Cellectar Biosciences reports ‘positive’ results from CLOVER WaM study

Cellectar Biosciences announced positive results from its CLOVER WaM pivotal study evaluating iopofosine I 131, a potential first-in-class, targeted radiotherapeutic candidate for the treatment of relapsed/refractory Waldenstrom’s macroglobulinemia patients that received at least two prior lines of therapy, including Bruton tyrosine kinase inhibitors. CLOVER WaM is the first and largest WM study to date in a highly refractory patient population, including patients who are refractory to all available treatment categories. As of May 31, 2024, results in the CLOVER WaM study (NCT02952508) had an overall response rate of 80% and a major response rate of 56.4%, which exceeded the agreed-upon primary endpoint of a 20% MRR. Median age was 70 years in the modified intent to treat population. The median number of prior lines of therapy was 4, with approximately 27% of patients refractory to all available therapies, and 40% of patients dual-class refractory. Notably, comparable ORRs were observed across all clinically challenging disease subgroups, including: MYD88-wt, P53-mutated, and clinical patient cohorts including post-BTKi, as well as dual-class, and triple-class refractory patients. Secondary endpoints of disease control rate and duration of response presented evidence that iopofosine provided durable clinical benefit across all response categories. The median DoR in patients achieving major response and overall response were not reached as of the data cutoff, with 78% and 72% of patients remaining free from disease progression at 18 months, respectively.