Pardanani, Animesh

Abstract Introduction: Several groups are developing orally bioavailable small molecule JAK2 inhibitors as an approach to targeted therapy of myeloproliferative disorders. We previously reported that one such inhibitor (TG101209) potently inhibits JAK2V617F in vitro, and was effective in reducing tumor growth in a mouse xenograft model (Leukemia, 2007 Aug;21(8):1658–68). Here, we expand our analysis using TG101348, a highly selective JAK2 inhibitor currently in preclinical development, using cell lines and primary cells harboring JAK2V617F, MPLW515L/K, or JAK2 exon 12 mutations. Methods: Cell proliferation was assessed using the XTT assay. For primary cell experiments, PBMCs were plated in methylcellulose medium at 0, 300nM, 600nM, and 1200nM TG101348, both with and without erythropoietin (Epo). Hematopoietic colonies were scored after 12–16 days culture, and harvested for genotyping. Results: TG101348 inhibits growth of human erythroleukemia (HEL) and Ba/F3-V617F cells (IC50=300nM and 580nM, respectively), as well as Ba/F3-(MPL)W515L cells (IC50=620nM). JAK2:JAK3 selectivity of TG101348 was demonstrated by its 10-fold more potent inhibition of CHRF (JAK2T875N) as compared to CMK (JAK3A572V) cell proliferation. TG101348’s inhibitory effect on ex vivo hematopoietic colony growth was studied in 12 MPD patients (JAK2V617F=9, MPLW515L/K=1, JAK2 exon 12 mutation [N542-E543del]=1, no mutation=1), and 2 healthy controls (Table). Conclusions: (1) TG101348 inhibits colony growth from MPD patients more potently than healthy controls, reflecting its potential therapeutic window. (2) Endogenous colony growth is inhibited at nanomolar concentrations in all cases, with some alleles showing greater sensitivity than others (MPLW515K = exon 12 mutation > JAK2V617F). The corresponding Epo-supported erythroid colonies are less potently inhibited, reflecting the generally lower prevalence of JAK2 mutations in such colonies. (3) EEC growth in the absence of known JAK2 or MPLW515 mutations is also inhibited, indicating a similar dependence on dysregulated JAK-STAT signaling in such cases. (4) The ability of TG101348 to selectively suppress mutation-positive hematopoietic colonies will be discussed. Inhibitor effect on ex vivo hematopoietic colony growth Paient Mutation IC50 (nM) % Mutation-positive colonies Epo No Epo Epo No Epo (EEC) Normal 1 None >1200 n/a n/a n/a Normal 2 None >1200 n/a n/a n.a PV1 V617F 600 <300 5 40 PV2 V617F 600 300 33 50 PV3 V617F 600–1200 300–600 9 70 PV4 V617F 300–600 600 0 15 PV5 V617F 600–1200 300 80 100 PV6 V617F 600 300–600 7 19 PV7 V617F 600–1200 600 32 36 PV8 V617F 600–1200 <300 45 37 PV9 V617F 600 600–1200 20 12 PV10 Exon 12 (N542–E543del) 900 <300 9 60 PMF1 W515K 300–600 <300 100 33 PMF2 None >1200 300 n/a n/a

Abstract Abstract 3915 Poster Board III-851 Background Thromboembolic disease (TE) is a major cause of morbidity and mortality in polycythemia vera (PV) and essential thrombocythemia (ET). There is limited information on the prevalence of TE in primary myelofibrosis (PMF) and associated prognostic factors. Methods Study patients were recruited form the Mayo Clinic database for PMF. Diagnosis was according to the 2001 WHO criteria. Clinical and laboratory information was collected at time of diagnosis and correlated with the occurrence of TE in general and arterial (AT) or venous (VT) thrombosis in particular. Leukocytosis was defined as a leukocyte count of > 10 × 109/L. Qualitative JAK2V617F analysis was done according to previously published PCR-based methods. In addition, a subset of the study patients underwent quantitative PCR for JAK2V617F and rs12343867 SNP genotyping (performed by a commercially available Taqman assay). All molecular studies were performed on stored bone marrow. Standard statistical methods were used to test significance of associations between thrombosis and other variables. Results 207 patients with PMF were studied (median age 62, range 28-87; 132 males). At presentation, the median (range) of hemoglobin (Hb), leukocytes (WBC) and platelets (plt) were 11 g/dl (6.4-15.4), 8.6 × 109/L (0.8-156.7) and 273 × 109/L (13-1916), respectively. Dupriez prognostic scores at diagnosis were low, intermediate and high in 57%, 33% and 10% of the patients, respectively. 