NCT07311993

Phase 1 Study of CLR 125 in Triple Negative Breast Cancer

A Phase 1b, Open-Label Parallel Study Evaluating CLR 125 in Patients With Relapsed or Refractory Triple Negative Breast Cancer

• Status: Recruiting
• Phase: Phase 1
• Study type: Interventional
• Enrollment: 60 (estimated)
• Sponsor: Cellectar Biosciences, Inc. · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

The goal of this clinical trial is to evaluate the safety and efficacy of 3 different dose levels of CLR 125 in patients with advanced triple negative breast cancer. The main questions the study aims to answer are: * What dose and regimen should be used in future trials of CLR 125 in patients with advanced triple negative breast cancer. * What side effects do participants have when taking CLR 125. Participants will: * Have CLR 125 administered via infusion 4 times each cycle; repeated every 8 weeks. * Visit the clinic once every 3 weeks for checkups and testing. * Report any side effects or new medications. Some participants may also receive one dose of CLR 131 to evaluate the amount of radiation delivered to various organs and to the tumor. These participants will: * Have 4 scans completed over 2 weeks * Have blood drawn 6 times over 2 weeks.

Detailed description

This study is designed to determine the recommended dose and regimen for future trials and to evaluate the safety and tolerability of CLR 125 at the selected doses in patients with advanced triple negative breast cancer. It will also determine the antitumor activity (treatment response by RECIST v1.1) through assessment of overall response rate, progression free survival, overall survival, duration of response and duration of clinical benefit of CLR 125 in patients with advanced triple negative breast cancer. Total body, organ, and tumor dosimetry will be assessed in a select number of patients prior to CLR 125 dosing. At the conclusion of the study, total body, organ, and tumor dosimetry will be calculated for the intended patient population, to inform future studies. Up to 60 evaluable patients will be enrolled.

Conditions

• Breast Cancer

Interventions

Type	Name	Description
DRUG	Iopofosine I 131	Investigational radiopharmaceutical product intended for IV administration.
DRUG	CLR 125	Investigational radiopharmaceutical product intended for IV administration.

Timeline

• Start date: 2025-12-05
• Primary completion: 2028-02-01
• Completion: 2029-07-01
• First posted: 2025-12-31
• Last updated: 2026-04-14

Locations

3 sites across 1 country: United States

Regulatory

• FDA-regulated drug study