Results from the phase 3 PROLONG study demonstrated that maintenance therapy with ofatumumab was superior to observation in terms of progression-free survival in patients with relapsed chronic lymphocytic leukemia (CLL), according to an article published online in the Lancet Oncology.1
Ofatumumab is a human anti-CD20 monoclonal antibody with efficacy as monotherapy in refractory CLL. Investigators sought to determine the efficacy and safety of ofatumumab as maintenance treatment for patients in remission after re-induction treatment for relapsed CLL.
Investigators enrolled 474 patients: 238 patients were randomly assigned to receive ofatumumab maintenance treatment and 236 were randomly assigned to observation.
With a median follow-up of 19.1 months, progression-free survival was 29.4 months in the ofatumumab group (95% CI: 26.2-34.2) compared with 15.2 months in the observation group (HR: 0.50; 95% CI: 0.38-0.66; P<0.0001).
In regard to safety, the most common grade 3 or higher adverse events up to 60 days after last treatment were neutropenia (24% in ofatumumab group; 10% in the observation group); infections (13% compared with 8%). Eight percent of patients in the ofatumumab group and 1% of patients in the observation group experienced adverse events that led to treatment discontinuation.
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Up to 60 days after final treatment, two deaths related to adverse events occurred in the ofatumumab group compared with five deaths in the observation group. None of the deaths were treatment-related.
Investigators concluded that these data are important for the development of optimum maintenance treatment strategies in patients with relapsed CLL.
- van Oers MHJ, Kuliczkowski K, Smolej L, et al. Ofatumumab maintenance versus observation in relapsed chronic lymphocytic leukaemia (PROLONG): an open-label, multicentre, randomised phase 3 study. [published online ahead of print September 13, 2015]. Lancet Oncol. doi: 10.1016/S1470-2045(15)00143-6.