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We integrated molecular data with available prognostic factors in patients undergoing allogeneic hematopoietic cell transplantation (alloHCT) for myelodysplastic syndrome (MDS) or secondary acute myeloid leukemia (sAML) from MDS to evaluate their impact on prognosis. Three hundred four patients were sequenced for mutations in 54 genes. We used a Cox multivariate model and competing risk analysis with internal and cross validation to identify factors prognostic of overall survival (OS), cumulative incidence of relapse (CIR), and non-relapse mortality (NRM). In multivariate analysis, mutated NRAS, U2AF1, IDH2, and TP53 and/or a complex karyotype were significant prognostic markers for OS besides age above 60 years, remission status, IPSS-R cytogenetic risk, HCT-CI > 2 and female donor sex. Mutated NRAS, IDH1, EZH2, and TP53 and/or a complex karyotype were genetic aberrations with prognostic impact on CIR. No molecular markers were associated with the risk of NRM. The inclusion of molecular information results in better risk prediction models for OS and CIR when assessed by the Akaike information criterion. Internal cross validation confirmed the robustness of our comprehensive risk model. In summary, we propose to combine molecular, cytogenetic, and patient- and transplantation-associated risk factors into a comprehensive risk model to provide personalized predictions of outcome after alloHCT.

A 73-year-old patient with permanent atrial fibrillation presented for left atrial appendage (LAA) occlusion. Transesophageal echocardiography demonstrated a thrombus in the distal LAA. This image series illustrates a "no touch" technique that was used to ensure successful implantation of an Amplatzer Amulet LAA occlusion device without the use of an embolization protection system.

SF3B1 mutations in myelodysplastic syndromes: clinical associations and prognostic implications

Germline mutations in SET binding protein 1 (SETBP1) have been reported in children with Schinzel–Giedion syndrome, a congenital condition characterized by facial as well as skull abnormalities, hydronephrosis and developmental delay.1 Recently, exome sequencing identified recurrent somatic mutations in SETBP1 in atypical chronic myeloid leukemia (aCML).2 Of 70 examined patients with aCML, 17 patients (24%) were found to carry mutations in SETBP1. These mutations clustered between codon 858 and 871, all located in the SKI-homologous region of SETBP1. This is a highly conserved region with unknown biological function. In aCML, SETBP1 mutations were associated with worse prognosis and a higher white blood cell count compared with patients with wild-type SETBP1.2 A search for the presence of SETBP1 mutations in other hematological malignancies closely related to aCML, revealed the presence of SETBP1 mutations in chronic neutrophilic leukemia, chronic myelomonocytic leukemia, unclassified myelodysplastic syndromes/myeloproliferative neoplasms and secondary AML (sAML) evolving from MDS at variable frequencies (4–25%).2, 3, 4, 5

Mutations in genes of the splicing machinery have been described recently in myelodysplastic syndromes (MDS). In the present study, we examined a cohort of 193 MDS patients for mutations in SRSF2, U2AF1 (synonym U2AF35), ZRSR2, and, as described previously, SF3B1, in the context of other molecular markers, including mutations in ASXL1, RUNX1, NRAS, TP53, IDH1, IDH2, NPM1, and DNMT3A. Mutations in SRSF2, U2AF1, ZRSR2, and SF3B1 were found in 24 (12.4%), 14 (7.3%), 6 (3.1%), and 28 (14.5%) patients, respectively, corresponding to a total of 67 of 193 MDS patients (34.7%). SRSF2 mutations were associated with RUNX1 (P < .001) and IDH1 (P = .013) mutations, whereas U2AF1 mutations were associated with ASXL1 (P = .005) and DNMT3A (P = .004) mutations. In univariate analysis, mutated SRSF2 predicted shorter overall survival and more frequent acute myeloid leukemia progression compared with wild-type SRSF2, whereas mutated U2AF1, ZRSR2, and SF3B1 had no impact on patient outcome. In multivariate analysis, SRSF2 remained an independent poor risk marker for overall survival (hazard ratio = 2.3; 95% confidence interval, 1.28-4.13; P = .017) and acute myeloid leukemia progression (hazard ratio = 2.83; 95% confidence interval, 1.31-6.12; P = .008). These results show a negative prognostic impact of SRSF2 mutations in MDS. SRSF2 mutations may become useful for clinical risk stratification and treatment decisions in the future.

