Prospective, multicenter, randomized GITMO-IIL trial comparing intensive (R-HDS) to conventional chemoimmunotherapy (CHOP-R) in high-risk follicular lymphoma (FL) at diagnosis

8006 Background: The GITMO-IIL trial evaluated if an intensified treatment with ASCT is better than conventional chemotherapy (both supplemented with Rituximab) in high-risk FL at diagnosis. Methods: Eligibility required a FL with aaIPI>1 or IIL>2 score and an age of 18–60. Primary endpoint was EFS. The analysis was intention to treat. Secondary endpoints were PFS, DFS, OS, rate and prognostic value of MR. R-HDS and CHOP-R have been already described (Ladetto et al ASH 2005, Rambaldi et al Blood 2002). Planned sample size was 240 to detect a 20% absolute increase in the 3-years EFS. However the trial was stopped at 136 pts due to R-HDS superiority in EFS at a planned interim analysis. Cross-over was allowed after CHOP-R failure. Centralized PCR-based molecular analysis was planned on BM cells. Results: Age, stage, LDH, bulky disease, B-symptoms ECOG PS, extranodal disease aaIPI, IIL and retrospectively assigned FLIPI were similar in the two arms. CRs were 59% with CHOP-R and 85% with R-HDS (p<0.001). At a median follow-up of 39 months EFS and PFS are 36% and 38% for CHOP-R and 66% and 72% for R-HDS. OS is 83% in each arm. 67% of relapsed R-CHOP pts underwent R- HDS. MRs were 44% after CHOP-R and 80% after R-HDS (p<0.001). MR was associated to a better PFS (p<0.001). Of note, 3yrs PFS of pts with or without MR was similar in the two arms (MR: 67% with CHOP-R and 76% with R-HDS) (no MR: 25% for CHOP-R and 32% for R-HDS). MR was the strongest independent prognostic factor for PFS, EFS and DFS by multivariate analysis. Conclusions: This is the first phase III trial including MR analysis in a high proportion of pts and comparing intensified versus conventional therapy in the rituximab age. This trial indicates that: a) R-HDS has a better EFS and PFS in truly high-risk FL patients; b) MR is the strongest outcome predictor available in FL; c) the similar outcome in pts achieving (or not achieving) MR, regardless of treatment received, indicates that the superior performance of R-HDS is mostly due to its superior MR rate. [Table: see text]