130 (63%) patients were JAK2V617F positive. Among 73 patients in whom quantitative JAK2V617F analysis was performed, the mutation was not detected in 30 (41%) patients and the median mutant allele burden in the 43 mutation-positive patients was 28% (range 1-85). The same 73 patients had rs12343867 SNP genotyping performed that revealed C/C genotype in 14 (19%) patients, C/T in 34 (47%) and T/T in 25 (34%). At or before diagnosis, a total of 29 patients (14 %) had TE: 23 (11%) AT and 9 (4%) VT. The AT included acute coronary syndromes (ACS; n=19), transient ischemic attack/ cerebrovascular accidents (TIA/CVA; n=6) and peripheral arterial thrombosis (PAT; n=1). The VT included abdominal vein thrombosis (AVT; n=4), deep vein thrombosis/pulmonary embolism (DVT/PE; n=6) and dural sinus thrombosis (n=1). Several patients had more than one event and some both AT and VT. During follow-up, 22 (11%) patients experienced TE: 17 (8%) VT and 8 (4%) AT. The post-diagnosis VT included AVT (n=8), DVT/PE (n=13) and both DVT/PE and AVT (n=4). Post-diagnosis AT included CVA (n=4), TIA (n=1), ACS (n=2) and PAT (n=1). AT at or before diagnosis was associated with advanced age (p=0.003) but not with sex, leukocytosis, hemoglobin level, platelet count, JAK2 mutational status, JAK2 mutant allele burden or rs12343867 SNP genotype. VT at or before diagnosis also did not correlate with all these variables or age. These variables were also evaluated regarding their relationship with post-diagnosis AT, which showed significant associations with hemoglobin level (p=0.006), platelet count (p=0.04) and high JAK2V617F allele burden (0.03). The corresponding significant variables for post-diagnosis VT were leukocytosis (p=0.02) and high JAK2V617F allele burden (p=0.01). Of note, AT or VT at or before diagnosis did not predict post-diagnosis events. During multivariable analysis, only higher hemoglobin level predicted post-diagnosis AT. Conclusion The current study provides an accurate description of both arterial and venous thrombotic events in PMF. The association between higher hemoglobin and leukocyte counts at diagnosis and post-diagnosis occurrence, respectively, of arterial and venous thrombosis is similar to observations in patients with PV or ET and suggests a potential benefit from early institution of cytoreductive therapy for the appropriate patient groups. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: JAK2V617F is a recurring mutation in patients with polycythemia vera (PV) (95%) and essential thrombocythemia (ET) (50%), diseases that are frequently complicated by arterial and/or venous thrombosis. JAK2V617F is also frequently identified in patients with splanchnic vein thrombosis, including in those with occult myeloproliferative disorder (MPD). We previously reported a low prevalence of JAK2V617F in thrombosis patients - only 2% of 210 patients with non-splanchnic vein thrombosis (Leukemia, 2007 Aug;21(8):1828–9), and <1% of 136 patients with arterial stroke (J Thromb Haemost. 2007 Aug;5(8):1784–5). Here, we expanded the analysis to 664 thrombosis patients to describe: JAK2V617F prevalence, and clinical course of patients harboring this mutation. Methods: In Phase I, we screened 439 consecutive patients who underwent thrombophilia testing at our institution in early 2005 - patients with splanchnic vein thrombosis or overt MPD were excluded. In Phase II, we identified 228 additional patients considered to be at high risk for harboring JAK2V617F, who were seen at our institution from 2004 to 2006. JAK2V617F screening (assay sensitivity <1%) was performed as described in the aforementioned references. Results: In the initial cohort of 439 patients (median age=56 years; range 17–93 years; 222 female), 136 (31%) presented with stroke, 114 (26%) with deep venous thrombosis (DVT), 95 (22%) with pulmonary embolism (PE), 50 (11%) with DVT and PE, 10 (2%) with central retinal vein occlusion (CRVO), 7 (2%) with cerebral vein thrombosis, and the remaining 27 (6%) with other thromboses. Five patients (MC1-MC5; median age=78 years) were found to harbor JAK2V617F (prevalence=1%) - none had overt clinical features of MPD and all harbored a low level of JAK2V617F in peripheral blood (median=5–2%; range=2.2–7.5%) (Table). One patient (MC2) carried the Prothrombin G20210A mutation In the subsequent cohort, we studied 197 patients (median age=39 years; range=16–84 years) with recurrent DVT and/or PE, and 28 patients (median age=27 years; range=31–49 years) with acute