García‐Sánz, Ramón

Abstract INTRODUCTION Central nervous system (CNS) relapse is a challenging situation in diffuse large B-cell lymphoma (DLBCL). High CNS-International Prognostic Index (IPI), activated B-cell (ABC) subtype and MYD88 L265P mutation, features often found in transformed Waldenström macroglobulinemia (WM), are associated with a higher risk for developing CNS relapse. This study was aimed to describe CNS involvement in a large cohort of transformed WM. METHODS This international multicenter retrospective study included patients with a diagnosis of WM and a concurrent or sequential histological diagnosis of DLBCL. CNS disease was diagnosed by detection of DLBCL cells in the cerebrospinal fluid and/or by brain biopsy. Patients with CNS involvement by lymphoplasmacytic cells (Bing-Neel syndrome) were excluded. Of 254 identified patients with a diagnosis of histological transformation (HT) between 1988 and 2020, 19 were excluded due to lack of data on extranodal involvement. The first part of the analysis focused on baseline CNS involvement. Clinicobiological characteristics were compared between groups using Chi-square or Fisher's exact tests or Mann Whitney tests as appropriate. We analyzed CNS recurrence in the second part of the study. Forty-eight additional patients were excluded due to baseline CNS involvement (n = 25), absence of treatment at HT (n = 14) and lack of details on follow-up (n = 9). Cumulative incidence of CNS relapse was analyzed using competing-risk models that accounted for other events like systemic relapse or death from any cause, reporting sub-hazard ratio (SHR). RESULTS Baseline CNS involvement was present in 25 patients (11%) with transformed WM, including 10 (4%) with parenchymal disease, 10 with leptomeningeal, 4 (2%) with both, and 1 with unspecified CNS involvement. Characteristics associated with baseline CNS involvement were performance status 2-4 (P=0.03) and ≥2 extranodal sites (P=0.02). Median survival after HT was 1 year [0.7-2.5], comparable to the one of patients without CNS disease (1.8 year [1.2-2.6], P=0.74). We observed no difference in survival based on isolated CNS involvement (n = 10) compared to CNS and systemic involvement (n = 15) (P=0.94). Twenty-three CNS relapses occurred (12%). The 2-year and 3-year rates of CNS relapse were 9% (95% CI, 6-14) and 11% (95% CI, 7-16) (Figure 1). The median time to relapse in the CNS was 11 months (95% CI, 7-25). Thirteen CNS recurrences (57%) occurred during the first year of follow-up. Seventy percent were isolated CNS relapses. The location was leptomeningeal in 43% of cases, parenchymal in 35%, both in 17%, and unspecified in 4%. According to CNS-IPI risk groups (data available for 20 patients), 9 patients (45%) belonged to the high-risk group, 10 (50%) to the intermediate-risk group and 1 (5%) to the low-risk group. Prior to CNS relapse, 87% of patients had received rituximab, and 39% had received CNS prophylaxis (30% intrathecal chemotherapy, 4% high-dose methotrexate (HD-MTX), and 4% both). After CNS recurrence, 96% of patients received salvage treatment: combination of HD-MTX and HD-cytarabine (48%), HD-MTX alone (30%), or HD-cytarabine alone (9%). Four patients underwent consolidative autologous stem cell transplantation. The median survival after CNS relapse was 5.6 months. Factors associated with 3-year cumulative incidence of CNS recurrence in univariate analysis were involvement of kidney/adrenal glands (HR, 4.4; P=0.01) and MYD88 L265P mutation (P=0.01) (Figure 2A and B). Of note, among 74 patients (over 187, 40%) with data available for MYD88 mutation status, 11 CNS relapses occurred in patients with MYD88 L265P mutation (n = 54, 20%) whereas no relapse were observed in MYD88 WT cohort (n = 20). A trend toward higher risk of CNS relapse for ≥2 extranodal sites (HR, 2.3, 95% CI 0.98-5.3; P=0.06) was observed. Cumulative incidence according to CNS-IPI risk groups (0% in the low-risk, 9% in the intermediate-risk and 14% in the high-risk group) was not statistically significant (P=0.47). CONCLUSION CNS involvement occurs frequently in transformed WM. Rate of CNS relapse seems similar to DLBCL patients belonged to the CNS-IPI high-risk group. Special attention should be paid to patients with kidney/adrenal involvement and MYD88 L265P mutation. Figure 1 Figure 1. Disclosures Vos: Sanofi: Membership on an entity's Board