Core Insights - Cellectar Biosciences has submitted a protocol to the FDA for a Phase 1b dose-finding study of CLR 125, an iodine-125 Auger-emitting radiopharmaceutical targeting relapsed triple-negative breast cancer (TNBC) [1][2] - The study aims to evaluate the safety, tolerability, and optimal dosing of CLR 125, with a focus on its ability to deliver iodine-125 directly to tumor cells [2][3] - TNBC is a challenging subtype of breast cancer with limited treatment options, affecting approximately 12% of breast cancer diagnoses in the U.S. [4] Company Overview - Cellectar Biosciences is a late-stage clinical biopharmaceutical company focused on developing proprietary drugs for cancer treatment, utilizing its Phospholipid Drug Conjugate™ (PDC) delivery platform [5] - The company's pipeline includes iopofosine I 131, which has received Breakthrough Therapy Designation from the FDA, and other programs targeting various solid tumors [6][7] Clinical Study Details - The Phase 1b study will assess three doses of CLR 125 (32.75 mCi for 4 cycles, 62.5 mCi for 3 cycles, and 95 mCi for 2 cycles) across 15 patients per arm, with the primary endpoint being the recommended Phase 2 dose [2] - The study will also evaluate initial response assessments, including RECIST and progression-free survival [2] Industry Context - TNBC is characterized by the absence of common therapeutic targets, leading to a high recurrence rate of approximately 25% after standard treatments [4] - There is a critical need for innovative therapies to improve outcomes for patients with TNBC, highlighting the potential significance of CLR 125 in addressing this unmet medical need [4]