Relay Stock Soars on Upbeat Data From Breast Cancer Study
Shares of Relay Therapeutics RLAY soared 52.4% on Sept. 9 after the company announced positive interim data from the early-stage study of its lead investigational candidate, RLY-2608, to treat heavily pretreated breast cancer patients.
The enrolled population included PI3Kα-mutated, HR+, HER2- locally advanced or metastatic breast cancer (MBC) patients who received the combo regimen of twice-daily, 600 mg dose of RLY-2608 and AstraZeneca’s AZN Faslodex (fulvestrant). Interim data from the study showed that treatment with this two-drug therapy resulted in a clinically meaningful progression-free survival (PFS).
Several PI3Kα inhibitors, like Novartis’ NVS Piqray (alpelisib) and AstraZeneca’s Truqap (capivasertib), are already approved for the treatment of this MBC indication. However, Relay’s management claims that RLY-2608’s novel mechanism of action that selectively targets mutant PI3Kα has the potential to offer a level of benefit to patients that has not previously been possible with existing treatment options, while also having significantly less toxicity.
Superior Efficacy Data From Relay’s Breast Cancer Study
The ongoing ReDiscover study is evaluating RLY-2608 in MBC patients. The candidate is being developed as a monotherapy, in combination with AstraZeneca’s Faslodex and also in combination with Faslodex and Novartis’ Kisqali (ribociclib) or Prizer’s PFE investigational candidate, atirmociclib.
The data readout is from the RLY-2608 + AstraZeneca’s Faslodex arm of the MBC study. Per the data readout from the 52 evaluable patients receiving the combo therapy, the median PFS was 9.2 months across all mutations and 10.3 months among patients with kinase mutations. The Clinical benefit rate (CBR), defined as the proportion of patients with complete response, partial response or stable disease for at least 24 weeks, was 57% across the 35 CBR-evaluable patients.
Among the 30 patients with measurable disease, one-third achieved a partial response (PR), while nearly three-quarters of patients experienced tumor reductions. Additionally, among the 15 patients with measurable disease who had a kinase mutation, more than half achieved a PR.
The median follow-up duration in the MBC study was 7.5 months.
Year to date, shares of RLAY have lost 13.6% compared with the industry’s 3.3% decline.
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RLAY further reported that the RLY-2608/Faslodex combo was generally safe and overall well tolerated in the 118 patients treated across all doses as of the data cut-off date. Treatment-related adverse events were mostly mild to moderate in severity and were manageable and reversible.
Pfizer’s atirmociclib, a CDK4 inhibitor, is undergoing phase III development to treat HR+/HER2- MBC. Novartis’ Kisqali, a CDK4/6 inhibitor, on the other hand, is currently the standard-of-care therapy for the HR+, HER2- MBC indication.
Relay’s Future Development Plans for RLY-2608 in MBC
Based on the encouraging data from the doublet arm of the MBC study, Relay Therapeutics is gearing up to initiate a pivotal study of RLY-2608 + AstraZeneca’s Faslodex for the same indication in the second-line setting in 2025, following regulatory discussions.
The company also anticipates reporting initial safety data from the RLY-2608 + Novartis’ Kisqali + Faslodex triplet therapy arm for MBC in the fourth quarter of 2024. Dose expansion cohort(s) in this arm are expected to be initiated in the first half of 2025. RLAY is also looking to initiate an RLY-2608 + Pfizer’s atirmociclib + Faslodex triplet therapy arm for MBC by the end of 2024.
The company is also evaluating RLY-2608 in two triplet regimens, one with Novartis’ Kisqali and the other with Pfizer’s atirmociclib, for the front-line treatment of MBC.
Apart from the combination studies, Relay also plans to study RLY-2608 as a monotherapy for solid tumors and vascular malformations.
Relay Therapeutics, Inc. Price and Consensus
Relay Therapeutics, Inc. price-consensus-chart | Relay Therapeutics, Inc. Quote
Updates on Relay’s Other Clinical-Stage Candidate
In the same press release, Relay stated that it has met with the FDA to discuss the regulatory pathway for its other clinical-stage candidate, lirafugratinib. Per RLAY, the FDA has suggested that the company should first submit a new drug application (NDA) for lirafugratinib to treat cholangiocarcinoma (bile duct cancer) and then file a tumor agnostic supplemental NDA for FGFR2 fusions.
However, RLAY stated that it is looking for a global commercialization partner for lirafugratinib to maintain focus on the remainder of the portfolio.
Zacks Rank
Relay Therapeutics currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.
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