Abstract: Abstract 2608 Poster Board II-584 Background: Myeloproliferative neoplasms (MPN) represent a heterogeneous group of acquired hematopoietic stem cell disorders. Clonality leads to exceeding production of myeloid cells resulting in an inherent tendency for thrombotic and hemorrhagic complications as well as transformation into acute myeloid leukemia (sAML). While vascular complications predominantly account for the morbidity in essential thrombocythemia (ET) and polycythemia vera (PV), the mortality of MPN is significantly related to leukemic transformation. Secondary AML occurs more frequently in primary and secondary myelofibrosis (PMF and SMF) than in ET and PV, and the risk for leukemic transformation increases with the duration of the disease. The molecular basis underlying the progression of MPN is poorly understood. Clonal evolution due to genomic instability is considered to play an important role. Aim: To identify genomic lesions associated with leukemic transformation, we applied 250K single-nucleotide polymorphism (SNP) arrays that allow for genome-wide screening of both copy-number alterations (CNAs) and copy-neutral runs of homozygosity (ROH) at high resolution. Method: An unpaired SNP-array analysis of 23 sAML samples was performed [former diagnosis: ET, n=5; PV, n=7; PMF, n=9; SMF, n=2;]. An own set of 30 reference samples was used for normalization. CNAs and ROH were analyzed by CNAG 3.0 software. Aberrations were compared with the 250K SNP-array dataset of 151 MPN patients [ET, n=45; PV, n=45; PMF, n=47, SMF, n=14] . In one sAML patient corresponding SNP-array data from the time of ET diagnosis were available. Results: CNAs were present in 15 of 23 (65%) sAML patients. Thirty-five percent of cases (n=8) exhibited complex genomic aberrations with up to 20 CNAs in one patient (range 5–20). The most frequent larger ( 〉 5 Mb) CNAs were trisomy 8 (n=7), gain of 1q, loss of 5q, and deletion in 6p25-pter (16.2–26.7 Mb) and 20q11-q13 (13.6–16.9 Mb) in three cases each, followed by gain in 3q24-qter (51.7 and 54.1 Mb) in two patients. Of note, one case with deletion in 17p12-pter (64.4 Mb) encompassing TP53 and a second with gain in 21q22.12-qter (11.8 Mb) were identified; in the latter one the proximal breakpoint of the gain was located at RUNX1. Smaller CNAs ( 〈 5 Mb) were restricted to single cases with four cases exhibiting micro-deletions ranging from 0.7 to 2.7 Mb in size. Interestingly, three chromosomal regions harbour single genes: 11p11.2 (FOLH1), 18q21.2 (TCF4), and 21q22.12 (RUNX1). ROH comprising the terminal end of the chromosome were detectable in 13 of 23 (57%) sAML cases. The most frequent ROH included the JAK2 locus in 9p24 (n=6; 15.6–38.7 Mb), followed by ROH in 17p13-pter (16.3 and 17.7 Mb) covering TP53 and an overlapping segment in 1p32-pter (53 Mb) affecting MPL in two cases each. All cases with 9p ROH were JAK2 V617F mutated, whereas the MPL W515L mutation was found in one of the two 1p ROH cases. Moreover, sequencing analyses in both patients with ROH in 17p revealed TP53 missense mutations in exon 7 and exon 8, respectively. In addition, non-recurrent ROH covering the long arm of chromosome 7, 11, and 21 as well as ROH in the chromosomal segments 14q32-qter (12.6 Mb) and 17q31-qter (31 Mb) were identified. In one sAML patient SNP-array data performed at the time of ET were available for comparative analysis. While 20q deletion was present as sole aberration in ET, complex genomic aberrations (7 CNAs) were identified after development of sAML. Merging the results from our recent 250K SNP-array analysis (Stegelmann et al., Blood 2008; 112: Abstract #2794) on 61 PMF and SMF cases with data from this study, we were able to identify a second case with micro-deletion in 12q24. The commonly deleted region of both cases is 1.3 Mb in size and encompasses TCF1 as a novel recurrent aberration in MPN. Conclusion: In summary, our data on a large series of well-defined sAML cases that evolved from MPN demonstrate that 250K SNP-array profiling is an excellent tool to identify genomic aberrations. In contrast to MPN, genomic alterations in sAML are characterized by a marked complexity reflecting both genomic instability and genetic heterogeneity of sAML. However, in our study several regions of interest including recurrently affected candidate genes such as TCF1, RUNX1, and TP53 were identified that need to be further investigated on a single gene level. Disclosures: No relevant conflicts of interest to declare.

