Statistical analysis
EVENT
In the Phase Ib escalation, 9–12 patients were planned to be assessed, assuming that two cohorts were needed to determine the MTD, 3–6 patients per cohort. In the Phase Ib expansion, a 30% PSA response rate was assumed [PFS and OS were assessed based on the Kaplan–Meier method. Point estimates, together with confidence intervals (CIs; based on Greenwood’s method) were provided for median time to event and quartiles. An estimation of the effect of xentuzumab plus enzalutamide on PFS compared with enzalutamide alone was given by the hazard ratio (HR) and its 95% CIs using a Cox proportional hazards model (HR <1 favoured treatment with xentuzumab plus enzalutamide) and an exploratory 