Ketterling, Rhett P.

Abstract Background : Anemia is one of the most prominent symptoms in primary myelofibrosis (PMF) and is often associated with inferior quality of life and survival. Current drugs, including JAK inhibitors, are suboptimal in the treatment of PMF-associated anemia and better information on its pathogenesis is critical for the development of more effective drugs. In the current study of JAK2/CALR/MPL annotated patients with PMF, we examined its correlation with both "driver" and "non-driver mutations", as well as cytogenetic abnormalities, in order to gain better insight into its pathogenesis. Methods: Study patients were selected based on availability of "driver" mutation information. PMF diagnosis was according to World Health Organization criteria (Blood. 2009;114:937). Previously published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Considering their relatively high mutational frequency in PMF, subsets of patients were also screened for ASXL1, spliceosome component (SF3B1, U2AF1, SRSF2, ZRSR2) and TET2 mutations. Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature. Statistical analyses considered clinical and laboratory parameters obtained at time of first referral at the Mayo Clinic. Results : Analysis was conducted on 722 patients (median age 64 years; 64% males). DIPSS-plus risk distribution was 14% low, 17% intermediate-1, 37% intermediate-2 and 33% high. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 477 harbored JAK2, 139 CALR and 41 MPL mutations; 65 patients were triple-negative. The 139 CALR -mutated patients included type 1/type 1-like (n =115) and type 2/type 2-like (n =24). Non-driver mutations screened included ASXL1 (n =480; mutated 38%), SRSF2 (n =474; mutated 14%), U2AF1 (n =457; mutated 16%), SF3B1 (n =328; mutated 8%), ZRSR2 (n =180; mutated 11%) and TET2 (n =180; mutated 18%). Karyotype was normal in 60%, favorable in 28% and unfavorable in 12%. Anemia was defined as being absent (normal sex-adjusted hemoglobin level; n =110; 15%), mild (hemoglobin level of ≥10 g/dL but below sex-adjusted normal value; n =263; 36%), moderate (hemoglobin level below 10 g/dL but not transfusion-dependent; n =108; 15%) and severe (transfusion-dependent anemia; n =241; 33%). Presence of at least mild anemia was associated with abnormal karyotype (p=0.006) with no difference between favorable and unfavorable abnormalities, U2AF1 (p=0.002), TET2 (p=0.02) and ASXL1 (p=0.04) mutations; other significant associations included male sex and older age. Presence of moderate to severe anemia was associated with U2AF1 (p<0.0001), SRSF2 (p=0.007) and driver mutations other than CALR type 1/type 1-like (p<0.0001). Presence of severe anemia was associated with U2AF1 (p<0.0001), SRSF2 (p=0.003) and non-CALR driver mutations (17% incidence in both types of CALR variants vs 51% in triple negative, 35% JAK2, 39% MPL mutated cases; p<0.0001). An association with older age but not gender was also noted for both moderate to severe and severe anemia (p<0.0001). During multivariable analysis, independent associations with moderate to severe anemia were confirmed for U2AF1 (p<0.0001), SRSF2 (p=0.007) and age (p=0.0001), but not driver mutation profile (p=0.30). A similar analysis for severe anemia also identified U2AF1, SRSF2 and age as being significantly relevant. Conclusions : The current study identifies older age and the spliceosomal mutations U2AF1 and SRSF2 as having strong and independent association with moderate to severe anemia in PMF. Targeting the spliceosome machinery or its mutant components offers a potential approach in the treatment of PMF-associated anemia. Disclosures Pardanani: Stemline: Research Funding.

