(RTTNews) - Cellectar Biosciences Inc. (CLRB), a late-stage clinical biopharmaceutical company, on Monday released positive results from the Phase 2b CLOVER WaM trial for Iopofosine I 131 in treating patients with relapsed/refractory Waldenstrom macroglobulinemia, including those immediately post-BTKi therapy. Data were presented at the 2026 annual meeting of the American Society of Clinical Oncology (ASCO).
Waldenstrom macroglobulinemia (WM), is a type of indolent B-cell non-Hodgkin lymphoma characterized by the accumulation of lymphoplasmacytic cells and the overproduction of monoclonal immunoglobulin M (IgM). The cancer is typically treated with Bruton Tyrosine Kinase inhibitor (BTKi) therapy, yet there are no FDA-approved treatments for patients showing rapid disease progression after discontinuing the therapy.
Iopofosine I 131 is a phospholipid-drug conjugate (PDC) designed for the targeted delivery of the radioisotope iodine-131 to various tumor types. The FDA has granted the drug a Breakthrough designation, six Orphan Drug, four Rare Pediatric Drug designations, and two Fast Track Designations for various cancer indications, and the EMA has granted it a PRIority MEdicines (PRIME) designation.
The Phase 2b CLOVER WaM trial evaluated Iopofosine I 131 in patients of Waldenstrom macroglobulinemia by administering 15 mCi/m2 on days 1 and 15 of a 57-day cycle. Eligible patients had received at least two prior therapies and has symptomatic disease.
Significant efficacy results were observed, including a 100% clinical benefit rate (CBR), an 87.5% objective response rate (ORR), and a 79.2% rate of major response, partial response, or better. The median duration of response was 16 months, and 20% of participants showed a duration of response of 30 months or more.
Treatment was well-tolerated, with cytopenias as the only Grade 3 or greater adverse event reported.
The company plans to initiate a Phase 3 pivotal trial in the fourth quarter of 2026.
Company executives emphasized the significance of these results. COO Jarrod Longcor noted the strong efficacy in patients post-BTKi therapy while CEO James Caruso highlighted the potential path toward accelerated approval.
Additionally, Iopofosine I 131 is being advanced in a Phase 1 trial for treating high-grade pediatric gliomas and may receive a Pediatric Review Voucher upon FDA approval. The drug is also being explored for the treatment of relapsed/refractory multiple myeloma, and central nervous system lymphoma.
Cellectar's pipeline also includes CLR 125, a targeted radiotherapy for solid tumors, and CLR 225, a next-generation PDC platform.
CLRB closed Monday at $2.97, down 5.41%. In the pre-market, shares are trading at $3.09, up 3.96%.
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