January 20, 2016 – The American Food and Drug Administration (FDA) just approved Ofatumumab (Arzerra) Injection for extended treatment of patients who are in complete or partial response after at least two lines of therapy for recurrent or progressive chronic lymphocytic leukemia (CLL). Ofatumumab, also known as HuMax-CD20, is a fully human monoclonal antibody directed against the CD20 protein which appears to inhibit early-stage B lymphocyte activation. Ofatumumab (Arzerra) was previously approved for the treatment of previously untreated patients with CLL for whom fludarabine-based therapy was considered inappropriate and also for patients with CLL refractory to Fludarabine and Alemtuzumab (Campath).
The recommended dose and schedule for Ofatumumab (Arzerra) therapy in this indication is 300 mg by intravenous infusion on day 1 followed by 1,000 mg on day 8 and then 7 weeks later and every 8 weeks thereafter for up to a maximum of 2 years.
This new approval was based on demonstration of an improvement in progression-free survival (PFS) in a randomized, open-label trial comparing Ofatumumab (Arzerra) to observation in patients whose disease had a complete or partial response after at least two lines of prior therapy. A total of 474 patients were randomized (1:1) to Ofatumumab (Arzerra) (n=238) or observation (n=236). The median age was 64.5 years (range 33-87). Patients in the Ofatumumab (Arzerra) arm had received a median of 2 prior therapies (range 2-5). The investigator-assessed median PFS was 29.4 months (95% CI: 26.2, 34.2) and 15.2 months (95% CI: 11.8, 18.8) in the Ofatumumab (Arzerra) and observation arms, respectively [HR: 0.50 (95% CI: 0.38, 0.66), p-value < 0.0001].
Ofatumumab (Arzerra) comes with serious adverse effects for some patients. The most common adverse reactions (greater than or equal to 10%) in patients treated with Ofatumumab (Arzerra) therapy were infusion reactions, neutropenia and upper respiratory tract infection. Thirty-three percent of patients treated with Ofatumumab (Arzerra) reported serious adverse reactions. The most common serious adverse reactions were pneumonia, pyrexia and neutropenia (including febrile neutropenia). In addition, Ofatumumab (Arzerra) comes with a Boxed Warning which very prominently warns about the possibility of Hepatitis B Virus (HBV) Reactivation in patients receiving CD20-directed cytolytic antibodies, including Ofatumumab (Arzerra), resulting in some cases in fulminant hepatitis, hepatic failure, and death. Progressive Multifocal Leukoencephalopathy (PML) resulting in death can occur in patients receiving CD20-directed cytolytic antibodies, including Ofatumumab (Arzerra), as well.