Key Points• The intensified standard-ofcare regimens for younger patients with MCL do not overcome the deleterious effects of TP53 mutations.• MCLs with TP53 mutations should be considered for alternative frontline treatment.Despite recent advances in lymphoma treatment, mantle cell lymphoma (MCL) remains incurable, and we are still unable to identify patients who will not benefit from the current standard of care. Here, we explore the prognostic value of recurrent genetic aberrations in diagnostic bone marrow (BM) specimens from 183 younger patients with MCL from the Nordic MCL2 and MCL3 trials, which represent current standard-of-care regimens. In the univariate model, mutations of TP53 (11%) and NOTCH1 (4%), and deletions of TP53 (16%) and CDKN2A (20%), were significantly associated with inferior outcomes (together with MIPI, MIPI-c, blastoid morphology, and Ki67 > 30%); however, in multivariate analyses, only TP53 mutations (HR, 6.2; P < .0001) retained prognostic impact for overall survival (OS), whereas TP53 mutations (HR, 6.9; P < .0001) and MIPI-c high-risk (HR, 2.6; P 5 .003) had independent prognostic impact on time to relapse. TP53-mutated cases had a dismal outcome, with a median OS of 1.8 years, and 50% relapsed at 1.0 years, compared to a median OS of 12.7 years for TP53-unmutated cases (P < .0001). TP53 mutations were significantly associated with Ki67 > 30%, blastoid morphology, MIPI high-risk, and inferior responses to both induction-and high-dose chemotherapy. In conclusion, we show that TP53 mutations identify a phenotypically distinct and highly aggressive form of MCL with poor or no response to regimens including cytarabine, rituximab, and autologous stem-cell transplant (ASCT). We suggest patients with MCL should be stratified according to TP53 status, and that patients with TP53 mutations should be considered for experimental frontline trials exploring novel agents. (Blood. 2017;130(17):1903-1910

In recent decades, the prognosis of Mantle Cell Lymphoma (MCL) has been significantly improved by intensified first-line regimens containing cytarabine, rituximab and consolidation with high-dose-therapy and autologous stem cell transplantation. One such strategy is the Nordic MCL2 regimen, developed by the Nordic Lymphoma Group. We here present the 15-year updated results of the Nordic MCL2 study after a median follow-up of 11·4 years: For all patients on an intent-to-treat basis, the median overall and progression-free survival was 12·7 and 8·5 years, respectively. The MCL International Prognostic Index (MIPI), biological MIPI, including Ki67 expression (MIPI-B) and the MIPI-B including mIR-18b expression (MIPI-B-miR), in particular, significantly divided patients into distinct risk groups. Despite very long response durations of the low and intermediate risk groups, we observed a continuous pattern of relapse and the survival curves never reached a plateau. In conclusion, despite half of the patients being still alive and 40% in first remission after more than 12 years, we still see an excess disease-related mortality, even among patients experiencing long remissions. Even though we consider the Nordic regimen as a very good choice of regimen, we recommend inclusion in prospective studies to explore the benefit of novel agents in the frontline treatment of MCL.

I n recent years, the outcome of mantle cell lymphoma (MCL) has improved, especially in younger patients, receiving cytarabine-containing chemoimmunotherapy and autologous stem cell transplantation. Nevertheless, a proportion of MCL patients still experience early failure. To identify biomarkers anticipating failure of intensive chemotherapy in MCL, we performed target resequencing and DNA profiling of purified tumor samples collected from patients enrolled in the prospective FIL-MCL0208 phase 3 trial (high-dose chemoimmunotherapy followed by autologous transplantation and randomized lenalidomide maintenance). Mutations of KMT2D and disruption of TP53 by deletion or mutation associated with an increased risk of progression and death, both in univariate and multivariate analysis. By adding KMT2D mutations and TP53 disruption to the MIPI-c backbone, we derived a new prognostic index, the "MIPI-genetic" ("MIPI-

Janssen and Celgene.