The FDA has approved a supplemental biologics license application for the use of ofatumumab (Arzerra, Genmab/Novartis) 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 approval was based on an interim analysis of the phase 3 PROLONG trial, which evaluated ofatumumab maintenance therapy compared with no further treatment in patients with a complete or partial response after second- or third-line treatment for CLL.
PROLONG was designed to randomly assign up to 532 patients with relapsed CLL who had 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, followed one week later by a second dose of 1,000 mg, and then doses of 1,000 mg every eight weeks for up to two years, while patients in the observation arm received no further treatment.
The study’s primary endpoint was progression-free survival (PFS). Secondary objectives will evaluate clinical benefit, overall survival, safety, tolerability, the health-related quality of life of subjects treated with ofatumumab compared with no further treatment, and pharmacokinetics among relapsed CLL patients receiving maintenance therapy with ofatumumab.
A total of 474 patients were included in the interim analysis. Patients who received ofatumumab maintenance treatment lived 14.2 months longer without their disease worsening than did patients who received no further treatment. Median PFS was 29.4 months for the ofatumumab arm and 15.2 months for the observation arm (hazard ratio, 0.50; P < 0.0001).
In the U.S., ofatumumab is approved for use in combination with chlorambucil for the treatment of previously untreated patients with CLL for whom fludarabine-based therapy is considered inappropriate and for extended treatment of patients who are in complete or partial response after at least two lines of therapy for recurrent or progressive CLL.
Source: Genmab; January 19, 2016.