Abstract Background The 2016 revised World Health Organization (WHO) classification system distinguishes prefibrotic (pre-PMF) from overtly fibrotic (overt PMF) primary myelofibrosis, based on the respective absence or presence of grade ≥2 bone marrow (BM) reticulin fibrosis (Blood. 2016;127:2391). The main objective of the current study was to determine the prognostic relevance of this distinction and compare clinical and genetic features between the two entities. Methods Study patients fulfilled the 2016 WHO criteria for the diagnosis of pre-PMF or overt PMF (Blood. 2016;127:2391). The degree of BM reticulin fibrosis was based on "real life" BM reports from Mayo Clinic hematopathologists and often in accordance with the European consensus scoring system (Haematologica 2005;90:1128). Targeted next generation sequencing was used to screen for prognostically-relevant mutations (Blood 2015 126:354). Statistical analyses considered clinical and laboratory parameters obtained at time of BM examination that was graded for reticulin fibrosis. Results Patient characteristics: Analysis was conducted on 467 patients (median age 64 years; 62% males), including 63 with pre-PMF and 404 with overt PMF. 302 (65%) patients harbored JAK2 mutations, 90 (19%) CALR, 24 (5%) MPL and 51 (11%) were "triple-negative"; among the 90 CALR-mutated cases, 74 (82%) were classified as "type 1/type 1-like". Dynamic international prognostic scoring system (DIPSS)-plus risk distribution (JCO 2011;29:392) was 30% high, 38% intermediate-2, 16% intermediate-1 and 15% low; 29% displayed red cell transfusion-dependency, 29% constitutional symptoms, 70% palpable splenomegaly and 37% abnormal karyotype, including 13% with unfavorable karyotype. 308 patients were screened for ASXL1 mutations with 39% mutated, 305 for SRSF2 mutations with 16% mutated, 291 for U2AF1 with 18% mutated, 264 for SF3B1 with 6% mutated, 240 for EZH2 with 5% mutated and 118 for IDH1/2 with 7% mutated. BM reticulin fibrosis was reported as grade '0' in 5 (1%) patients, grade '1' in 58 (12%), grade '2' in 169 (36%) and grade '3' in 235 (50%). After a median follow up of 3 years, 273 (59%) deaths and 42 (9%) leukemic transformations were documented. Clinical, cytogenetic and molecular comparisons between pre-PMF vs overt PMF: Significant differences included higher hemoglobin level (p<0.0001), higher platelet count (p<0.0001), higher incidence of thrombocytosis (p<0.0001), lower circulating blast percentage (p=0.0002), lower incidence of constitutional symptoms (p=0.003), lower incidence of palpable splenomegaly and lower DIPSS-plus risk distribution (p=0.0004), in pre-PMF, compared to overt PMF. There were significantly more triple-negative patients with pre-PMF (22% vs 9% for overt PMF; p=0.02) but otherwise no significant difference in the distribution of ASXL1, SRSF2, U2AF1, SF3B1, EZH2 or IDH1/2 mutations or incidence of unfavorable karyotype. Survival analysis: In univariate analysis, all 8 variables included in DIPSS-plus were significantly associated with shortened survival (p<0.001 in all instances). Significant risk factors in univariate analysis also included overt PMF vs pre-PMF (p=0.002; HR 2.0, 95% CI 1.3-3.1), absence of CALR type 1/type 1-like (p<0.0001) and presence of ASXL1 (p<0.0001) or SRSF2 (p<0.0001) mutations. The significant difference in survival between pre-PMF and overt PMF was independent of DIPSS-plus (p=0.03), driver mutational status (p=0.001), ASXL1 (p=0.008) and SRSF2 (p=0.02) mutations; no significant difference in leukemia-free survival was noted (p=0.25). The survival difference between pre-PMF and overt PMF was most evident in high/intermediate-2 DIPSS-plus risk groups (Figure). Of note, we found no difference in survival when patients with grade '0' were compared to those with grade '1' reticulin fibrosis (p=0.96) and when those with grade '2' were compared with grade '3' (p=0.08). Conclusion The current study demonstrates the risk-adjusted prognostic relevance of the WHO distinction between pre-PMF and overt PMF. The two clinic-pathologic entities were otherwise similar in their spectrum of prognostically-relevant mutations or cytogenetic abnormalities, although pre-PMF clustered with thrombocythemic and triple-negative phenotype and overt PMF with adverse clinical features. Figure Figure. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 524 The International UKALLXII/E2993 trial enrolled 2091 pts with newly diagnosed adult ALL between 1993 and 2006. Patients received 2 months of combination induction chemotherapy followed by an intensification course of high dose methotrexate and L-asparaginase after which pts were randomized to autologous hematopoietic stem cell transplant (HSCT) or consolidation and maintenance chemotherapy. Patients <55 years of age with a matched sibling donor were assigned myeloablative allogeneic HSCT (Goldstone, et al, Blood 2008; 111:1827). Here we report a detailed analysis of 1,229 pts from this trial with B-ALL, excluding Philadelphia-chromosome-positive patients. The median age was 30 years (range 14–65) and 59% were male. The median WBC was 9.2×109/L (range 0.1–930) and 73% of pts had a WBC <30 × 109/L. CNS involvement was present in 4% of pts at