4082 Background: For patients with advanced BTC, standard chemotherapy has limited benefit and no molecular targeted agents have been approved. Pembrolizumab is an anti PD-1 immune checkpoint inhibitor which has shown modest activity for advanced BTC patients in prior single-arm phase I/II studies. Considering the heterogeneity of BTC, more data are needed to evaluate the clinical outcomes of pembrolizumab in unresectable or metastatic BTC. Methods: In this prospective cohort study, 39 patients with PD-L1 positive BTC who received pembrolizumab in Asan Medical Center, Seoul, Korea were included (ClinicalTrials.gov identifier, NCT03695952). PD-L1 expression was assessed using immunohistochemistry and PD-L1 positive tumors were defined as the expression of PD-L1 in ≥ 1% of tumor cells. Pembrolizumab was given at a fixed dose of 200 mg intravenously, every 3 weeks. Results: The median age was 61 years old (range, 41-76) and 22 (56.4%) patients were male. Intrahepatic cholangiocarcinoma (CCA) was the most common type (n = 18, 46.2%), followed by gallbladder cancer (n = 12, 30.8%) and extrahepatic CCA (n = 9, 23.1%). Most of the patients had distant metastasis (n = 37, 94.9%). Pembrolizumab was administered as 2nd-, 3rd- and 4th or greater line chemotherapy in 18 (46.2%), 16 (41.0%) and 5 (12.8%) patients, respectively, and median 2 cycles (range 1-10) of pembrolizumab were given. In 36 patients whose response was assessable, partial response (PR) and stable disease were achieved in 4 (11.1%) and 13 (36.1%), respectively. In 19 (52.8%) patients, progressive disease was the best response. In patients with PR, the median time to response was 2.1 months (95% confidence interval (CI), 0.4 – 3.9). With a median follow-up duration of 4.4 months (95% CI, 2.4 – 6.4), median progression-free survival and overall survival was 1.5 months (95% CI, 0.4 – 2.6) and 4.3 months (95% CI, 2.6 – 6.1), respectively. No grade 3/4 adverse events (AEs) were reported and grade 1/2 fatigue (n = 4, 10.3%) was the most common AE. Conclusions: In PD-L1 positive BTC, pembrolizumab showed modest efficacy with 11.1% of response rates although our patients were heavily pretreated. Considering the limited therapeutic options and poor survival for these patients, further evaluation of immunotherapy including biomarker analysis is needed.
Determining universal processes related to best outcome in emergency abdominal surgery: a multicentre, international, prospective cohort study
