Cambridge, U.K.-based Astrazeneca plc and its Medimmune unit will introduce the first new drug for hairy cell leukemia (HCL) in more than two decades, with the FDA's approval Thursday for Lumoxiti (moxetumomab pasudotox-tdfk). The CD22-targeted cytotoxin is indicated for adults with relapsed or refractory disease who have received at least two prior systemic therapies, including a purine nucleoside analogue.
Approval was based on data from an 80-patient, single-arm, phase III trial, which met its primary endpoint, showing a durable complete response (CR) rate of 30 percent, and demonstrated an objective response rate of 75 percent. Further data, presented at this year's American Society of Clinical Oncology meeting, showed a CR rate of 41 percent. Other findings highlighted that 80 percent of patients (64/80) achieved hematologic remission, which is defined by neutrophils greater than 1.5 x 10^9/L, platelets greater than 100 x 10^9/L, hemoglobin greater than 11 g/dL and no transfusions/growth factors at more than four weeks. (See BioWorld, June 5, 2018.)
"Lumoxiti fills an unmet need for patients with hairy cell leukemia whose disease has progressed after trying other FDA-approved therapies," said Richard Pazdur, director of the FDA's Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research.
According to estimates from Astrazeneca, roughly 1,000 people in the U.S. are diagnosed each year with HCL, a slow-growing leukemia that causes the bone marrow to overproduce abnormal B cells. The result is infections, bleeding and anemia that are sometimes life-threatening. Treatment options are few, with no standard of care, and up to 40 percent of HCL patients who initially respond to treatment end up relapsing.
Lumoxiti originally was developed at the National Cancer Institute and licensed by Medimmune, which moved the candidate into phase III testing in 2013 following promising phase I data. The drug received FDA fast track and orphan status in HCL. (See BioWorld Today, May 17, 2013.)
Lumoxiti became the first candidate from Astrazeneca's antibody-drug conjugate platform to be submitted for approval. The FDA accepted the BLA in April and granted priority review.
In addition to common side effects such as infusion-related reactions, nausea, fatigue and anemia, the prescribing information for Lumoxiti contains a boxed warning citing the risk of developing capillary leak syndrome, a condition in which fluid and proteins leak out of tiny blood vessels and into surrounding tissues, as well as the risk of hemolytic uremic syndrome.
Details on the drug's launch and cost were not immediately available.