses). The primary end point was progression-free survival (PFS) defined as time to disease relapse or death due to any reason. Secondary end points included overall survival (OS), and evaluation of adverse events (AEs) after Nivo administration. Eighty patients were enrolled with median duration of follow-up of 24 months (33 months among survivors). PFS was 13.2 months in the Nivo arm and 10.9 months in the Obs arm. Overall PFS curves were not statistically significantly different. The median OS was 53.9 months in the Nivo arm and 30.9 months in the Obs arm. There were more AEs of any type (regardless of attribution) on the Nivo arm; 27 patients (71%) on the Nivo arm had a grade ≥3 AE compared with 5 patients (12%) on the Obs arm (P < .001). Nivo maintenance after AML chemotherapy failed to improve the PFS and OS in this randomized phase 2 study. There were increased AEs and serious AEs (SAEs) with Nivo, but these AEs and SAEs were expected and manageable. This trial was registered at www.ClinicalTrials.gov as #NCT02275533.