NCT06982521 · Relay Therapeutics, Inc.
Phase 3 Study of RLY-2608 + Fulvestrant vs Capivasertib + Fulvestrant as Treatment for Locally Advanced or Metastatic PIK3CA-mutant HR+/HER2- Breast Cancer
(ReDiscover-2)
What this study is about
This is a global, conducted at multiple hospitals, where both patients and doctors know the treatment given, randomly assigned Phase 3 study comparing the effectiveness 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.
View original scientific description
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.
Interventions
DRUG
RLY-2608
400 mg orally BID administered daily on a 28-day treatment cycle
DRUG
Capivasertib
400mg orally BID administered on an intermittent weekly dosing schedule. Patients will dose on Days 1 through 4 each week of a 28-day treatment cycle
DRUG
Fulvestrant
500 mg intramuscularly administered on Cycle 1 Day 1, Day 15, and Day 1 of each subsequent cycle (28-day treatment cycle)
Primary outcome measures
Progression-Free Survival (PFS) within the overall and kinase population by blinded independent central review (BICR)
Time frame: The time from date of randomization until radiographic progression per RECIST v1.1, or death due to any cause, up to approximately 77 months
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patient has ECOG performance status of 0-1
- One or more known primary oncogenic PIK3CA mutation(s)
- Adult females, pre- and/or post-menopausal, and adult males. Pre-menopausal (and peri-menopausal) women can be enrolled if amenable to treatment with a gonadotropin-releasing hormone (GnRH) agonist. Patients are to have commenced treatment with a GnRH agonist at least 4 weeks prior to randomization and must be willing to continue on it for the duration of the study.
- Histologically or cytologically confirmed diagnosis of HR+/HER2- locally advanced or metastatic breast cancer (ABC) with radiological or objective evidence of recurrence or progression; locally advanced disease must not be amenable to resection with curative intent
- Measurable disease per RECIST v1.1 or evaluable bone-only disease.
- Must have radiological evidence of progression on or after previous treatment for HR+/HER2- ABC with: 1. At least 1 and no more than 2 lines of endocrine therapy (E
Where
- Gilbert, Arizona
- Beverly Hills, California
- Duarte, California
- Los Angeles, California
- Palo Alto, California
- Sacramento, California
- San Diego, California
- San Francisco, California
- Vallejo, California
- Longmont, Colorado
- New Haven, Connecticut
- Newark, Delaware
And 33 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Jul 8, 2026 · Source of record for eligibility and locations