Abstract: Patients (pts) with polycythemia vera (PV) suffer from pruritus, night sweats, and other symptoms, as well as from thromboembolic complications and progression to post-PV myelofibrosis. Ruxolitinib (RUX) is approved for second-line therapy in high-risk PV pts with hydroxyurea intolerance or resistance. The RuxoBEAT trial (NCT02577926, registered on October 1, 2015, at clinicaltrials.gov) is a multicenter, open-label, two-arm phase-IIb trial with a target population of 380 pts with PV or ET, randomized to receive RUX or best available therapy. This pre-specified futility analysis assesses the early clinical benefit and tolerability of RUX in previously untreated PV pts (6-week cytoreduction was allowed). Twenty-eight patients were randomly assigned to receive RUX. Compared to baseline, after 6 months of treatment, there was a significant reduction of median hematocrit (46 to 41%), the median number of phlebotomies per year (4.0 to 0), and median patient-reported pruritus scores (2 to 1), and a trend for reduced night sweat scores (1.5 to 0). JAK2V617F allele burden, as part of the scientific research program, also significantly decreased. One hundred nine adverse events (AEs) occurred in 24/28 patients (all grade 1 to 3), and no pt permanently discontinued treatment because of AEs. Thus, treatment with ruxolitinib in untreated PV pts is feasible, well-tolerated, and efficient regarding the above-mentioned endpoints.

Abstract: Recently, the identification of the gain of function mutation JAK2V617F delivered important insights into the pathogenesis of BCR/ABL negative myeloproliferative disorders (MPD). JAK2V617F is detectable in more than 90% of polycythemia vera (PV) patients (pts) and in approximately 50% of pts with essential thrombocythemia (ET) or primary myelofibrosis (PMF), representing the genetic hallmark of BCR/ABL negative disease. However, about 30% of MPD pts lack the JAK2V617F mutation and previous studies on ET and PV demonstrated that clonality exceeds the percentage of V617F mutated cells. These findings suggest that additional genetic alterations are involved in the pathogenesis of MPD, in both JAK2 mutated and unmutated pts. To identify novel genetic aberrations and to determine whether specific lesions are associated with disease phenotype, genomic DNA from granulocytes of 72 MPD pts classified according to the WHO criteria was analyzed using high-resolution, genome-wide microarray techniques [disease, number analyzed, JAK2 mutation status: PMF, n=14, 9/14; post-ET MF, n=5, 3/5; post-PV MF, n=5, 5/5; PV, n=37, 37/37; ET, n=11, 11/11] . In a first approach, all cases were investigated by comparative genomic hybridization to 8k arrays (array CGH) with an average probe spacing of less than 1 Mb. While no genomic imbalances were found in ET, 11% of PV pts (n=4) exhibited large ( & gt;10 Mb) deletions on 20q (n=2) or gains on 9p and 1q (n=1, each). In addition, small ( & lt;1 Mb) recurrent gains in 1q21.1 (n=2) and 22q11.23 (n=2) were identified. In MF pts the incidence of large genomic imbalances was 25% (n=6) with trisomy 9 (n=3) being the most frequent aberration followed by loss of 20q, 5q, and 13q in single cases. Furthermore, in one pt with post-PV MF small genomic losses in 17q11.2 (2 Mb) and 17p13.2 (0.8 Mb) were identified harbouring NF1 but not TP53. Deletion of the NF1 allele without concomitant loss of TP53 was confirmed by FISH. To further increase resolution and to investigate the role of uniparental disomy (UPD), single nucleotide polymorphism (SNP) analysis using the Affymetrix 250k Nsp SNP array was performed in all MF cases. Copy number estimation and loss of heterozygosity probability were analyzed using a set of 117 remission samples from acute myeloid leukemia pts as a common reference. SNP analysis confirmed all anomalies detected by array CGH. In addition, SNP analysis revealed small genomic losses (1.6–2.6 Mb) in 1q21.2 (n=3), 5q13.2, and 3p13 (n=1, each), and in one secondary MF pt another microdeletion in 17q11.2 (1.2 Mb). UPDs recurrently affected 9p (n=5) in a region harbouring the JAK2 locus. In single cases, large UPDs of 1q (25 Mb), 2p (14 Mb), 5q (4 Mb), 6p (11 Mb), and 7q (11 Mb) were identified. Of note, all JAK2V617F mutated post-PV and post-ET MF cases exhibited 9p abnormalities represented either by trisomy 9 or UPD of 9p. In conclusion, using a combined microarray approach we were able to detect novel submicroscopic alterations in addition to known abnormalities. Parallel analysis of both techniques clearly demonstrated the superiority of array-SNP mapping. Further analyses on larger pt populations and correlation with global gene expression data will facilitate the identification of disease-related genes that are involved in the pathogenesis of BCR/ABL negative MPD.

