Background: Preclinical models showed that blocking PD-1/PD-L1 pathways enhanced anti-leukemic responses. Azacitidine up-regulates PD-1 and interferon-gamma signaling. Methods: In this single arm trial, patients with relapsed/refractory (R/R) AML were treated with azacitidine 75mg/m2 Days 1–7 intravenously or subcutaneously with nivolumab 3mg/kg intravenously on Day 1 and 14, every 4–6 weeks. Findings: Seventy patients were treated. The median age was 70 years (range, 22–90). The median number of prior therapies received was 2 (range, 1–7). The overall response rate (ORR) was 33% including 15 (22%) complete remission (CR)/complete remission with insufficient recovery of counts (CRi), 1 partial response, and 7 patients with hematologic improvement (HI) maintained >6 months. Six patients (9%) had stable disease >6 months. The ORR was 58% and 22%, in HMA-naïve (n=25) and HMA pre-treated (n=45) patients, respectively. Grade 3–4 immune related adverse events occurred in 8 (11%) patients. Pretherapy bone marrow and peripheral blood CD3 and CD8 were significantly predictive for response on flow-cytometry. CTLA-4 was significantly up-regulated on CD4+Teff in non-responders after 2 and 4 doses of nivolumab. Interpretation: Azacitidine and nivolumab therapy produced an encouraging response rate and overall survival in patients with R/R AML, particularly in HMA-naïve and Salvage 1 patients. Pretherapy bone marrow aspirate and peripheral blood CD3 percentage may be biomarkers for patient selection. Trial Registration ID: Clinicaltrials.gov identifier: NCT02397720

The NCCN Guidelines for Acute Myeloid Leukemia (AML) provide recommendations for the diagnosis and treatment of adults with AML based on clinical trials that have led to significant improvements in treatment, or have yielded new information regarding factors with prognostic importance, and are intended to aid physicians with clinical decision-making. These NCCN Guidelines Insights focus on recent select updates to the NCCN Guidelines, including familial genetic alterations in AML, postinduction or postremission treatment strategies in low-risk acute promyelocytic leukemia or favorable-risk AML, principles surrounding the use of venetoclax-based therapies, and considerations for patients who prefer not to receive blood transfusions during treatment.

The OFAR regimen is highly active in RS and has activity in fludarabine-refractory patients with CLL. This regimen warrants further investigation in the treatment of these disorders.