Relay Therapeutics Inc. (RLAY) shared encouraging interim data from its ongoing ReDiscover study evaluating the safety and efficacy of its drug candidate RLY-2608 in treating breast cancer. The study is looking at RLY-2608 alone, in combination with fulvestrant, and in combination with fulvestrant and ribociclib or atirmociclib (Pfizer Inc.’s PFE selective CDK4 inhibitor).
The data showed promising results in patients with PI3Kα-mutated, HR+, HER2- locally advanced or metastatic breast cancer who received RLY-2608 600mg BID+fulvestrant. These patients demonstrated clinically meaningful progression-free survival (PFS).
As of the August 12 interim data cut-off, among the 52 patients who received the recommended Phase 2 dose and did not have a PTEN or AKT co-mutation, the median PFS was 9.2 months across all mutations and 10.3 months among patients with kinase mutations. The clinical benefit rate (CBR) was a notable 57% across all patients. This means that almost 60% of the patients experienced a complete response, partial response, or stable disease for at least 24 weeks.
The data also showed that nearly three-quarters of patients experienced tumor reductions, with one-third achieving a partial response. These results suggest a strong potential for RLY-2608 to be an effective treatment option for patients with this type of breast cancer.
RLY-2608 + fulvestrant was generally well tolerated in the 118 patients treated across all doses as of the data cut-off date, further highlighting the potential of this drug candidate.
Meanwhile, Relay Therapeutics also met with the FDA regarding the regulatory path for lirafugratinib, another drug in their pipeline. The FDA suggested that the company first file a new drug application (NDA) in cholangiocarcinoma, followed by a tumor-agnostic supplemental NDA for FGFR2 fusions with data from more patients and more follow-up.
The company plans to seek a global commercialization partner for lirafugratinib while continuing to focus on the rest of their portfolio. As of the end of the second quarter of 2024, Relay Therapeutics had approximately $688 million in cash, cash equivalents, and investments, which they expect to be sufficient to fund their current operating plan into the second half of 2026.
RLAY stock rose significantly following the release of this positive data, up 55.6% at $9.71 at last check on Monday.
