How much is reasonable to expect about overall survival (OS) benefit when designing studies with new drugs for patients affected by castration resistant prostate cancer (CRPC)? Meta-analysis of 23 randomized clinical trials (RCT) including 17,640 patients.

e16053 Background: Treatment decision making in patients affected by CRPC is difficult because the numerous available therapeutic opportunities can significantly affect OS. To demonstrate that comparing results in absence of head-to-head studies may lead to biased survival estimations, a literature-based meta-analysis was conducted. Methods: Hazard Ratios (HR) with 95% confidence intervals (CI) were extracted and cumulated according to a random-effect model from phase III trials. Sensitivity analyses were performed according to: 1) Treatment Strategy (TS, Chemotherapy versus Hormonal versus Immunotherapy versus Other), 2) Comparison (Chemotherapy versus Placebo versus Other), and 3) Disease setting with regard to treatment with Docetaxel (DOC),. Testing for heterogeneity was performed as well. Results: A significant heterogeneity for the 3 sensitivity analyses was found (p<0.0001). The cumulative HR in favor of (any) experimental arm was 0.91 (95% CI 0.84-0.99, p=0.028). We found a significant interaction...