STATISTICAL CONSIDERATIONS 13.1 Study Design/Endpoints Sample size . The primary endpoint is ORR, defined as the proportion of subjects with PR or CR according to RECIST 1.1. Subjects who discontinue due to toxicity or clinical progression prior to post - baseline tumor assessments will be considered as non -responders. Subjects who discontinue for other reasons prior to their first dose of study drug will be replaced and not included in the primary J1790 / Version 7.0/ December 10, 2020 73 analysis . With a total of 30 evaluable subjects in each arm , the treatment will be considered successful if 5 or more subjects respond in a single arm . If the number of responses is 4 or less, the preliminary anti-tumor activity of the treatment will be rejected. The study is powered to assess each arm separately. The sample size is based on an A’Hern single - stage phase 2 design20. A sample size of 3 0 evaluable subjects per arm are required to decide whether the proportion responding is less than or equal to 0. 06 or greater than or equal to 0. 2221. If the number of responses is 5 or more, the hypothesis that P <= 0. 06 is rejected with a target error rate of 0.05 (alpha). If the number of responses is 4 or less, the hypothesis that P >= 0. 22 is rejected with a target error rate of 0.20 (power = 0.80).