MTD determination
Nine patients were evaluable for MTD (one was not evaluable due to missing >3 consecutive doses of enzalutamide in cycle 1). There were no DLTs in either dose cohort in cycle 1. Based on the definition of the MTD as the dose level at which ≤1 DLT was observed in six patients during cycle 1, Xe1000 + En160 was defined as the MTD and the RP2D.