Final results of a randomized phase II GELA/LYSA study of rituximab plus ACVBP or CHOP, using a PET-driven consolidation strategy, in patients with high-risk diffuse large B-cell lymphoma (DLBCL).

8503 Background: GELA standard for young patients (pts) with high-risk DLBCL (aaIPI 2-3) is R-ACVBP induction plus consolidative BEAM and autologous stem cell transplantation (ASCT). R-CHOP induction might be as efficient and possibly less toxic than R-ACVBP. Also, early PET-negative patients may not need first-line ASCT. A phase II randomized trial was designed in 2007 to test both induction regimen and a PET-driven consolidation strategy (NCT00498043). Methods: Eligible pts were 18-59 years with a previously untreated CD20+ DLBCL, an aaIPI 2-3. Pts were randomly assigned to 4 cycles of either R-ACVBP14 or R-CHOP14 induction. Consolidation treatment was driven by centrally reviewed PET assessment (IHP visual criteria) after 2 (PET2) and 4 (PET4) induction cycles. Pts classified as PET2-/PET4- received a sequential immuno-chemotherapy consolidation; PET2+/PET4- pts underwent ASCT; PET4+ pts were considered as induction treatment failure and eligible for a salvage therapy. Primary endpoint was to evaluate the complete response (CR) rate after 4 induction cycles according to IWG 07 criteria. Results: 222 pts (R-ACVBP: 114; R-CHOP: 108) with a median age of 46 yrs were included: 97% had stage III/IV, 95% elevated LDH, 24% ECOG≥2. After induction treatment, 47% of the R-ACVBP arm and 39% of the R-CHOP arm pts achieved a CR. PET2 and PET4 were negative in 30% and 53% of pts in the R-ACVBP arm, and 25% and 40% in the R-CHOP arm, respectively. PET2-/PET4- pts were 27% and 24% in the R-ACVBP and R-CHOP arms respectively. Due to more frequent PET4+, pts in the R-CHOP arm more often received salvage therapy as post-induction treatment (39%) than pts in the R-ACVBP arm (27%) (p = 0.048). With a median follow-up of 45 months, PFS and OS were similar in both arms (4y-PFS=75%; 4y-OS=83%). Conclusions: A PET driven treatment of high risk DLBCL pts is feasible in a multicenter trial setting. Based on PET visual criteria at 4 cycles, CR rate was higher in the R-ACVBP arm and salvage was more frequently used after R-CHOP, possibly explaining similar PFS and OS in the two induction arms. 25% of pts found to be PET2-/PET4- do not require ASCT. Clinical trial information: NCT00498043.