162P - Efficacy and safety of GEMOX (Gemcitabine plus Oxaliplatin) plus Sintilimab and Bevacizumab as a conversion therapy in patients with initially unresectable biliary tract cancers (BTC): A single-arm, phase II study

Background

Gemcitabine-based chemotherapy and durvalumab plus GC are currently the standard regimens for advanced biliary tract cancers (BTC). Further, chemotherapy combined with PD-1 inhibitor and Bevacizumab improved the survival benefits in lung cancer. The effectiveness and safety of GEMOX plus Sintilimab and Bevacizumab in treating initially unresectable BTC are being evaluated in this study.

Methods

Treatment-naïve patients (pts) with histologically or cytologically confirmed unresectable BTC (T_anyN₁M₀) were enrolled. GEMOX (Gemcitabine 1000mg/m², iv, d1,8; Oxaliplatin 100mg/m², iv, d1) plus Sintilimab (200mg, iv, d1) and Bevacizumab (7.5mg/kg, iv, d1) were given every 3 weeks for 5 cycles. pts with partial response (PR) or complete response (CR) and eligible for R0 resection were referred for surgery. After treatment for 5 cycles, subsequent therapy was recommended by the investigator. Tumor response and resectability were assessed every 3 weeks according to RECIST v1.1. The primary endpoint was objective response rate (ORR), and secondary endpoints included surgical conversion, disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety.

Results

Between 08/2020 and 6/2022, 37 pts were enrolled with a median age of 63 years (range 36-78), 49% were male, and 76% had an ECOG PS of 1. Of them, 23 pts (62%) were ICC, 4 pts (11%) were ECC and 10 pts (27%) were GBC. All of the pts were diagnosed with stage III. At a median follow-up duration of 12.7 months (range 3.1-22.0), ORR was 49% in 37 evaluable patients and DCR was 86%. 1 pts achieved CR, and 17 pts achieved PR. 9 pts met the pre-designated criteria for surgery and 3 pts received surgery. Median PFS was 9.82 months (95% CI 5.19-NA), and median OS was 12.6 months (95% CI 9.5-13.9). Most treatment-related AEs (TRAEs) were Grade 1-2, and the incidence of grade 3-4 TRAEs was 35%. The most common TRAEs were asthenia (75%), peripheral neuropathy (46%), and nausea (35%).

Conclusions

Given the encouraging ORR and tolerable safety, the combination of GEMOX plus Sintilimab and Bevacizumab as a conversion therapy may be a new option for initially unresectable BTC.

Legal entity responsible for the study

Longrong Wang.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.