Relay Therapeutics Inc. (NASDAQ:RLAY) saw its stock climb about 15% on Tuesday after releasing initial findings from the Phase 2 ReInspire study of zovegalisib in patients with PIK3CA-driven vascular anomalies. The company presented the interim data at the International Society for the Study of Vascular Anomalies (ISSVA) World Congress 2026 in Philadelphia.
According to Relay, the trial demonstrated a 60% volumetric response rate across dose cohorts when assessed at 12 weeks. The company reported that all patients remained on treatment through that assessment window. At the study's lowest tested dose - 100 mg given twice daily - 29% of patients met the volumetric response threshold.
Vascular anomalies are described in the company materials as rare disorders involving abnormal development of blood vessels, lymphatic vessels and surrounding tissues. Relay reported that, as of the April 15, 2026 data cut-off, a total of 32 patients had been enrolled and randomized across three dosing cohorts in the adults and adolescents group.
Of those enrolled, 20 patients were considered response-evaluable. Among those 20, 60% achieved what the company defined as a volumetric response - a 20% or greater reduction in target lesion volume from baseline. Relay noted that all volumetric responses were observed at the first MRI scan following treatment initiation.
Interim clinical outcome measures included both investigator-reported and patient-reported assessments. At week 12, 89% of patients met investigator-reported criteria for clinical improvement, while 79% reported clinical improvement themselves.
On safety, Relay reported no treatment discontinuations due to adverse events through the interim period. The company provided additional tolerability data for a subgroup: among 22 patients treated at either 100 mg or 300 mg twice daily, 23% required dose reductions, and median dose intensity across that group exceeded 99%.
Following these results, Relay said it has opened expansion cohorts for adults and adolescents at two additional dosing regimens - 400 mg once daily and 300 mg twice daily - while pediatric dose-finding remains ongoing. The company also continues to run a separate Phase 3 study evaluating zovegalisib in combination with fulvestrant for patients with PIK3CA-mutated, CDK4/6 pre-treated, hormone receptor-positive/HER2-negative advanced breast cancer.
The data set reported at ISSVA represents an interim cut-off and a relatively small number of response-evaluable patients. Relay framed the findings as initial clinical evidence of zovegalisib's safety and activity in this specific, mutation-driven population of vascular anomaly patients.