A First-in-human, Phase 1/2, Open-label, Multi-center, Dose-escalation, Dose-optimization, and Dose-expansion Study to Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Anti-tumor Activity of PARP1 Selective Inhibitor, IMP1734, as Monotherapy in Patients With Advanced Solid Tumors

Key Inclusion Criteria * Breast cancer; must have received at least one prior chemotherapy in neoadjuvant/adjuvant/metastatic setting, must have received hormonal therapy if HR+, * HGSOC or high grade endometrioid EOC, fallopian tube or primary peritoneal cancer; must have received at least one prior platinum-based chemotherapy for advanced disease * mCRPC with ongoing ADT, must have received NHA and up to 1 prior line of taxane chemotherapy * Age ≥ 18 years at the time of informed consent * Eastern Cooperative Oncology Group (ECOG) performance status ≤1 * Adequate organ function * Life expectancy ≥ 12 weeks * Should have evaluable disease as defined by RECIST1.1 and/or CA125 or PSA * Female subjects of childbearing potential and male subjects must agree to use an effective method of contraception from study entry up to 6 months after the last dose of IMP1734 * deleterious or suspected deleterious germline or somatic mutations of select HRR genes * up to 1 prior line of PARP inhibitor containing treatment Key Exclusion Criteria: * Any investigational or approved anti-cancer therapies administered within 28 days/ before the first dose of IMP1734 * Have received prior PARP1 selective inhibitors * Mean resting QTcF \> 470 ms or QTcF \< 340 ms * Active or untreated central nervous system (CNS) metastases and/or carcinomatous meningitis. * Infections \- An active hepatitis B/C infection * Any known predisposition to bleeding * Unable to swallow oral medications OR have malabsorption syndrome or any other uncontrolled gastrointestinal condition that might impair the bioavailability