Rituximab in the treatment of refractory follicular lymphoma -- six doses are better than four.

Seventeen patients with refractory follicular lymphoma heavily treated with chemotherapy (>2 regimens), radiotherapy, and biological modifiers were enrolled in a pilot study to receive six weekly doses, instead of the more frequent four doses, of monoclonal anti CD20, at a standard dose of 375 mg/m(2). In an intent-to-treat analysis, overall response was 76%, of which 47% (8 patients) were a complete response. With a median follow-up of 33.6 months, 7 complete responders remained alive and free of disease, and 2 partial-response patients remained stable without additional treatment. Actuarial curves showed that at 3 years, 53% of patients should be alive and free of disease. The 4 patients who were failures died secondary to tumor progression. Overall survival at 3 years was 76%. Toxicity was mild; all patients completed the schedule on time and doses. The addition of two doses of anti-CD 20 clearly improved the outcome in a group of patients with refractory follicular lymphoma heavily treated and poor prognostic factors. However, the number is too small to drawn definitive conclusions, and more clinical trials are necessary to determine if four of six doses of anti-CD20 therapy are better in this setting of patients.