Cellectar Biosciences’ iopofosine conjugate shows efficacy in CNS malignancies

Cellectar Biosciences’ novel phospholipid radiotherapeutic conjugate, iopofosine I 131, demonstrated a pathological response with complete clonal clearance in a relapsed/refractory Waldenstrom’s macroglobulinemia – WM – patient with CNS involvement, also known as Bing-Neel Syndrome – BNS -, enrolled in its Phase 2b CLOVER WaM pivotal trial. As part of the CLOVER WaM pivotal trial, the patient with BNS received the standard WM dosing regimen of two treatment cycles with two doses per cycle for a total of four fixed doses of iopofosine I 131 over 75 days. Cerebrospinal fluid flow cytometry showed no evidence of clonal B-cells, and molecular analysis did not detect the MYD88 mutation. Cellectar previously announced a complete response in a patient with relapsed/refractory primary central nervous system lymphoma as part of its ongoing Phase 2a trial of iopofosine I 131. Currently, there are no approved therapies available to CNSL patients. Additionally, with the support of a $2M grant from the National Institute of Health’s National Cancer Institute, during 3Q23, Cellectar initiated a Phase 1b study in pediatric high-grade gliomas, currently enrolling, with the objective to identify the recommended iopofosine I 131 Phase 2 dose in pHGG patients. The NCI funding was in part granted due to the Phase 1a trial data demonstrating five months of progression free survival, greater than what is typically observed in relapsed/refractory patients.