Genmab A/S has announced that the U.S. Food and Drug Administration (FDA) has approved a supplemental Biologics License Application (sBLA) for the use of Arzerra® (ofatumumab) 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). The application was submitted by Novartis under the ofatumumab collaboration between the two companies.

This FDA approval is based on data from an interim analysis from a Phase III study, PROLONG (OMB112517) which evaluated ofatumumab maintenance therapy versus no further treatment in patients with a complete or partial response after second or third line treatment for CLL.

"The approval of Arzerra in the U.S. as extended treatment provides patients with relapsed CLL with a new treatment option that can help delay disease progression," said Jan van de Winkel, Ph.D., Chief Executive Officer of Genmab.

A total of 474 patients were included in the analysis. Patients who received ofatumumab maintenance treatment lived 14.2 months longer without their disease worsening than patients who received no further treatment. Median progression free survival (PFS) as assessed by the investigators was 29.4 months for the ofatumumab treatment arm and 15.2 months for the observation arm (Hazard Ratio 0.50; p<0.0001).1

There were no unexpected safety findings. The most common adverse reactions (≥10%) were infusion reactions, neutropenia, and upper respiratory tract infection. The two most common grade 3-4 adverse events were neutropenia (22% in ofatumumab arm vs 8% in observation arm), and pneumonia (5% in ofatumumab arm vs 3% in observation arm). During the period between the first dose and 60 days after last dose there were two patients (1%) in the ofatumumab group who died due to adverse events and five patients (2%) in the observation group.1

About CLL

CLL, the most commonly diagnosed adult leukemia in Western countries, accounts for approximately 1 in 4 cases of leukemia.2,3 Most CLL patients experience disease progression despite initial response to therapy and may require additional treatment.4


This Phase III study was designed to randomize up to 532 patients with relapsed CLL who have responded to treatment at relapse, to either ofatumumab maintenance treatment or no further treatment (observation). Patients in the ofatumumab arm received an initial dose of 300 mg of ofatumumab, followed one week later by a second dose of 1,000 mg, then doses of 1,000 mg every 8 weeks for up to two years, while patients in the observation treatment arm received no further treatment.

The primary endpoint of the study was PFS. Secondary objectives will evaluate clinical benefit, overall survival, safety, tolerability, the health-related quality of life of subjects treated with ofatumumab versus no further treatment, and pharmacokinetics among relapsed CLL patients receiving maintenance therapy with ofatumumab.