Abstract: Abstract 4179 In acute myeloid leukemia (AML), complex karyotype is defined as the presence of three or more chromosome abnormalities in the absence of one of the recurrent genetic abnormalities as defined by the recent WHO classification. AML with complex karyotype (CK-AML) account for approximately 10 to 15% of all cases and are associated with preceding myelodysplasia (MDS) or exposure to toxic agents; the prognosis of patients is very poor. So far, little is known about the molecular mechanisms underlying initiation or progression of CK-AML. To identify genomic regions of potential pathogenic relevance, we used microarray-based techniques [array-comparative genomic hybridization (CGH) and single-nucleotide polymorphism (SNP) analysis] for high-resolution genome-wide analysis in 242 cases, including 171 (71%) cases enrolled on clinical protocols using intensive chemotherapy. Among other genomic imbalances, we identified loss of chromosome band 17q11.2 encompassing the NF1 locus in 55 (23%) of the 242 cases. Interestingly, three of these cases exhibited homozygous loss of NF1. Based on these findings and the fact that NF1 is recurrently altered in myeloid malignancies, we further investigated its role in CK-AML. Therefore, we analyzed 11 cases with heterozygous microdeletions of NF1 for mutations in the remaining allele by direct sequencing of exons 1 to 60 and identified 5 mutations in 4 cases; all of these mutations resulted in a premature stop codon (3 frameshift mutations, 2 nonsense mutations); one frameshift mutation (c.2033dupC) was recurrent. Combining the findings from array-based and mutation analyses, we so far identified 7 patients with biallelic NF1 gene alterations, i.e. homozygous loss or loss of one allele and at least one mutation in the remaining allele. Since correlation of NF1 alteration with data from array-based genomic profiling revealed a significant correlation with loss of chromosome band 17p13 encompassing TP53 (P 〈 .001), we correlated NF1 alteration with the TP53 status (mutation and/or loss), which was available for all 242 cases, and found a positive correlation with both TP53 alteration (mutation and/or loss) and TP53 mutation (P 〈 .001 each). In addition, NF1 alteration was significantly correlated with biallelic TP53 alterations (loss and mutation or homozygous mutations) (P 〈 .001). We than further investigated the two genotypes NF1alteration/TP53alteration (n=50) and NF1no alteration/TP53alteration (n=109) with regard to their association with other genomic imbalances. The genotype NF1alteration/TP53alteration was significantly correlated to the total number of deletions (median 9 vs 7; P = .025), the genomic complexity as measured by the total number of aberrations per case (median 13 vs 11; P = .039), and the presence of 16q loss (50% [25/50] vs 29% [32/109], P = .014) when compared with the NF1no alteration/TP53alteration genotype. Notably, in a recently published murine model deficiency of ICSBP, located on 16q24, was shown to synergize with NF1 haplo-insufficiency in leukemogenesis. In conclusion, the NF1 gene is found to be recurrently altered in CK-AML. Being associated with specific genomic aberrations, NF1 alteration is likely cooperating in myeloid leukemogenesis or disease progression. One important co-player might be TP53 that has an important role in genomic stability. The exact mechanism of interaction between NF1 and TP53 or other concurrent genetic alterations have to be further investigated. Disclosures: Döhner: Pfizer: Research Funding.