diagnosis. Comprehensive centralized immunophenotyping was performed in 372 of the 409 (91%) ECOG pts enrolled and initial analysis demonstrated pro-B/pre-pre-B in 17%, early pre-B in 52%, pre-B in 14%, either early pre-B or pre-B in 6%, mature B in 2% and B-lineage, not otherwise specified, in 9%. Outcomes were similar between patients with immunophenotyping data and those without. The complete remission (CR) rate was 93% and there were 4% induction deaths. The overall survival (OS), event-free survival (EFS), relapse risk (RR) and non-relapse mortality (NRM) at 5 years for the overall group is shown in the table. There were no significant differences in CR rate, OS, EFS, RR or NRM for the immunophenotypic subgroups. There was better OS and EFS with less relapse and similar risk of NRM for pts randomized to chemotherapy as compared with autologous HSCT (Figure 1). In the matched sibling donor-no donor comparison, OS and EFS were improved, RR was less and NRM was higher in the donor group (Figure 2). Cytogenetic analysis confirmed that patients with t(4;11) (n=77, 8% total), t(8;14) (n=19, 2% total), a complex karyotype (≥5 abnormalities in the absence of an established chromosomal abnormality) (n=38, 5% total), or low hypoploidy/near triploidy (n=41, 5% total) had an inferior OS and patients with high hyperdiploidy had a superior OS when compared to other patients. In conclusion, this is the largest series of B-ALL in uniformly treated adults ever reported and confirms the superior outcome of patients randomized to chemotherapy as compared with autologous HSCT and shows that patients with a matched sibling donor have an improved survival over patients without a donor. No difference in CR rates or outcome was noted for patients with different immunophenotypic subtypes of B-ALL. Future improvements in outcome of pts with B-ALL will rely on the addition of new agents such as B cell monoclonal antibodies and improvements in allogeneic HCT.Table.Outcomes at 5 years of follow-upnCR rate (%)OSEFSRRNRMOverall12299342375021Pro-B/pre-pre-B639236345421Early pre-B/pre-B2689340345421Age ≤ 35 years746 (61%)9653454516Chi square p<0.0001<0.0001<0.0001<0.0001<0.0001Age >35 years483 (39%)8932265930Randomized to autologous HSCT15735316610Log rank p0.030.010.01NSRandomized to chemotherapy1694742558Matched sib donor34452483032Chi square p0.050.03<0.001<0.001No Donor47445415510Values are % except n and p values. CR=complete remission, OS=overall survival, EFS=event-free survival, RR=relapse risk, NRM=non-relapse mortality NS=not significant. The p values represent the difference between age groups for the first comparison, randomized to autologous HSCT versus chemotherapy for the second comparison and between matched sibling donor and no donor for the third comparison. Overall survival by randomized allocation at 10 years Overall survival by donor availability at 10 years Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 579 Background: In AML, age and cytogenetics remain among the major prognostic factors. Age above 55 years and a complex karyotype (CK; ≥ 3 abnormal clones) or the presence of monosomy 7 (M7) are universally associated with unfavorable prognosis. Recent data from HOVON-SAKK (J Clin Onc 26: 4791) suggest that in patients under the age of 60 years, subgroups with poor risk versus very poor risk can be delineated based on the presence of a MK. MK was defined as either the presence of at least two autosomal monosomies or one monosomy plus at least one structural abnormality. Limited data exists regarding the impact of MK in AML patients over the age of 55 years. Methods: Data from 935 AML patients above age 55 enrolled on three prospective ECOG therapeutic clinical trials (E1490, E3993, E3999) between 1990 and 2005 were retrospectively reviewed to identify those with MK with single and/or multiple monosomies, MK in the presence or absence of a CK, CK with/without MK, MK with/without M7, and normal karyotype (CN). CK was defined as ≥ 3 clonal abnormalities for the purposes of this study. Complete remission (CR), disease-free survival (DFS), and overall survival (OS) were assessed. Results: The median age of evaluable patients was 68 years (range 56 – 93) with a male/female ratio of 391/299. Cytogenetic data were evaluable in 690 (74%) subjects. Clonal cytogenetic abnormalities occurred in 399 (58%). Core-binding factor (CBF) abnormalities accounted for 16/399 (4%) whereas CK was detected in 181/399 (45%). MK was present in 172 (25%) evaluable cases, predominantly in the setting of CK (140/172, 81%). Overall CR was 44%. CR was achieved in 49% MK−, 29% MK+, 31% CK+, and 49% of CK−. Data for the combinations of MK and CK are presented in Table 1. Median follow-up for survivors was 5.0 years. OS at 4-years was 9% for all evaluable patients and 4y-DFS was 12% in those achieving CR. Median OS of MK+/CK+ (0.3y) was significantly worse (p<0.001) than MK+/CK−(0.6y), MK−/CK+ (0.8y), and MK−/CK−(0.9y). Median DFS of MK+/CK+ (0.3y) was also significantly poorer (p<0.001) than MK+/CK− (0.9y), MK−/CK+ (0.8y), and MK−/CK− (0.9y). M7 was present in 82 (13%) enrolled patients with 98% (80/82) of M7 occurring within a MK. CR was achieved in 31% of MK+/M7+ and 27% of MK+/M7−. Neither median OS nor DFS were significantly impacted by M7 status as noted in Table 2. Conclusions: AML patients above the age of 55 years have an unfavorable prognosis with the majority of patients harboring adverse clonal cytogenetic abnormalities and failing to achieve a CR. Fewer than 10% survive 4-years from diagnosis. Results from the ECOG experience demonstrate the prognostic predictive value of MK in older AML patients. In contrast to the data presented by the HOVAN-SAKK group, the prognostic value of MK in patients over 55 years is limited to those with MK in combination with CK. These results also demonstrate the failure of monosomy 7 to provide prognostic value in the setting of MK. