Background: Immune checkpoint inhibitors, such as nivo, an anti−PD-1 antibody, have demonstrated antitumor activity in various cancers. Chemotherapy has demonstrated immune system activation via multiple mechanisms, providing a rationale for combination approaches. nab-P + Gem is a standard of care in PC which does not require immunosuppressive corticosteroids. Here we report interim results from 2 PC cohorts (Arms A and B) of a phase I study in patients (pts) receiving nivo + nab-P ± Gem for locally advanced or metastatic PC. Methods: This 2-part study was designed to identify dose-limiting toxicities (DLTs) of nivo + nab-P ± Gem in Part 1 and assess tolerability and efficacy in Part 2 dose expansion (+ Gem). Pts were DLT evaluable if they received ≥ 2 cycles of treatment and remained on study for 14 days after last dose or discontinued due to a DLT prior to completing 2 cycles. After Arm A, Part 1 was deemed safe, Arm B, Part 1 was initiated. In Arm A, pts with 1 prior chemotherapy regimen received nab-P 125 mg/m² on days 1, 8, and 15 of a 28-day cycle (qw 3/4) + nivo 3 mg/kg on days 1 and 15 of a 28-day cycle starting with cycle 1. In Arm B, treatment-naive pts received the same regimen in Arm A + Gem 1000 mg/m²qw 3/4. Results: As of June 28, 2016, 11 and 6 pts were treated in Arms A and B in Part 1, respectively. No DLTs were reported in Arm A, and 1 in Arm B (nonimmune hepatitis, suspected to be due to Gem; resolved and pt continued nivo + nab-P without Gem). The most common grade 3/4 teatment-emergent AEs were pulmonary embolism, neutropenia, and anemia in 2/11 pts (18%) in Arm A and anemia in 2/6 pts (33%) in Arm B. Nine patients discontinued due to progressive disease (8 in Arm A, 1 in Arm B). Best overall response is shown in the Table. Median treatment duration was 12.6 and 15.5 weeks for Arms A and B, respectively. Clinical trial information: NCT02309177Conclusions: These results indicate that adding nivo to nab-P ± Gem is feasible for pts with advanced PC, and antitumor activity of this regimen appears to be encouraging. Based on promising results from Part 1, Arm B, Part 2, is enrolling pts.

^a 2 pts unevaluable for response