Abstract: Introduction: Mutations (muts) in JAK2, MPL, and CALR are genetic hallmarks in myeloproliferative neoplasms such as myelofibrosis (MF). Prognostication in MF is predominantly based on clinical parameters according to the Dynamic International Prognostic Scoring System (DIPSS). However, gene mutations become increasingly important allowing for a more precised assessment of prognosis. For instance, CALR mutated MF is associated with favorable prognosis, while mutations in distinct high molecular-risk (HMR) genes are considered adverse. Our multicenter phase-Ib/II MPNSG-0212 trial (NCT01644110) investigating ruxolitinib plus pomalidomide in a total cohort of 92 patients with advanced MF and anemia provides an ideal basis for investigating the genomic landscape and molecular risk in a well-defined study population. Aims & Methods: To assess the genomic landscape in MF patients treated within the MPNSG-0212 trial and to correlate the results with clinical parameters and overall survival (OS). So far, targeted next generation sequencing (NGS) of 269 candidate genes was performed in peripheral blood or bone marrow from 81/92 patients using libraries prepared with SureSelectXT HS (Agilent, Santa Clara, USA). NGS was carried out on a NextSeq550 (Illumina, San Diego, USA). Results: At study entry, median age of the 81 patients was 71 years (range 52-86), median Hb 8.6 g/dL (range 5.4-11.7 g/dl); 30% of patients were RBC transfusion-dependent; 67% had primary MF (PMF) and 33% secondary MF (SMF), respectively. According to DIPSS, the vast majority of the patients were categorized as intermediate-2 (63%) or high-risk (26%) MF; 11% were low- and intermediate-1 risk patients. Overall, 315 muts were identified in 80/81 (99%) patients with a median of 3 muts/patient (range 0-9). Recurrent muts (≥5%) were identified in JAK2 (60%), ASXL1 (30%), SRSF2 (21%), CALR (20%; type-1: 75% [n=12], type-2 and non-type-1/2: 12.5% [n=2] each), MPL (19%), SF3B1 (19%), TET2 (16%), U2AF1 (15%), CBL and EZH2 (10% each), IDH2 and DNMT3A (7% each), PHF6, ZRSR2, and CUX1 (5% each). The majority of the patients (95%) was characterized by the presence of a driver mut in JAK2, CALR, or MPL; 4/81 patients (5%) were triple negative (Figure 1). JAK2mut was associated with TET2mut (p=.047), whereas muts in CALR and TET2 were mutually exclusive (p=.05). CALRmut patients had less co-muts than patients with JAK2/MPL muts (mean 2.5 vs. 4.1, p=.007) and were mutually exclusive with muts in the spliceosome regulating genes SRSF2, SF3B1, U2AF1, and ZRSR2 (p=.009). Compared to MF with mutated JAK2 or MPL, MF patients with mutated CALR had a longer median OS (not reached vs. 3.1 years; p=.04). With regard to high molecular risk (HMR) muts, n=56 were detected in 38 patients (47%), with 40% (15/38) of the patients harboring ≥2 HMR muts. The most commonly mutated HMR genes were ASXL1 (43%; 24/56), followed by SRSF2 (30%), EZH2 (14%), IDH2 (11%), and IDH1 (2%). MPLmut but not JAK2mut or CALRmut were significantly associated with HMR mut (p=.023). HMR mut patients harbored more co-muts than HMR wt patients (median 5 vs. 3; p & lt;.0001). There were no significant differences in the variables age, sex, WBC, Hb, PLT, or LDH level between patients with HMR mut and HMR wt MF. In univariate analysis, patients with HMR mut MF had shorter median OS (2.3 vs 3.7 years, p=.007). In multivariate analysis (HMR mut, age, DIPSS-category, SMF vs. PMF) a higher DIPSS-score (HR, 3.2; 95% CI, 1.5-7.0; p=.004) and muts in HMR genes (HR, 3.5; 95% CI, 1.5-8.1; p=.003) were significant adverse prognostic factors for OS. Conclusions: Our NGS data underline the genomic complexity of advanced MF. CALR mutations were only found in 20% of the patients that were characterized by less co-mutations, mutual exclusivity with spliceosome mutations, and with more favorable outcome suggesting a distinct disease biology. Almost 50% of patients showed mutations in HMR genes which were associated with an inferior OS in univariate and multivariate analyses. §Frank Stegelmann and Konstanze Döhner contributed equally to this work. Figure 1 Figure 1. Disclosures Koschmieder: Shire: Honoraria, Other; Alexion: Other: Travel support; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support); Geron: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; AOP Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Research Funding; Baxalta: Membership on an entity's Board of Directors or advisory committees, Other; Abbvie: Other: Travel support; CTI: Membership