Relay Therapeutics (RLAY) shares climbed ahead of a series of critical clinical and regulatory milestones for its pipeline, as management provided updates on two leading programs — vodegalisib in breast cancer and its oral small-molecule inhibitor in vascular anomalies — during a presentation at the Wells Fargo 21st Annual Healthcare Conference on Tuesday.
The company reported that vodegalisib delivered an 11-month median progression-free survival in a second-line breast cancer setting, a result management said was bolstered by a cleaner safety profile compared with non-selective alternatives. Relay also disclosed a 44% overall response rate in the median third-line triplet setting for breast cancer. The stock rose 0.03, or 0.16%, to close at $19.04 on April 9.
On the breast cancer front, Relay outlined its Phase III ReDiscover-2 study, which compares vodegalisib plus fulvestrant against capivasertib plus fulvestrant in second-line hormone receptor-positive, HER2-negative metastatic breast cancer. The last-patient-in guidance is expected before the end of 2024. A separate frontline study — vodegalisib combined with atirmociclib and endocrine therapy — is slated to begin enrolling in the first half of 2027, targeting endocrine-sensitive patients.
Management noted that capivasertib in the post-CDK4/6 setting showed a nominally smaller median progression-free survival, underscoring Relay's thesis that vodegalisib's selective mechanism could deliver both improved efficacy and tolerability. Atirmociclib was found to increase vodegalisib exposure by 2.5-fold, a pharmacokinetic interaction management said the company is accounting for in trial design.
In vascular anomalies, Relay presented initial data from a study started in mid-2025, first disclosed at the ISSVA conference in May 2024. The program targets patients with PIK3CA-mutated PROS and lymphatic malformations, conditions that account for roughly 70-75% and 25-30% of the patient population, respectively. About 80% or more of lymphatic malformation patients carry the mutation; PROS patients are uniformly mutated.
Vodegalisib achieved a 60% response rate across all doses in the study's dose-randomized portion, with a 100% response rate observed at the 300 mg twice-daily dose. Management identified 400 mg once daily as the preferred dose, balancing safety, tolerability and efficacy. Dose-finding is underway in children ages 6 to 11, with an expansion planned for ages 2 to 5.
Relay estimated the U.S. addressable market for moderate-to-severe disease at approximately 15,000 patients who could benefit from chronic systemic therapy with vodegalisib. On a per-patient basis, management suggested that every 2,500 to 3,000 chronically treated patients could represent roughly $1 billion in peak sales. For context, management noted that alpelisib, marketed as Vijoice at approximately $36,000 per month, has shown a 20% to 30% response rate at labeled doses.
Grade 3 hyperglycemia remained in the low single digits across more than 100 treated patients, and no stomatitis or rash was reported in the second-line patient population. Management emphasized that CDK4/6 inhibitors plus endocrine therapy will likely remain the standard of care for at least five years, providing a consistent comparator environment for Relay's late-stage trials.
