Systematic literature review and meta-analysis of clinical outcomes for previously-treated patients with advanced biliary tract cancer.

e16143 Background: There is no standard chemotherapy available for previously treated, advanced (unresectable and/or metastatic) biliary tract cancer (BTC). This systematic literature review and meta-analysis were conducted to assess clinical outcomes of chemotherapies in this patient population. Methods: A systematic literature search was conducted through mid-2021 to identify relevant studies using Embase, MEDLINE, and Cochrane Central Register of Controlled trials (January 1, 2000–July 6, 2021) with additional searches of recent ASCO and ESMO conferences. Eligible study designs included randomized controlled trials, controlled clinical trials, and non-randomized clinical trials in patients (≥18 years age, Eastern Cooperative Oncology Group performance score 0 or 1) previously treated for advanced BTC and who had progressed on prior treatment (i.e., ≥2L). The outcomes of interest were objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). A meta-analysis among chemotherapies was performed to obtain a pooled estimate of the efficacy of standard treatments in BTC. The ORR meta-analysis was performed using the Freeman-Tukey double arcsine transformation. For time-to-event outcomes, published Kaplan-Meier curves for OS and PFS were digitized to create pseudo- individual patient data. A meta-analysis of the resulting pooled survival curves for OS and PFS were conducted following the methodology of Combescure et al. (2014). Results: In total, 39 unique studies were identified. Seventeen studies representing 22 unique therapy arms evaluating chemotherapies among 903 patients were included in the meta-analysis for ORR. The random effects pooled estimate for ORR was 6.6% (95% confidence interval [CI]: 4.1-9.7%). Median PFS (12 studies; 16 survival curves) was 3.1 months (95% CI: 2.5-3.8) with PFS rates at 6 and 12 months of 26.7% (95% CI: 19.8-36%) and 6.9% (95% CI: 4.1-11.7%), respectively. Median OS (15 studies; 19 survival curves) was 6.8 months (95% CI: 5.9-7.5) with OS rates at 6, 12, and 24 months of 55.3% (95% CI: 49.9-61.3%), 24.6% (95% CI: 20.0-30.2%), and 2.0% (95% CI: 1.1-3.8%), respectively. Conclusions: The limited efficacy of clinical outcomes for chemotherapies used in the treatment of advanced BTC suggest an opportunity to explore the potential clinical benefits of newer treatments (e.g., immunotherapies).