This section highlights FDA-related milestones and regulatory updates for drugs developed by Relay Therapeutics (RLAY).
Over the past two years, Relay Therapeutics has reported clinical trial outcomes, regulatory submissions, approvals, and other FDA events for drugs and therapies such as
zovegalisib and RLY-2608. For definitions of regulatory abbreviations such as NDA, BLA, or PDUFA, see the event status legend.
Select a button below to view the list of FDA events for that drug.
Zovegalisib + atirmociclib FDA Regulatory Events
Zovegalisib + atirmociclib is a drug developed by Relay Therapeutics for the following indication: patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- zovegalisib + atirmociclib
- Announced Date:
- April 27, 2026
- Indication:
- patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer.
Announcement
Relay Therapeutics, Inc announced plans to move zovegalisib + atirmociclib, Pfizer's investigational, potential first-in-class CDK4 inhibitor, into Phase 3 development for frontline patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer..
AI Summary
Relay Therapeutics announced plans to advance zovegalisib combined with Pfizer’s investigational CDK4 inhibitor atirmociclib into a randomized Phase 3 trial for frontline, endocrine‑sensitive patients with PIK3CA‑mutated, HR+/HER2‑ metastatic breast cancer. The planned study, expected to start in early 2027 pending regulatory feedback, will evaluate the triplet of zovegalisib + atirmociclib + an aromatase inhibitor. Pfizer has agreed to supply atirmociclib for the experimental arm and palbociclib for the control arm. Relay will sponsor, fully operationalize, and fund the trial while retaining global rights to zovegalisib.
Support for the move comes from ReDiscover dose‑finding data showing compelling efficacy and tolerability: a 44% overall response rate in heavily pretreated, CDK4/6‑experienced patients, with similar responses across kinase and non‑kinase PIK3CA mutations. Pharmacokinetics showed atirmociclib raises zovegalisib exposure ~2.5‑fold; a potential Phase 3 zovegalisib dose of 150 mg twice daily is under consideration. Continued regulatory feedback will guide the final design.
Read Announcement
RLY-2608 FDA Regulatory Timeline and Events
RLY-2608 is a drug developed by Relay Therapeutics for the following indication: For metastatic breast cancer.
This drug is under review by the U.S. Food and Drug Administration (FDA).
Below is a timeline of key regulatory milestones for this therapy.
- Drug:
- RLY-2608
- Announced Date:
- April 2, 2026
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced that initial clinical results and preclinical data for zovegalisib (RLY-2608) in vascular anomalies will be presented at the International Society for the Study of Vascular Anomalies (ISSVA) World Congress 2026, taking place May 19-22, 2026, in Philadelphia.
AI Summary
Relay Therapeutics announced that initial clinical results and supporting preclinical data for zovegalisib (RLY-2608) will be presented at the International Society for the Study of Vascular Anomalies (ISSVA) World Congress, May 19–22, 2026, in Philadelphia. Zovegalisib is a mutant-selective PI3Kα inhibitor being studied for PIK3CA-driven vascular malformations in both adults and children. Early clinical findings focus on safety and activity in patients with these malformations, while preclinical work reports lesion regression in animal models with minimal hyperinsulinemia, suggesting a potentially favorable side‑effect profile compared with less selective PI3K inhibitors.
Two abstracts will be presented: a late‑breaking clinical abstract titled “Initial Results of Zovegalisib (RLY-2608), a Mutant-selective PI3Kα Inhibitor in Adult and Pediatric Patients with PIK3CA-Driven Vascular Malformations” (Abstract 488) on Wednesday, May 20 at 4:30 p.m. ET, and a preclinical abstract titled “Zovegalisib (RLY-2608)…Induces Lesion Regression, with Minimal Hyperinsulinemia, in Murine Models” (Abstract 404) on Friday, May 22 at 11:10 a.m. ET.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- March 16, 2026
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, announced data from the Phase 1/2 ReDiscover trial of zovegalisib (RLY-2608) + fulvestrant at the recommended Phase 3 dose of 400mg twice daily (BID) taken with food (fed) in patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer.
AI Summary
Relay Therapeutics reported Phase 1/2 ReDiscover data for zovegalisib (RLY-2608) 400 mg BID taken with food, given with fulvestrant to patients with PI3Kα‑mutated, HR+/HER2‑ metastatic breast cancer. As of the January 13, 2026 cut‑off, 60 patients received the regimen and 57 were efficacy‑evaluable (no PTEN or AKT co‑mutation). All had prior CDK4/6 inhibitor therapy and at least one prior endocrine treatment. Median progression‑free survival was 11.1 months in this heavily pretreated group, with similar benefit by mutation location: 11.2 months for kinase‑domain mutations and 11.0 months for non‑kinase domain mutations.
