Relay Therapeutics reported a Phase 2 efficacy signal for zovegalisib (RLY-2608) in patients with PIK3CA-driven vascular anomalies, delivering a 60% volumetric response that exceeded expectations in an interim look. The company positioned the result as a proof point for its isoform-selective PI3Kα inhibitor beyond its breast cancer combination programs, with vascular anomalies representing a second development lane. Leerink Partners previously forecast substantial peak sales for the indication, and the new data strengthens the case for continued trial expansion. The update comes as the company continues to test zovegalisib in broader late-stage settings, where demonstrating consistent clinical activity is crucial for maintaining investor confidence.