PMV Pharmaceuticals Publishes First-in-Human Data for Rezatapopt p53 Reactivator in the New England Journal of Medicine
PMV Pharmaceuticals, a Princeton-based precision oncology company listed on Nasdaq as PMVP, has published Phase 1 results from its PYNNACLE study of rezatapopt p53 reactivator in the New England Journal of Medicine. The publication reports safety and efficacy data from 77 patients with advanced solid tumors harboring a TP53 Y220C mutation who received oral rezatapopt across dose-escalation cohorts. The Phase 1 portion of the trial was designed to identify the maximum tolerated dose and recommended Phase 2 dose, while characterizing pharmacokinetics, biomarker effects, and tolerability. Dose-limiting toxicities were infrequent, and objective responses were observed across multiple tumor types. The trial is registered as NCT04585750 and is listed on AllSci as PYNNACLE.
The ongoing Phase 1/2 PYNNACLE study has since advanced into a registrational Phase 2 expansion, structured as a single-arm basket trial across five cohorts — ovarian, lung, breast, endometrial cancers, and other solid tumors — all selected for TP53 Y220C mutation and KRAS wild-type status. Updated interim Phase 2 data presented in October 2025 reported an overall response rate of 34% across 103 patients, rising to 46% in the 48-patient ovarian cancer cohort, with a median duration of response of 8.0 months and median time to response of 1.3 months. PMV Pharmaceuticals has stated it plans to submit a New Drug Application for rezatapopt in platinum-resistant or refractory ovarian cancer in the first quarter of 2027. The U.S. Food and Drug Administration has granted Fast Track designation to the molecule.
Rezatapopt (PC14586) is a small molecule designed to bind a structural pocket created by the Y220C missense mutation in the p53 protein, stabilizing the mutant protein and restoring its wild-type tumor-suppressor function — a mechanism the company describes as mutant p53 reactivation. PMV Pharmaceuticals was co-founded by Arnold Levine, who discovered the p53 protein in 1979, and the company has built its pipeline around four decades of p53 structural biology research. Rezatapopt remains wholly owned by PMV Pharma, with no disclosed licensing or partnership agreements.
Research context
How rezatapopt p53 reactivation aligns with disease biology
TP53 is the most frequently mutated gene in human cancer, altered in roughly half of all tumors and in more than 96% of high-grade serous ovarian cancers. For decades, mutant p53 was considered undruggable. The Y220C mutation, which accounts for approximately 2–3% of all TP53 missense mutations, introduces a cavity on the protein surface that destabilizes the folded structure and abolishes transcriptional activity governing cell-cycle arrest and apoptosis. Rezatapopt was designed through structure-based drug discovery to exploit this cavity — binding the Y220C pocket, thermostabilizing the protein, and reactivating wild-type p53 function. The discovery and characterization of rezatapopt has been described in the literature, detailing how the molecule selectively engages the mutation-created pocket and restores p53-dependent transcriptional programs. A broader review of strategies targeting mutant p53 for cancer treatment has placed rezatapopt within the context of multiple mutant-p53 reactivating approaches under clinical evaluation, noting the particular tractability of Y220C relative to other p53 mutations. The PYNNACLE study results published in the New England Journal of Medicine p53 paper now provide clinical proof-of-concept that this structural reactivation translates into measurable antitumor activity in patients, with biomarker data consistent with selective Y220C pocket binding and restoration of p53 function.
Current standard of care and its limitations
Platinum-resistant ovarian cancer — defined as disease progressing within six months of platinum-based chemotherapy — carries a median overall survival of approximately 12 months. Standard single-agent chemotherapies such as pegylated liposomal doxorubicin, topotecan, and weekly paclitaxel produce response rates of only 10–15%. Adding bevacizumab to chemotherapy provides modest progression-free survival gains of one to three months. PARP inhibitors, including olaparib, niraparib, and rucaparib, have transformed outcomes for patients with BRCA mutations or homologous recombination deficiency, but their utility in the platinum-resistant setting is limited, and they benefit only the 25–30% of patients with these specific molecular features. The most notable recent approval came with mirvetuximab soravtansine (Elahere), an antibody-drug conjugate targeting folate receptor alpha, which received traditional FDA approval in 2024 based on the MIRASOL Phase 3 trial for FRα-positive platinum-resistant ovarian cancer — but only 35–40% of patients have sufficiently high FRα expression to qualify. The majority of patients with platinum-resistant disease, particularly those lacking BRCA alterations or FRα expression, remain without a biomarker-directed therapy. Rezatapopt addresses a molecular subset — TP53 Y220C-mutated, KRAS wild-type tumors — that has had no targeted treatment option. The 46% response rate and 8.0-month duration of response reported in the PYNNACLE study results ovarian cohort, if confirmed in the registrational dataset, would compare favorably against existing later-line options in this population.