DLT was defined as: Grade \>=3 hematologic parameters, Grade ≥ 3 neutropenia with infection, Grade 4 neutropenia lasting \> 5 days, Febrile neutropenia, Grade 3 thrombocytopenia with clinically significant bleeding, Grade 4 thrombocytopenia, any toxicity requiring dose interruption for \>=14 days; Grade \>=3 non-hematologic toxicities considered clinically significant and non-clinically significant Grade \>=3 toxicities requiring dose interruption for \>=10 days that determined by the investigator to be clinically relevant. Severity graded according to National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) version 5.0.

Dose limiting toxicities in first 4 weeks of the study combination treatment assessed to determine the dose of bavdegalutamide associated with acceptable safety and tolerability.

An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease (new or exacerbated) temporally associated with the use of study drug, whether or not considered related to the study drug. A serious adverse event (SAE) was an AE that resulted in any of the following outcomes: death; life threatening; persistent/significant disability/incapacity; initial or prolonged inpatient hospitalization; congenital anomaly/birth defect or was otherwise considered medically important. A TEAE is an AE occurring on/after the date of first dose of bavdegalutamide and on-study abiraterone and within 30 days of the last dose of bavdegalutamide and on-study abiraterone. TEAEs included both Serious TEAEs and non-serious TEAEs.