An Open-label Study of JSB462 (Luxdegalutamide) in Combination With Abiraterone in Adult Male Patients With Metastatic Hormone-sensitive Prostate Cancer (mHSPC)

This Phase II study aims to evaluate efficacy and safety of the combination of JSB462 (also known as luxdegalutamide) at 100 mg and 300 mg once a day (QD) doses + abiraterone compared with an androgen receptor pathway inhibitor (ARPI, abiraterone or enzalutamide) in participants with metastatic Hormone Sensitive Prostate Cancer (mHSPC) and to select the recommended dose of the combination for phase III. Towards that end, the totality of the efficacy, safety, tolerability and PK data from participants randomized in the study will be evaluated

The study for each participant consists of a Screening period (28 days), a treatment period, a post-treatment safety follow-up (30 days) followed by a long-term follow-up period. During the treatment period: * JSB462 is administered from randomization, orally, daily and continuously (100 mg or 300 mg QD) until disease progression per PCWG3-modified RECIST 1.1 as assessed by the investigator, the occurrence of unacceptable toxicities, death, participant decision or investigator decision. * Abiraterone 1000 mg or enzalutamide 160 mg are administered from randomization, orally, daily, and continuously until disease progression per PCWG3-modified RECIST 1.1 as assessed by the investigator, the occurrence of unacceptable toxicities, death, participant decision or investigator decision. During the post-treatment follow up period: * Safety follow-Up: After discontinuation of study treatment, all participants will be followed for at least 1 safety follow-up visit (30 days \[+/- 7 days\] after treatment discontinuation). Subsequent lines of therapy may be administered according to investigator's discretion after treatment discontinuation. * Long-term follow-up: Starts after the Safety follow-up period and lasts until the end of study. Safety, efficacy and survival information may be collected from participants during this period.