Rituximab as first-line and maintenance therapy for patients with indolent non-hodgkin's lymphoma.

Purpose: To evaluate response to single-agent rituximab in patients with indolent non-Hodgkin's lymphoma (NHL) and no previous systemic therapy, and the feasibility, toxicity, and efficacy of maintenance rituximab, administered at 6-month intervals, in patients with objective response or stable disease after first-line rituximab therapy.

Patients And Methods: Patients with indolent NHL (follicular or small lymphocytic subtypes) previously untreated with systemic therapy received rituximab 375 mg/m(2) intravenously weekly for 4 weeks. Patients were restaged at week 6 for response; those with objective response or stable disease received maintenance rituximab courses (identical dose and schedule) at 6-month intervals. Maintenance was continued for a maximum of four rituximab courses or until progression. Between March 1998 and May 1999, 62 patients were entered onto this trial; minimum follow-up was 24 months.

Results: Sixty patients (97%) completed the first 4-week course of rituximab and were assessable for response. All have now completed rituximab therapy; 36 (58%) received four courses at 6-month intervals. The objective response rate at 6 weeks was 47%; 45% of patients had stable disease. With continued maintenance, final response rate increased to 73%, with 37% complete responses. Response was similar in patients with follicular versus small lymphocytic subtypes (76% v 70%, respectively). Median actuarial progression-free survival was 34 months. Two patients experienced grade 3/4 toxicity with the first dose; one patient was removed from treatment. No cumulative or additional toxicities were seen with maintenance courses.

Conclusion: Rituximab is highly active and extremely well tolerated as first-line single-agent therapy for indolent NHL. First-line treatment with scheduled maintenance at 6-month intervals produces high overall and complete response rates and a longer progression-free survival (34 months) than has been reported with a standard 4-week treatment.