Final Results Of Phase II Study Of Lenalidomide Plus Rituximab-CHOP21 In Elderly Untreated Diffuse Large B-Cell Lymphoma Focusing On The Analysis Of Cell Of Origin: REAL07 Trial Of The Fondazione Italiana Linfomi (2013)

Abstract Introduction The standard treatment for elderly untreated diffuse large B-cell lymphoma (DLBCL) is RCHOP21, however up to 40% of patients experienced failures. Lenalidomide showed activity in heavily pretreated DLBCL and in vivo and in vitro data demonstrated a synergism with rituximab. In the phase I trial REAL07 (Chiappella et al, Haematol 2013), FIL demonstrated that the association of LRCHOP21 was feasible in elderly untreated DLBCL and identified 15 mg lenalidomide from day 1 to day 14 as the maximum tolerated dose in combination with RCHOP21. Patients and methods. The phase II trial REAL07 was designed based on Simon's two stage design to demonstrate an improvement of overall response rate (ORR) of 15% in LRCHOP21 compared to 70% of standard RCHOP21. Secondary endpoints were progression-free survival (PFS), overall survival (OS), event-free survival (EFS) and to correlate outcome with cell of origin (COO) profile. Response was evaluated according to 2007 Cheson criteria. Inclusion criteria were: age 60-80 FIT at the comprehensive geriatric assessment; untreated CD20+ DLBCL; Ann Arbor stage II/III/IV; international prognostic index (IPI) at low-intermediate/intermediate-high/high (LI/IH/H) risk. Treatment plan was: RCHOP21 plus 15 mg lenalidomide from day 1 to 14 for 6 courses. All cases were centrally reviewed by expert pathologist; COO profile analysis was conducted with immunohistochemistry according to Hans' algorithm and with gene expression profile (DASL assay). Results. From April 2010 to May 2011, 49 patients were enrolled. Clinical characteristics were: median age 69 years (range 61-80); stage III/IV 43 (88%), IPI IH/H 30 (61%). At the end of 6 LRCHOP21, ORR was 92%. Complete remissions (CR) were 42 (86%) and partial remission 3 (6%); 3 patients (6%) did not respond and one (2%) died for homicide. At a median follow-up of 28 months, 2-year OS was 92% (95% CI: 79-97), 2-year PFS was 80% (95% CI: 64-89) and 2-years EFS was 70% (95% CI: 55-81); 2-year PFS for IPI LI was 89% (95% CI: 62-97) and for IPI IH 76% (95% CI: 47-90) and for IPI H 72% (95% CI: 36-90). Hematological and extra-hematological toxicities were mild, with no grade IV extra-hematological events and no toxic deaths during treatment. Of the 294 planned courses of LRCHOP21, 277 (94%) were administered; median dose of lenalidomide delivered was 1185 mg (94% of the planned dose); at least 90% of the planned dose of each drug was administered in 91% of the RCHOP21 courses. Median interval time between RCHOP21 courses was 21 days (range 19-48). All 49 cases underwent central pathology review and diagnosis of DLBCL was confirmed. Regarding COO analysis, tissue block or stained slides were collected in 40/49 (82%), of which 32 were adequate for analysis. At the time of this abstract, COO analysis was reported according to immunohistochemistry data; DASL analysis is ongoing. Clinical characteristics between germinal center (GCB, 16 patients) and non-GCB (16 patients) were superimposable, excepted for a majority of H IPI risk in non-GCB group (p 0.067). ORR for GCB and non-GCB were 88% (CR 81%) and 88% (CR 88%), respectively. At a median follow-up of 28 months, 2-year PFS was 71% (95% CI: 40-88) in GCB-group and 2-years PFS was 81% (95% CI: 51-93) in non-GCB-group (Figure 1). Conclusions. In conclusion, LRCHOP21 is effective, also in poor risk patients, namely in non-GCB subgroup. These encouraging data warrant a future phase III randomized trial comparing LRCHOP21 vs. RCHOP21 in untreated non-GCB DLBCL. Disclosures: Off Label Use: lenalidomide in first line DLBCL is off lable. drug provided free by Celgene. Vitolo:Roche: Speakers Bureau; Celgene: Speakers Bureau; Takeda: Speakers Bureau.