Prolonging remission with rituximab maintenance therapy.

Maintenance therapy using rituximab is currently under consideration as a means of prolonging remission in patients with indolent non-Hodgkin's lymphoma. A phase II trial using rituximab as first-line therapy followed by maintenance treatment was carried out in patients with previously untreated indolent non-Hodgkin's lymphoma. The overall response rate improved from 47% (7% complete response) after initial treatment to 73% (37% complete response) after maintenance treatment; median progression-free survival was 37 months. A similar study in patients with previously untreated chronic lymphocytic leukemia or small lymphocytic lymphoma (SLL) also showed some improvement in response rates after maintenance therapy and a median progression-free survival of 19 months. The improved remission duration suggested in these phase II trials has been confirmed in a randomized, phase III trial performed by the Swiss Group for Clinical Cancer Research. Patients with follicular non-Hodgkin's lymphoma who had objective response or stable disease after a standard 4-week course of rituximab were randomized to either observation or further maintenance rituximab treatment. Median event-free survival was longer in patients who received maintenance therapy (23 v 12 months; P = .02). The toxicity of maintenance rituximab has been minimal in all trials to date. Although prolongation of progression-free survival has been shown in all completed trials, multiple other questions regarding maintenance rituximab are being addressed in ongoing trials. These include optimum schedule/duration, use after initial chemotherapy/rituximab combinations, efficacy versus retreatment at progression, and efficacy in other B-cell neoplasms.