of Directors or advisory committees; Celgene: Other: Travel reimbursement. Treon: X4: Research Funding; Janssen: Consultancy, Research Funding; Dana Farber Cancer Institute: Current Employment; BMS: Consultancy, Research Funding; Self: Patents & Royalties: Holder of multiple patents related to testing and treatment of MYD88 and CXCR4 mutated B-cell malignancies; AbbVie: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Dimopoulos: Janssen: Honoraria; Beigene: Honoraria; Amgen: Honoraria; BMS: Honoraria; Takeda: Honoraria. Kapoor: Cellectar: Consultancy; Karyopharm: Consultancy; BeiGene: Consultancy; Pharmacyclics: Consultancy; Sanofi: Consultancy; Amgen: Research Funding; Ichnos Sciences: Research Funding; Regeneron Pharmaceuticals: Research Funding; Glaxo SmithKline: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Castillo: Abbvie: Consultancy, Research Funding; BeiGene: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding; Janssen: Consultancy; Roche: Consultancy; TG Therapeutics: Research Funding.

AbstractGene expression profiling can be used for predicting survival in multiple myeloma (MM) and identifying patients who will benefit from particular types of therapy. Some germline single nucleotide polymorphisms (SNPs) act as expression quantitative trait loci (eQTLs) showing strong associations with gene expression levels. We performed an association study to test whether eQTLs of genes reported to be associated with prognosis of MM patients are directly associated with measures of adverse outcome. Using the genotype‐tissue expression portal, we identified a total of 16 candidate genes with at least one eQTL SNP associated with their expression with P < 10−7 either in EBV‐transformed B‐lymphocytes or whole blood. We genotyped the resulting 22 SNPs in 1327 MM cases from the International Multiple Myeloma rESEarch (IMMEnSE) consortium and examined their association with overall survival (OS) and progression‐free survival (PFS), adjusting for age, sex, country of origin and disease stage. Three polymorphisms in two genes (TBRG4‐rs1992292, TBRG4‐rs2287535 and ENTPD1‐rs2153913) showed associations with OS at P < .05, with the former two also associated with PFS. The associations of two polymorphisms in TBRG4 with OS were replicated in 1277 MM cases from the International Lymphoma Epidemiology (InterLymph) Consortium. A meta‐analysis of the data from IMMEnSE and InterLymph (2579 cases) showed that TBRG4‐rs1992292 is associated with OS (hazard ratio = 1.14, 95% confidence interval 1.04‐1.26, P = .007). In conclusion, we found biologically a plausible association between a SNP in TBRG4 and OS of MM patients.

Abstract In relapsed/refractory Hodgkin lymphoma (R/R HL), immunotherapies such as the anti-programmed death-1 inhibitor pembrolizumab have demonstrated efficacy as monotherapy and are playing an increasingly prominent role in treatment. The CD30/CD16A-bispecific antibody AFM13 is an innate immune cell engager, a first-in-class, tetravalent antibody, designed to create a bridge between CD30 on HL cells and the CD16A receptor on natural killer cells and macrophages, to induce tumor cell killing. Early studies of AFM13 have demonstrated signs of efficacy as monotherapy for patients with R/R HL and the combination of AFM13 with pembrolizumab represents a rational new treatment modality. Here, we describe a phase 1b, dose-escalation study to assess the safety and preliminary efficacy of AFM13 in combination with pembrolizumab in patients with R/R HL. The primary objective was estimating the maximum tolerated dose; the secondary objectives were to assess safety, tolerability, antitumor efficacy, pharmacokinetics, and pharmacodynamics. In this heavily pretreated patient population, treatment with the combination of AFM13 and pembrolizumab was generally well tolerated, with similar safety profiles compared to the known profiles of each agent alone. The combination of AFM13 with pembrolizumab demonstrated an objective response rate of 88% at the highest treatment dose, with an 83% overall response rate for the overall population. Pharmacokinetic assessment of AFM13 in the combination setting revealed a half-life of up to 20.6 hours. This proof-of-concept study holds promise as a novel immunotherapy combination worthy of further investigation. This phase 1b study was registered at www.clinicaltrials.gov as NCT02665650.

