Phase 1 Study of RBN-2397, an Oral PARP7 Inhibitor, in Patients With Solid Tumors

This is a first-in-human, Phase 1, multi-center, open-label, dose-escalation study to: * Evaluate the safety profile and MTD of RBN-2397 administered orally and establish the RBN-2397 dose(s) and schedule(s) recommended for further investigation in Phase 2 * Characterize the PK profile of RBN-2397 * Identify preliminary antitumor activity. * Biomarkers and their correlation with response to RBN-2397 and other outcomes will be examined. Cohorts will follow a traditional 3 + 3 design. After enrollment of the first participant within a cohort, there must be a wait period of at least 1 week before enrollment of additional participants in that cohort. This dose escalation phase of the study is complete. The study is currently in the Relative Bioavailability and Expansion Cohort(s) phase where approximately 20 participants each will be enrolled to further examine the safety, PK, pharmacodynamics, and antitumor activity of RBN-2397 at the recommended phase 2 dose. Relative Bioavailability Assessment: An evaluation of relative bioavailability of a micronized RBN-2397 tablet versus the standard RBN-2397 tablet (manufactured with unmicronized RBN-2397 and used in the dose escalation phase of the study) will be performed as part of the dose escalation phase. Micronized tablets will be used in the Dose Expansion Phase of the study after the relative bioavailability assessment has been completed. Dose Expansion Phase The recommended phase 2 dose will be investigated in the following cancer types: squamous cell carcinoma of the lung (SCCL), head and neck squamous cell carcinoma (HNSCC), hormone receptor positive (HR+) breast cancer, and PARP7 amplified cancer. Duration of treatment: It is anticipated that the minimum study involvement will be one cycle. Participants are eligible to have an indefinite number of additional cycles of treatment if their disease does not progress and they do not have unacceptable side effects.