Clinical, Metabolic and Molecular Responses After 4 Courses of R-DHAP and After Autologous Stem Cell Transplantation for Untreated Mantle Cell Lymphoma Patients Included in the LyMa Trial, a Lysa Study
Authors: Le Gouill Steven , Callanan Mary , Macintyre Elizabeth , delfau-Larue marie-Hélène , bodet-Milin Caroline , Meignan Michel , Moreau Anne , Travers-Glehen Alexandra , Béné Marie-christine , Haouin Corinne , Gressin Remy , Casasnovas Rene-Olivier , Ribrag Vincent , Damaj Gandhi , Gyan Emmanuel , Oberic Lucie , Bouabdallah Krimo , Thieblemont Catherine , Hermine Olivier 
Published: October 2019

Abstract
Abstract 152
Mantle cell lymphoma (MCL) is a rare B-cell malignancy characterized by the t(11;14) translocation. The European MCL network has demonstrated that a sequential R-CHOP/R-DHAP chemotherapy regimen prior to autologous stem cell transplantation (ASCT) provides better disease control than R-CHOP (Hermine et al, ASH 2010, abstract 110) and that molecular minimal residual disease (MRD) measured by IGH real-time quantitative polymerase chain reaction (PCR) before and after ASCT is an important prognostic factor to predict progression-free survival (PFS) (Pott et al. Blood. 2010;115(16):3215–23). Indeed, the use of high-dose aracytine upfront before ASCT is now recommended and molecular remission appears to be a major objective for future clinical trials in MCL. It therefore appeared interesting to appreciate response rates combining standard evaluation (Cheson 1999), FDG-PET imaging (Cheson 2007) and PCR techniques after rituximab plus upfront high-dose aracytine (R-DHAP) followed by ASCT. Response rates after 4 courses of R-DHAP were one of the objectives of the LyMa trial (NCT00921414). This trial is a randomized, open-label, phase III study that evaluates the efficacy of rituximab maintenance therapy in MCL patients aged between 18 and 66 years old, undergoing first-line treatment with 4xR-DHAP and exhibiting a response after ASCT (R-BEAM). Patients who do not reach a sufficient partial remission after R-DHAP are planned to receive 4 additional courses of R-CHOP before ASCT. The LyMa trial started in September 2008 and was designed to enroll 299 patients over a 4 years period. To date (August 2012), 295 patients have been included. Herein, we report response rates according to the combination of Cheson 1999 and 2007 criteria plus molecular response rates after 4xR-DHAP and after ASCT for the first 200 enrolled patients (last inclusion in August 2011).

Results:
One patient withdrew consent and the analysis is therefore on 199 patients. The cohort's median age is 57.2 years (range 29.7–65.7) and 41 patients are female (20%). At diagnosis, simplified MIPI was low in 104 cases (52%), intermediate in 55 (28%) and high in 40 (20%).Twenty-five patients (12.5%) presented with a blastoid variant. The panel of pathologist experts confirmed the diagnosis in all reviewed cases. Among the 199 evaluable patients, 182 (91%) received 4 courses of R-DHAP and 12 patients (all in PR according to Cheson 99 criteria) received 4 additional courses of R-CHOP because of insufficient clinical response after R-DHAP. Among these 12 patients, 5 reached CR/CRu after R-CHOP. Ultimately, 164 patients (82%) proceeded to ASCT (158 after R-DHAP and 6 after RDHAP/R-CHOP) and 154 (77.4%) have been randomized between rituximab maintenance or no maintenance. In an intention-to-treat (ITT) analysis and according to Cheson 1999 criteria, 152 patients (76.3%) reached CR (n=74) or CRu (n=78) after 4 courses of R-DHAP while 25 patients reached PR and 8 presented with SD/Prog. According to Cheson 2007 criteria (n= 170; PET not done in 17 cases and data missing in 12 cases), 129 patients reached CR while 41 patients remained FDG-TEP positive. Response rates according to Cheson 1999 and 2007 criteria for transplanted patients (n=164) were CR (n=109)/CRu (n=45) in 94% and CR in 84.5% (129 patients underwent FDG-PET after ASCT), respectively. Regarding MRD, diagnosis samples were available for 186/199 patients. Forty-one diagnosis samples have not yet been analyzed and 14 proved to be not informative. To date, the molecular response on peripheral blood (PB) after 4 courses of R-DHAP has been assessed in 103 cases and found negative in 80 cases and positive in 22 cases (not evaluable in one case). MRD on bone marrow (BM) after 4 courses of R-DHAP has been measured in 97 cases and found negative in 59 and positive in 36 (not evaluable in one case). After ASCT, PB and BM MRD were found negative in 91 patients (95 samples have been analyzed to date) and 67 (87 samples analyzed), respectively. Thus, in the LyMa trial,CR/CRu rates after only 4 courses of RDHAP, according to Cheson 1999 and 2007 criteria, are very high confirming the major anti-tumoral impact of high-dose aracytine upfront in MCL. In addition, these encouraging results seem to be confirmed at the molecular level strengthening the interest of an MRD-guided management of MCL patients. Results will be updated at the time of the meeting and patients' outcome according to disease status will be presented.

Disclosures:
Ribrag: Servier: Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Bayer: Research Funding; Sanofi-Aventis: Research Funding; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees.