PMV Pharmaceuticals Announces Board Chair Transition

PMV Pharma Appoints Laurie Stelzer as New Board Chair

PMV Pharmaceuticals announced a leadership transition on its Board of Directors, with Laurie Stelzer appointed as the new Chair, succeeding Rich Heyman, Ph.D. The change is effective at the Company’s 2026 Annual Meeting of Stockholders on June 4, 2026. Ms. Stelzer, a director since 2020, brings over 25 years of senior finance and business development leadership experience in the biopharmaceutical industry. This transition occurs as PMV Pharma continues enrollment in its registrational PYNNACLE clinical trial evaluating rezatapopt as monotherapy in patients with TP53 Y220C advanced solid tumors. The company also anticipates submitting a New Drug Application (NDA) for rezatapopt in platinum-resistant/refractory ovarian cancer patients with a TP53 Y220C mutation in the first quarter of 2027.

• Laurie Stelzer, who has served on PMV Pharma's Board of Directors since 2020, has been appointed as the new Chair, effective at the Company’s 2026 Annual Meeting of Stockholders on June 4, 2026. She succeeds Rich Heyman, Ph.D., whose term as Chair and Board member will expire at the Meeting, and who will not stand for re-election. This marks a significant change in the company's governance structure.
• Ms. Stelzer brings over 25 years of senior finance and business development leadership experience across the biopharmaceutical industry. Her background includes serving as CFO for several clinical-stage biopharmaceutical companies like Mirati Therapeutics and Arena Pharmaceuticals, and holding leadership roles at Shire Plc and Amgen, Inc. She currently serves on the Boards of Sionna Therapeutics, Spyre Therapeutics, Inc., and MBX Biosciences, Inc., demonstrating a proven track record in guiding companies through strategic and value-creating milestones.
• The leadership transition coincides with PMV Pharma's continued progress in its clinical pipeline. Enrollment is ongoing in the registrational PYNNACLE clinical trial, which is evaluating rezatapopt as a monotherapy for patients with TP53 Y220C advanced solid tumors. Furthermore, the company is preparing to submit a New Drug Application (NDA) for rezatapopt in platinum-resistant/refractory ovarian cancer patients with a TP53 Y220C mutation to the FDA in the first quarter of 2027, indicating a clear path towards potential commercialization.

Addressing Unmet Needs in TP53 Y220C Advanced Solid Tumors

Current treatment approaches for TP53 Y220C advanced solid tumors face several significant challenges that limit therapeutic efficacy. A phase I study with the p53 reactivator rezatapopt has revealed key limitations in targeting this specific mutation. While the study demonstrated proof of concept for p53 reactivation, several critical barriers remain.

• Limited efficacy in KRAS co-mutated tumors — Rezatapopt was ineffective in tumors harboring concurrent KRAS mutations, representing a significant therapeutic limitation given the frequency of KRAS mutations in solid tumors

• Uncertain applicability to other TP53 mutations — Whether the p53 reactivation strategy can be successfully applied to more common TP53 missense mutations beyond Y220C remains unclear, limiting broader clinical utility

• Narrow therapeutic validation — While rezatapopt showed safety and some responses in Y220C mutant tumors, the evidence base remains limited to early-phase data, requiring further validation of efficacy across larger patient populations

• Lack of predictive biomarkers — Current approaches lack robust biomarkers to identify which patients with TP53 Y220C mutations are most likely to respond to targeted therapies, hampering treatment selection

PYNNACLE Trial Design for Rezatapopt in TP53 Y220C Tumors

The PYNNACLE trial represents a first-in-class Phase 1 dose-escalation study evaluating rezatapopt, an oral selective p53 reactivator, in heavily pretreated patients with locally advanced or metastatic solid tumors harboring TP53 Y220C mutations. The study established key dosing parameters and demonstrated proof-of-concept for targeted p53 reactivation therapy in this molecularly defined patient population.

Evolving Treatment Landscape for TP53 Y220C Advanced Solid Tumors

The treatment landscape for TP53 Y220C advanced solid tumors has been fundamentally transformed by the development of rezatapopt, an investigational first-in-class oral selective p53 reactivator. This novel therapeutic approach represents a paradigm shift from traditional cytotoxic therapies to precision oncology targeting the specific Y220C mutation. Rezatapopt functions by specifically binding to Y220C-mutated p53, stabilizing the protein in its wild-type conformation and restoring its tumor suppressor functionality—a mechanism that addresses the root cause of malignancy in these tumors rather than merely treating downstream effects.

Clinical validation came through a comprehensive phase 1 dose-escalation and optimization study involving 77 heavily pretreated patients with locally advanced or metastatic solid tumors harboring the TP53 Y220C mutation. The study systematically evaluated eight escalating doses ranging from 150 mg to 2500 mg once daily, plus a 1500 mg twice-daily regimen, administered during continuous 21-day treatment cycles. While the maximum tolerated dose was established at 1500 mg twice daily, the recommended phase 2 dose of 2000 mg once daily with food was selected based on integrated safety, efficacy, and pharmacokinetic considerations, demonstrating the sophisticated approach to dose optimization in this patient population.

The efficacy results have established a new benchmark for outcomes in this challenging patient cohort, with an overall response rate of 20% across all patients and a notably higher 30% response rate among patients with KRAS wild-type tumors receiving doses of at least 1150 mg once daily. Confirmed responses were observed across multiple tumor types, including ovarian and breast cancers, with all responding patients harboring both TP53 Y220C and wild-type KRAS mutations. The safety profile proved manageable, with nausea (58%), vomiting (44%), increased blood creatinine (39%), fatigue (39%), and anemia (36%) representing the most common adverse events, most of which were grade 1-2 and could be effectively managed through supportive care measures.

Rezatapopt's Strategic Trajectory: Advancing a Pioneering p53 Therapy

The journey of rezatapopt, a pioneering small-molecule reactivator of the p53 Y220C mutant, represents a significant stride in oncology, targeting a specific mutation within the TP53 gene—a notorious driver in over half of human cancers. Traditionally deemed 'undruggable,' the p53 protein is now within therapeutic reach for a subset of patients, offering a glimmer of hope where options were previously limited. Clinical trials have demonstrated rezatapopt's ability to restore p53 tumor suppressor functions, showing a favorable safety profile and preliminary efficacy in heavily pretreated patients with various TP53 Y220C mutant solid tumors, including ovarian and breast cancers.

As PMV Pharmaceuticals progresses with its registrational PYNNACLE trial and prepares for an NDA submission in platinum-resistant/refractory ovarian cancer, the strategic appointment of Laurie Stelzer as Board Chair underscores a sharpened focus on commercial readiness. Her extensive experience in finance and business development will be critical in navigating the complexities of market entry and establishing rezatapopt as a viable treatment option.

However, the path forward is not without its challenges. Research indicates that acquired on-target resistance mechanisms, such as secondary TP53 alterations, can emerge, potentially limiting the drug's long-term efficacy. Furthermore, the importance of precise patient selection cannot be overstated; studies have shown rezatapopt to be ineffective in KRAS-mutant tumors, and previous p53 reactivators have faced setbacks due to a lack of robust TP53 mutation stratification. This highlights the urgent need for advanced biomarker platforms that integrate mutation subtypes, dynamic ctDNA monitoring, and tumor immune microenvironment features to ensure optimal patient outcomes. Addressing these risks will be paramount to fully unleash the therapeutic potential of p53 targeting and deliver on the promise of precision oncology.