Introduction: The landscape of molecular aberrations in patients with myelodysplastic syndromes (MDS) has been well characterized and has identified ASXL1, BCOR, CUX1, IDH1, IDH2, SRSF2, RUNX1, U2AF1, TP53 and others as negative prognostic markers for overall survival (OS). We comprehensively investigated the prognostic impact of genetic aberrations in the context of allogeneic hematopoietic stem cell transplantation (alloHSCT) in a large cohort of patients with high risk MDS or secondary AML following MDS (sAML). Patients and Methods: 308 Patients with a diagnosis of MDS (47.4%) or sAML (52.6%) who received an alloHSCT at four German university medical centers and for whom genomic DNA was available at a time with active disease before transplantation were evaluated for the presence of mutations in 54 genes by Illumina high-throughput sequencing. Results: At least one mutation was identified in 82% of our patients with a median number of 2 mutations per patient. The most frequently mutated genes were ASXL1 (24.4%), DNMT3A, (23.1%), RUNX1 (16.9%), TET2 (16.9%), STAG2 (12%), TP53 (11.7%), and SRSF2 (11%) in agreement with previous reports. Mutation frequencies were similar between MDS and sAML patients for all mutated genes except SRSF2, TET2 and WT1, which were more frequently mutated in sAML. We grouped the mutated genes into functional classes and found that patients most frequently had mutations in modifiers of DNA methylation (42.2%), followed by chromatin modifiers (41.5%), splicing genes (31.1%), transcription factors (30.8%), signal transducers (28.8%) and tumor suppressors (14.6%). Mean variant allele frequencies were highest in modifiers of DNA methylation (33.2%), while signal transducers had the lowest allele frequency (20.4%). We next assessed the prognostic impact of gene classes and individual genes on outcome of patients after alloHSCT. Median follow up from transplantation was 4.15 years. Median patient age at time of HSCT was 58 years (range 19-75). 76 patients (25%) werein complete remission and 232 patients (75%) had active disease before transplantation. Low, intermediate, and high risk cytogenetics according to IPSS were found in 116 (38%), 59 (19%), and 115 (37%) patients, respectively. Matched and mismatched related donor HSCT was performed in 71 and 4 patients, respectively (23.1 and 1.3%), and matched and mismatched unrelated donor HSCT in 171 and 62 patients, respectively (55.5 and 20.1%). The six functional gene classes had no prognostic impact on survival, cumulative incidence of relapse and non-relapse mortality. We therefore evaluated the prognostic impact of individual gene mutations, of aberrations of chromosomes 3, 5, 7, 8, 17, 20 or a complex karyotype, and of transplant characteristics on OS. Parameters with significant impact on OS in univariate analysis were included in a multivariate cox proportional hazards model. Significant predictors of OS in multivariate analysis were mutations in PTPN11 (HR 3.1, present in 2.3% of pts.), IDH2 (HR 2.6, present in 4.2%), PHF6 (HR 2.2, present in 4.9%), NRAS (HR 1.8, present in 7.5%), presence of a complex karyotype (HR 1.8, present in 16.6%), transplantation from haploidentical donor (HR 5.5), RAEB/sAML not in complete remission before transplantation compared to untreated RA/RARS or RAEB/sAML and treated RAEB/sAML in remission (HR 2.0), GvHD prophylaxis other than calcineurin inhibitor with methotrexate or mycophenolate mofetil (HR 1.7) and female sex of the donor (HR 1.7). TP53 mutations lost their unfavorable prognostic impact when complex karyotype was added to the multivariate model. Competing risk analysis for cumulative incidence of relapse and non-relapse mortality showed that IDH2 and NRAS mutations and a complex karyotype were significantly associated with higher risk for relapse while PTPN11 and PHF6 mutations predicted for a higher incidence of non-relapse mortality. Importantly, a negative prognostic impact of ASXL1, BCOR, CUX1, IDH1, SRSF2, RUNX1 and U2AF1 seen previously in MDS patients not undergoing alloHSCT was not found in the transplant setting, suggesting that alloHSCT may overcome the unfavorable effect of these mutations. Conclusion: By extensive genetic characterisation of 308 MDS or sAML patients undergoing alloHSCT we identified mutations in IDH2, NRAS and complex karyotype as predictors of relapse and reduced OS and provide a matrix to refine risk prediction for allogeneic HSCT. Disclosures Heuser: Karyopharm: Research Funding. Platzbecker:Boehringer: Research Funding; Celgene: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Thiede:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AgenDix GmBH: Equity Ownership.

