Iopofosine (CLR 131) - (CLOVER-WaM)

October 15, 2026: Cellectar Biosciences (NASDAQ: CLRB) reported a subgroup analysis from the Phase 2b CLOVER WaM trial of iopofosine I 131 in relapsed/refractory Waldenström macroglobulinemia, presented at the International Workshop for Waldenström Macroglobulinemia (October 14-16, 2026). In patients treated immediately after a BTK inhibitor regimen (n=24), iopofosine I 131 produced 87.5% overall response rate, 79.2% major response rate, 100% clinical benefit rate, 16.0-month median duration of response, and 19.1-month treatment-free survival. Seventy-five percent were BTKi-refractory, more than 54% had received multiple BTK inhibitors, median prior lines were three, 17% had TP53 mutations, and 29% were MYD88 wild type. Treatment-emergent adverse events occurred in less than 10% of patients; the only grade 3+ TEAEs were cytopenias.

The company said Phase 3 confirmatory randomized trial startup and site selection are underway in a post-first-line, post-BTKi population, with progression-free survival as the primary endpoint and first-patient dosing expected in 1Q27. Cellectar also plans to submit an FDA New Drug Application for accelerated approval in 1H27, supported by the CLOVER WaM dataset and existing Breakthrough Therapy Designation.