Pharmacokinetic analyses showed the 400 mg BID fed dose yields exposures comparable to the previously studied 600 mg BID fasted dose, with mean concentrations near the IC90 and most patients above the IC80 across the dosing interval. Safety was consistent with prior experience and generally well tolerated, with mostly low‑grade, manageable, and reversible treatment‑related adverse events. The 400 mg BID fed dose is the recommended Phase 3 dose and is being used in the ongoing ReDiscover‑2 trial.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- February 3, 2026
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy designation (BTD) to zovegalisib (RLY-2608) in combination with fulvestrant for the treatment of adults with PIK3CA mutant, hormone receptor positive, human epidermal growth factor receptor 2-negative (HR+/HER2-) locally advanced or metastatic breast cancer following recurrence or progression on or after treatment with a CDK4/6 inhibitor.
AI Summary
Relay Therapeutics announced that the U.S. Food and Drug Administration has granted Breakthrough Therapy designation to zovegalisib (RLY-2608) in combination with fulvestrant for adults with PIK3CA‑mutant, hormone receptor–positive, HER2‑negative locally advanced or metastatic breast cancer that recurred or progressed on or after treatment with a CDK4/6 inhibitor.
The designation is supported by robust clinical data from the ReDiscover trial, which tested zovegalisib at 600 mg twice daily (fasted) and 400 mg twice daily (fed). The 400 mg BID fed dose is the Phase 3 dose, and initial Phase 1/2 data for this dose in CDK4/6‑experienced patients will be presented for the first time at the ESMO Targeted Anticancer Therapies Congress on March 16, 2026.
Breakthrough Therapy designation is intended to accelerate development and review when early evidence suggests a substantial improvement over available treatments. It affords eligibility for Fast Track features, enhanced FDA guidance, and increased engagement with senior agency leadership.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- December 12, 2025
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced a subset analysis of interim clinical data for zovegalisib (RLY-2608), the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα.
AI Summary
Relay Therapeutics presented a subset analysis of interim data for zovegalisib (RLY-2608), the first investigational allosteric, pan‑mutant, isoform‑selective PI3Kα inhibitor. The analysis focused on 52 patients who received zovegalisib 600 mg twice daily (fasted) without PTEN or AKT co‑mutations from the ReDiscover first‑in‑human study; median follow‑up was 20.2 months. In total, 118 patients had been enrolled in the zovegalisib plus fulvestrant arm. Zovegalisib is being studied for HR+/HER2‑ metastatic breast cancer after prior CDK4/6 inhibitor therapy.
Results were consistent across subgroups: median progression‑free survival (PFS) was 10.3 months overall and 11.4 months in second‑line patients. Among 31 patients with measurable disease, objective response rate (ORR) was 39% (47% in 2L). Patients with prior SERD had 11.4‑month PFS (ORR 44%); those with ESR1 mutations had 8.8‑month PFS (ORR 60%). The safety profile was mainly low‑grade, manageable and reversible. Relay is continuing Phase 3 ReDiscover‑2 enrollment and further dose escalation and triplet cohorts in ReDiscover.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- June 2, 2025
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced updated interim clinical data for RLY-2608, the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα.
AI Summary
Relay Therapeutics, Inc. announced updated interim clinical data for RLY-2608, the first investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα. The data, based on a median follow-up of 12.5 months, showed a progression-free survival (PFS) of 11.0 months in second-line patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer treated with RLY-2608 600 mg twice daily plus fulvestrant. The overall median PFS for all patients in the study was 10.3 months. The results support the favorable efficacy and tolerability of this targeted approach, with most treatment-related side effects being low-grade and manageable. These encouraging findings have paved the way for the planned initiation of a Phase 3 trial, expected to begin in mid-2025, and bolster ongoing efforts to evaluate combination therapies with other agents such as CDK4/6 inhibitors. The data will be presented at the ASCO 2025 Annual Meeting.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- December 11, 2024
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc announced updated interim clinical data for RLY-2608, the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα.
AI Summary
Relay Therapeutics, Inc. announced updated interim clinical data for RLY-2608, the first investigational allosteric, pan-mutant, and isoform-selective inhibitor of PI3Kα. In a study with patients having PI3Kα-mutated, HR+/HER2- metastatic breast cancer, those receiving RLY-2608 600mg twice daily plus fulvestrant showed a median progression-free survival of 11.4 months in second-line treatment. The data also revealed a 39% confirmed objective response rate overall, with a striking 67% response rate in patients with kinase mutations at the recommended phase 2 dose.
