Cellectar's Iopofosine I 131 Shows 79.2% Major Response Rate in Waldenström Macroglobulinemia Subset

Cellectar Biosciences (CLRB) said on September 29, 2026, that a Phase 2 CLOVER WaM subset analysis showed encouraging efficacy for iopofosine I 131 in Waldenström macroglobulinemia patients refractory or resistant to BTK inhibitor therapy. The analysis reported a major response rate of 79.2% and an overall response rate of 87.5%, with duration of response exceeding 16 months in patients treated immediately after BTK inhibitor therapy. Iopofosine I 131 is an investigational targeted radiotherapy. Cellectar plans to advance the therapy into a Phase 3 confirmatory trial in early 2027 and seek accelerated U.S. approval in the first half of 2027. The stock closed September 28 at $1.83, up 1.67%, and traded premarket at $1.79, down 1.67%.