A phase I study to evaluate safety and antitumor activity of biweekly BMS-936558 (Anti-PD-1, MDX-1106/ONO-4538) in patients with RCC and other advanced refractory malignancies.

Abstract

331 Background: Programmed death-1 (PD-1), a T-cell inhibitory receptor, may suppress antitumor immunity. BMS-936558, a fully human PD-1 blocking antibody, has shown antitumor activity and manageable toxicity after biweekly dosing (Sznol, ASCO 2010, #2506). This report provides an update on safety and antitumor activity with special emphasis on RCC. Methods: An open-label phase I dose escalation study of BMS-936558 was conducted in patients (pts) with treatment refractory metastatic clear-cell renal cell carcinoma (RCC), castrate-resistant prostate cancer (CRPC), melanoma (MEL), non-small cell lung cancer, or colorectal cancer (CRC). Dose escalation continued to 10 mg/kg when an expansion cohort for pts (16) with each tumor type was opened for additional safety and efficacy information. Tumor response (RECIST) was evaluated every 8 weeks. Clinically stable pts with early PD could continue until further PD or clinical deterioration. Results: 126 pts (18 RCC) were treated with 1, 3, or 10 mg/kg. MTD was not reached. Across all doses, the most common AEs (Any/grade 3-4) were fatigue (45.2%/6.3%) and diarrhea (30.2%/0.8%) while the most common drug-related AEs (Any/grade 3-4) were fatigue (20.6%/0.8%), rash (11.9%/0%), pruritus (11.3%/0%), and diarrhea (10.3%/0.8%). There was no apparent relationship between dose and frequency of AEs. One pt died with sepsis while being treated for drug-related grade 4 pneumonitis. The median number of prior treatment regimens in the RCC cohort was 2 (range 1-6). Of the 18 RCC pts, 16 were treated with 10 mg/kg. The median duration of treatment was 7.6+mo. ORR was 5/16 (31.2%) and SD>4mo was 6/16 (37.5%). The median duration of response was 4.0+ mo (3.7-7.4+ mo). Of the 2 RCC pts treated with 1 mg/kg, 1 obtained a CR (12+ mo) and 1 had SD (21+ mo). For evaluable CRPC pts, 1/15 pts (6.7%) obtained a PR (2+ mo) and 3/15 (20%) had SD>4mo. Conclusions: BMS-936558 administered biweekly is tolerable and has encouraging antitumor activity in a previously treated patients with RCC. Data on baseline characteristics, long-term toxicity and response duration will be updated at the meeting. [Table: see text]