NCT07340619

Clinical Trial Evaluating the Biological Activity of a New Drug Identified as Prifetrastat (PF-07248144), Combined With Fulvestrant for the Treatment of Patients With Hormone Receptor Positive (HR+) and HER2 Negative (HER2-) Breast Cancer Extended to Other Organs.

UNLOCK - EPIBREAST, a Phase II Study of Prifetrastat (PF-07248144), a KAT6 Inhibitor, Plus Fulvestrant for Advanced HR+/HER2- Breast Cancer, With Biomarkers Analyses

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 51 (estimated)
• Sponsor: UNICANCER · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Although treatments for breast cancer have improved, 20-30% of patients with early disease develop metastases (cancer that spreads to other parts of the body). Among the different types of breast cancer, hormone-sensitive cancers that do not overexpress the HER2 protein (HR+/HER2-) are the most common. For patients with this type of cancer, an endocrine treatment such as aromatase inhibitors, tamoxifen or fulvestrant, is often used and may be combined with drugs called CDK4/6 inhibitors, which help improve survival rate. However, when the cancer becomes resistant to these treatments, treatment strategies are more limited A new drug, prifetrastat (PF-07248144), which targets KAT6 proteins, which play a role in the growth of cancer cells, has shown promising results. Indeed, associated with fulvestrant, it allowed to fight against cancer in some patients who had already received many treatments. The UNLOCK-EPIBREAST study aims to investigate whether the combination of prifetrastat plus fulvestrant could offer a new therapeutic option for people with HR+/HER2- metastatic breast cancer who have already received endocrine therapy plus CDK4/6 inhibitors.

Conditions

• Metastatic (Stage IV) Melanoma

Interventions

Type	Name	Description
DRUG	prifetrastat monotherapy for 15 days then combination with fulvestrant	Patients will receive prifetrastat 5mg QD monotherapy for 2 weeks and then combination of prifetrastat 5mg QD plus fulvestrant 500-mg intramuscular injection on day 15 cycle 1, on day 1 and day 15 of cycle 2 and then on day 15 of subsequent 28-day (±3 days) cycles.
DRUG	prifetrastat in combination with fulvestrant	Patients will receive combination prifetrastat 5mg QD plus fulvestrant 500-mg intramuscular injection on days 1 and 15 of cycle 1 and on day 1 of subsequent 28-day (±3 days) cycles

Timeline

• Start date: 2026-05-18
• Primary completion: 2028-11-18
• Completion: 2029-11-18
• First posted: 2026-01-14
• Last updated: 2026-01-14