LAUSR

7026Background: Blocking PD-1/PD-L1 pathways enhances anti-leukemia responses in murine AML (Zhang et al, Blood 2009). PD-1 positive CD8 T-cells are increased in bone marrow (BM) of pts with AML (Daver et al, ASH 2016). AZA up-regulates PD-1 in AML (Yang et al., Leukemia 2013). Methods: Pts were eligible if they had AML and failed prior therapy, had adequate performance status (ECOG ≤ 2), and organ function. AZA 75mg/m2Days 1-7 with nivolumab 3mg/kg on Day 1 and 14 was established as the recommended phase II dose. Courses were repeated every 4-5 weeks indefinitely. Responses were evaluated at the end of 3 courses. Results: 53 pts with med age 68 years (range, 44 – 90), secondary AML (43%), poor risk cytogenetics (43%), med prior regimens 2 (range, 1-7) have been enrolled. Common mutations included DNMT3A (n = 11), TP53 (n = 11), TET2 (N = 8), CEBPA (n = 8), ASXL1(n = 8). All 53 pts are evaluable for response: 11 (21%) achieved CR/CRi and 7 (14%) had hematologic improvement (HI) for an overall response rat...