BilT03: Phase 1b/2 multicenter trial of nivolumab with 5-fluorouracil and liposomal irinotecan for previously treated advanced biliary tract cancer.

Background: Second-line chemotherapy with 5-fluorouracil/leucovorin (5FULV) and liposomal irinotecan improves survival in advanced biliary tract cancer (BTC). In this phase 1b/2 trial, we investigated the combination of 5FULV and liposomal irinotecan with nivolumab following progression on first-line chemotherapy for advanced BTC.

Methods: Patients received 2,400 mg/m 5-fluorouracil, leucovorin (dose level: 0:400 or -1:200 mg/m), 70 mg/m liposomal irinotecan, and 240 mg nivolumab every 2 weeks (ClinicalTrials.gov: NCT03785873). The phase 1b and 2 primary objectives included recommended phase 2 dose (RP2D) and median progression-free survival (PFS; null and alternative hypotheses of 2.9 and 5.0 months) with a two-sided alpha of 0.05 and >80% power. Secondary objectives were safety, objective response rate (ORR), and overall survival (OS).

Findings: Of 30 patients with a median age of 63.5 years, 18 (60%) were men, 25 (83%) were White, 16 (53%) had an ECOG performance status of 0, and 19 (63.3%) had intrahepatic cholangiocarcinoma. In phase 1b, the RP2D was dose level 0 after a dose-limiting toxicity event of enterocolitis (n = 1). Median PFS was 4.1 months (95% confidence interval [CI], 1.9-9.9). The ORR was 16.7% (5 partial responses) per irRECIST, the median OS was 7.4 months (95% CI, 5.7-15.9), and the 24-month survival rate was 23.3%. The most common grade ≥3 treatment-related adverse events were diarrhea (5; 16.7%), fatigue (4; 13.3%), and neutropenia (3; 10%).

Conclusions: Treatment was well tolerated, but the primary endpoint was not met. The median OS was similar to prior trials with this drug combination, but the 24-month survival rate was higher than expected.

Funding: This work was funded by Ipsen Biopharmaceuticals, Bristol-Myers Squibb (CA209-8LF), and the University of Michigan Rogel Cancer Center (P30CA046592).