Cellectar Biosciences (CLRB) said Wednesday the US Food and Drug Administration has granted breakthrough therapy designation to its experimental cancer drug, iopofosine I 131, for the treatment of relapsed or refractory Waldenstrom macroglobulinemia, a rare and currently incurable form of lymphoma.

The company said the designation was based on results from a phase 2 trial, where the drug achieved an 83.6% overall response rate and a 58.2% major response rate, significantly exceeding its 20% target.

Cellectar said it also submitted a data package to the European Medicines Agency to determine whether it can pursue conditional marketing authorization in the EU, adding that a recommendation on whether to proceed with a full application is expected by late July 2025.

Shares of the company were up more than 43% in Wednesday's premarket activity.

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