Principles of maintenance therapy.

Although follicular non-Hodgkin's lymphoma may respond well to induction therapy, almost all patients will eventually relapse. To reduce the frequency of relapses and prolong disease-free intervals, maintenance treatment may be given to patients who respond or have stable disease after induction therapy. Maintenance treatment is given at regular intervals over prolonged periods in patients who may be asymptomatic, and so it is important that administration is simple, toxicity is minimal and that there is clear evidence of efficacy. The monoclonal antibody rituximab has many characteristics essential for a maintenance therapy: it is both effective and very well tolerated, and can maintain active concentrations in the blood with intervals of several months between administrations, enabling patients to continue with normal life while on maintenance therapy. Randomized trials of rituximab maintenance therapy have confirmed that remissions can be prolonged, and in one randomized trial, early results suggest a survival benefit. The optimal schedule for maintenance therapy has not yet been defined.