Abstract Fluorescence in situ hybridization (FISH) is an effective alternative for the analysis of cytogenetic abnormalities of low proliferative entities such as Waldenström macroglobulinemia (WM) but, to date, no studies have been carried out to explore the potential impact of molecular cytogenetics on disease evolution. Deletion of the long arm of chromosome 6 (6q-) is the most frequent cytogenetic abnormality in WM. In this study we have analyzed the incidence of this aberration (using both conventional cytogenetics and FISH analysis) in 102 WM patients, and we have correlated it with disease characteristics. Deletion of 6q21 was detected in 6% of patients by conventional cytogenetics, while FISH studies increased this incidence up to 39%. Moreover, in those patients analyzed by cIgM-FISH, the incidence of 6q- was higher (54%). Interestingly, 6q- patients displayed features associated with adverse prognosis (higher levels of ESR, CRP and beta-2 microglobulin), and a greater tendency to display anemia and hypoalbuminemia. Other differentiating variables without reaching statistical significance were a tendency of displaying a higher bone marrow lymphoplasmacytoid infiltration and the amount of monoclonal component in 6q- patients (table). In addition, patients with 6q- displayed shorter survival from time of diagnose (log-rank; p=0.09). In summary, our results show that 6q deletion in WM patients is currently the most frequently found cytogenetic abnormality. Patients with this deletion also shows a trend towards an aggressive disease and poorer outcome in WM. Further studies should focus on possible tumor suppressor genes in the minimal area of deletion at 6q and to determine their role in disease progression. table del6q present del6q absent p-value n 40 (39%) 62 (61%) β2M ≥4mg/dL 48% 16% 0.005 CRP ≥3.5 mg/dL 47% 11% 0.006 Albumin &lt;4mg/dL 86% 55% 0.006 ESR ≥100 mm/h 73% 44% 0.02 Hb &lt;11 g/dL 63% 40% 0.02 serum IgM &gt;20 g/L 86% 73% 0.10 BM infiltration &gt;40% 44% 31% 0.20

Abstract The outcome of patients (pts) with WM, a rare B-cell malignancy, varies widely. The international community has convened a panel to develop a prognostically meaningful staging system for survival after treatment initiation. Toward establishing IPSS, we performed multivariate analyses with bootstrap validation in a series of 587 pts (median age 67, range: 28 to 95, M/F ratio: 1.7) diagnosed between September 1979 and December 2001. Diagnostic and treatment criteria fulfilled recommendations of the 2nd international WM workshop. Front-line treatment was initiated at diagnosis in 69% and 4 mo to 164 mo later in the remaining pts. Criteria for initiation of therapy included cytopenia, constitutional symptoms, organomegaly, hyperviscosity, IgM-related disorders, which pertained to 51%, 44%, 35%, 31% and 13%, respectively. Treatment regimens comprised alkylating agents, fludarabine and rituximab in 369, 195 and 23 subjects, respectively. Baseline parameters included age&gt;65 yr in 57%, Hb≤11.5 g/dL in 65%, platelet count ≤100 x109/L in 9%, granulocyte count ≤1.5 x109/L in 9%, B2M &gt;3 mg/L in 56%, albumin ≤3.5 g/dL in 36% and monoclonal protein &gt;7.0 g/dL in 7%. With a median follow-up of 64 mo (range, 6 mo–182 mo), the median survival after treatment initiation was 87 mo (95%CI 79–103) regardless of the type of therapy applied (p=0.3). Using results of univariate survival analyses, recursive partitioning and martingale residuals analyses, 7 adverse characteristics for inclusion in multivariate