A Phase I Study of RGT-419B in Patients With HR-Positive, HER2-Negative Advanced Breast Cancer or Other Solid Tumors

August 25, 2026 updated by: Regor Pharmaceuticals Inc.

A Phase I Study Evaluating Safety and Tolerability of RGT-419B Monotherapy in Chinese Patients With Hormone Receptor Positive, Human Epidermal Growth Factor Receptor 2 Negative Advanced/Metastatic Breast Cancer or Other Solid Tumors

This is a Phase 1 dose escalation and dose expansion phase I study to evaluate the safety, tolerability, pharmacokinetic profile and preliminary efficacy of RGT-419B as monotherapy in Chinese patients with HR+/HER2- advanced/metastatic breast cancer and other advanced solid tumors.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

40

Phase

  • Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • China
    • Shanghai Municipality
      • Shanghai, Shanghai Municipality, China, 200032
        • Fudan University Shanghai Cancer Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male or female ≥ 18 years of age
  • Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1
  • Subjects with pathologically confirmed advanced solid tumors who have failed standard-of-care therapy, or have no standard-of-care therapy available, or are currently not eligible for standard-of-care therapy; Subjects with HR+/ HER2- advanced or metastatic breast cancer are preferred.
  • Estimated life expectancy of at least 12 weeks

Exclusion Criteria:

  • Presence of visceral metastases with severe organ dysfunction
  • Known active hepatitis B or C infection
  • Prior irradiation to >25% of the bone marrow and/or inadequate bone marrow function or evidence of clinicallysignificant end-organ damage
  • History of allergic reactions attributed to compounds of similar chemical or biologic composition to the drugs usedin the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: RGT-419B monotherapy
Dose escalation and dose expansion of RGT-419B monotherapy
Drug: RGT-419B
RGT-419B will be administered orally
Other Names:
  • Active drug

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety & Tolerability - Number of subjects with Dose-Limiting Toxicities (DLTs) at each cohort dose level
Time Frame: 4 weeks (1 cycle)
Number of subjects who have a confirmed DLT at each cohort dose level during the first 28-day cycle of RGT-419B treatment.
4 weeks (1 cycle)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Safety & Tolerability - Incidence, Severity, and Causality of all Treatment Emergent Adverse Events (TEAEs)
Time Frame: through study completion, an average of 1 year
Incidence, severity, and causality of all TEAEs will be assessed for all patients participating from Day 1 dosing through end of study.
through study completion, an average of 1 year
Day 1 and steady-state pharmacokinetics(PK) assessment of RGT-419B and major metabolites - Cmax
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Area Under Concentration-TimeCurve to Infinity (AUC0-inf)
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Plasma Decay Half-Life (t1/2)
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Time to Reach Maximum ObservedPlasma Concentration (Tmax)
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Accumulation rate after multipledoses
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Cumulative urinary excretion
Time Frame: 4 weeks (1 cycle)
4 weeks (1 cycle)
Tumor Response assessed by Investigator according to RECIST v1.1
Time Frame: through study completion, an average of 1 year
through study completion, an average of 1 year
QTc Interval - Changes in corrected QT interval
Time Frame: through study completion, an average of 1 year
Number of subjects with a clinically significant increase from baseline in corrected QT (QTc) interval onrepeated ECGs
through study completion, an average of 1 year

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Regor Pharmaceuticals Inc.

Investigators

  • Principal Investigator: Jian Zhang, MD, Fudan University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

April 17, 2023

Primary Completion (Estimated)

December 30, 2026

Study Completion (Estimated)

December 30, 2026

Study Registration Dates

First Submitted

March 1, 2024

First Submitted That Met QC Criteria

March 1, 2024

First Posted (Actual)

March 7, 2024

Study Record Updates

Last Update Posted (Actual)

August 27, 2026

Last Update Submitted That Met QC Criteria

August 25, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • RGT-419B-102

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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