Rituximab plus chemotherapy in follicular and mantle cell lymphomas.

Rituximab shows high single-agent activity in both previously untreated and relapsed or refractory indolent non-Hodgkin's lymphoma. In combination with chemotherapy, rituximab has achieved response rates higher than 90% with long duration of remission in phase II studies. Therefore, randomized phase III studies have been undertaken to determine whether rituximab plus chemotherapy can significantly improve outcomes compared with conventional chemotherapy in indolent non-Hodgkin's lymphoma. A study by the German Low-Grade Study Group has evaluated rituximab in combination with FCM (fludarabine/cyclophosphamide/mitoxantrone) in a randomized setting versus FCM alone in patients with relapsed or refractory follicular, mantle cell, or lymphoplasmacytic lymphoma. An interim analysis of 94 evaluable patients has shown a significantly higher response rate for rituximab plus FCM (overall response rate [ORR] 83%; complete response [CR] 35%) compared with FCM alone (ORR 58%; CR 13%), with no increase in toxicity. Superiority of rituximab plus FCM was seen in both follicular lymphoma (n = 53; ORR 92% v 75%; CR 40% v 21%) and, most strikingly, in mantle cell lymphoma (n = 38; ORR 65% v 33; CR 35% v 0%). A trend towards longer overall and disease-free survival for rituximab plus FCM has been observed, but longer follow-up is required.