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

Overview

RBN-2397 inhibits PARP7, an enzyme that is switched on by cancer stresses, such as the toxins in cigarette smoke. Cancer cells use PARP7 to hide from the immune system by stopping the cell from sending a signal (Type 1 interferon) that tells the immune system that something is wrong and to kill the cell. RBN-2397 has been shown in animal studies to inhibit tumor growth and also shuts down the "don't kill me" signal the tumor is sending to evade the immune system. As a PARP7 inhibitor RBN-2397 is different from drugs inhibiting PARP1, PARP2 and PARP3 enzymes which are approved for the treatment of certain ovarian and breast cancers. The primary purpose of this study is to determine the maximum tolerated dose (MTD) of orally administered RBN-2397 in patients with advanced or metastatic solid tumors. This study will also evaluate the safety and tolerability of RBN-2397, examine the pharmacokinetics (PK) (measure how the body absorbs, breaks down and eliminates RBN-2397) and investigate whether it has antitumor activity in solid tumor cancers.

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.