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: In a previously published phase-1/2 study, momelotinib (a JAK 1/2 inhibitor) induced 53% anemia, 39% spleen and >50% constitutional symptoms response rates in patients with myelofibrosis (MF) (Pardanani A, et al. Leukemia. 2013;27:1322). The particular study included 100 patients from the Mayo Clinic who experienced 43% spleen and 44% anemia response rates (Pardanani et al. Leukemia. 2015;29:741); CALR and ASXL1 mutations independently predicted spleen but not anemia response. In the current study, we examined the impact of momelotinib therapy on DIPSS-plus- and molecular risk-adjusted survival. Methods: The current study represents sponsor-independent analysis of long-term survival among 100 consecutive Mayo Clinic patients who received momelotinib therapy as part of a larger (n =166) phase-1/2 study (NCT00935987). Safety and efficacy data from NCT00935987, as well as protocol design and drug dosing and schedule, have already been formally reported and not reiterated here (Pardanani A, et al. Leukemia. 2013;27:1322; Pardanani A, et al. Leukemia. 2015;29:741; Abdelrahman RA, et al. BJH. 2015;169:77). All statistical analyses considered clinical and laboratory parameters obtained at the time of entry to study. Survival analysis was considered from the date of study entry to date of death or last contact. Cox proportional hazard regression model was used for multivariable analysis of survival. Samples from time of study entry were used for mutation screening. Driver mutations were classified into two prognostically-relevant groups: CALR type 1/type 1-like (favorable) vs all others including CALR type 2/type 2-like, JAK2, MPL and triple-negative (unfavorable). Results: 100 patients with MF (median age 66 years; 58% males) were treated at the Mayo Clinic between 11/20/09 and 11/10/10; 64 patients had primary MF, 22 post-polycythemia vera MF and 14 post-essential thrombocythemia MF. Baseline data: DIPSS-plus risk distribution was 63% high, 36% intermediate-2 and 1% intermediate-1 (JCO 2011;29:392); for the purposes of the current analysis, the single patient with intermediate-1 risk disease was included in the intermediate-2 category. 54 (54%) patients displayed abnormal karyotype. 73 (73%) patients harbored JAK2, 16 (16%) CALR, 7 MPL and 4 "triple-negative". Among the 16 CALR -mutated cases, 13 were classified as "type 1/type 1-like". 94 patients were screened for ASXL1 mutations; 41 (44%) were mutated. Follow-up data was updated in July 2015, providing a minimum follow-up of over 4.5 years since the last patient registration on the protocol. At a median follow-up of 3.2 years, 67 (67%) deaths and 13 (13%) leukemic transformations were documented. Median survival from the time of study entry was 3.2 years and was affected by driver mutation prognostic groups (median survival "not reached" for "favorable" vs 3 years for "unfavorable"; p=0.01), ASXL1 mutational status (median survival 3.9 years in unmutated vs 2.5 years in mutated; p=0.02) and DIPSS-plus risk stratification (median survival 2.6 years in high-risk vs 4 years in intermediate-2 risk; p=0.07). In order to assess the impact of momelotinib on long-term outcome, we compared survival of the study cohort (n =100) with that of 442 consecutive Mayo Clinic patients with high or intermediate-2 risk primary MF (median age 67 years; 66% males). There was no significant difference between this control group of PMF patients versus the momelotinib patient cohort in distribution of age (p=0.56), sex (p=0.12), JAK2/CALR/MPL mutational status (p=0.41) or ASXL1 mutational status (p=0.9); however, the momelotinib cohort had a higher fraction of patients with DIPSS-plus high-risk disease (63% vs 47%; p=0.004). Overall survival was similar between the momelotinib cohort and the control group of PMF patients who were not treated with momelotinib (Figure 1; p=0.99); the difference in survival remained not significant during multivariable analysis that included risk stratification by DIPSS-plus (p=0.32), "favorable" vs "unfavorable" driver mutational status (p=0.78) or ASXL1 mutational status (Figure 2; p=0.61). Conclusions: In the current long-term study, we could not demonstrate a survival impact from momelotinib therapy in myelofibrosis. Although adjusted for clinical and molecular risk status, our study is retrospective and cannot be relied upon to discount marginal survival effect. Disclosures Al-Kali: Novartis: Research Funding. Pardanani:Stemline: Research Funding.

