A Study Evaluating the Safety, Pharmacokinetics, and Clinical Effects of Intravenously Administered PT-112 Injection in Subjects With Advanced Solid Tumors and Subsequent Dose Expansion Cohorts

Key Inclusion Criteria: * Male \>/= 18 years of age * Histologically or cytologically confirmed adenocarcinoma of the prostate. * Document current evidence of metastatic castration-resistant prostate cancer (mCRPC), where metastatic status is defined as having documented metastatic lesion(s) on either bone scan or CT/MRI scan. * Patients who have received at least three prior intended life-prolonging therapies for metastatic disease. * Eastern Collaborative Oncology Group (ECOG) Performance Status of 0-1. * Progressive disease, either measurable on physical examination or imaging by Response Evaluation Criteria in Solid Tumors (RECIST v1.1) or PCWG3 or by informative tumor marker(s). * Adequate organ function based on laboratory values. * If there is a known history of brain metastases, either treated or untreated, the disease must be stable. Key Exclusion Criteria: * Any cytotoxic chemotherapy within 21 days prior to initiation of study drug. * Any immunomodulatory drug therapy, anti-neoplastic hormonal therapy, immunosuppressive therapy, corticosteroids, or growth factor treatment within 14 days prior to initiation of study drug. * Bone marrow reserve which is not adequate for participation in this trial. * Radiotherapy within 14 days prior to baseline. * Fraction of radiotherapy to \>25 % of active bone marrow. * Major surgery within 28 days prior to initiation of study drug.