The inclusion criteria:
* Age: ≥18 years old.
* Ability to understand and provide informed consent: Participants must be able to understand the study and provide written informed consent fulfilling all relevant Institutional Review Board (IRB) or Independent Ethics Committee (IEC) guidelines.
* Histologically confirmed prostate adenocarcinoma: A diagnosis confirmed through a pathology report or a clinical course consistent with the disease, as determined by a local pathologist, if a pathology specimen is unavailable.
* ECOG performance status: 0 or 1 (fully active or restricted in strenuous activity but ambulatory).
* Life expectancy: \>5 years.
* Germline testing: Must have germline testing completed at the time of initial diagnosis and, if applicable, at recurrence.
* No evidence of distant metastasis: No evidence of soft tissue disease metastasis (visceral or lymph nodes) on CT/MRI scan.
* No active or organ-threatening autoimmune disease: Participants must not have an active or organ-threatening autoimmune disease.
* High-risk or very high-risk prostate cancer: Based on 2024 NCCN guidelines: PSA \>20 ng/mL or Gleason Grade Group ≥4 or ≥cT3a.
* Adequate hematologic and organ function: Defined by specific laboratory values (ANC, lymphocyte count, platelet count, hemoglobin, INR/aPTT, AST, ALT, alkaline phosphatase) obtained within 14 days prior to baseline, with specific exceptions stated in the protocol for participants with liver or bone metastases or those with known Gilbert disease.
* Ability to attend study visits and return for adequate follow-up.
* Agreement to practice effective contraception: Non-sterile males must agree to use effective contraception (condom, vasectomy, or other barrier methods) for up to 7 months after treatment.
Exclusion Criteria:
* Prior treatment for prostate cancer: Participants who have undergone any prior surgical, cryotherapy, or high-intensity focused ultrasound treatment for prostate cancer are excluded.
* Prior hormonal therapy: Prior orchiectomy or hormonal therapy (GnRH agonists, NSAA) is an exclusion criterion.
* Prior treatment with androgen receptor (AR) inhibitors: Prior treatment with first-generation (bicalutamide, flutamide, nilutamide, cyproterone acetate) or second-generation (enzalutamide, apalutamide, or darolutamide) AR inhibitors is an exclusion criterion.
* Organ transplantation: Receipt of any organ transplantation (excluding those not requiring immunosuppression, such as corneal or hair transplants) excludes participants from the study.
* Chronic systemic corticosteroid use: Chronic administration (\>14 days) of systemic corticosteroids within 28 days of study treatment initiation excludes participants. However, minimal systemic absorption (inhaled steroids, nasal sprays, topical agents) is permitted.
* Active autoimmune disease: Active autoimmune diseases (Addison's disease, Hashimoto's thyroiditis, systemic lupus erythematosus, Sjögren syndrome, scleroderma, myasthenia gravis, Goodpasture syndrome, or active Grave's disease) exclude participants. However, a history of autoimmunity that did not require systemic immunosuppression and did not threaten vital organ function is permitted.
* Use of medications affecting PSA: Use of medications known to alter PSA levels (5-alpha reductase inhibitors, phytoestrogens, saw palmetto) within 28 days before study treatment initiation excludes participants.
* Major surgery: Major surgery within 28 days of study treatment initiation excludes participants.
* Systemic therapy: Systemic therapy (including any investigational therapy) within 28 days of study treatment initiation is an exclusion criterion.
* Allergic reactions: A history of allergic reactions to compounds with similar chemical or biologic composition to the study drugs excludes participants.
* Clinically significant cardiovascular/cerebrovascular disease: This includes cerebral vascular accident/stroke, myocardial infarction, or unstable angina, congestive heart failure, or uncontrolled hypertension within specific timeframes before study enrollment.
* Serious intercurrent medical illness: Any serious intercurrent medical illness that could interfere with treatment participation.
* Active infections: Active HIV, hepatitis B (positive HBsAg), or hepatitis C infections exclude participation.
* Live attenuated vaccine administration: Administration of a live, attenuated vaccine within 3 weeks prior to study entry or anticipated during the study.
* Inability or unwillingness to comply: Participants assessed by the investigator as unable or unwilling to comply with the study requirements are excluded.
