This is a phase 1 study to evaluate investigational drug RP-6306 in combination with carboplatin and paclitaxel in patients with TP53 mutated ovarian or uterine cancer. The dose escalation part of the study will determine the maximum tolerated dose (MTD) and recommended Phase 2 Dose (RP2D) and schedule of RP-6306 in combination with carboplatin and paclitaxel and the dose expansion will further assess the safety and tolerability as well as determine the preliminary efficacy of RP-6306 in combination with carboplatin and paclitaxel.