on an entity's Board of Directors or advisory committees, Other; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: (e.g. travel support), Research Funding; Image Biosciences: Other: Travel support; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Karthos: Other: Travel support. Heidel: Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; CTI: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene/BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AOP: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Hochhaus: Bristol-Myers Squibb: Research Funding; Pfizer: Research Funding; Incyte: Research Funding; Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding. Hebart: AbbVie: Honoraria; AstraZeneca: Honoraria; BMS: Honoraria; Janssen: Honoraria; Roche: Honoraria. Isfort: Alexion: Other: Travel reimbursement; Roche: Other: Travel reimbursement; Amgen: Other: Travel reimbursement; Mundipharma: Other: Travel reimbursement; Hexal: Other: Travel reimbursement; BMS: Honoraria; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Ariad: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel reimbursement. Reiter: AOP Orphan Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Deciphera: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Abbvie: Membership on an entity's Board of Directors or advisory committees; Celgene/BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: travel support; Incyte: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Blueprint Medicines: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Research Funding. Waller: Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Astra Zeneca: Membership on an entity's Board of Directors or advisory committees; Mylan: Consultancy; Alvotech: Consultancy; Takeda: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees; Lilly: Membership on an entity's Board of Directors or advisory committees, Other: travel support; Chugai: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees, Other: travel support; Amgen: Membership on an entity's Board of Directors or advisory committees; IPSEN: Other: travel grant. Scheid: Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Goethert: Pfizer: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: Travel support; Incyte: Consultancy, Honoraria, Other: Travel support; zr pharma & : Honoraria; BMS: Consultancy, Honoraria, Other: Travel support; AOP Orphan Pharmaceuticals: Honoraria, Other: travel support; Proteros Biostructures: Consultancy. Schafhausen: Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Swedish Orphan Biovitrum AB: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Honoraria, Membership on an entity's Board of Directors or advisory committees; Alexion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees. Radsak: Otsuka: Consultancy, Honoraria; Abbvie: Other: e.g. travel support; Astellas: Other: e.g. travel support; TEVA: Consultancy, Honoraria; Novartis: Consultancy, Honoraria, Other: e.g. travel support; Daiichi Sankyo: Consultancy, Honoraria, Other: e.g. travel support; Celgene/BMS: Consultancy, Honoraria, Other: e.g. travel support; Amgen: Other: e.g. travel support; Takeda: Consultancy, Honoraria; Incyte: Consultancy, Honoraria; Corat: Consultancy, Honoraria; Cogent Biosciences: Consultancy, Honoraria; JAZZ: Other: e.g. travel support. Gattermann: Takeda: Research Funding; Novartis: Honoraria; Celgene: Honoraria. von Bubnoff: Novartis: Honoraria; Takeda: Honoraria. Brümmendorf: Bristol Myers: Research Funding; Janssen: Honoraria; Novartis: Honoraria, Patents & Royalties, Research Funding; Pfizer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Repeat Diagnostics: Research Funding; Takepart Media: Honoraria. Döhner: Celgene: Honoraria, Research Funding; Agios: Honoraria, Research Funding; GEMoaB: Honoraria; Astex Pharmaceuticals: Honoraria; Astellas: Honoraria, Research Funding; Oxford Biomedica: Honoraria; Novartis: Honoraria, Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Janssen: Honoraria; Helsinn: Honoraria; Gilead: Honoraria; AstraZeneca: Honoraria; Abbvie: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Bristol Myers Squibb: Honoraria, Research Funding; Berlin-Chemie: Honoraria; Roche: Honoraria; Pfizer: Research Funding. Griesshammer: Amgen: Consultancy, Honoraria; AOP Orphan: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; CTI: Consultancy, Honoraria; Shire: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Astra Zeneca: Consultancy, Honoraria. Stegelmann: BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Döhner: Abbvie: Consultancy, Honoraria; Janssen: Honoraria, Other: Advisory Board; Jazz Roche: Consultancy, Honoraria; Daiichi Sankyo: Honoraria, Other: Advisory Board; Astellas: Research Funding; Celgene/BMS: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Agios and Astex: Research Funding. OffLabel Disclosure: Pomalidomide was shown to be active in patients with myelofibrosis in particular in the treatment of anemia (Tefferi et al 2009, Begna et al 2011, Mesa et al 2010)