analyses were identified during an expert meeting: age &gt;65 yr, platelet count ≤ 100x109/L, B2M &gt;3 mg/L, M-protein &gt;7.0 g/dL, granulocytes ≤1.5 x109/L, Hb ≤11.5 g/dL and albumin ≤3.5 g/dL. The Cox proportional hazard model with stepwise selection selected the first 6 covariates. Bootstrap resampling (500 replicates) validated the selection of the first 4 covariates in at least 80% of the replicates. Selection of at least one of the last 2 covariates in more than 80% of the replicates indicated a correlation between these 2 covariates, and validated the inclusion of Hb only. Using the combination of age, Hb, platelet count, B2M and M-protein, low risk was defined by the presence of ≤1 adverse characteristic except age, high risk by the presence of &gt;2 adverse characteristics; the remaining patients with 2 adverse characteristics or age &gt;65yr had intermediate risk, comprising 27%, 38% and 35% of patients with 5-yr survival rates of 87%, 68% and 36% (p&lt;0.0001), independent of treatment and age. IPSS split each subgroup identified by previous scoring systems (Morel, Merlini, Dhodapkar). Conversely, log-rank test was significant only when the latter prognostic system was assessed in low IPSS-risk pts. Thus the combination of age, B2M, M-protein and blood counts provides simple prognostic model for survival in WM, hopefully serving as an objective basis for initiation of therapy and comparison of treatment results.

Abstract Background AFM13 is a bispecific, tetravalent NK cell-engaging antibody construct binding to CD30 on CD30+ tumor cells and CD16A on NK cells. By engaging CD16A-positive NK cells, AFM13 leads to NK cell-mediated killing of CD30-positive lymphoma cells (Reusch et al., 2014) making it an attractive agent to target classical Hodgkin lymphoma (HL). Pembrolizumab is a PD-1 blocking antibody which has shown high single-agent response rates in patients (pts) with relapsed/refractory HL (RRHL; Armand et al., 2016, Chen et al., 2017). AFM13 has shown clinical activity in RRHL as a single agent in a preceding Phase 1 study (Rothe et al., 2015). Preclinical in vivo data of the combination of AFM13 with PD-1 blockade showed synergistic activity and the potential for induction of cross-talk between innate and adaptive immunity (Zhao et al., 2016). We hypothesize that the combination of the two agents could improve outcomes in pts with RRHL. Methods This Phase 1b study is evaluating the safety and tolerability of the combination of AFM13 with pembrolizumab (Keytruda) as salvage therapy after failure of standard therapies including brentuximab vedotin (BV) in HL (NCT02665650). Pts receive escalating doses of AFM13 in combination with pembrolizumab at a dose of 200 mg flat administered every 3 weeks following a classical 3+3 design, followed by enrollment into an extension cohort at the maximum tolerated dose (MTD)/maximum administered dose (MAD). Response assessment is performed every 12 weeks by PET/CT according to the Lugano Classification (Cheson et al., 2014). The main objectives of the study is to ascertain the MTD/MAD along with the preliminary efficacy of the combination. Results As of June 29, 2018, 30 pts have been enrolled into the study. The median age is 34 years (range, 18-73), with a median of 4 (range 3-7) prior lines of therapy. All pts had relapsed or refractory disease (43% relapsed, 57% refractory) and had failed standard treatments including BV and 43% of pts (13/30) had BV as their latest therapy. Thirty seven percent (11/30) had undergone prior