FDA approves Pfizer, Arvinas breast cancer pill for mutation-specific patients

The Food and Drug Administration’s approval of Veppanu gave Pfizer and Arvinas a sharply limited new option for adults with estrogen receptor-positive, HER2-negative advanced or metastatic breast cancer, but only if their tumors carry an ESR1 mutation and the disease has progressed after at least one line of endocrine therapy. The label makes mutation status the gatekeeper, turning biomarker testing into the first practical step before treatment can begin.

That gatekeeping role now belongs to Guardant360 CDx, which the FDA approved at the same time as a companion diagnostic. The test is designed to identify ESR1 missense mutations in blood, allowing oncologists to match patients to vepdegestrant only when the mutation is present. In real-world practice, that means access will depend on both the patient’s prior hormone-therapy history and a confirmed molecular result, not just a diagnosis of advanced breast cancer.

The approval rested on VERITAC-2, a phase 3 randomized, open-label, active-controlled, multicenter trial of 624 patients with ER-positive, HER2-negative advanced or metastatic breast cancer, including 270 patients with ESR1 mutations. In that subgroup, vepdegestrant improved median progression-free survival to about 5 months, compared with 2.1 months for fulvestrant, and reduced the risk of disease progression or death by 43 percent. Pfizer said the drug was generally well tolerated, with few discontinuations and low rates of gastrointestinal adverse events, though the prescribing information also carries warnings for QTc interval prolongation and embryo-fetal toxicity.

The FDA acted ahead of its June 5, 2026 PDUFA deadline, giving Arvinas, based in New Haven, Conn., and Pfizer, based in New York, an early regulatory win. The companies had planned to out-license commercialization rights to a third party, and Arvinas said it remained on track to announce that partner, a step that will shape how quickly oncologists can adopt the drug and how coverage decisions are handled once it reaches routine care. Veppanu is being described as the first FDA-approved PROTAC in oncology, a milestone that extends beyond breast cancer to the broader protein-degradation field.