Relay Therapeutics Advances Towards Pivotal Trial As It Shares Encouraging Breast Cancer Data In Heavily Pretreated Patients

Monday, Relay Therapeutics Inc. RLAY shared interim data for RLY-2608 from ReDiscover study, an ongoing first-in-human study, to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and preliminary antitumor activity of RLY-2608 alone, in combination with fulvestrant, and combination with fulvestrant and ribociclib or atirmociclib (Pfizer Inc‘s PFE selective CDK4 inhibitor).

The data showed that despite heavy pre-treatment, patients with PI3Kα-mutated, HR+, HER2- locally advanced or metastatic breast cancer who received RLY-2608 600mg BID+fulvestrant 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:

• Median PFS was 9.2 months across all mutations and 10.3 months among patients with kinase mutations.
• The clinical benefit rate (CBR) was 57% across all patients (20 of 35 CBR-evaluable patients; CBR is defined as the proportion of patients with complete response, partial response, or stable disease for at least 24 weeks).
• Among the 30 patients with measurable disease, one-third achieved a partial response (PR) (33% objective response rate, ORR; n=10; 8 confirmed, one confirmed post-data cut-off date, one unconfirmed in an ongoing patient)Nearly three-quarters of patients experienced tumor reductions (73%; n=22).
• Among the 15 patients with measurable disease who had a kinase mutation, more than half achieved a PR (53% ORR; n=8; 7 confirmed, one confirmed post-data cut-off date)
• The median follow-up was 7.5 months.

RLY-2608 + fulvestrant was generally well tolerated in the 118 patients treated across all doses as of the data cut-off date.

The company met with the FDA regarding the regulatory path for lirafugratinib. 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 remaining focused on the remainder of the portfolio.

As of the end of the second quarter of 2024, cash, cash equivalents and investments were approximately $688 million, which the company expects to be sufficient to fund its current operating plan into the second half of 2026.

Price Action: RLAY stock is up 55.6% at $9.71 at last check Monday.

Image by PDPics from Pixabay

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