autologous stem cell transplantation. All 30 pts have completed the 6-week dose-limiting toxicity (DLT) observation period. Twelve pts were enrolled into the dose escalation cohorts (Cohorts 1 (n=3), 2 (n=3), and 3 (n=6)) and 18 into the Extension Cohort, with a total of 24 patients treated at the MAD (dose level 3). One DLT was observed in Cohort 3 (missing ≥25% of AFM13 during the DLT period) and another observed in the Extension Cohort (G4 infusion-related reaction; IRR). The most common related adverse events (AEs) were IRRs (80%), rash (30%), pyrexia (23%), nausea (23%), diarrhea (20%), fatigue (17%), headache (17%), increased aspartate aminotransferase (13%), and increased alanine aminotransferase (10%). Treatment related G3/4 AEs included IRRs (13%), elevated AST (3%), gastritis (3%), hypotension (3%), nausea (3%), neutropenia (3%), and vomiting (3%). The majority of IRRs were manageable with standard of care measures and did not lead to treatment discontinuations. Included in the efficacy analysis were the best response from 29 evaluable pts who had at least one post-baseline disease assessment as of the data cutoff on June 29, 2018. The overall response rate (ORR) and complete response (CR) rate for evaluable pts treated at the dose and schedule chosen for expansion (n=23; Cohort 3 and Extension Cohort) were 87% and 35% by the investigator-confirmed assessment, respectively. Independent assessment resulted in an ORR of 87% and CR rate of 39% for these pts. Updated data for all 30 patients will be presented at the meeting. Conclusions The combination of AFM13 and pembrolizumab is a well-tolerated salvage therapy in pts with RRHL. IRRs were the most frequently observed adverse events; however, most of these events were of mild or moderate severity and manageable. Both the ORR and CR rate compare favorably to monotherapy pembrolizumab in a similar RRHL population (Chen et al., 2017). The combination of AFM13 and pembrolizumab could be a potential new therapeutic option for HL patients. Disclosures Bartlett: Immune Design: Research Funding; Affimed: Research Funding; Bristol-Meyers Squibb: Research Funding; Merck & Co: Research Funding; Pharmacyclics: Research Funding; Celgene: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding; Forty Seven: Research Funding; Novartis: Research Funding; Novartis: Research Funding; Millennium: Research Funding; ImaginAB: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Astra Zeneca: Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees. Chen:Affimed: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Genentech Inc.: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Merck & Co., Inc.: Consultancy, Research Funding, Speakers Bureau; Millennium Pharmaceuticals: Consultancy, Research Funding; Pharmacyclics: Consultancy, Research Funding. Domingo-Domenech:Affimed: Research Funding. Forero-Torres:Affimed: Research Funding. Garcia-Sanz:Affimed: Research Funding. Devata:Affimed: Research Funding. Rodriguez Izquierdo:Affimed: Research Funding. Lossos:Affimed: Research Funding. Reeder:Affimed: Research Funding. Sher:Affimed: Research Funding. Choe-Juliak:Affimed: Employment. Prier:Affimed: Research Funding. Schwarz:Affimed: Employment. Strassz:Affimed: Employment. Alland:Affimed: Employment. Ansell:Bristol-Myers Squibb: Research Funding; Celldex: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Pfizer: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Merck & Co: Research Funding; Affimed: Research Funding; Takeda: Research Funding.

