Actively Recruiting

Phase 1
Age: 18Years +
All Genders
NCT05304962

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

Led by Regor Pharmaceuticals Inc. · Updated on 2026-04-02

64

Participants Needed

8

Research Sites

251 weeks

Total Duration

On this page

AI-Summary

What this Trial Is About

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.

CONDITIONS

Official Title

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

Who Can Participate

Age: 18Years +
All Genders

Eligibility Criteria

Eligible

You may qualify if you...

  • Male or female 18 years or older
  • ECOG Performance Status of 0 to 1
  • Diagnosis of estrogen receptor-positive, HER2-negative advanced breast cancer that is locally advanced and unresectable (Stage III) or metastatic (Stage IV)
  • Measurable and evaluable lesions at baseline according to RECIST v1.1
  • Disease progression after 1 line of prior CDK4/6 inhibitor therapy combined with hormonal therapy in the metastatic setting or up to 1 additional line in the adjuvant setting
  • Prior therapy for at least 3 months in the metastatic setting or 6 months in the adjuvant setting before progression
  • Disease progression after 3 or fewer lines of prior hormonal therapy
  • Prior hormonal therapy agents must be formally approved therapies including SERD, SERM, or aromatase inhibitors
  • No more than 1 prior line of chemotherapy in the metastatic setting
  • Adequate organ function
  • Ability and willingness to provide written informed consent
Not Eligible

You will not qualify if you...

  • Presence of visceral metastases causing severe organ dysfunction or rapid disease progression
  • Pregnant or planning to become pregnant
  • Prior radiation to more than 25% of bone marrow or inadequate bone marrow function or significant organ damage
  • Recent major surgery, chemotherapy, targeted therapy, experimental agents, or radiation within 14-28 days prior to study start
  • Active, serious medical conditions not well controlled with medications
  • History of allergic reactions to compounds similar to the study drugs

AI-Screening

AI-Powered Screening

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Trial Site Locations

Total: 8 locations

1

University of California, San Diego

La Jolla, California, United States, 92037

Actively Recruiting

2

University California, Los Angeles

Los Angeles, California, United States, 90404

Actively Recruiting

3

Hem-Onc Associates of the Treasure Coast

Port Saint Lucie, Florida, United States, 34952

Active, Not Recruiting

4

Moffitt Cancer Center

Tampa, Florida, United States, 33612

Actively Recruiting

5

Emory University

Atlanta, Georgia, United States, 30322

Actively Recruiting

6

Massachusetts General Hospital

Boston, Massachusetts, United States, 02142

Actively Recruiting

7

Washington University School of Medicine

St Louis, Missouri, United States, 63110

Actively Recruiting

8

New York Cancer and Blood Specialists

Port Jefferson Station, New York, United States, 11776

Actively Recruiting

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Research Team

J

Joanna Dojillo, MSc

CONTACT

R

Regor Pharmaceuticals Central Office

CONTACT

How is the study designed?

Study Type

INTERVENTIONAL

Masking

NONE

Allocation

NON_RANDOMIZED

Model

SEQUENTIAL

Primary Purpose

TREATMENT

Number of Arms

2

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