7.6.1. Analysis of Primary Efficacy Endpoint For each tumor-specific cohort, a Bayesian approach with non -informative Jeffreys prior beta distribution with parameters a = 0.5 and b = 0.5 will be used to estimate the ORR and its 95% credible interval based on the posterior distribution. At the time of analysis, within each tumor -specific cohort, the prior distribution will be updated with all available data to obtain the posterior distribution of the true ORR. The posterior probabilities that ORR exceeds TV and LRV will be reported for each cohort. A high posterior probability that ORR > LRV will support a “Go” decision to continue development in the cohort, and a low posterior probability that ORR > TV will su pport a “Stop” decision to halt development in the cohort. A “Consider” decision results if neither a Stop nor a Go decision can be made. The specific criteria for making a Stop, Consider, or Go decision within each tumor-specific cohort are derived using the following acceptable risks: • 10% false stop risk: maximum acceptable probability that ORR > TV given that a Stop decision is made. SELLAS Life Sciences Group Galinpepimut -S Protocol : SLS17 -201/ MK3475 -770 Protocol v1.1 (Amendment 1.0) 12 April 2019 Page 214 • 20% false go risk: maximum acceptable probability that ORR ≤ LRV given that a Go decision is made Before reaching the planned sample size in a cohort, the posterior probabilities will be updated continuously after each patient or group of patients and will be used to determine, within each cohort, the predictive probability of eventually reaching a Sto p decision at the planned sample size. If this predictive probability is ≥ 80%, then enrollment in that cohort may be stopped early for futility. Definitions of the decision boundaries can be found in Section 7.6.6. In general, Stop/Go and futility decision criteria are non -binding and may be regarded as guidance and information to be integrated with a full medical review of safety and efficacy data observed at the time of analysis in determining the next course of action. No tests of statistical significance are planned . Patients with missing ORR will be conservatively classified as non -responders for the primary analysis. 7.6.2. Analysis of Secondary Effica cy Endpoints Secondary endpoints will be summarized by cohort using descriptive statistics. No formal tests of hypotheses are planned. Duration of response (DOR) and TTR will be evaluated using Kaplan-Meier estimates and curves will be generated based on these estimate s. 7.6.3. Analyses of Exploratory Endpoint Analysis of exploratory endpoints will be defined in the study SAP. 7.6.4.