Hairy cell leukemia (HCL), a rare B-cell leukemia, also saw new advances this year with the approval of the CD22-directed cytotoxin moxetumomab pasudotox. The antibody portion of the compound directs the agent to CD22-expressing leukemic cells, where upon entry, the toxin inhibits protein synthesis, inducing apoptosis.

This approval came from the phase III study evaluating the efficacy of moxetumomab  pasudotox in 80 patients with relapsed or refractory HCL, in which the objective response rate (ORR) at 16.7 months was 75%. Futher, 33 patients (41%) had achieved a complete response.