Abstract BACKGROUND: The first step to the cure of Multiple myeloma (MM) is achieving a clinical complete response (CR). However, a majority of patients relapse in part due to the persistence of low levels of pathological plasma cells after treatment (minimal residual disease (MRD)). In previous work, we have shown that Next generation sequencing (NGS) of immunoglobulin (IG) rearranged genes is an effective technology to identify and quantify pathological clonal cells in MM, and also it is a good predictor of patient prognosis. However, this technology is a proprietary multiplex PCR, uses a reference plasmid, it is performed at the centralized laboratories, and it is not broadly available. AIMS: To present a new in-house simplified method for quantification of IG gene clonal rearrangements by NGS. To test the suitability of the method for MRD detection in MM patients compared with 8-color high sensitivity Flow Cytometry (8c-MFC) data on a prospective way. To determine its capability as a predictor of patient prognosis. METHOD: We use deep sequencing to prospectively analyzed DNA from bone marrow samples of 58 patients (58 diagnostic samples and 80 follow-up samples) of patients included the GEM10 clinical trial. The method employs the primers developed by BIOMED-2 for IGH and IGK, and a set of specific mathematical and bioinformatics tools. First, we identified the clonal rearrangement(s) (clonotype) in the diagnostic sample by fragment analysis and NGS. Second, we searched the NGS sequences from follow-up samples to detect and quantitate (MRD) the presence of the clonotype identified in the diagnostic sample. Overall Survival (OS) and Progression free Survival (PFS) were estimated by Kaplan-Meier survival analysis. The survival curves generated were compared with the log-rank test for trend. RESULTS: The sensitivity of the method is 10-5 for 150.000 cells. Reproducibility is >90%. The Spearman correlation coefficient between NGS and 8c-MFC data for diagnosis and follow-up samples was R=0.6903, p<0.0001. When we applied the criteria of 10-5 for NGS, discordant results were as follow: 121 cases were positive by both methods, 2 cases were positive (>10-5) by 8c-MFC but negative (<10-5) by NGS; 7 samples were negative (<10-5) by 8c-MFC but positive (>10-5) by NGS; and 7 cases were negative by both methods. Next we analyzed de correlation of OS and PFS with MRD levels determined by NGS and by 8c-MFC. For NGS data, median PFS (FigA) was 34 months for patients with values of MRD>10-5 vs not reached for patients with values of MRD<10-5 (hazard ratio [HR] = 3.69, P =0 .0109). Also, for 8c-MFC data, the patients with values of MRD<10-5 had longer PFS than those with values of MRD>10-5 (34 months versus 47; HR = 3.69, P =0 .0109). Median OS (FigB) was also significantly longer in MRD<10-5 (NGS) patients (not yet reached), compared to MRD>10-5 (NGS) patients (41 months, HR = 3.6, P =0.0495). For 8c-MFC we did not get a significant association (41 vs 50 months, HR=1.979, p=0.228). It should be noted that this comparison was made with the standard 8c-MFC and it is probable that the sensitivity will be inferior to that of the Next generation flow. There were no significant differences in terms of PFS between the data obtained by our in-house method, 8c-FCM and previous data obtained with LymphoSight technology. CONCLUSIONS: Our data confirms that analysis of MRD levels determined by deep sequencing is capable of predict survival outcomes in myeloma patients. NGS sequencing of Ig genes is an effective technology to identify and quantify pathological clonal cells in MM. This approach is a methodological and economical alternative to MFC and other methods for MRD follow-up. Figure 1. Figure 1. Disclosures Paiva: Janssen: Consultancy; Celgene: Consultancy; BD Bioscience: Consultancy; Sanofi: Consultancy; Binding Site: Consultancy; Onyx: Consultancy; Millenium: Consultancy; EngMab AG: Research Funding. Ocio:Pharmamar: Consultancy, Research Funding; MSD: Research Funding; Novartis: Consultancy, Research Funding; Mundipharma: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy; Amgen/Onyx: Consultancy, Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Array BioPharma: Consultancy, Research Funding; Jassen: Honoraria. Mateos:Celgene: Consultancy, Honoraria; Takeda: Consultancy; Janssen-Cilag: Consultancy, Honoraria; Onyx: Consultancy. San Miguel:Novartis: Honoraria; Celgene: Honoraria; Janssen-Cilag: Honoraria; Bristol-Myers Squibb: Honoraria; Millennium: Honoraria; Onyx: Honoraria; Sanofi-Aventis: Honoraria.

