[Increased response rate with rituximab in relapsed and refractory follicular and mantle cell lymphomas -- results of a prospective randomized study of the German Low-Grade Lymphoma Study Group].

BACKGROUND AND OBJECTIVE: Rituximab has shown a high activity in relapsed follicular lymphomas when given alone. Further on, phase-II-studies indicate that its addition to chemotherapy may improve the response rate substantially. However, so far, prospective randomized studies have not been available. PATIENTS AND METHODS: In 1998 the GLSG started a multicenter trial in patients with relapsed or refractory indolent lymphoma or mantle cell lymphoma. A fludarabine-containing regimen (FCM) was chosen for salvage therapy, with fludarabine 25 mg/m(2)/d 1-3, cyclophosphamide 200 mg/m(2) d 1-3 and mitoxantrone 8 mg/m(2) d 1. A total of four courses, every 4 weeks were given. Patients were prospectively randomized for FCM alone or the immunochemotherapy with R-FCM (375 mg/m(2) one day before FCM) RESULTS: About 147 randomized patients 93 had follicular, 40 mantle cell and 14 lymphoplasmocytic/-cytoid lymphoma. Statistical analysis was performed by sequential testing and indicated for 94 fully evaluable patients a significant advantage for the R-FCM-arm, with an overall response rate of 83 % as compared to 58%, when treated with FCM alone (CR: 35 % vs. 13 %). Similar improvements of remission rate were detected in the different lymphoma subgroups, especially in MCL (OR: 65 % vs. 33 %). Both treatment options were associated with hematological toxicities of grade III and IV, but well tolerated; infectious complications were rare, with no difference between the two treatment groups. CONCLUSION: This prospectively randomized trial demonstrates for the first time a significant improvement of the combined immunochemotherapy related to the remission rate in patients with relapsed or refractory indolent lymphoma.