Cellectar Biosciences is a clinical-stage biopharmaceutical company focused on developing targeted radiopharmaceutical cancer therapies. The company has no approved products or revenue. Its lead asset is iopofosine I 131, a radioconjugate that delivers a cytotoxic radioisotope (iodine-131) directly into cancer cells by exploiting the overabundance of lipid rafts in tumor cell membranes — a delivery mechanism Cellectar argues does not rely on a specific cell-surface antigen, giving it broad applicability across tumor types. The primary target indication is relapsed/refractory Waldenstrom's macroglobulinemia (WM), a rare blood cancer for which no approved therapies exist after BTK inhibitor failure. Iopofosine's Phase 2 CLOVER-WaM study met its primary endpoint with a major response rate of 58.2%, well above the FDA-agreed hurdle of 20%. The FDA has granted iopofosine Breakthrough Therapy and Fast Track Designations for WM, and the EMA has granted PRIME designation. Cellectar's near-term strategy involves filing for EU conditional approval based on existing Phase 2 data while initiating a Phase 3 confirmatory trial for U.S. accelerated approval, targeting a potential 2027 launch in both regions. Both tracks depend on securing a licensing or co-development partner to fund the roughly $40M Phase 3 trial. Beyond iopofosine, the company is advancing CLR 125 (iodine-125, targeting triple-negative breast cancer) in Phase 1 and has designed a Phase 1 trial for CLR 225 (actinium-225, targeting pancreatic cancer). Manufacturing is fully outsourced, and the company operates with 11 employees.