Study of RP-3500 (Camonsertib) With Niraparib or Olaparib in Advanced Solid Tumors

Inclusion Criteria:

* Male or female and ≥18 years-of-age at the time of signature of the informed consent
* Confirmed advanced solid tumors resistant or refractory to standard treatment
* Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1.
* Evaluable disease as per RECIST v1.1
* Next generation sequencing (NGS) report obtained in CLIA-certified or equivalent laboratory demonstrating eligible tumor biomarkers.
* Submission of available tumor tissue or willingness to have a biopsy performed if safe and feasible
* Acceptable hematologic and organ function at screening
* Negative pregnancy test for women of childbearing potential at Screening and prior to first study drug.
* Ability to swallow and retain oral medications.

Exclusion Criteria:

* Prior therapy with an ATR or DNA-dependent protein kinase (DNA-PK) inhibitor.
* Chemotherapy, small molecule anticancer or biologic anticancer therapy given within 10 days or 5 half-lives (whichever is longer), prior to first dose of study drug.
* Use of radiotherapy (except for palliative reasons) within 7 days prior to first dose of study drug.
* History or current condition, therapy, or laboratory abnormality that might confound the study results, or interfere with the patient's participation for the full duration of the study treatment.
* No other anticancer therapy is to be permitted while the patient is receiving study treatment.
* Major surgery ≤28 days or minor surgical procedures ≤7 days prior to first study treatment dose.
* Uncontrolled, symptomatic brain metastases.
* Uncontrolled high blood pressure
* History of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) diagnosis
* Presence of other known active invasive cancers.
* Pregnant or breastfeeding women.
* Psychological, familial, sociological, or geographical conditions that do not permit compliance with the study protocol and/or follow-up procedures outlined in the protocol.