The U.S. Food and Drug Administration (FDA) has approved ofatumumab (Arzerra), a CD20-directed cytolytic monoclonal antibody, 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 was already approved for the treatment of previously untreated patients with chronic lymphocytic leukemia for whom fludarabine-based therapy was considered inappropriate and also for patients with disease refractory to fludarabine and alemtuzumab (Campath).
Improved Progression-Free Survival
This new approval was based on demonstration of an improvement in progression-free survival in a randomized, open-label trial comparing ofatumumab 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 randomly assigned (1:1) to ofatumumab (n = 238) or observation (n = 236) following complete or partial response after second- or third-line treatment for CLL. The median age was 64.5 years (range, 33–87). Patients in the ofatumumab arm had received a median of two prior therapies (range, 2–5).
The investigator-assessed median progression-free survival was 29.4 months (95% confidence interval [CI] = 26.2–34.2) and 15.2 months (95% CI = 11.8–18.8) in the ofatumumab and observation arms, respectively (hazard ratio = 0.50, 95% CI = 0.38–0.66, P < .0001).
Safety Data
The most common adverse reactions (≥ 10%) in patients treated with ofatumumab therapy were infusion reactions, neutropenia, and upper respiratory tract infections. Thirty-three percent of patients treated with ofatumumab reported serious adverse reactions. The most common serious adverse reactions were pneumonia, pyrexia, and neutropenia (including febrile neutropenia).
The recommended dosing schedule for ofatumumab therapy 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 a maximum of 2 years.
For more information, visit the FDA website at FDA.gov. ■
