Safety and clinical activity of oleclumab (o) 6 durvalumab (d) + chemotherapy (ct) in patients (pts) with metastatic pancreatic ductal adenocarcinoma (mpdac): a phase 1b/2 randomized study.

Abstract

Background: In a phase 1 study, the anti-CD73 monoclonal antibody (mAb) O plus the anti-PD-L1 mAb D showed antitumor activity and manageable safety in previously treated pts with advanced PDAC (Overman et al, J Clin Oncol 2018;36[suppl 15]:abs 4123). Here we report a multicenter, open-label study of O 6 D + CT in pts with mPDAC. Method(s): Pts were >=18 years old with ECOG PS 0-1. Part 1 was a dose escalation phase: in Cohort A, previously untreated (1L) pts received O 1500 or 3000 mg IV Q2W for 4 doses then Q4W + D 1500 mg IV Q4W, with Q4W gemcitabine and nab-paclitaxel (GnP). In Cohort B, pts with previous G-based CT (2L) received O 1500 or 3000 mg Q2W for 4 doses then Q4W + D 1500 mg Q4W, with Q4W mFOLFOX. The primary objective for Part 1 was safety and tolerability; secondary objectives included antitumor activity and pharmacokinetics (PK). Part 2 was an expansion phase in which pts were stratified by high/low tumoral CD73 expression by IHC. In Cohort A, 1L pts were randomized 1:1:1 to GnP alone (Arm A1), O + GnP (Arm A2) or O + D + GnP (Arm A3). O was given at the recommended phase 2 dose, 3000 mg. Cohort B did not proceed to dose expansion due to emerging therapies in 2L PDAC pts. The primary endpoint for Part 2 was investigator-assessed objective response rate (ORR) by RECIST v1.1; secondary included PFS, OS, safety, PK and antidrug antibody data. Result(s): As of November 11, 2022, 25 pts were treated in Part 1 (Cohort A, n=14; Cohort B, n=11), and 170 pts were treated in Part 2 (Arm A1, n=62; Arm A2, n=38; Arm A3, n=70). In Part 1, dose-limiting toxicities occurred in 1 pt (Cohort B, O 3000 mg: Gr 3 nausea and Gr 3 localized edema). Safety was generally similar in Parts 1 and 2. In Part 2, Gr >=3 treatment-emergent adverse events (TEAEs) occurred in 85.5%, 89.5% and 90.0% of pts in Arms A1, A2 and A3 respectively, most commonly neutropenia (22.6%, 34.2% and 17.1%). In Part 2, TEAEs led to discontinuation in 11.3%, 23.7% and 24.3% of pts respectively. In Part 2, ORR was similar across Arms with a trend toward longer PFS and OS in Arm 3 vs Arm 1. There was a trend toward greater clinical benefit in pts with high CD73 expression when comparing Arm A3 vs Arm A1. Conclusion(s): O + D + GnP had similar safety and a trend toward improved outcomes compared to GnP. (Table Presented).