Dr. Kreitman on the Use of Moxetumomab Pasudotox in Hairy Cell Leukemia

Robert J. Kreitman, MD, senior investigator and head of the Clinical Immunotherapy Section in the Laboratory of Molecular Biology at the National Cancer Institute, discusses the use of moxetumomab pasudotox-tdfk (Lumoxiti) in heavily pretreated patients with relapsed/refractory hairy cell leukemia (HCL).

In September 2018, the FDA approved the CD22-directed recombinant immunotoxin for the treatment of adult patients with relapsed/refractory HCL who received ≥2 prior lines of therapy, including treatment with a purine nucleoside analog. The agent is essentially the only non-chemotherapy drug that can induce minimal residual disease (MRD) negativity in the majority of patients with HCL, says Kreitman. This is important because data from the phase I trial examining the agent demonstrated that the presence of MRD confers a higher risk of relapse.

According to long-term follow-up from the pivotal phase III Study 1053 trial presented at the 2019 ASH Annual Meeting, moxetumomab pasudotox-tdfk led to a durable complete response (CR) of 36.3%. Durable CR served as the primary end point of the trial and was defined as the achievement of a CR and maintained hematologic remission for >180 days. Moreover, 81.6% of patients who achieved a CR also achieved MRD negativity.