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

Conditions

• Advanced Breast Cancer
• Breast Cancer
• HER2- Negative Breast Cancer
• Hormone Receptor Positive Tumor
• Metastatic Breast Cancer
• PIK3CA Mutation

Eligibility Criteria

Sex

ALL

Age

18 Years - N/A

Healthy Volunteers

Not accepted

Interventions

• RLY-2608 — DRUG
  400 mg orally BID administered daily on a 28-day treatment cycle
• Capivasertib — DRUG
  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
• Fulvestrant — DRUG
  500 mg intramuscularly administered on Cycle 1 Day 1, Day 15, and Day 1 of each subsequent cycle (28-day treatment cycle)

Study Details

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.

Key Dates

Start date

Aug 26, 2025

Status verified

Jun 2026

Primary completion

Apr 30, 2028

Completion

Dec 31, 2031

Study Design

Enrollment

540 participants (estimated)

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

TREATMENT

Arms

• Experimental: RLY-2608 + fulvestrant
  RLY-2608 + fulvestrant combination for participants with HR+/HER2- advanced breast cancer
• Active Comparator: capivasertib + fulvestrant
  capivasertib + fulvestrant combination for participants with HR+/HER2- advanced breast cancer

Primary Outcome Measure

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 ]

Central Contacts

• Relay Therapeutics, Inc
  617-322-0731
  [email protected]

Locations (51)

Find similar trials in Gilbert, AZ

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