Maintenance rituximab versus observation after R-CHOP or R-EPOCH in patients with untreated poor-prognosis diffuse large B-cell lymphoma and grade III follicular lymphoma.

8084 Background: The prognosis of diffuse large-B-cell lymphoma (DLBCL) with poor risk (International Prognostic Index, IPI=3-5 or bulky disease) is poor. A considerable proportion of patients with poor-risk relapsed after rituximab in combination with CHOP or CHOP-like chemotherapy. It has been widely demonstrated that maintenance rituximab (MR) can improve survival rate in follicular lymphoma (FL), but it's unclear in DLBCL. The objective of this study is to investigate the efficacy and safety of maintenance rituximab therapy in DLBCL patients with poor risk. Methods: 50 untreated DLBCL patients (including 6 FL III) with poor risk (IPI=3-5 or bulky disease) who achieve complete remission (CR) or complete remission unconfirmed (CRu) after 6∼8 cycles of R-CHOP or R-EPOCH (±invasion field radiotherapy) were enrolled. They were assigned to MR (n=21) for two years or till to relapse or death or observation only (OBS) (n=29). Results: Two-year disease-free survival (DFS) and overall survival (OS) rates for MR were 93.3% and 93.8%, respectively. 2-year DFS and OS rates for OBS were 69.4% and 87.7%, respectively. DFS was significantly prolonged (p=0.046), but no significant difference in OS was seen (p=0.519). Median DFS and OS of both arms were not reached. The main toxicities of MR were grade I-II hematological toxicity. Grade III-IV toxicities were rare (3.9%). Conclusions: Our results suggest that maintenance rituximab for two years significantly prolonged DFS but not OS in untreated DLBCL patients with poor risk. The toxicities were few and mild. No significant financial relationships to disclose.