Nivolumab (Nivo) maintenance (maint) in high-risk (HR) acute myeloid leukemia (AML) patients.

7014 Background: Frontline AML induction produces 60-70% complete remission (CR) rates but relapse is a major source of failure. Beside stem cell transplant (SCT), few options exist for post-CR maint in HR pts. Prior maint studies of cytotoxics were unsuccessful. Post SCT immune surveillance via tumor-specific cytotoxic T-cells may be important in suppressing AML relapse. Immune checkpoint inhibitors may restore host immune surveillance in post-CR maint. Methods: This is a pilot phase II study of nivo maint in HR AML pts in CR, ineligible for SCT. Pts ≥ 18 yrs with a HR feature in 1st CR (CR1) or any pt in 2nd CR (CR2) who received induction 11 pts (79%) were in CR1, 2 pts (14%) in CR2, 5 pts had grade 3/4 immune-related events. 1 pt had thyroiditis, treated with steroids 1 pt with transaminitis responded to dose interruption; 2 pts had pneumonitis treated with steroids 1 pt cleared MRD & 1 pt normalized CG. Conclusions: Maint nivo is safe & feasible in HR AML. The study continues to surpass expected rate of 6-mo CRd of HR pts. Correlatives profiling the immune repertoire are being analyzed. Clinical trial information: NCT02532231.