Abstract Background : In essential thrombocythemia (ET) , ̴ 85% of patients harbor one of three "driver" mutations, with mutational frequencies of approximately 58%, 23% and 4%, for JAK2, CALR and MPL, respectively; ̴ 15% are wild type for all three mutations and are operationally referred to as "triple negative" (Blood. 2014;124:2507). In one of the original descriptions on CALR mutations, CALR -mutated patients with ET, compared to their JAK2-mutated counterparts, were reported to have better survival (NEJM. 2013;369:2379). However, this observation was not supported by subsequent studies while other reports suggested differential prognostic effect from distinct CALR variants in myelofibrosis (Blood. 2014;124:2465). In this study, we sought to clarify the impact of all three mutations, and CALR variants, on overall (OS), myelofibrosis-free (MFS) and leukemia-free (LFS) survival. Methods: Patientswere selected from our institutional database of myeloproliferative neoplasms, based on availability of mutational status inforomation. ET diagnosis was according to WHO criteria (Blood. 2009;114:937). Published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Kaplan-Meier survival analysis was considered from the date of diagnosis to date of death or last contact. MFS and LFS calculations considered fibrotic or leukemic transformation events as uncensored variables, respectively. Cox proportional hazard regression model was used for multivariable analysis. Results : A total of 502 patients (median age 59 year; 61% females) met study eligibility criteria. Median levels of hemoglobin, platelet count and leukocyte counts were 13.7 g/dL, 893 x 10 (9)/L and 8.8 x 10(9)/L, respectively. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 324 harbored JAK2, 111 CALR and 13 MPL mutations; 54 patients were triple-negative. The 111 CALR-mutated patients included type 1 (n=55), type 2 (n=41) or other (n=15) CALR variants. At a median follow-up time of 9.9 years, 172 (34.3%) deaths, 42 (8.4%) fibrotic progressions, 15 (3%) blast transformations and 12 (2.4%) polycythemic conversions were documented. In univariate analysis, survival data appeared significantly better in "triple negative" patients (median not reached) and inferior in MPL-mutated cases (median 8.5 years) whereas median survival times were similar for JAK2 (18.5 years) and CALR (22.1 years) mutated cases (Figure 1; p=0.0006). However, the difference in survival was no longer apparent (p=0.60) during multivariable analysis that included age and sex, which are known to differentially cluster with specific driver mutations; in the current study, median age/sex distributions for "triple-negative", CALR, JAK2 and MPL mutated cases were 44 years/72% females, 48 years/46% females, 60 years/65% females, 70 years/46% females, respectively (p=<0.0001/0.0007). Of note, both age and sex were independently predictive of shortened survival. OS data remained unchanged when CALR-mutated patients were further stratified into type 1 vs type 2 vs other CALR variants, with similar survival data between the three CALR mutation groups (p=0.98). In univariate analysis, MPL-mutated patients were significantly more prone to fibrotic progression (Figure 2; p=0.0083). The prognostic relevance of MPL mutations to MFS remained significant when age and sex were included in multivariable analysis (p=0.008). In the current cohort, univariate analysis identified lower hemoglobin and lower platelet count as the only other risk factors for fibrotic progression. Multivariable analysis confirmed the independent prognostic relevance of MPL mutations (p=0.003), lower hemoglobin level (p=0.0009) and lower platelet count (p=0.0094) for MFS. There was no significant difference in LFS among the four driver mutational categories (p=0.9): 9 events in JAK2, 6 in CALR, none in triple negative and none in MPL mutated cases. Among the 6 leukemic transformations in CALR-mutated cases, three were type 1, two type 2, and one other CALR variants. Conclusions : Age- and sex-adjusted survival is similar among ET patients with JAK2 vs CALR vs MPL vs "triple-negative" mutational status. Survival is also similar between patients with distinct CALR variants. MPL -mutated patients with ET might be at a higher risk of fibrotic progression. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Pardanani: Stemline: Research Funding.

Abstract Background: Over the last decade there have been three FDA-approved agents available for the treatment of myelodysplastic syndromes (MDS); azacitidine was approved in 2004 for all subtypes of MDS; lenalidomide in 2005 for MDS with del(5q); and decitabine in 2006 for intermediate/high risk MDS. However the ability of these drugs to improve survival outside of clinical trials remains controversial (Neukirchen J, Leuk Res 2015, Bernal T, Leukemia 2015). Objectives : i) Evaluate trends in overall survival (OS) and leukemic transformation (LT) rate amongst primary MDS patients (pts) by year of diagnosis and, ii) Evaluate trends in OS by treatment received. Methods : The Mayo Clinic database was used to identify pts with primary MDS in whom bone marrow histologic and cytogenetic information was obtained at the time of diagnosis. WHO criteria were used for MDS diagnosis and LT. A comparative analysis was performed based on year of diagnosis commensurate with the approval of the aforementioned drugs (Group 1- diagnosis prior to the year 2000, Group 2- year 2001-2004, Group 3- year 2005-2009, and Group 4- year 2010-2014). Results : i) Patient characteristics: A total of 1000 pts met the above-stipulated criteria. 