Evaluation on a Six-Dose Treatment of Anti CD 20 Monoclonal Antibody in Patients with Refractory Follicular Lymphoma

Abstract

Treatment of refractory follicular lymphoma with monoclonal antibody CD 20 has been proven to be a good therapeutic option. However, most studies used four weekly doses and time to treatment failure (TTF) and overall survival (OS) could be considered very short: 11.0 and 13.6 months respectively. We started a pilot study to evaluate if six infusions at the same doses and schedule could improve the outcome in these patients. Seventeen patients with refractory follicular lymphoma heavily treated with chemotherapy (> 2 regimens), radiotherapy and biological modifiers were enrolled in a pilot study. They received 6 weekly doses, at 375 mg/m², of monoclonal anti CD 20. In an intent to treat analysis, overall response was 76%, of which 47% (8 patients) were complete response and 5 patients were partial response. With a median follow-up of 28.6 months, 7 complete responders remain alive, free of disease, and 2 partial responses remain stable without additional treatment. Median to TTF has not been reached; yet, actuarial curves showed that at 3 years, 53% of patients are alive. The four patients who were failure died secondary to tumor progression. Overall survival (OS) at 3-year 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 OS and TTF in a group of patients with refractory follicular lymphoma heavily treated and with poor prognostic factors. However, the number is too short to draw definitive conclusions; more clinical trials are necessary to determine if 4 or 6 doses of anti CD 20 therapy are better in this setting of patients.