Early Phase 2 data highlight promising efficacy and safety profile
Relay Therapeutics Inc. (NASDAQ:RLAY) shares climbed 15% on Tuesday after the company released initial clinical results from its Phase 2 ReInspire study, showing that zovegalisib demonstrated encouraging safety and efficacy in patients with PIK3CA-driven vascular anomalies.
The company reported a 60% volumetric response rate across dose groups at the 12-week mark, with all enrolled patients remaining on treatment throughout the study period.
At the lowest evaluated dose of 100mg administered twice daily, 29% of patients achieved a volumetric response. Vascular anomalies are rare diseases involving abnormal growth and development of blood vessels, lymphatic vessels and surrounding tissue structures.
Majority of evaluable patients showed lesion reduction
As of the April 15, 2026 data cutoff, the trial had enrolled and randomized 32 patients across three dose cohorts within the adult and adolescent population.
Among the 20 patients eligible for response evaluation, 60% achieved a volumetric response, defined as at least a 20% reduction in target lesion volume relative to baseline measurements. All responses were observed during the first MRI assessment.
Interim findings from investigators and patients also showed clinical improvement rates of 89% and 79%, respectively, at week 12.
Company expands study cohorts as development advances
Relay Therapeutics said no patients discontinued treatment because of adverse events.
Among the 22 patients receiving doses of 100mg and 300mg twice daily, dose reductions were reported in 23% of cases, while median dose intensity remained above 99%.
The company has now opened expansion cohorts for adult and adolescent patients at doses of 400mg once daily and 300mg twice daily, while dose-finding work in pediatric patients continues.
Relay is also advancing zovegalisib in oncology, including an ongoing Phase 3 study evaluating the drug in combination with fulvestrant for patients with PIK3CA-mutated, CDK4/6 pre-treated, HR+/HER2- advanced breast cancer.
The clinical data were presented at the International Society for the Study of Vascular Anomalies World Congress 2026 held in Philadelphia.