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

Inclusion Criteria:

1. Participant with histologically confirmed diagnosis of prostate cancer, with one ofthe following:

2. Newly diagnosed androgen-sensitive locally advanced or metastatic disease; or

3. Localized disease not suitable for local primary intervention with curativeintent.

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

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

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

7. Life expectancy of at least 6 months.

8. 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. Participant requires combination with androgen deprivation therapy with theexception of enzalutamide.

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]