ALBERT

Description: Introduction: AITL, one of the most common peripheral T-cell Lymphoma portends a poor prognosis. AITL is characterized by neoplastic T cells with a follicular helper immunophenotype, frequent mutations in epigenetic regulators TET2, IDH2, DNMT3A and in RHOA, and a prominent tumor microenvironment that could contribute to lymphomagenesis. Aiming to target this microenvironment and given the promising activity of lenalinomide (Len) in a relapsed setting (PMID: 23731832), we postulated that AITL patients (pts) might benefit from a treatment with Len combined with a classical CHOP regimen. This multicenter, open label, phase 2 trial (NCT01553786) investigates this treatment in previously untreated elderly pts. Patients and methods: Patients older than 59 years were treated with 8 cycles of Len + CHOP 21 (Len 25 mg/day (d), d1 to 14) and received intrathecal methotrexate prophylaxis. Thromboprophylaxis with low molecular weight heparin was mandatory. PET CTs at diagnosis and at the end of treatment were centrally reviewed. The primary objective was to evaluate the complete metabolic response rate according to the Lugano 2014 Classification. Secondary endpoints were safety, progression-free (PFS) and overall survival (OS). Mutations in TET2, IDH2, DNMT3A, RHOA, CD28, PLCG1, STAT3 and STAT5B were analyzed by deep sequencing (1000X) using DNA extracted from formalin-fixed paraffin-embedded tumor samples by PGM technology and were correlated to clinical parameters. Results: Between November 2011 and March 2017, 80 pts were enrolled, and 78 were evaluable. Central pathology review confirmed the diagnosis of AITL in 72 cases (92%). Median age was 69 (59-80), 52 % were female, 68% had a performance status of 0 to 1, 94% an Ann Arbor stage ≥III, 82% IPI≥3. Forty-five patients (58 %) completed the 8 planned cycles (mean number of cycles delivered, 5.9). Of the 624 planned treatment cycles, 458 (72 %) were completed. Treatment was stopped in 8 pts because of progressive disease, and in 15 because of adverse events. Toxicity was within the range expected of R-CHOP therapy with 70% grade 4 neutropenia and 31 % thrombocytopenia. Deep vein thrombosis occurred in 8 pts. Four secondary primary malignancies were reported. Five patients died from toxicity (4 from infection). Len dose reductions or interruptions were applied in 37 (5%) and 59 (9%) cycles, respectively, related to toxic effects. The median dose of Len per patient was 2275 mg (IQR 95-2825)-i.e. 81% of the planned dose of 2800 mg. Doxorubicin and cyclophosphamide were administrated at 98% and 97% of the planned dose. Complete metabolic response was observed in 34 patients (43.6%) (90%CI = [34.0%; 53.5%]), partial metabolic response in 3 (3.8%), no metabolic response in 2 (2.6%) and progressive metabolic disease in 16 (20.5%), the other being not evaluated because of progression (N=20) or death (N=3). With a median follow-up duration of 31.5 months (95%CI = [23.0; 43.7]) at the time of the cut-off, 2-year PFS is 42.3% (95%CI = [30.9%; 53.2%]) and 2-year OS is 60.1% (95%CI = [47.4%; 70.7%]). IPI was strongly associated with the survival (figure 1A). Mutational status was successfully determined in 64 pts with confirmed AITL diagnosis. TET2 mutations were detected in 49 cases (77%), with 28 (43%) pts bearing ≥2 TET2 mutations. RHOAG17V mutations in 34 pts (53%), DNMT3A mutations in 20 (31%) pts, including 6 with the DNMT3AR882X variant and IDH2 mutations in 14 (22%). CD28, PLCCG1 and STAT mutations were detected in less than 10% of pts (figure 1B). TET2 mutations correlated to age〉65 years (p=0.006) and IPI 3-5 (p=0.007). Interestingly, DNMT3A mutations were associated with a decreased response rate (p=0.003), a shorter PFS (p=0.04) and a trend toward a shorter OS (0.08). It is noteworthy that none of the 6 pts with the DNMT3AR882X mutant had response, suggesting that the resistance to anthracycline reported in DNMT3AR882X mutated acute myeloid leukemia (PMID: 27841873) could also occur in DNMT3AR882X mutated AITL. No correlation between other detected mutations and outcome was observed (table 1C). Conclusion A combination of 25 mg of Len for 14 days with