85% of pts were above 60 years of age (median 72 years) with 69% being males. The distribution of pts by year of diagnosis was as follows: Group 1 (n=281)(28%), Group 2 (n=250)(25%), Group 3 (n=264)(26%), and Group 4 (n=205 (21%). Median follow-up of our cohort was 27 months (range; 0-300 months) during which time 808 (81%) deaths and 129 (13%) LT were documented. ii) Comparison of patient characteristics by year of diagnosis: Pts in group 1 and 2 compared with groups 3 and 4 were more likely to present with anemia defined as hemoglobin < 10 g/dl (61%/59% vs 50%/55%)(P =.04). In addition, groups 1 and 2 displayed a higher incidence of RA (5%/4% vs 1% each), and RARS (17%/16% vs 9%/8%), compared to groups 3 and 4 that had a higher incidence of RCMD (37%/44% vs 17%/28%) (P <.001). The IPSS-R risk distribution was not significantly different; 17% very low, 36% low, 21% intermediate, 15% high and 11% very high risk with median survivals of 72, 43, 24, 18 and 7 months, respectively (P <.001). As expected, a higher proportion of pts in groups 3 and 4 (41% and 57% respectively) received "disease-modifying" therapy including allogeneic transplant and hypomethylating agents as opposed to only 6% and 22% in groups 1 and 2 respectively (P <.001). iii) Trends in OS and LT rate by year of diagnosis: The median OS of the entire cohort was 30 months, with median OS and LT rates being similar amongst groups 1 through 4 at 31 vs 33 vs 30 vs 27 months (P =.79) (Figure) and 10% vs 16% vs 12% vs 15% (P =.25), respectively. iv) Trends in OS by treatment received: In univariate analysis survival was significantly better in pts who underwent allogeneic transplant (n=65) with median survival of 55 months vs 26 months for non-transplant pts (P<. 001); and among non-transplant lenalidomide-treated pts (n=44) with median survival of 54 months vs 26 months for the remainder of pts (P =.02). However, these results lost significance on multivariable analysis with the addition of age as a co-variate for transplant pts (P =.28), and IPSS-R as a co-variate for lenalidomide treated pts (P =.10). Excluding transplant pts, pts that received hypomethylating agents (n=158) had similar survival to pts not treated with hypomethylating agents (27 vs 29 months; P =.19, age-adjusted P =.11). In addition, the 54 pts who received other chemotherapeutic agents had similar survival to pts not treated with these agents (33 vs 26 months; P =.57, age-adjusted P =.80). Supportive care alone was utilized in 702 pts that had comparable survival to the 298 pts that received "disease-modifying" therapy (27 months vs 34 months; P =.05, age-adjusted P =.11). Conclusions : In this single center analysis of 1000 pts with primary MDS, stratified by year of diagnosis, the poor outcome of these pts has not improved over the last two decades, in spite of the significantly higher utilization of "disease-modifying" therapy, including hypomethylating agents since 2005. The lack of improvement in survival with hypomethylating therapy is consistent with recently published results from the Spanish MDS registry (Bernal T, Leukemia 2015). However, our retrospective study is not designed to detect marginal survival benefit, which has thus far been reported in only one clinical trial. Figure 1. Figure 1. Disclosures Al-Kali: Novartis: Research Funding. Pardanani:Stemline: Research Funding.

Abstract Background : Hydroxyurea has been the mainstay of cytoreductive therapy in essential thrombocythemia (ET) for over four decades. In 1988, anagrelide was first reported as an effective drug in ET (Silverstein et al. NEJM 1988;318:1292) and hundreds of patients were enrolled in clinical trials, which subsequently led to FDA approval in 1997. As a result, an increasing number of patients with ET were being treated with anagrelide until a subsequent controlled study suggested an inferior treatment outcome with anagrelide compared to hydroxyurea (Harrison et al. NEJM 2005;353:33). In the current study, we examined the impact of the corresponding practice changes on overall, myelofibrosis-free and leukemia-free survival, by comparing patients with ET diagnosed before 1988, between 1988 and 1997, and between 1998 and 2005 Methods: More than 45,000 patient charts with "thrombocytosis" were reviewed to identify those who met either PVSG (older patient cohort) or WHO criteria for diagnosis of ET. Survival was calculated from time of initial diagnosis to the time of last follow-up or death. For leukemia- or fibrosis-free survival, the time of the transformation events was considered as the uncensored variable. Conventional statistics was utilized for all analyses. Patients were divided into three groups commensurate with changes in treatment practices, corresponding to the aforementioned publications; Group 1 patients were diagnosed prior to 1988 (n =222), Group 2 1988 to 1997 (n =253), and Group 3 1998 to 2005 (n =264). Results : A total of 739 patients met the above-stipulated criteria (median age 57 years; 65% females). At a median follow-up of 12.2 years (range: 0.01-43.6 years), 368 (50%) deaths, 48 (6.5%) fibrotic transformations and 23 (3%) leukemic transformations were documented. Median overall survival (OS) was 18.6 years. On multivariable analysis, older age (P <0.001), increased leukocyte count (P <0.001), thrombosis history (P =0.04), and male sex (P<0.0001) were identified as predictors of inferior OS. Myelofibrosis-free survival (MFS) was predicted by platelet count <100 x 10(9)/L and lower hemoglobin level (multivariate P values 0.03 and <0.001, respectively). Leukemia-free survival (LFS) was predicted by increased leukocyte count, on multivariable analysis (P =0.002). Comparison of presenting features and outcome by period of diagnosis: Significant differences, in presenting features, between groups 1, 2, and 3 included age (median 55, 56, and 59 years, respectively; P =0.003), female preponderance (68, 69, and 58%, respectively; P =0.02), platelet count (1080, 995, and 890 x 10(9)/L, respectively; P <0.001), and leukocyte count (10, 9.6, and 8.4 x 10(9)/L, respectively; P <0.001). Median survival was 20.7 years, 19 years and 14.3 years, in groups 1, 2 and 3, respectively (P =0.02) (Figure 1). However, the difference in survival was no longer apparent during multivariable analysis that included age as a covariate (P=0.88). In univariate analysis, MFS was significantly shorter in group 3 patients (P=0.02; Figure 2); borderline significance was retained during multivariable analysis (p=0.13). LFS was similar among the three groups (P = 0.27). Conclusions : The results from the current retrospective study suggest increased rate of progression to myelofibrosis in ET patients diagnosed in the anagrelide era, an observation that is consistent with the results from a previous controlled study (Harrison et al. NEJM 2005;353:33). Regardless, survival in ET in the last four decades remains unchanged. Figure 1. Figure 1. Figure 2. Figure 2. Disclosures Pardanani: Stemline: Research Funding.

