Combined Immuno-Chemotherapy Followed by Rituximab Maintenance Is an Effective Salvage Treatment after Prior Rituximab Containing Therapy: Results of a GLSG-Subgroup Analysis in Patients with Relapsed Indolent Lymphoma.

Background: Combined immuno-chemotherapy incorporating Rituximab with various chemotherapy regimens has resulted in increased response rates and prolonged progression-free and even overall survival in numerous trials. However, a constant relapse pattern has been observed even after such an optimized first line treatment.

Methods: In a subgroup analysis of the GLSG trial for relapsed indolent lymphoma (R-FCM followed by Rituximab maintenance), response and long term results of patients with previous Rituximab containing treatment were compared with the Rituximab naive control group. Induction comprised of 4 courses of chemotherapy with Fludarabine, Cyclophosphamide and Mitoxantrone (FCM) plus Rituximab. Patients responding with a complete (CR) or partial remission (PR) were randomized for observation only versus Rituximab maintenance (4 applications at month 3 and 9).

Results: 18 of 268 patients (arm A) with relapsed lymphoma had already previously received a R-containing regimen, the remainder 250 patients (arm B) were Rituximab naive. Overall response (arm A: 83 % vs. group B: 77%) and CR rate (arm A: 39% vs. arm B: 23%) were comparable in both subsets of study patients. Accordingly, progression-free survival after R-FCM was comparable in both subgroups of patients (median PFS in arm A: 15 months, arm B: 27 months) and overall survival as well. Especially, no disadvantage in the Rituximab pretreated patient group was detectable. 9 of the Rituximab pretreated patients responding to R-FCM induction therapy were randomized to maintenance treatment. After a median observation time of 20 months, 3 patients had relapsed and 6 patients remained in remission (3 of them for >20 months) resulting in a similar PFS after rituximab maintenance as in patients who were Rituximab naive.

Conclusion: This subgroup analysis strongly suggests that a Rituximab containing salvage therapy induction as well as maintenance is a highly effective treatment option even in patients who received Rituximab in first line therapy.