CHOP cycles gives acceptable toxicity in AITL elderly pts. However, response rate and outcome appear similar to previous studies. We also confirmed in a prospective study the frequency of mutations in epigenetic regulators and RHOA in AITL and clarified their prognostic impact. Figure Figure. Disclosures Bachy: Gilead Sciences: Honoraria; Sandoz: Consultancy; Janssen: Honoraria; Roche: Research Funding; Takeda: Research Funding; Amgen: Honoraria; Celgene: Consultancy. Cartron:Celgene: Consultancy, Honoraria; Sanofi: Honoraria; Gilead Sciences: Honoraria; Janssen: Honoraria; Roche: Consultancy, Honoraria. Casasnovas:Merck: Honoraria; Takeda: Honoraria; Roche: Honoraria; Gilead Sciences: Research Funding; Roche: Research Funding; Janssen: Consultancy; Gilead Sciences: Consultancy; MSD: Consultancy; merck: Consultancy; takeda: Consultancy; Roche: Consultancy; Janssen: Honoraria; Celgene: Honoraria; Gilead Sciences: Honoraria; MSD: Honoraria. Tilly:Celgene: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; BMS: Honoraria; Astra-Zeneca: Membership on an entity's Board of Directors or advisory committees. Gaulard:Celgene: Research Funding; Roche: Honoraria; Takeda: Consultancy, Honoraria, Research Funding. Haioun:Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Sciences: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Gilead Sciences: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Janssen: Consultancy, Honoraria.

Description: Background and aim of the study Primary mediastinal B-cell lymphoma (PMBL) is an entity of aggressive B-cell lymphoma that is clinically and biologically distinct from the other molecular subtypes of diffuse large B-cell lymphoma (DLBCL). We recently detected by Whole exome sequencing a recurrent point mutation in the XPO1 (exportin 1) gene (also referred to as chromosome region maintenance 1; CRM1), which resulted in the Glu571Lys (p.E571K) missense substitution in 2 refractory/relapsed PMBL (Dubois et al., ICML 2015; Mareschal et al. AACR 2015). XPO1 is a member of the Karyopherin-b superfamily of nuclear transport proteins. XPO1 mediates the nuclear export of numerous RNAs and cellular regulatory proteins, including tumor suppressor proteins. This mutation is in the hydrophobic groove of XPO1 that binds to the leucine-rich nuclear export signal (NES) of cargo proteins. In this study, we investigated the prevalence, specificity, and biological / clinical relevance of XPO1 mutations in PMBL. Patients and methods High-throughput targeted or Sanger sequencing of 117 PMBL patients and 3 PMBL cell lines were performed. PMBL cases were defined either molecularly by gene expression profile (mPMBL cohort) or by standard histological method (hPMBL cohort) and enrolled in various LYSA (LYmphoma Study Association) clinical trials. To assess the frequency and specificity of XPO1 mutations, cases of classical Hodgkin lymphoma (cHL) and primary mediastinal grey zone lymphoma (MGZL) were analysed. Cell experiments were performed to assess the impact of the E571 mutation on the activity of selective inhibitor of nuclear export (SINE) molecules. Results XPO1 mutations were present in 28/117 (24%) PMBL cases but were rare in cHL cases (1/19, 5%) and absent from MGZL cases (0/20). A higher prevalence (50%) of the recurrent codon 571 variant (p.E571K) was observed in PMBL cases defined by gene expression profiling (n = 32), as compared to hPMBL cases (n = 85, 13%). No difference in age, International Prognostic Index (IPI) or bulky mass was observed between the PMBL patients harboring mutant and wild-type XPO1 in the overall cohort whereas a female predominance was noticed in the mPMBL cohort. Based on a median follow-up duration of 42 months, XPO1 mutant patients exhibited significantly decreased PFS (3y PFS = 74% [CI95% 55-100]) compared to wild-type patients (3y PFS = 94% [CI95% 83-100], p=0.049) in the mPMBL cohort. In 4/4 tested cases, the E571K variant was also detected in cell-free circulating plasmatic DNA, suggesting that the mutation can be used as a biomarker at the time of diagnosis and during follow-up. Importantly, the E571K variant was detected as a heterozygous mutation in MedB-1, a