FIH Study of RGT-419B Alone and With Endocrine Therapy in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer

This is a phase I, First-in-Human (FIH), open-label study to evaluate the safety, tolerability, pharmacokinetic (PK) profile, and preliminary efficacy of RGT-419B administered orally as monotherapy OR in combination with Hormonal Therapy in subjects with HR+, HER2- locally advanced and unresectable (Stage III) or metastatic (Stage IV) breast cancer whose disease has progressed during prior therapy with an approved CDK4/6i plus hormonal therapy.

NCT Number	NCT05304962
Lead Sponsor	Regor Pharmaceuticals Inc.
Conditions	Breast Cancer
Enrollment	64 participants
Start Date	2022-03-04
Primary Completion	2026-12-30 (estimated)
Study Completion	2027-03-31 (estimated)
Updated on ClinicalTrials.gov	2026-08-12