Statistical analysis
toxicity
METASTATIC CASTRATION-RESISTANT PROSTATE CANCER, METASTASES
In part A, six patients were enrolled per schedule to obtain sufficient safety data to determine the recommended phase 2 schedule, without an a-priori assumption of the optimal schedule. In part B, using a historical control objective response rate with pembrolizumab monotherapy in metastatic castration-resistant prostate cancer of 10%, and an alternative hypothesis whereby objective response rate would be 40%, we calculated that a sample size of 25 patients would provide 93% power to detect a difference of this magnitude in response rate with a two-sided level of significance of 0·05.All patients who received at least one dose of protocol therapy (ie, one dose of pembrolizumab or A prespecified interim safety analysis was performed in part B after the enrolment of six patients; study accrual proceeded since the dose-limiting toxicity rate of 33% was not exceeded.The association between maximal percentage change in measurable soft tissue lesions and uptake on baseline PSMA PET was performed by fitting a linear mixed model with repeated measures (We did post-hoc analyses to determine PSA90 response rate in the overall cohort and in part B, the PSA50 response rate; ORR in patients with visceral metastases and with soft tissue lesions with low or no expression of PSMA; PSA50 response rate on post-progression treatment with All statistical analyses were done using R (version 4.3.1). The study is registered with 