A Study of PARP1 Selective Inhibitor, EIK1004 (IMP1707) in Participants With Advanced Solid Tumors.

• 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; Pancreatic cancer, must have prior 1L therapy * 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 EIK1004 (IMP1707) * Deleterious or suspected deleterious germline or somatic mutations of select HRR genes * Up to 1 prior line of PARP inhibitor containing treatment CNS Inclusion Criteria: * Untreated CNS metastases (measurable and/or non-measurable) not needing immediate local therapy. * Previously treated CNS metastases Key Exclusion Criteria: * Any investigational or approved anti-cancer therapies administered within 28 days/ before the first dose of EIK1004 (IMP1707) * Have received prior PARP1 selective inhibitors * Mean resting QTcF \> 470 ms or QTcF \< 340 ms * 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 CNS Exclusion Criteria * Any untreated brain lesions \> 2.0 cm in size. * Ongoing use of systemic corticosteroids for control of symptoms of CNS metastases \< 7 days prior to the first dose of study treatment or requirement for \> 10 mg prednisone/day. * Any brain lesion requiring immediate local therapy, including (but not limited to) a lesion in an anatomic site where an increase in size or possible treatment-related edema may pose risk to the participant (eg, brain stem lesions). * Known, symptomatic leptomeningeal disease. * Have poorly controlled seizures.