PMBL-derived cell line, whereas the two other PMBL cell lines tested, Karpas1106 and U-2940, did not display any variants in XPO1 exon 15. KPT-185, the SINE compound that blocks XPO1-dependent nuclear export, induced a dose-dependent decrease in cell proliferation and increased cell death in the PMBL cell lines harbouring wild type or mutated alleles. To test directly if XPO1 mutation from E571 to E571K alters XPO1 inhibition by SINE compounds, the mutated protein was tested in vitro. The E571XPO1 mutated allele was transiently transfected into osteosarcoma U2OS cells which stably express the fluorescently labelled XPO1 cargo REV. Cells were treated with the clinical SINE compound selinexor, which is currently in phase I/II clinical trials and nuclear localization of REV-GFP was analysed in red transfected cells. The results showed that the nuclear export of the mutated XPO1 protein was inhibited by selinexor similarly to the wild-type XPO1 protein (Figure 1). Conclusion Although the oncogenic properties of XPO1 mutations remain to be determined, their recurrent selection in PMBL strongly supports their involvement in the pathogenesis of this curable aggressive B-cell lymphoma. XPO1 mutations were primarily observed in young female patients who displayed a typical PMBL molecular signature. The E571K XPO1 mutation represents a novel hallmark of PMBL but does not seem to interfere with SINE activity. Rev-GFP (green fluorescent) expressing U2OS cells were transfected with wild type XPO1-RFP (red fluorescent protein), XPO1-C528S-RFP, XPO1-E571K-mCherry, and XPO1-E571G-mCherry. The cells were then treated with 1µM KPT-330 for 8 hours. Figure 1. Rev-GFP expressing U2OS cells transfected with XPO1 variants. Figure 1. Rev-GFP expressing U2OS cells transfected with XPO1 variants. Disclosures Landesman: Karyopharm Therapeutics: Employment. Senapedis:Karyopharm Therapeutics, Inc.: Employment, Patents & Royalties. Argueta:Karyopharm Therapeutics: Employment. Milpied:Celgene: Honoraria, Research Funding.

Description: Background: Angioimmunoblastic T cell lymphoma (AITL) is one of the most frequent peripheral T cell lymphoma, and has a poor prognosis. Neoplastic T cells originate from T follicular helper cells, and are admixed among a prominent microenvironment, making their identification sometimes difficult. IDH2 mutations are present in 20-30% AITL patients, where they often co-exist with TET2, DNMT3A and RHOA mutations. They affect almost exclusively the codon R172 of IDH2, providing to the IDH2 enzyme a neo-activity that converts α ketoglutarate (αKG) to D 2-hydroxyglutarate (2HG). D-2HG, the dextrogyre form of 2HG, is an oncometabolite present at very low level under physiological condition, which inhibits many αKG dependent dioxygenases, including TET proteins and is involved in oncogenesis of various cancers such as gliomas or acute myeloid leukemias (AML). Preliminary data, based on small series, showed that increased level of 2HG was detectable in tumor and in serum of IDH2 mutated AITL. However, 2HG level, as well as D/L ratio, has not been evaluated as a surrogate marker of IDH2 mutation in AITL, at diagnosis or during the follow-up. Patients and Methods: Serum from 69 AITL patients, collected in REVAIL trial (NCT00169156) (N=48), RAIL trial (NCT01553786) (N=9) or TENOMIC collection (N=12) were included in this study. IDH2 mutations were assessed in formalin fixed paraffin embedded tumor tissue by deep next generation sequencing of exon 4, using PGM technology (N=63) or allele specific PCR (N=6). For the purpose of the study the cohort was enriched in mutated patients. Serum was collected at diagnosis and at the end of the frontline treatment in 6 patients, 5 of them being IDH2 mutated. D and L 2HG was measured in serum using a liquid tandem mass spectrometry method as previously described (Poinsignon et al. J Chromatogr B 2016) to determine total (D+L) 2HG and D/L 2HG ratio. Results: Twenty-four patients (35%) were IDH2 mutated. Median IDH2 variant allele frequency (VAF) was 7% (IQR, 4%-12.5%). Median total 2HG was 3.63 µM (IQR, 1.6-6.1) in mutated patients versus 1.17 µM (IQR, 0.85-1.68) in wild type patients (p