RecruitingPhase 3

Phase 3 Study of RLY-2608 + Fulvestrant vs Capivasertib + Fulvestrant as Treatment for Locally Advanced or Metastatic PIK3CA-mutant HR+/HER2- Breast Cancer

United States540 participantsStarted 2025-08-26

Plain-language summary

This is a global, multicenter, open-label, randomized Phase 3 study comparing the efficacy and safety of RLY-2608 + fulvestrant to capivasertib + fulvestrant for the treatment of patients with HR+/HER2- ABC with PIK3CA mutation following recurrence or progression on or after treatment with a CDK4/6 inhibitor.

Who can participate

Age range18 Years

SexALL

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Inclusion criteria

✓. At least 1 and no more than 2 lines of endocrine therapy (ET) in the (neo)adjuvant setting with recurrence on or within 12 months of completion or in the ABC setting
✓. 1 prior line of CDK4/6 inhibitor therapy in one of the following settings:
✓. CDK4/6 inhibitor + ET in the ABC setting
✓. CDK4/6 inhibitor therapy in the adjuvant setting if progression occurred during or within 12 months of completion of adjuvant CDK4/6 inhibitor with ET
✓. Patients who progressed during or within 12 months of completion of adjuvant CDK4/6 inhibitor and after receiving CDK4/6 inhibitor therapy in the advanced setting are considered to have had \>1 prior line of CDK4/6 inhibitor and are not eligible

Exclusion criteria

✕. CDK2 or selective CDK4 inhibitors or any investigational therapies targeting cyclin dependent kinases
✕. PIK3, AKT, or mTOR inhibitors or any agent whose mechanism of action is the inhibit the PIK3/AKT/mTOR pathway
✕. Immunotherapy
✕. Antibody drug conjugates

What they're measuring

Progression-Free Survival (PFS) within the overall and kinase population by blinded independent central review (BICR)

Timeframe: The time from date of randomization until radiographic progression per RECIST v1.1, or death due to any cause, up to approximately 77 months

Trial details

NCT IDNCT06982521

SponsorRelay Therapeutics, Inc.

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2028-04-30

Contact for this trial

Relay Therapeutics, Inc

617-322-0731 ClinicalTrials@relaytx.com

View on ClinicalTrials.gov More PIK3CA Mutation trials