Abstract Background: Cytogenetic evaluation, especially using fluorescence in situ hybridization (FISH), at the time of diagnosis is essential for initial risk stratification and the employment of risk-adapted treatment strategies in multiple myeloma. Little is known about the occurrence and prognostic significance of cytogenetic evolution during follow up. Methods: We studied 433 patients who were diagnosed with multiple myeloma between January 2000 and December 2011 and had at least two FISH evaluations at Mayo Clinic Rochester, including the diagnostic specimen. Bone marrow aspirates were evaluated for deletions, monosomies, trisomies, and tetrasomies using chromosome- or centromere-specific FISH probes. IGH rearrangements were evaluated using an IGH break-apart probe and up to five potential partners (FGFR3, CCND1, CCND3, MAF, and MAFB). Cytogenetic evolution was defined as a new deletion, monosomy, trisomy, tetrasomy, or translocation during follow up. Multivariable-adjusted logistic regression models were used to assess the associations between the parameters of interest and the presence of cytogenetic evolution in follow-up specimens. Multivariable-adjusted Cox proportional hazards models were used to assess the effect of cytogenetic evolution on overall survival. All models were adjusted for sex, age, the presence of high-risk FISH abnormalities, and the number of abnormalities at the time of diagnosis. Likelihood ratio tests were used to assess the goodness of fit of nested models. The χ2 or Fisher's exact test was used to assess the distribution of cytogenetic abnormalities in subgroups. Results: The median age at diagnosis was 60 years (32 - 82), 264 (61%) of the patients were male. The median overall survival for the entire cohort was 7.0 years (6.2 - 7.8). At the time of diagnosis, 150 (35%) and 57 (13%) of the 433 patients presented with a hyperdiploid karyotype and cytogenetic high-risk abnormalities, respectively. Independent of each other, the presence of a translocation at the time of diagnosis was associated with decreased odds of cytogenetic evolution during follow up (OR 0.39, 95% CI 0.24 - 0.63, p < 0.001) while the presence of at least one trisomy or tetrasomy at the time of diagnosis was associated with increased odds (OR 2.53, 95% CI 1.37 - 4.70, p = 0.003). A greater proportion of patients presenting with a hyperdiploid karyotype experienced cytogenetic evolution during follow up. Those patients more frequently evolved additional trisomies and tetrasomies, while translocations were more common in those presenting with a non-hyperdiploid karyotype (Table 1). The development of additional abnormalities during the three years following diagnosis (compared to no new abnormalities) was associated with increased subsequent mortality in those who survived at least three years (HR 3.22, 95% CI 1.82 - 5.68, p < 0.001). Including the time between first and last cytogenetic evaluation as a covariate did not significantly change the parameter estimates or improve model fit (p = 0.727). Conclusions: Demographics, risk profile, and overall survival of this cohort reflect the fact that patients had to survive long enough to undergo repeated cytogenetic evaluation. Hyperdiploid and non-hyperdiploid genotypes were associated with distinct behavior regarding cytogenetic evolution during follow up. The identification of cytogenetic evolution was an adverse prognostic factor in those who survived at least three years after diagnosis. These findings emphasize the importance of the dynamics of the underlying clonal disease process for accurate risk assessment and suggest that selected subgroups of patients may benefit from risk stratification during follow up. Table 1. Cytogenetic evolution during follow up in 433 patients with multiple myeloma stratified by karyotype at the time of diagnosis Hyperdiploid (n = 150) Non-hyperdiploid (n = 283) p New abnormality 76 (51%) 108 (38%) 0.012 New monosomy 8 (5%) 24 (8%) 0.243 New trisomy 48 (32%) 55 (19%) 0.004 New tetrasomy 37 (25%) 27 (10%) < 0.001 New deletion 17 (11%) 27 (10%) 0.557 New translocation 1 (1%) 11 (4%) 0.065 Most common new abnormality [type (percent of type in each group)] Monosomy mono(13) (75%) mono(13) (62%) Trisomy tri(11) (22%) tri(3) (22%) Tetrasomy tetra(15) (48%) tetra(15) (30%) Deletion del(17p) (79%) del(17p) (63%) Translocation t(11;14) (100%) t(11;14) (36%) Data are given as count (percent) unless denoted otherwise. Disclosures Binder: American Society of Hematology: Research Funding. Kumar:AbbVie: Research Funding; Onyx: Research Funding; Sanofi: Research Funding; Celgene, Millenium, Sanofi, Skyline, BMS, Onyx, Noxxon,: Other: Consultant, no compensation,; Skyline, Noxxon: Honoraria; Millenium/Takeda: Research Funding; Janssen: Research Funding; Celgene: Research Funding.

