A phase II study of nivolumab in patients with advanced refractory biliary tract cancers (BTC).

Abstract

4097 Background: Biliary tract cancers (BTC) are often typically diagnosed at an advanced stage. There is no established second line option for patients with advanced BTC who have failed one prior systemic therapy. The phase II study evaluated safety and efficacy of nivolumab, anti PD-1 antibody in refractory BTC patients. Methods: Pts with histologically proven BTC who progressed on at least one line but no more than three lines of systemic therapy received nivolumab 240mg IV q2weeks for 16 weeks and then 480 mg IV every 4 weeks until disease progression or unacceptable toxicity. The primary endpoint of the study was objective response rate (ORR) by RECIST 1.1 every 8 weeks. The Simon two staged design was used to assess ORR.18 patients were accrued and if one response was seen, the plan was to accrue additional 34 patients. Secondary endpoints were PFS, OS and safety profile. Results: At data cutoff (Jan 14, 2018), 54 patients with BTC (female: 50%, Median age: 65 years) were enrolled. The primary sites of tumor were intrahepatic cholangiocarcinoma (63%) extrahepatic (11%), and gallbladder (26%). 30 pts (56%) failed 1 line of therapy and 24 (44%) failed more than one line of therapy. 45 pts (1 pt withdrew consent, 1pt just enrolled prior to data cutoff and 7 pts came off the study due to clinical progression) were evaluable for response rate. Out of 45 pts, 10 pts (22%) achieved PR (1 unconfirmed PR) and 17 pts (37.8%) achieved SD. DCR was 60%. All patients who responded were microsatellite stable. For evaluable 45 pts with median follow up of 13.34 months, median PFS was 3.98 months (95% CI: 2.33-5.98) and the median OS was 14.22 months (95% CI: 6.64-NA). 6 and 12month OS was 71.4 and 52.3% and 6 and 12 month PFS was 35.2% and 24.1% respectively. Most common treatment related AEs (TRAE) was alkaline phosphatase increased (24.5%). Grade III/IV TRAEs were seen in 11 pts (20.4%); most common were hyponatremia (3 pts) and elevated alkaline phosphatase (2 pts). No treatment related AEs led to discontinuation of the study drug. Tissue samples were collected in all pts with planned correlative studies underway including the PDL 1 status. Conclusions: Nivolumab was well tolerated and has shown promising efficacy in refractory BTC including durable responses lasting 2 years. Further randomized trial is warranted in refractory BTC. Clinical trial information: NCT02829918.