Ofatumumab plus chlorambucil as a first-line therapy in less fit patients with chronic lymphocytic leukemia: analysis of COMPLEMENT1 and other monoclonal antibodies association data.

The management of patients with chronic lymphocytic leukemia (CLL) has radically improved over the last few years with the addition of anti-CD20 monoclonal antibodies (MoAbs) to chemotherapy. Chlorambucil has been considered for decades as a suitable therapeutic option for frail patients. Taking into account the advantage offered by the addition of MoAbs to chemotherapy, different studies up to now have explored the feasibility of chlorambucil-based chemoimmunotherapies in treatment-naïve CLL. COMPLEMENT1 is a prospective, randomized, open-label trial evaluating the efficacy and safety of ofatumumab added to chlorambucil, compared with chlorambucil in monotherapy, in the setting of untreated patients with CLL considered unsuitable for a fludarabine-based approach. Progression-free survival was significantly longer in the chemoimmunotherapy arm when compared with the single-agent chlorambucil (22.4 months versus 13.1 months). Response rate and quality were also improved in the combination arm. Furthermore, the addition of ofatumumab did not lead to an unmanageable toxicity. While the employment of anti-CD20 antibodies represents an advantage in the treatment of the CLL symptomatic population, at present different patient selection and treatment schedules do not allow a reliable comparison between chlorambucil-based regimens. The addition of ofatumumab to chlorambucil represents a further therapeutic gain in CLL. Longer follow up and direct comparison with other MoAbs are warranted to establish the preferred first-line treatment in elderly and unfit patients.