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

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: Breast Cancer; Advanced Solid Tumor
• Intervention / Treatment: Drug: RGT-419B

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Phase 1

Contacts and Locations

Study Locations

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

Participation Criteria

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

How is the study designed?

Design Details

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

Number of Arms

1

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	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)	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		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)		4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Plasma Decay Half-Life (t1/2)		4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Time to Reach Maximum ObservedPlasma Concentration (Tmax)		4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Accumulation rate after multipledoses		4 weeks (1 cycle)
Day 1 and steady-state PK assessment of RGT-419B and major metabolites - Cumulative urinary excretion		4 weeks (1 cycle)
Tumor Response assessed by Investigator according to RECIST v1.1		through study completion, an average of 1 year
QTc Interval - Changes in corrected QT interval	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

• Sponsor: Regor Pharmaceuticals Inc.
• Investigators: Principal Investigator: Jian Zhang, MD, Fudan University

Study record dates

Study Major Dates

• Study Start (Actual): April 17, 2023
• Primary Completion (Estimated): July 30, 2025
• Study Completion (Estimated): July 30, 2025

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): March 25, 2025
• Last Update Submitted That Met QC Criteria: January 16, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Skin Diseases; Breast Diseases; Breast Neoplasms
• 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