Gemox chemotherapy in combination with anti-PD1 antibody toripalimab and lenvatinib as first-line treatment for advanced intrahepatic cholangiocarcinoma: A phase 2 clinical trial.

4094 Background: The outcome of advanced intrahepatic cholangiocarcinoma (ICC) remains poor with current gemcitabine-based chemotherapy. This study is to evaluate the safety and efficacy of anti-PD1 agent toripalimab, lenvatinib in combination with oxaliplatin and gemcitabine (Gemox) chemotherapy. Methods: Locally advanced or metastatic ICC patients (pts) were given 240 mg toripalimab Q3W via intravenous (IV) infusion, 8 mg lenvatinib QD orally, and 1g/m² gemcitabine on Day 1 and Day 8, and 85 mg/m² oxaliplatin Q3W by IV for 6 cycles. The primary outcome was objective response rate (ORR), which was evaluated according to RECIST v1.1. Secondary outcomes included safety, progression-free survival (PFS) and overall survival (OS). Treatment would be terminated by confirmed disease progression, unacceptable toxicity, or voluntary withdrawal. Whole exome sequencing was performed on available tumor tissues and PD-L1 expression was determined by immunohistochemistry staining. Results: From May 2019 to Oct 2019, 30 pathologically-confirmed advanced ICC pts with a mean age of 56.5 (range, 25-73) years, including 11 women (37%), were enrolled at Zhongshan Hospital, Fudan University (one pt withdrawn). At the end of last follow-up (February 1, 2021), the ORR was 80% (24/30; 95% CI: 61.4%-92.3%), and disease control rate (DCR) was 93.3% (28/30; 95% CI:77.9%-99.2%). Median follow-up was 16.6 months. One pt achieved complete response (CR). Three pts with locally advanced disease were down-staged and then underwent resection. They remained disease-free survival at the end of last follow-up. 23 pts experienced disease progression and 12 pts (including one pt withdrawn) have died. The median PFS was 10.0 months and median duration of response (DOR) was 9.8 months. The median OS have not been reached. 12-months OS rate was 73.3% (95% CI: 57.5%-89.2%). No grade 5 adverse event (AE) was observed in present study. Grade 3 or 4 neutropenia and thrombocytopenia observed in 3 (10%) and 1 (3.3%) patient, respectively. Non-hematological toxic effects were jaundice (10 %), rash (6.7 %), proteinuria (6.7 %), increased AST level (3.3%), vomiting (3.3%), upper gastrointestinal hemorrhage (3.3%), sepsis (3.3%), gastrointestinal fistula (3.3%), adrenocortical insufficiency (3.3%), interstitial pneumonia (3.3%), and hyponatremia (3.3%). High ORR was significantly associated with positive PD-L1 expression ( p= 0.048) and DNA damage repair (DDR)-related mutations ( p= 0.022) in tumor samples. Conclusions: Gemox chemotherapy in combination with Anti-PD1 antibody Toripalimab and Lenvatinib provided remarkable efficacy with reasonable tolerability in advanced ICC patients. These findings warrant further validation in a large randomized clinical trial. Clinical trial information: NCT03951597.