Efficacy and safety of a combination of sintilimab, bevacizumab plus gemcitabine, and albumin-bound paclitaxel for initially unresectable gallbladder carcinoma: A prospective, single-arm phase II study.

Abstract

489 Background: Immune checkpoint inhibitors plus chemotherapy had demonstrated important therapeutic advantages in biliary tract cancers (TOP-AZ and Keynote-966). At present the data of gallbladder carcinoma (GBC) is in blank condition almost, and the effectiveness remains to be improved. Further, the addition of bevacizumab to PD-1 inhibitors has improved the clinical results in carcinomas, such as hepatocellular carcinoma, for which therapeutic options have been limited. This study intended to explore the safety and efficacy of sintilimab combined bevacizumab with chemotherapy in the first-line treatment of initially unresectable GBC. Methods: The study was an ongoing open-label, single-arm, phase II trial (Clinical Trial ID: NCT05757336), which consisted of 2 parts: safety-run-in part, where pts received sintilimab (200mg/kg, iv, d1, Q3W) + bevacizumab (7.5mg/kg, iv, d1, Q3W) + gemcitabine (1000mg/m2, iv, d1, Q3W) and albumin-bound paclitaxel (125mg/m2, iv, d1, Q3W), followed by experimental part to evaluate the efficacy and safety of this strategy. The primary endpoint was safety and objective response rate (ORR) assessed by RECIST v1.1. Secondary objectives included disease control rate (DCR), progression free survival (PFS) and overall survival (OS). Results: No DLT was reported at safety-run-in part. Up to the end of Sept 2023, 15 patients were enrolled with a median age of 60.4 years (range 46-75), 26.7% were male. Median follow-up time was 3.68 months. All patients completed at least one tumor response evaluation, confirmed ORR was 60.0% and DCR was 93.3%. Median PFS and OS was not reached yet. Grade 3 TRAEs occurred in 40.0% of patients (n=6), and the most common TRAEs (incidence≥5%) among them were rash (20.0%), AST elevation (6.7%), fever (6.7%), platelet count decreased (6.7%), fatigue (6.7%), pneumonitis (6.7%). Conclusions: The combination of sintilimab, bevacizumab and AG chemotherapy was tolerable and showed a promising ORR in initially unresectable GBC patients. This regimen could be a feasible and safe option for initially unresectable GBC, but this needs further validation. Clinical trial information: NCT05757336 .