Shares of Relay Therapeutics Inc. experienced a significant uptick in premarket trading Tuesday, climbing 11.3% to $13.47, following the release of encouraging early-stage data for its lead drug candidate, zovegalisib. The biopharmaceutical company reported that 60% of evaluable patients in a Phase 2 trial targeting vascular anomalies achieved a volumetric response, defined as at least a 20% reduction in target lesion volume.
The results, drawn from 20 evaluable patients in the ongoing ReInspire study, also indicated that 95% of participants experienced some degree of lesion shrinkage after 12 weeks of treatment. Importantly, no patients withdrew from the study due to adverse events, a key safety metric that has garnered investor attention.
Relay Therapeutics is positioning zovegalisib as a potential treatment for diseases driven by PIK3CA mutations, a genetic alteration implicated in abnormal cell growth and certain cancers. The company's research and development chief, Don Bergstrom, highlighted the "promise of PI3Kα mutant-selective inhibition" in vascular anomalies, underscoring the drug's targeted mechanism that aims to block the mutated enzyme while preserving normal PI3Kα function.
The data surpassed the expectations of some Wall Street analysts. Andrew Berens at Leerink Partners had previously indicated that a 20% to 25% response rate at 12 weeks would constitute a strong initial signal, making the 60% rate a notable outperformance. The company also noted that if a later, unconfirmed response recorded after the data cut-off is included, the response rate rises to 65% across doses.
Safety data from the trial revealed that among 22 patients receiving 100 mg or 300 mg doses twice daily, 23% required dose reductions, but no one stopped treatment due to side effects. Two patients experienced Grade 3 or higher treatment-related adverse events, with Grade 3 indicating a severe side effect. The company has deprioritized the 400 mg twice-daily dose for this patient population.
Relay Therapeutics is not alone in this therapeutic space. Novartis's drug Vijoice (alpelisib) received FDA accelerated approval in 2022 for certain patients with severe PIK3CA-related overgrowth spectrum, a subset of vascular anomaly diseases. However, Relay's trial is not a direct comparison with Vijoice, and the company is pursuing a broader indication.
Beyond vascular anomalies, zovegalisib is being evaluated in Relay's Phase 3 ReDiscover-2 study for breast cancer in combination with fulvestrant. The company also plans to initiate a Phase 3 trial in frontline breast cancer, combining zovegalisib with Pfizer's atirmociclib and an aromatase inhibitor, targeting early 2027 pending regulatory discussions. As of the end of the first quarter, Relay reported $642.1 million in cash, cash equivalents, and investments, which it expects to fund operations into 2029.
The premarket surge in Relay's stock comes amid broader market pressure, with S&P 500 futures down 0.4% and Nasdaq futures off 0.8%. The regular Nasdaq session is scheduled to open at 9:30 a.m. ET. Investors will be watching to see if the premarket gains hold through the trading day, especially given the early nature of the data and the limited patient sample size. Relay cautioned that interim results could shift as additional scans and safety data are collected, and that early clinical data may not match final outcomes.
