Impact of Autologous Stem Cell Transplantation and/or Rituximab on Outcome of Patients with Relapsed Follicular Lymphoma- Retrospective Analysis of 2 Randomized Trials of the German Low Grade Lymphoma Study Group (GLSG).

Background: There is no standard therapeutic approach for patients (pts) with relapsed advanced stage follicular lymphoma (FL). The impact of high-dose therapy followed by autologous blood stem cell transplantation (ASCT) with or without addition of rituximab (R) to salvage regimens was evaluated.

Methods: Patients with advanced stage FL from 2 successive prospective randomized trials of the GLSG (MCP vs. CHOP and CHOP vs. R-CHOP, both followed by randomization for IFN maintenance vs. ASCT) were eligible for retrospective analysis of subsequent therapy if they had progressive, relapsed or refractory disease following 1^st line treatment, were <65 years, had no prior ASCT and required treatment according to our established criteria.

Results: 222 patients were identified of whom 167 data sets were available for analysis (n=36 lost to follow-up, n=6 dead before initiation of salvage therapy, n=13 no indication for treatment). Median age was 50 years (range 19–64), 97 pts (58%) were male, 20 pts (12%) had previously received R (R-CHOP 1^st line). 87 pts (53%) were treated with a R-containing salvage regimen. Most commonly used chemotherapy protocols were purin-analogue based (26%), followed by alkylator (22%) and anthracycline (13%) based regimens. Overall response rate (ORR) for chemotherapy with or without R 2^nd line was 86% (CR 39%, PR 47%) and 78% (CR 26%, PR 52%), respectively. Median PFS for pts treated with or without Rituximab 2^nd line was 3.4 and 2.8 years (yrs), median OS 8.3 and 7.2 yrs, respectively. Adequate numbers of peripheral blood stem cells could be harvested in 92% of evaluable patients. 66 pts received ASCT (40%) of whom 31 were also treated with R. 26 pts (39%) received a TBI-containing conditioning therapy. Most common non-hematologic grade 3/4 toxicity of ASCT were mucositis (43%) and infectious complications (30%). 4 pts died within 3 months after ASCT (6%). ORR before and after ASCT was 79% (CR 19%, PR 60%) and 95% (CR 60%, PR 35%), respectively. Median PFS for pts receiving ASCT or not was 5.5 and 2.3 yrs (p=0.038), median OS 7.2 yrs and not reached yet, respectively.

Conclusion: This retrospective analysis of two prospective multicenter trials suggests that patients with relapsed FL qualifying for ASCT may profit from that approach in terms of improved response rates and prolonged remission duration, albeit with more toxicity and an early death rate of 6%. Subgroup analysis revealed that the addition of R to salvage therapy primarily benefited patients not receiving ASCT 2^nd line. Comparison of these results with ASCT in 1^st remission with or without R is ongoing and will be presented at the meeting.