Rituximab as first-line and maintenance therapy for patients with indolent non-Hodgkin's lymphoma: interim follow-up of a multicenter phase II trial.

The purpose of this study is to evaluate the activity of rituximab (Rituxan; Genentech, Inc, South San Francisco, CA, and IDEC Pharmaceuticals, San Diego, CA) in the first-line treatment of patients with indolent non-Hodgkin's lymphoma, and to evaluate the role of scheduled maintenance courses of rituximab in prolonging duration of remission. Sixty-two patients with stages II to IV indolent non-Hodgkin's lymphoma (follicular or small lymphocytic) who had received no previous systemic therapy entered this multicenter, community-based trial. All patients received rituximab 375 mg/m(2) weekly for 4 consecutive weeks, and were evaluated for response at week 6. Patients who had an objective response or stable disease continued treatment every 6 months with repeat 4-week courses of rituximab for a total of four treatment courses. Interim results of this ongoing trial are available. When evaluated at week 6, 28 of 60 evaluable patients (47%) had objective response and 27 patients (45%) had minor response or stable disease. With further follow-up and repeat courses of rituximab, the major response rate increased from 47% to 65% and the complete response rate increased from 7% to 27%. Response rates were similar in patients with follicular lymphoma and small lymphocytic lymphoma (63% and 66%, respectively). Median progression-free survival has not been reached, but will be greater than 24 months. There has been no cumulative toxicity observed with repeat courses of rituximab. Rituximab is highly effective as a first-line single agent for the treatment of indolent non-Hodgkin's lymphoma. The initial response rate can be improved by using scheduled maintenance courses of rituximab administered every 6 months. Final information regarding duration of response and time to progression awaits further follow-up.