Cellectar Biosciences, Inc., a late-stage clinical biopharmaceutical company focused on the discovery and development of drugs for the treatment of cancer, announced that the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation for iopofosine I 131, a potential first-in-class, novel cancer targeting agent utilizing a phospholipid ether as a radioconjugate monotherapy, for the treatment of relapsed/refractory Waldenstrom macroglobulinemia (r/r WM).
WM is the dominant subtype of lymphoplasmacytic lymphoma and remains incurable with available therapies according to the International Waldenstrom’s Macroglobulinemia Foundation. Approved WM treatment options are limited, underscoring the need for new therapies with novel mechanisms of action.
“The FDA’s Breakthrough Therapy Designation underscores the potential of iopofosine I 131 as it may offer substantial improvement on at least one clinically significant endpoint over available therapies to address the substantial unmet medical need in this life-threatening cancer,” said James Caruso, president and chief executive officer of Cellectar. “With robust clinical data, a favorable safety profile, expedited review designations in the United States and Europe and a compelling commercial market potential, we believe iopofosine I 131 represents an attractive candidate for potential collaborations or partners seeking impactful innovation and accelerated development pathways.”
Data from the Phase 2 CLOVER WaM study (NCT02952508), including the overall response rate (ORR) of 83.6% and a major response rate (MRR) of 58.2% (95% CI, 0.42 to 0.67), which exceeded the agreed-upon primary endpoint of a 20% MRR, were presented as a podium presentation during the 66th Annual American Society of Hematology Conference in December 2024 by Sikander Ailawadhi, M.D., Professor of Medicine, Mayo Clinic.
As previously announced, the FDA also granted iopofosine I 131 Fast Track Designation and Orphan Drug Designation. The European Medicines Agency (EMA) granted Orphan Drug Designation to iopofosine I 131 for treatment of r/r WM, as well as PRIME Designation for WM.
Separately, the company announced that it has provided the EMA with a data package that includes extensive supportive preclinical, regulatory and manufacturing data, as well as safety and efficacy data from the CLOVER WaM Phase 2b clinical trial. The EMA will review the package to determine whether there is enough clinical evidence to address the required criteria for Cellectar to apply for a fast-track, conditional marketing authorization approval. In late July 2025 the company expects a recommendation from the EMA on whether Cellectar should file a Medical Authorization Application (MAA).