The Addition of Rituximab to First-Line Chemotherapy (R-CHOP) Results in Superior Response Rates, Time to Treatment Failure and Response Duration in Patients with Advanced Stage Mantle Cell Lymphoma: Long Term Results of a Randomized GLSG Trial

Background: The addition of rituximab to chemotherapy (R-CHOP) has been shown to improve response rates in mantle cell lymphoma (MCL), but prolongation of response duration or overall survival was not observed (Lenz et al., JCO 2005). In a similar randomized comparison of 90 patients, again the addition of rituximab to MCP showed a tendency towards higher CR rates, but no improvement of overall response rate, progression free, or overall survival (Herold et al., ICML-10, 2008).

Methods: We present an update of a previously published trial randomly comparing efficacy and safety of R-CHOP to CHOP induction in previously untreated patients with advanced stage MCL.

Results: Of the 123 evaluable patients, 63 patients were randomized to R-CHOP. Median age was 62 years, and risk profiles of the two treatment arms were comparable. Overall response rates were 92% vs. 75% for R-CHOP vs. CHOP (p = 0.0139) and complete remission rates 33% vs. 8% (p = 0.0008). After a median follow-up of 65 months, median time to treatment failure was prolonged from 14 months for CHOP to 28 months for R-CHOP (p = 0.0003). Similarly, median response duration was prolonged from 18 (CHOP) to 29 months (R-CHOP, p = 0.0052). So far, no significant improvement of overall survival has been observed with median not reached vs. 59 months and 5-years OS rates of 59% and 46% (p = 0.27) after R-CHOP and CHOP, respectively. Toxicity was not significantly higher for R-CHOP treated patients.

Conclusions: After longer follow-up, superior remission rates, time to treatment failure, and response duration of combined immuno-chemotherapy were confirmed. However, in contrast to other lymphoma entities, improvement of overall survival has not yet been proven in MCL patients. Therefore new therapeutic options are urgently warranted to further improve the long term outcome in this otherwise dismal disease.