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Recruiting Phase 1 NCT05304962

NCT05304962 FIH Study of RGT-419B Alone and With Endocrine Therapy in HR-Positive, HER2-Negative Advanced/Metastatic Breast Cancer

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Clinical Trial Summary
NCT ID NCT05304962
Status Recruiting
Phase Phase 1
Sponsor Regor Pharmaceuticals Inc.
Condition Breast Cancer
Study Type INTERVENTIONAL
Enrollment 64 participants
Start Date 2022-03-04
Primary Completion 2026-09-30

Eligibility & Interventions

Sex All sexes
Min Age 18 Years
Max Age N/A
Study Type INTERVENTIONAL
Interventions
RGT-419BRGT-419B in combination with hormonal therapy

Eligibility Fast-Check

Enter your details for a quick preliminary check. This does not replace medical advice.

What to Expect as a Participant

You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.

Phase 1 is the earliest stage of human testing — safety and dosage are the primary focus. Visits are frequent and medical supervision is intensive. You will be among the first people to receive this treatment.

This trial targets 64 participants in total. It began in 2022-03-04 with a primary completion date of 2026-09-30.

⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.

Brief Summary

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.

Eligibility Criteria

Inclusion Criteria: 1. Male or female \>/= 18 years old 2. ECOG Performance Status 0 to 1 3. Subjects must have histologically or cytologically confirmed diagnosis of ER+, HER2- ABC consistent with ASCO CAP guidelines that is locally advanced and unresectable (Stage III) or metastatic (Stage IV) BC. 4. Measurable AND evaluable lesions at baseline per RECIST v1.1. 5. Eligible subjects must meet all of the following criteria: * 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 * Progression after ≤3 lines of prior HT therapy (regardless of whether it is HT alone or in combination with other therapies) * Prior HT combination agents, including SERD, SERM or AI, must have received formal approval by regulatory agency. * ≤ 1 prior line of chemotherapy in the metastatic setting 6. Adequate organ function 7. Ability to understand and the willingness to sign a written informed consent document Exclusion Criteria: 1. Presence of visceral metastases with severe organ dysfunction as evidence by signs and symptoms, laboratory studies, lymphangitic spread and/or rapid progression of disease 2. Pregnant or planning to become pregnant 3. Prior irradiation to \>25% of the bone marrow and/or inadequate bone marrow function or evidence of clinically significant end-organ damage 4. Major surgery, chemotherapy, targeted therapy, experimental agents, or radiation within 14-28 days prior to Cycle 1, Day 1 5. Active, serious medical condition that is not well controlled with locally approved medications allowed by the protocol 6. History of allergic reactions attributed to compounds of similar chemical or biologic composition to the drugs used in the study

Contact & Investigator

Central Contact

Joanna Dojillo, MSc

✉ joanna.dojillo@regor.com

📞 617-315-9070

Frequently Asked Questions

Who can join the NCT05304962 clinical trial?

This trial is open to participants of all sexes, aged 18 Years or older, studying Breast Cancer. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.

What phase is the NCT05304962 trial and what does that mean for participants?

Phase 1 trials are the first stage of human testing. The primary goal is to assess safety and determine appropriate dosage levels. Participants are closely monitored. These trials typically involve a small number of volunteers.

Is NCT05304962 currently recruiting?

Yes, NCT05304962 is actively recruiting participants. Contact the research team at joanna.dojillo@regor.com for enrollment information.

Where is the NCT05304962 trial being conducted?

This trial is being conducted at La Jolla, United States, Los Angeles, United States, Port Saint Lucie, United States, Tampa, United States and 4 additional locations.

Who is sponsoring the NCT05304962 clinical trial?

NCT05304962 is sponsored by Regor Pharmaceuticals Inc.. The trial plans to enroll 64 participants.

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ClinicalMetric — Independent clinical trial intelligence platform. Not affiliated with NIH, ClinicalTrials.gov, the U.S. FDA, or any pharmaceutical company, hospital, or clinical research organization. Trial data is sourced from ClinicalTrials.gov for informational purposes only and does not constitute medical advice. Do not make any treatment, enrollment, or health decisions based solely on information found here — always consult a qualified healthcare professional. Full Disclaimer  ·  Last Reviewed: April 2026  ·  Data Methodology