Abstract: Abstract 2840 Background: Pomalidomide in a single arm phase-I/II study and one randomized four arm phase-II study in primary myelofibrosis (MF) and post-polycythemia vera/essential thrombocythemia (post-PV/ET) MF showed efficacy in particular with respect to improvement in anemia. To date, pomalidomide has been evaluated in MF at two dose levels, 0.5mg and 2.0 mg/day. Aims: To evaluate clinical efficacy of pomalidomide alone and in combination with prednisolone (PRED) in patients with primary or post-PV/ET MF and cytopenia. Methods: The main inclusion criteria for primary or post-PV/ET MF patients were red blood cell (RBC)-transfusion-dependence or hemoglobin 〈 10 g/dl, and/or thrombocytopenia 〈 50/nl and/or neutropenia 〈 1.0/nl; patients 〉 =50 years were eligible. Treatment consisted of pomalidomide (POM) 2mg/day; prednisone (PRED) 30mg/day was added in patients who did not respond (≤ stable disease) within three months of therapy. The primary endpoint was response assessed by IWG criteria and extended by the criterion red blood cell transfusion-independence (Gale RP et al., Leuk Res. 2011). Concurrent hydroxyurea in patients with proliferative disease and aspirin 100 mg/d in patients with platelets between 50/nl and 1000/nl were administered. The statistical design of the study was based on the Simon optimal two-stage design. Here we report on the first stage of the study. Median follow-up according to the method of Korn was 18 months. Results: Thirty-eight patients were treated with POM 2 mg/d, the median age was 71 years (range 51–83), 34% were female. Twenty-seven had primary and 11 post-PV/ET MF. Disease stage at study-entry according to the DIPSS was high-risk in 13 (34%), intermediate-2 risk in 22 (58%) and intermediate-1 risk in 3 (8%). Incidence of high-risk cytogenetics, JAK2 V617F mutation and MPL W515L mutation were 29% (10/34), 55% (21/38) and 18% (7/38), respectively. Twenty-seven patients (71%) were RBC-transfusion- and 7 (18%) platelet-transfusion dependent. Median duration of treatment with POM was 11.4 months with 5 patients continue on treatment 24+ months. PRED was added after 3 months in 19 of 28 eligible patients. POM dose-reduction (n=8, 1mg/d; n=2, 0.5mg/d) was performed after a median time of 34 days (range 3–308 days) due to fatigue (n=2), thrombo- and/or neutropenia (n=7), rash (n=1). Seven patients with high risk characteristics (n=6 RBC-transfusion dependent, n=4 high risk cytogenetics) experienced transformation into blast phase (BP), the actuarial probability of transformation to BP measured from diagnosis was 6.0% (SE 4.1%) at 2 years and 22.4% (SE 8.4%) at 5 years. Response was observed in 14 patients (37%) after a median time of 4.8 months (n=1 complete remission, n=5 clinical improvement-platelets, n=3 clinical improvement-erythrocytes, n=5 red cell transfusion-independence); 8 responders received concomitant PRED and responded after a median of three months (range 0.8–11.7 months) of the addition of PRED. In 5 of 14 responders POM dose was reduced due to toxicity, notably before response occurred. Responses were observed within the first 3 months (n=4), between month 4 to 6 (n=4) and beyond month 6 (n=6) with the latest response seen at 12.7 months. There was no correlation between response and JAK2/MPL mutation status or cytogenetics. Basophilia defined as greater than 50% increase in absolute basophil count at month 3 was in trend associated with response (p=0.06). Conclusions: POM with or without PRED in patients with different risk groups of patients with primary and post-PV/ ET MF was effective with a response rate of 37%. Based on results of this first cohort the protocol was amended; i) POM dose has been adjusted to 0.5 mg/d, ii) up-front randomization of PRED at month 4 or month 7 in patients without response but stable disease to single agent POM was introduced. Disclosures: Schlenk: Celgene: Research Funding. Off Label Use: Pomalidomide is so far not approved for the treatment of primary and secondary myelofibrosis.

