Cellectar Biosciences announces improved tolerability of CLR 131
Cellectar Biosciences announced data from Cohort 5 of the company's ongoing Phase 1b clinical trial evaluating CLR 131 for the treatment of relapsed/refractory, or R/R, multiple myeloma, or MM. Unlike prior cohorts that used single doses of CLR 131, Cohort 5 utilized a fractionated two-dose regimen of 15.625 mCi/m2 given approximately one week apart. This dosing schedule provides higher average drug exposure but lower peak serum levels than non-fractionated dosing potentially reducing adverse events and improving efficacy. The independent Data Monitoring Committee, or DMC, determined the fractionated dose used in Cohort 5 to be safe and well tolerated and recommended advancement to a higher dose cohort. Results from Cohort 5 indicate enhanced tolerability and safety in comparison to Cohort 4 despite an 18% increase in total average dose from 55.29 mCi to 65.15 mCi of CLR 131. Patients in Cohort 5 required less supportive care such as transfusions of platelets or packed red blood cells than seen in previous cohorts. Based on the results and DMC recommendation, the company plans to initiate a sixth cohort using a fractionated dose regimen of two doses of 18.75 mCi/m2 administered one week apart and to modify the dosing regimen of its ongoing Phase 2 trial of R/R hematologic malignancies to use fractionated dosing.