A Phase II Trial of an Extended-Release siRNA Implant Targeting KRAS^G12D/V in Locally Advanced Pancreatic Cancer

Purpose: Locally advanced pancreatic cancer (LAPC) accounts for 30% of pancreatic cancers. We assessed the efficacy and safety of a novel extended-release siRNA targeting KRAS^G12D/V mutations (siG12D-LODER) combined with chemotherapy in LAPC. Patients and Methods: This two-cohort, phase II multicenter, open-label study (NCT01676259) evaluated siG12D-LODER with chemotherapy in patients with LAPC, regardless of KRAS status. In cohort 1, patients were randomized to siG12D-LODER plus gemcitabine/nab-paclitaxel (arm 1) or gemcitabine/nab-paclitaxel alone (arm 2). In cohort 2, patients with LAPC or borderline resectable disease received siG12D-LODER plus standard chemotherapy (modified FOLFIRINOX or gemcitabine/nab-paclitaxel) in a single-arm, nonrandomized design. Primary endpoints were overall survival (OS) for cohort 1 and objective response rate (ORR) for cohort 2. Secondary endpoints included progression-free survival, duration of response, OS (cohort 2), and ORR (cohort 1). Results: Across two cohorts, 59 patients were enrolled. In cohort 1, the median OS in the modified intent-to-treat (mITT) population unselected for KRAS status was 22.7 months for siG12D-LODER + gemcitabine/nab-paclitaxel versus 21.9 months for chemotherapy alone (P > 0.05). Among patients with KRAS^G12D/V mutations, OS was 22.7 versus 13.5 months [HR, 0.59; 95% confidence interval (CI), 0.18–1.96; P = 0.39]. In cohort 2, ORR was 31.6% (95% CI, 0.13–0.57) in the mITT (unselected for KRAS); in the G12D/V subgroup, ORR was 57.1%, similar to 63.6% in cohort 1. Treatment-emergent adverse events were mainly procedure related, including grade 1/2 gastrointestinal events and higher infection rates in the intervention arm. Conclusions: siG12D-LODER plus chemotherapy is safe, tolerable, and warrants further investigation in KRAS^G12D/V-mutant LAPC.