Abstract: Tyrosine kinase inhibitors (TKI) have changed the natural course of CML. Their efficacy leads to normal life expectancy in the vast majority of patients. With the advent of 2nd generation TKI and the now available choice of drugs, safety issues have gained interest. We have used the randomized CML-Study IV for a long-term safety evaluation of imatinib. Study and Patients CML-Study IV comprises 1551 patients randomized to 5 treatment arms with 3 imatinib-based combinations and 2 different imatinib-dose schedules. 1501 patients have received imatinib and were evaluable. Median age at diagnosis was 53 years, 88% were EUTOS low risk. At the last evaluation (04/11/2013) 1003 patients still received imatinib, 164 had died, 275 were switched to a 2nd generation TKI, 106 were transplanted. The longest observation time was 11.5 years, the median observation time was 6.5 years, with a 10-year survival probability of 84 %. The median time to imatinib discontinuation has not been reached after 10.2 years. 80 patients are under observation for more than 10 years, 18 of these have discontinued imatinib. Out of the 1501 patients that had received imatinib, 1375 patients received imatinib as first-line treatment and had a sufficient documentation of treatment. Methods AE were reported at each follow-up visit. The CTC AE list of the NCI was used for coding of AE and severity grading. Additionally, for detection of hematologic AE lab results were screened for deviations from reference ranges. The AE were analyzed according to the “as treated” principle, using Kaplan-Meier curves (virtually no competing risks, almost all patients died after end of imatinib treatment). Only the first event of the respective type was considered. All analyses started at the first day of imatinib treatment and were censored when the patient discontinued imatinib, received another treatment or died. To assess the differences between men and women, Cox models were estimated. Results In 1137 out of 1375 patients (83%) non-hematologic AE (5160 singular events) were reported during imatinib treatment (all grades), in 322 grade 3/4 AE (23%) (645 singular events). At 3 years, probability of a non-hematologic AE (any grade) was already 76% (95%-CI: 73-79%), at 6 years 85% (95%-CI: 82-88%) and at 8 years 91% (Fig.1). The probability of grade 3/4 non-haematologic AE was 38% (95%-CI: 34-42%) at 6 years and 43% (CI: 37-48%) at 8 years. 156 patients reported hematologic grade 3/4 AE (187 singular events).The probability of hematologic grade 3/4 AE was 17% at 6 years (95%-CI: 15-21%) with most events observed during the first year of treatment (probability after one year 10.5%). The most frequently reported non-hematologic AE (all grades, any time) were gastrointestinal (6-year-probability 52%, 95%-CI: 48-56%), fluid overload or edema (6y-prob. 45%, 95%-CI: 40-49%), rash (6y-prob. 32%, 95%-CI: 28-36%), myalgia or arthralgia (6y-prob. 30%, 95%-CI: 27-34%), fatigue (6y-prob. 26%, 95%-CI: 22-29%), flu-like symptoms (6y-prob. 22%, 95%-CI: 19-26%), infections (6y-prob. 24%, 95%-CI: 20-28%) and neurological symptoms (6y-prob. 26%, 95%-CI: 22-29%). AE probability profiles over time have been generated for each AE (Figs. 2-3). For women the risk for non-hematologic events was increased 1.35-fold (95% CI: 1.18-1.55) for all grades (Figs. 1-3) and 1.13-fold (95% CI: 0.91-1.41) for grade 3/4, and 1.26-fold (95% CI: 0.91-1.71) for grade 3/4 hematologic AE. In 5 patients peripheral arterial occlusive disease grade 2 or 3 was reported, but none could be clearly assigned to imatinib (vascular risk profile of one patient incompletely reported). A definite association between any AE and death was not found. Conclusion As AE by definition may or may not be considered related to the medical treatment an exact assessment of the safety of imatinib is difficult. Most AE were recorded during the first three years with decreasing frequency later on. The increased AE risk in women was mostly grade 1/2 and is commonly seen also in other treatment areas. Given that no imatinib-related death was recorded and that grade 3/4 AE could typically be properly treated we consider imatinib as a safe, comparably well tolerated TKI even after prolonged treatment. After 10 years imatinib continues to be an excellent choice for the treatment of CML in most patients. Disclosures: Hehlmann: Novartis: Research Funding; BMS: Consultancy, Research Funding. Hochhaus:Novartis: Consultancy, Honoraria, Research Funding, Travel Other; BMS: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria; Ariad: Consultancy, Honoraria. Müller:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding; Ariad: Honoraria. Saussele:Novartis: Honoraria, Research Funding, Travel Other; BMS: Honoraria, Research Funding, Travel, Travel Other; Pfizer: Honoraria.