Abstract Next-generation sequencing (NGS) has revealed new insight into the complexity of clonal and subclonal architecture of multiple myeloma (MM). The introduction of targeted studies allows the detection of mutations with very low allele frequencies at affordable price. However, there is few information about the prognostic impact of this mutational profile in series of homogeneously treated MM patients. In this study, we analyzed the most frequently mutated genes in MM from patients included in a randomized clinical trial applying the highest read depth to date. We performed a correlation study between our results and cytogenetics aberrations and clinical outcomes. We used Ampliseq Library Kit 2.0 to target 77 genes (M3Pv2.0 panel) related to critical pathophysiological pathways, associated to drug resistance or targetable with molecular drugs in MM. We sequenced DNA (15ng) from CD138+ purified plasma cells from 80 MM patients at diagnosis included in GEM2010MAS65 clinical trial. We sequenced at an average read depth of 1500X and using Ion Proton sequencer (Thermo Fisher, USA, PaloAlto, CA). We used Ion Reporter software applying in-house modifications in call variants process. We also sequenced DNA from CD138 negative population in 30% of patients in order to filter out potential artifacts and stablish conditions for excluding germline variants. We first fitted a cox-proportional hazard model to predict survival and a second approach using a penalized regression LASSO. We identified 137 gene mutations in the 80 patients analyzed, 54 mutations were predicted pathogenic by Shif and Poliphen and 65 have been described in COSMIC database. 85% of patients harbored at least 1 mutation. The most frequently mutated genes were KRAS (16%), DIS3 (15%), NRAS (13%), BRAF (6%), and TP53 (5%), accounting for the 54% of the total number of mutations. The most frequently mutated pathways were RAS and NFKB in 34% and 28% of patients respectively. Mutational allele frequency for KRAS, BRAF and TP53 was, in all cases, lower than 50% while DIS3 showed mutations in a broad range (from 2 to 85%). Only one patient presented one mutation in NRAS at 73 % of allele frequency. For patients with more than one mutation, two different scenarios have been found. Some patients showed several genes mutated in a similar allele frequency values. On the contrary, a complex subclonal structure was confirmed in 3 patients, with mutations at very different clonal frequency. CD138 negative fraction was sequenced to confirm that these mutations were exclusive of plasma cells. The first of them had two mutations in DIS3 at 8 and 53% of allele frequency, second in KRAS and DIS3 at 13 and 63% respectively and the third in NRAS and IFNGR2 at 5 and 37% respectively. We found no differences in the survival based on pathway, mutational allele frequency or number of mutations. We also investigated pairwise associations between events and we not found significant correlations (Figure 1). Cox-proportional hazard model only showed a negative impact in survival of patients with TP53 mutations. This ultra-deep targeted sequencing strategy is able to detect mutations in most of patients, at very low allele frequency and using a minimal amount of DNA. Despite of its huge capacity to detect mutations, we have not identified new prognostic factors in MM patients treated with highly efficient therapies. However, this study again confirms the complexity of the genomic landscape of MM and the great heterogeneity between patients. The role of theses mutations at relapse as well as in the subsequent treatment effectiveness remains unknown and should be preferably investigated in larger cohorts of homogeneously treated MM patients. Figure 1 Figure 1. Disclosures Martínez-López: Novartis: Honoraria, Speakers Bureau. Oriol:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees. Stewart:celgene: Consultancy.

Abstract Waldenström macroglobulinemia (WM) is a distinct B-cell lymphoproliferative disorder for which clearly defined criteria for the diagnosis, initiation of therapy, and treatment strategy have been proposed as part of the consensus panels of the International Workshop on Waldenström’s Macroglobulinemia (IWWM). At IWWM-8, a task force for treatment recommendations was impanelled to review recently published and ongoing clinical trial data as well as the impact of new mutations (MYD88 and CXCR4) on treatment decisions, indications for B-cell receptor and proteasome inhibitors, and future clinical trial initiatives for WM patients. The panel concluded that therapeutic strategies in WM should be based on individual patient and disease characteristics. Chemoimmunotherapy combinations with rituximab and cyclophosphamide-dexamethasone, bendamustine, or bortezomib-dexamethasone provide durable responses and are still indicated in most patients. Approval of the BTK inhibitor ibrutinib in the United States and Europe represents a novel and effective treatment option for both treatment-naive and relapsing patients. Other B-cell receptor inhibitors, second-generation proteasome inhibitors (eg, carfilzomib), and mammalian target of rapamycin inhibitors are promising and may increase future treatment options. Active enrollment in clinical trials whenever possible was endorsed by the panel for most patients with WM.