A Phase 1, Open-label, Dose Escalation Clinical Trial to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of ARV-110 in Patients With Metastatic Castration-resistant Prostate Cancer Who Have Progressed on at Least Two Prior Systemic Therapies.

Primary Outcome Measures  :

1. Incidence of Dose Limiting Toxicities of ARV-110 [ Time Frame: 28 Days ]First Cycle Dose limiting toxicities characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), timing, seriousness, and relationship to study drug
   
2. Number of Patients with Adverse Events as a measure of safety and tolerability of ARV-110 [ Time Frame: 28 Days ]Adverse events as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), timing, seriousness, and relationship to study drug.
   
3. Incidence of laboratory abnormalities as a measure of safety and tolerability of ARV-110 [ Time Frame: 28 Days ]Laboratory abnormalities as characterized by type, frequency, severity (as graded by NCI CTCAE version 5.0), and timing.
   

Inclusion Criteria:

• Patients must be male and at least 18 years of age at the time of signing the informed consent.
• Patients must present with histological, pathological, or cytological confirmed diagnosis of advanced or metastatic castration resistant adenocarcinoma of the prostate.
• Patients must have progressed on at least 2 prior approved systemic therapies for CRPC (at least one must be abiraterone or enzalutamide).
• Patients with progressive mCRPC
• Patients must have ongoing ADT with a gonadotropin releasing hormone analog or inhibitor, or orchiectomy (surgical or medical castration).

Exclusion Criteria:

• Patients with known symptomatic brain metastases requiring steroids (above physiologic replacement doses)
• Major surgery (as defined by the Investigator) within 4 weeks of first dose of study drug.
• Radiation therapy within 4 weeks of first dose of study drug or prior irradiation to >25% of the bone marrow. Palliative radiation for the alleviation of pain due to bone metastasis will be allowed during the study
• Systemic anti cancer therapy within 2 weeks of first dose of study drug (6 weeks for bicalutamide, mitomycin C, or nitrosoureas and 4 weeks for abiraterone). Patients are ineligible if they received any other type of anti cancer agent (except agents to maintain castrate status) within 2 weeks before first dose of study drug.