OncoMatch/Clinical Trials/NCT05304962
FIH Study of RGT-419B Alone and With Endocrine Therapy in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer
Is NCT05304962 recruiting? Yes, currently enrolling (Jun 2026). This Phase 1 trial studies multiple treatments including RGT-419B and RGT-419B in combination with hormonal therapy for breast cancer.
Treatment: RGT-419B · RGT-419B in combination with hormonal therapy — 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.
Check if I qualifyExtracted eligibility criteria
Treatments studied
Other
Cancer type
Breast Carcinoma
Biomarker criteria
Required: ESR1 overexpression (ER+)
ER+ ABC consistent with ASCO CAP guidelines
Required: HER2 (ERBB2) wild-type (HER2-)
HER2- ABC consistent with ASCO CAP guidelines
Disease stage
Required: Stage III, IV
Performance status
ECOG 0–1(Restricted strenuous activity)
Prior therapy
Must have received: CDK4/6 inhibitor — metastatic and/or adjuvant
Progression after receiving 1 line of prior cyclin-dependent kinase 4 and 6 inhibitor (CDK4/6i) therapy combined with HT in the MBC setting (up to 1 additional line of CDK4/6i is permitted in the post-surgical adjuvant setting); Subjects must have received therapy for ≥3 months in the MBC setting, or for ≥6 months in the adjuvant setting, prior to progression
Structured fields extracted by AI. May contain errors — verify against the official protocol.
US trial sites
- University of California, San Diego · La Jolla, California
- University California, Los Angeles · Los Angeles, California
- Hem-Onc Associates of the Treasure Coast · Port Saint Lucie, Florida
- Moffitt Cancer Center · Tampa, Florida
- Emory University · Atlanta, Georgia
Showing up to 5 US sites.
See all sites on ClinicalTrials.gov →Frequently asked questions
Is NCT05304962 currently recruiting?
Yes, this trial is currently recruiting patients.
Is prior treatment required for enrollment?
Yes. Patients must have previously received CDK4/6 inhibitor.
Does this trial require ESR1?
Yes, ESR1 overexpression is a required biomarker for enrollment.
Does this trial require ERBB2?
Yes, ERBB2 wild-type is a required biomarker for enrollment.
What disease stage is eligible?
Stage III or IV is required.
Could you qualify for this trial?
Enter your biomarker results to see how this trial's eligibility criteria match your specific cancer profile.
Check if I qualifyRelated pages