Abstract Background : In primary myelofibrosis (PMF), ̴ 88% of patients harbor JAK2, CALR or MPL, with respective mutational frequencies of approximately 60%, 22% and 6%; ̴ 12% are wild type for all three driver mutations and are labelled as being "triple negative" (Blood. 2014;124:2507). It is now well-established that CALR-mutated patients with PMF display significantly better survival, compared to all the other mutational categories; in addition, preliminary data have suggested inferior survival for "triple-negative" cases (Leukemia. 2014;28:1472; Blood. 2014;124:1062) and the possibility that the favorable impact of CALR mutations might be restricted to CALR type 1 or type 1-like variants (Blood. 2014;124:2465). In the current study, we sought to clarify the prognostic impact of driver mutations, and CALR variants, on overall (OS) and leukemia-free (LFS) survival, in a two-center study involving 1118 patients. Methods: A total of 1118 patients with PMF from the Mayo Clinic (n =722) and University of Florence, Italy (n =396) were included in the current study. Study patients were selected based on availability of mutation information. PMF diagnosis was according to World Health Organization criteria (Blood. 2009;114:937). Previously published methods were used for CALR, JAK2 and MPL mutation analyses and determination of CALR variants (Blood. 2014;124:2465). Kaplan-Meier survival analysis was considered from the date of first referral for the Mayo cohort and date of diagnosis for the Florence cohort. Leukemic transformation events replaced death as the uncensored variable during LFS analysis and Cox proportional hazard regression model was used for multivariable analysis. Results : Analysis was first conducted on the Mayo cohort of 722 patients (median age 64 years; 64% males). DIPSS-plus risk distributions were 14% low, 17% intermediate-1, 37% intermediate-2 and 33% high. All patients were annotated for JAK2/CALR/MPL mutations as well as CALR variants; 477 harbored JAK2, 139 CALR and 41 MPL mutations; 65 patients were triple-negative. The 139 CALR -mutated patients included type 1/type 1-like (n =115) and type 2/type 2-like (n =24). At a median follow-up time of 3.1 years, 439 (61%) deaths and 63 (8.7%) blast transformations were documented. In univariate analysis, survival in patients with CALR type 1/type 1-like mutations was significantly longer than every other mutational category: HR (95% CI) were for triple-negative 2.7 (1.8-4.0), JAK2 2.7 (2.0-3.7), CALR type 2/type 2-like 2.3 (1.3-4.2) and MPL 1.9 (1.1-3.1) (Figure 1); these differences were sustained during multivariable analysis that included ASXL1 mutations (n =480) and DIPSS-plus, and were also apparent in the Florence cohort of 396 cases that included 251 JAK2, 53 CALR type 1/type 1-like, 21 CALR type 2/type 2-like, 50 triple-negative and 21 MPL mutated cases (Figure 2). There was no difference in survival among the Mayo cohort across mutational categories not including CALR type 1/type 1-like variants (p=0.33). Because specific driver mutations in PMF differentially cluster with age and sex, multivariable analysis including these two parameters was also performed and confirmed the significant survival advantage of CALR type 1/type 1-like over triple-negative, JAK2 and CALR type 2/type 2-like mutated cases. Based on the above information, we divided driver mutational categories into "type 1/type 1-like" (median survival 10.3 years) and "all other mutational categories" (median survival 3.9 years; p<0.01). The difference in survival between these two groups remained significant (HR 2.1, 95% CI 1.5-2.9) during multivariable analysis that included both DIPSS-plus (P<0.01) and ASXL1 mutation (HR 1.8, 95% CI 1.4-2.2). LFS was similar between these two groups (p=0.4) but it was inferior in triple-negative cases compared to CALR type 1/type 1-like variants (HR 2.8, 95% CI 1.3-6.2), MPL (HR 4.6; 95% CI 1.04-20.4) and JAK2 (HR 2.5, 95% CI 1.3-4.8) but not CALR type 2/type 2-like variants (p=0.56). There was no difference in LFS among mutational categories not including triple-negative cases (p=0.33). Conclusions : In PMF, driver mutations might be classified into two prognostically distinct categories: "favorable" (type 1/type 1-like) and "unfavorable" (all other mutational categories). In addition, triple-negative cases might be at a higher risk of leukemic transformation. Disclosures Pardanani: Stemline: Research Funding. Vannucchi:Novartis: Other: Research Funding paid to institution (University of Florence), Research Funding; Shire: Speakers Bureau; Baxalta: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.