These early results suggest that RLY-2608 could provide significant benefits over non-selective PI3Kα inhibitors. The positive outcomes have laid the groundwork for a planned pivotal second-line study set to start in 2025, offering new hope for a better treatment approach in advanced breast cancer care.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- December 9, 2024
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced that updated clinical data for RLY-2608 600mg BID + fulvestrant in patients with PI3Kα-mutated, HR+, HER2- locally advanced or metastatic breast cancer will be presented at the upcoming San Antonio Breast Cancer Symposium, taking place December 10-13, 2024.
AI Summary
Relay Therapeutics, Inc. announced that updated clinical data for its treatment combining RLY-2608 600mg taken twice daily with fulvestrant will be presented at the San Antonio Breast Cancer Symposium. This upcoming event is scheduled for December 10-13, 2024. The presentation will focus on patients with locally advanced or metastatic breast cancer who have PI3Kα-mutated, HR+, HER2- disease. The study, known as the ReDiscover trial, evaluates the efficacy of RLY-2608, a mutant-selective inhibitor designed to target PI3Kα—a kinase often mutated in cancers. The session featuring this data is scheduled on December 11, 2024, with the poster presentation set during a dedicated spotlight session. In addition to the poster, Relay Therapeutics will host a conference call to discuss the findings, providing more insights into this promising precision oncology approach for breast cancer patients.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- September 9, 2024
- Target Action Date:
- H1 2025
- Estimated Target Date Range:
- January 1, 2025 - June 30, 2025
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. Triplet combination with ribociclib expected to move into dose expansion in 1H 2025
AI Summary
Relay Therapeutics, Inc. announced plans to advance its triplet combination therapy involving RLY-2608, fulvestrant, and ribociclib. The company expects to begin the dose expansion stage for this triplet treatment in the first half of 2025. This combination is being studied for patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer. Early data from the study suggest that RLY-2608, a novel allosteric and mutant-selective PI3Kα inhibitor, shows promise when combined with current therapies, potentially offering meaningful benefits with a lower toxicity profile.
The dose expansion will follow initial safety evaluations from dose escalation, where biologically active doses of ribociclib have been identified. This next step is part of Relay Therapeutics’ overall effort to improve treatment options for heavily pre-treated breast cancer patients, and the company looks forward to further discussions with regulatory authorities as the study progresses.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- September 9, 2024
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced positive interim data for RLY-2608, the first known investigational allosteric, pan-mutant and isoform-selective inhibitor of PI3Kα.
AI Summary
Relay Therapeutics, Inc. announced positive interim data for RLY-2608, marking it as the first investigational allosteric, pan-mutant, and isoform-selective inhibitor of PI3Kα. In the study, heavily pre-treated patients with PI3Kα-mutated, hormone receptor–positive, HER2-negative metastatic breast cancer received RLY-2608 at the recommended Phase 2 dose together with fulvestrant. The results showed a promising median progression-free survival of 9.2 months, with an overall objective response rate of 33% and a notable 53% ORR in patients with kinase mutations. The treatment displayed a favorable tolerability profile, with very few treatment discontinuations and low rates of severe side effects. These encouraging results suggest that by targeting only the mutant form of PI3Kα, RLY-2608 may offer significant benefits while reducing toxicity compared to non-selective inhibitors. The positive data support plans to start a pivotal second-line study in 2025.
Read Announcement- Drug:
- RLY-2608
- Announced Date:
- September 6, 2024
- Target Action Date:
- September 9, 2024
- Indication:
- For metastatic breast cancer
Announcement
Relay Therapeutics, Inc. announced plans to host a conference call and webcast to report data for RLY-2608 600mg BID + fulvestrant in the ongoing ReDiscover trial in patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer and next steps on Monday, September 9, 2024, at 8:00 a.m. ET.
AI Summary
Relay Therapeutics, Inc. announced it will host a conference call and webcast on Monday, September 9, 2024, at 8:00 a.m. ET. During the call, the company plans to share data from its ongoing ReDiscover trial, which is studying RLY-2608 600mg BID in combination with fulvestrant. This study focuses on patients with PI3Kα-mutated, HR+/HER2- metastatic breast cancer who have previously received treatment, including a CDK4/6 inhibitor. The data provided will help inform next steps in the clinical development of RLY-2608, a promising allosteric inhibitor designed to selectively target mutant PI3Kα in cancer cells.
Interested parties can access registration details and dial-in information through Relay Therapeutics’ website under the “News & Events” section. An archived replay of the webcast will be available after the event.
Read Announcement