Abstract: We have previously reported on the significant, but heterogeneous baseline MPN symptom burden among an international sample of MPN patients (including essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)) utilizing the MPN Symptom Assessment Form (MPN-SAF) and the derivative Total Symptom Score (MPN-SAF TSS). Recent clinical trials have sought to determine optimal MPN symptom response criteria, such as absolute 10 point improvement in MPN SAF TSS for ET/PV (ELN Criteria, Barosi et. al. Blood 2013) and 50% reduction in MPN-SAF TSS for MF (IWG-MRT, Tefferi et. al. Blood 2013). We sought to determine the role of improvement in MPN-SAF TSS quartiles as potential thresholds to assess symptomatic response to therapy. Methods Utilizing prospectively gathered MPN-SAF TSS (Emanuel et. al. JCO 2012) in patients we assessed potential thresholds of response by evaluating quartile thresholds for severity of symptom burden. The MPN-SAF TSS was scored as the average of 10 symptoms (individual symptoms scores of 0-10, with a total score of 0 (best) to 100 (worst)). MPN-SAF TSS quartiles were identified by the percentage of scores between 0-24% (quartile 1 (Q1)), 25-49% (quartile 2 (Q2)), 50-74% (quartile 3 (Q3)), 75-100% (quartile 4 (Q4)). Results MPN-SAF TSS Quartiles: MPN-SAF TSS quartiles were identified among 1858 MPN patients (ET N=775, PV N=654, and MF N=423). Overall MPN-SAF TSS scores of 0 - 7 were designated as Q1, 8 - 17 as Q2, 18 - 31 as Q3, and ≥ 32 was as Q4. MPN-SAF TSS scores were significantly different between clusters (p 〈 0.001). Associations Between Quartiles and Demographic/ Disease Factors: As quartiles increased, the proportion of PV and ET patients diminished and MF increased (Table 1, p 〈 0.001). Cytopenias and transfusion dependence increased in prevalence in the higher quartiles (p 〈 0.001). A history of prior thrombosis was also significantly more prevalent in the quartiles with highest symptom burden (p 〈 0.001). The prevalence of women was significantly higher among the more symptomatic quartiles females 48.9% Q1, 49.4% Q2, 58.4% Q3, and 60.1% Q4; p 〈 0.001). Associations Between Individual Symptoms and MPN-SAF TSS Quartiles: All individual symptoms measured in the MPN-SAF TSS were significantly worse in quartiles as they increased (p 〈 0.0001). Evaluation of Prognostic Scoring and MPN-SAF TSS Quartiles: Comparison of each patients individual risk score (IPSET, PV, DIPSS for MF) and worsening symptom quartile showed the highest correlation with MF patients (DIPSS) (Table 1). However, ET and PV risk scores were not surrogates for symptom burden by quartile. Conclusions Distribution of MPN patient symptomatic burden by MPN-SAF TSS quartiles provides an easy-to-calculate method to cluster and analyze MPN patients of similar burden. Although MF patients are most prevalent in the most severe quartile of MPN symptomatology it is notable that Q4 has many patients with PV and ET. Future prospective efforts are ongoing to assess the potential of using changes in quartile (i.e. improving from Q3 to Q1) as potential symptomatic response thresholds. Disclosures: Etienne: novartis: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy, Membership on an entity’s Board of Directors or advisory committees; Pfizer: Membership on an entity’s Board of Directors or advisory committees; Ariad: Membership on an entity’s Board of Directors or advisory committees. Roy:Novartis, BMS: Honoraria. Harrison:Gilead: Honoraria, Membership on an entity’s Board of Directors or advisory committees; S Bio: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Shire: Speakers Bureau; Celgene: Honoraria; YM Bioscience: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Vannucchi:Novartis: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Birgegard:Vifor Pharma: Honoraria.