FLORHAM PARK, N.J. — September 29, 2026
Cellectar Biosciences announced that a subset analysis from the Phase 2 CLOVER-WaM study of iopofosine I 131 will be presented at the International Workshop for Waldenström Macroglobulinemia (IWWM) in October 2026. The analysis evaluates patients with Waldenström macroglobulinemia (WM) who received iopofosine I 131 immediately following treatment with a Bruton’s tyrosine kinase inhibitor (BTKi) after at least two prior lines of therapy. In the company-reported subset, iopofosine I 131 produced a major response rate of 79.2% and overall response rate of 87.5%, with duration of response exceeding 16 months. Cellectar said the findings support plans to advance the program into a confirmatory Phase 3 trial, with patient dosing expected to begin in early 2027 and a potential U.S. accelerated approval application planned for the first half of 2027.
CLOVER-WaM Analysis Evaluates Heavily Pretreated Patients
The upcoming IWWM presentation focuses on a particularly difficult-to-treat population of WM patients who were refractory or resistant to BTK inhibitor therapy. The subset includes patients who received iopofosine I 131 directly after BTKi treatment and had previously undergone at least two lines of therapy. Cellectar said the analysis demonstrated a major response rate of 79.2% and an overall response rate of 87.5%, while the duration of response exceeded 16 months. The company plans to present the detailed subgroup efficacy and safety findings in a poster titled “Iopofosine I 131 After BTK Inhibitors in Waldenström Macroglobulinemia: CLOVER-WaM Subgroup Efficacy and Safety” on October 15 at the 2026 IWWM meeting in Palm Springs, California. The reported findings are from a subset analysis and will require confirmation in the planned randomized confirmatory development program.
Iopofosine I 131 Advances as Targeted Radioisotope Therapy
Iopofosine I 131 is an investigational phospholipid drug conjugate designed to deliver the iodine-131 radioisotope to cancer cells. Cellectar is developing the candidate using its proprietary Phospholipid Drug Conjugate platform, which is intended to facilitate targeted delivery while potentially limiting exposure to healthy tissues. The program has previously been evaluated in relapsed or refractory WM, multiple myeloma and central nervous system lymphoma. The FDA has granted iopofosine I 131 Breakthrough Therapy, Orphan Drug, Rare Pediatric Disease and Fast Track designations across various cancer indications, while the European Medicines Agency has granted PRIME designation. Cellectar is also evaluating the platform in pediatric high-grade gliomas through the CLOVER-2 Phase 1b study and is developing additional radioisotope-based PDC programs for solid tumors.
Advertisement
Phase 3 Trial and Potential U.S. Filing Planned for 2027
Cellectar expects to initiate dosing in a confirmatory Phase 3 trial of iopofosine I 131 in early 2027, followed by a planned U.S. New Drug Application submission seeking accelerated approval in the first half of 2027. The company said the development strategy is supported by the clinical activity observed in the CLOVER-WaM program, although regulatory acceptance and the eventual approval pathway remain subject to future clinical and FDA review. Iopofosine I 131 remains investigational and the reported response rates come from a selected patient subset rather than a definitive controlled Phase 3 population. Cellectar’s broader pipeline includes CLR 121125, an iodine-125 Auger-emitting program being studied in triple-negative breast cancer, and CLR 121225, an actinium-225 program targeting solid tumors including pancreatic cancer. The planned confirmatory study is expected to provide additional evidence on the efficacy and safety of iopofosine I 131 in BTKi-refractory or resistant WM
Source :Cellectar Biosciences press release
