A Phase 1, Open-Label, Multicenter, First-In-Human Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Preliminary Efficacy of APR-1051 in Patients with Advanced Solid Tumors.

Inclusion Criteria: - Age ≥ 18 years - Diagnosis of advanced/metastatic solid tumor - Measurable or evaluable disease per RECIST version 1.1 (radiographic disease progression per PCWG3 criteria for patients with mCRPC) - Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1 or Karnofsky Performance Status (KPS) ≥ 70% - Patients must have recovered to Grade 1 or baseline levels from toxicity or adverse events related to prior treatment for their cancer, excluding Grade ≤ 2 neuropathy, alopecia, or skin pigmentation - Adequate bone marrow and organ function - Women of child-bearing potential (WOCBP) or men of child-fathering potential must agree to use adequate contraception prior to study entry Exclusion Criteria: - Patient has had prior systemic anti-cancer therapy (cytotoxic chemotherapy, immunotherapy, targeted therapy) within 3 weeks (6 weeks in cases of mitomycin C, nitrosourea, lomustine) or at least 5 half-lives (whichever is shorter, but no less than 2 weeks) prior to Day 1 - Prior radiation therapy at the target lesion unless there is evidence of disease progression. If patient has had prior radiation therapy for disease progression, see Exclusion Criterion 1 for allowed interval between radiotherapy and Day 1 and recovery of AEs - Treatment with any investigational agent administered within 30 days or 5 half-lives, whichever is shorter, before the first dose of APR-1051 - Major surgery within 21 days prior to Day 1 - Concomitant treatment with other anti-cancer therapy, including chemotherapy, immunotherapy, biological therapy, radiation therapy (except palliative local radiation therapy), or other novel anti-cancer agents. Note: endocrine therapy for breast and prostate cancer is allowed along with agents to treat or prevent skeletal related events (zoledronic acid, pamidronate, denosumab) - Subjects with active (uncontrolled, metastatic) second malignancies or requiring therapy