A Dose Finding Study of Debio 4228 in Participants With Locally Advanced/Metastatic Prostate Cancer

Inclusion Criteria:

1. Participant with histologically confirmed locally advanced/metastatic prostatecancer

2. Participant judged by the Study Investigator to be candidate for continuous androgendeprivation therapy (ADT)

3. Baseline morning serum testosterone levels >150 ng/dL at screening visit

4. Eastern Cooperative Oncology Group (ECOG) performance status of 0-2

5. Life expectancy of at least 6 months

6. Adequate bone marrow, hepatic, and renal function at the screening visit

[Note: Other protocol and subprotocol-defined criteria apply]

Exclusion Criteria:

1. Previous ADT (neoadjuvant or adjuvant hormonal therapy) for ≥6 months duration and <6 months treatment-free interval before start of screening

2. Indication for androgen deprivation combination therapy

3. History of bilateral orchiectomy, adrenalectomy, or hypophysectomy

4. Received chemotherapy or cryotherapy within 8 weeks prior to the start of screeningfor the treatment of prostate cancer

5. Abnormal cardiovascular function or diabetes

6. Use of exogenous testosterone within 6 months before the start of screening

7. Major surgery within 4 weeks before the start of screening

8. Cancer disease within the last two years except for prostate cancer and some skincancers

[Note: Other protocol and subprotocol-defined criteria apply]