This study will evaluate the safety, tolerability, and preliminary efficacy of EIK1004 (IMP1707) in participants with recurrent advanced/metastatic breast cancer, ovarian cancer, metastatic castrate resistant prostate cancer (mCRPC) and pancreatic cancer with deleterious/suspected deleterious mutations of select homologous recombination repair (HRR) genes.

Condition or disease Intervention/treatment Phase Advanced Solid Tumors Drug: EIK1004 (IMP1707) Phase 1/Phase 2

This study will evaluate the safety, tolerability and preliminary efficacy of EIK1004 (IMP1707) as monotherapy in patients with recurrent, advanced/metastatic solid tumors. The study consists of 2 parts: Dose escalation and dose optimization.

In dose escalation (Part1), the study will identify the maximum tolerated dose (MTD) or maximum achievable dose (MAD) in solid tumor.

In dose optimization (Part 2), the study will further evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and anti-tumor activity of select doses of EIK1004 (IMP1707)

• 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.