Abstract 1709 Introduction: Allogeneic hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with myelodysplastic syndromes (MDS), but it is associated with high mortality and morbidity. Predictors for treatment outcome after HSCT are limited. Recently, mutations in ASXL1 have been described as an independent adverse prognostic marker for MDS patients not undergoing HSCT. The aim of this study was to investigate the prognostic impact of ASXL1 in a large cohort of patients with high risk MDS or secondary AML following MDS (sAML) undergoing HSCT. Patients and Methods: Patients (n=105) with a diagnosis of MDS (34.3%) or sAML (65.7%) who received an allogeneic HSCT at Hannover Medical School between 1996 and 2010 and for whom genomic DNA was available from a time when the disease was active, were evaluated for the presence of ASXL1 mutations by direct sequencing. Patients gave their informed consent in accordance with the Declaration of Helsinki, and the study was approved by the institutional review board of Hannover Medical School. Overall survival (OS) and cumulative incidence of non-relapse mortality endpoints, measured from HSCT, were death (failure) and alive at last follow-up (censored). A Cox proportional hazards model was constructed for multivariate analysis and the two-sided level of significance was set at P Results: Median follow up from time of transplantation was 3.67 years. Median patient age at time of HSCT was 58 years (range 22–72) and the median donor age was 39 years (range 0–71). Twenty-seven patients (26.0%) were in complete remission and 78 patients (74%) had active disease before transplantation. In MDS, 9, 21, and 6 patients had intermediate-1, intermediate-2, or high risk IPSS, respectively. Low, intermediate, and high risk cytogenetics according to IPSS were found in 40, 21, and 44 patients, respectively. Related donor HSCT was performed in 24 patients (23%), and unrelated donor HSCT in 81 patients (77%). Six patients received bone marrow (6%), two cord blood (2%), and 97 (92%) received peripheral blood stem cells. Myeloablative preparative regimens were used in 17 patients (16%), and a non-myeloablative regimen was given to 88 patients (84%). Mutations in ASXL1 were detected in 21 (20%) patients with 17 (16.2%) mutations being frameshift mutations. Previously, we showed that only frameshift mutations are prognostically relevant in MDS patients and therefore considered only those for further analysis. ASXL1 frameshift mutations were not correlated with clinical parameters (age, sex, MDS vs. sAML, cytogenetics, bone marrow blasts, blood group, CMV status of patient, type of previous treatment, and remission status prior to transplantation). ASXL1 frameshift mutated patients had received a graft from a related donor (41 vs. 19%, respectively, P=.05) and from bone marrow (17.6 vs. 3.4%, respectively, P=.03) more often compared to wildtype patients, however, there were no differences regarding other transplant-related characteristics (reduced intensity vs. standard conditioning, GvHD prophylaxis, donor age, donor sex, and CMV compatibility between recipient and donor). The presence of ASXL1 frameshift mutations was associated by trend with a shorter overall survival (5-year OS 31 vs. 47%, HR 1.87; 95%CI 0.96–3.64; p=.06). In multivariate analysis, when considering variables with P Summary: ASXL1 frameshift mutations independently predicted worse patient outcome after allogeneic HSCT in MDS and sAML patients in our study. The high rate of non-relapse mortality in ASXL1 mutated patients warrants further investigation. *equal contribution Disclosures: No relevant conflicts of interest to declare.