Parker, Susan

2510 Background: Blocking the interaction between programmed death-1 (PD-1), a co-inhibitory receptor expressed by activated T cells, and its ligand PD-L1 may enhance T-cell function. Here we describe the safety and activity from the first clinical study of BMS-936559 in patients (pts) with advanced solid tumors, further validating the importance of the PD-1/PD-L1 pathway as a target for cancer therapy. Methods: BMS-936559 was given Q2 wk IV in a 6-wk cycle at doses of 0.3−10.0 mg/kg during dose escalation and/or cohort expansion; pts could receive up to 16 cycles (48 doses). Results: As of August 1, 2011, 162 pts with melanoma (MEL, n=53), non-small-cell lung (NSCLC, n=50), colorectal (n=18), renal cell (RCC, n=17), ovarian (n=17), and pancreatic (n=7) cancer were treated. Median therapy duration was 11 wks (max 99 wks). Common related adverse events (rAEs; ≥5% pts) included fatigue, diarrhea, infusion reaction, arthralgia, rash, and pruritus. The incidence of grade 3-4 rAEs was 8.6%. AEs of special interest included hypothyroidism, hepatitis, sarcoidosis, endophthalmitis, and myasthenia gravis; there were no drug-related deaths. Clinical activity was observed in MEL, RCC, and NSCLC. Objective responses (ORs; RECIST 1.0) were observed in heavily pretreated pts. ORs were durable; among 16 pts with ORs, 7 had responses lasting ≥1 yr. Two other pts had ongoing ORs with durations of 2.3 and 8.5 mo at data lock. Several pts had prolonged stable disease. Some pts had a persistent reduction in overall tumor burden in the presence of new lesions but were not categorized as responders. In NSCLC, ORs were observed irrespective of histology. Conclusions: BMS-936559 was active and generally well tolerated in pts with NSCLC, RCC, and MEL. In conjunction with data from anti-PD-1/BMS-936558 trials, this study concurrently validates the importance of the PD-1/PD-L1 pathway for cancer immunotherapy and supports further clinical development of anti-PD-1/PD-L1 directed therapy. [Table: see text]