ABSTRACT
PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) upregulates CD73, potentially contributing to immune surveillance evasion. Combining oleclumab (CD73 inhibitor) and durvalumab with chemotherapy may identify an effective treatment option. PATIENTS AND METHODS: Multicenter Phase 1b/2 randomized clinical trial in patients with metastatic PDAC, untreated (Cohort A) or previously received gemcitabine-based chemotherapy (Cohort B) (NCT03611556). During escalation, patients received oleclumab 1500 or 3000 mg, durvalumab 1500 mg, and gemcitabine plus nab-paclitaxel (GnP) (Cohort A; n=14) or modified FOLFOX (Cohort B; n=11). During expansion, Cohort A patients (n=170) were randomized to: GnP (Arm A1), oleclumab (recommended Phase 2 dose; RP2D) with GnP (Arm A2), or oleclumab (RP2D) with durvalumab plus GnP (Arm A3). Primary objectives were safety (escalation) and objective response rate (ORR) (expansion). Secondary objectives included progression-free survival (PFS) and overall survival (OS). RESULTS: During escalation, 1/11 patients from Cohort B (oleclumab 3000 mg) experienced two dose-limiting toxicities. Oleclumab RP2D was 3000 mg. During expansion, Grade ≥3 treatment-related adverse events occurred in 67.7% (42/62) of patients in A1, 73.7% (28/38) in A2, and 77.1% (54/70) in A3. ORR was 29.0%, 21.1%, and 32.9% in A1, A2, and A3, respectively (A1 vs A3; p=0.650). PFS (hazard ratio [HR]=0.72; 95% confidence interval [CI]: 0.47, 1.11) and OS (HR=0.75; 95% CI: 0.50, 1.13) were similar for A3 versus A1. Patients with high CD73 expression had improved PFS and OS in A3 versus A1, although this should be interpreted with caution. CONCLUSIONS: Although the safety profile was acceptable, this study did not meet its primary efficacy endpoint.