myocardial infarction at a young age (<50 years). One patient (MC6) who presented with recurrent idiopathic DVT was found to harbor JAK2V617F (prevalence <0.5%) (Table) - this patient had no features of underlying MPD and the mutation burden was low (9%). After a median follow up of 27 months (range=4–66 months), none of the 6 patients harboring JAK2V617F has developed overt MPD. Conclusions: In patients with thrombosis, JAK2V617F is infrequently detected in the absence of overt MPD and/or involvement of splanchnic veins. Thus, JAK2V617F screening cannot be recommended as part of the hypercoagulable workup in routine clinical practice in this setting. The risk of developing overt MPD may be quite low for patients harboring a low JAK2V617F burden at the time of thrombosis although longer follow up is needed in this regard. Furthermore, the thrombosis risk may be well controlled with standard warfarin therapy, and the role of myelosuppressive agents (eg. hydroxyurea) is unclear in these patients. Characteristics of patients harboring JAK2V617F Patient Age Sex Thrombosis JAK2V617F allele burden MPD Follow up (months) Status MC1 84 M PE, DVT 5.3% No 66 Alive MC2 82 F PE, cerebral vein 5% No 38 Alive MC3 74 F PE 2.2% No 4 Dead MC4 78 F Central retinal vein 5.2% No 22 Alive MC5 63 M Stroke 7.5% No 30 Alive MC6 69 M Recurrent DVT No No 24 Alive

Abstract Abstract 3903 Poster Board III-839 Background A peripheral blood (PB) absolute eosinophil count (AEC) of ≥ 1.5 × 109/L is operationally referred to as “hypereosinophilia”. In general, one can classify hypereosinophilia into 3 major categories: i) secondary, ii) clonal, and iii) idiopathic. The 2008 WHO proposal provides a modern-era framework for the classification of clonal eosinophilia and subcategories include (i) myeloid/lymphoid neoplasms associated with eosinophilia and PDGFRA-, PDGFRB-, or FGFR1-rearrangement; (ii) clonal eosinophilia associated with an otherwise WHO-defined myeloid malignancy such as systemic mastocytosis (MN-eo), and (iii) chronic eosinophilic leukemia, otherwise not specified (CEL-NOS). Idiopathic hypereosinophilia (IH) with organ damage and without clonal/abnormal lymphocytes is referred to as hypereosinophilic syndrome (HES). In the current study, we define the spectrum of disease phenotypes and survival in 357 consecutive patients with hypereosinophilia seen at a single institution. Methods Mayo Clinic patient records from January 1994 to October 2008 were reviewed, and those with persistent eosinophilia ≥1.5 × 109/L identified. Clinical data and bone marrow (BM) histology were reviewed, and the eosinophilic disorder classified as above. The aims of the current study were to: (i) study the spectrum of eosinophilic disorders within the context of the WHO proposal; (ii) describe the clinical, laboratory, and molecular/cytogenetic characteristics of patients with primary eosinophilia (i.e. clonal and idiopathic); and (iii) assess the prognostic relevance of the WHO proposal from the standpoint of life expectancy and risk of leukemic transformation. Results (i) Disease spectrum and clinical characteristics: A total of 357 cases (median age=52 years) were identified: (i) secondary eosinophilia 165 (46%; male ∼52%) (autoimmune 33%, non-myeloid malignancy 19%, drugs 12%, allergies 10%, parasitosis 2%, others 24%); (ii) PDGFRA- or PDGFRB-rearranged myeloid neoplasm 17 (5%; male 100%); (iii) CEL-NOS 6 (2%; male 67%); (iv) MN/eo 36 (10%; male 69%) (systemic mastocytosis 50%, chronic myeloproliferative neoplasm 33%, AML 6%, others 11%); (v) IH 115 (32%; male 58%); and (vi) eosinophilia associated with clonal/abnormal lymphocytes 14 (4%; male 57%). Of the 115 patients with IH, 72 (63%) had evidence of end-organ damage, and could be classified as having HES: 36 patients had 1 organ involved, 21 had 2, and 15 had 3-4. In HES patients, the major organs involved were: lung 23%, skin/mucosa 22%, cardiac 14%, nervous system 10%, and thrombosis 9%. (ii) Molecular and cytogenetic abnormalities: Complete karyotype information was available for 144 (77%) patients; 21 (15%) patients had an abnormal karyotype; MN/eo 12 (35%), PDGFRA- or PDGFRB-rearranged myeloid neoplasm 4 (31%), CEL-NOS 5 (83%), IH and eosinophilia associated with clonal/abnormal lymphocytes 0 (p<0.01). Of the 126 (67%) patients screened for FIP1L1-PDGFRA, 16 (13%) tested positive. Two patients (1%) harbored t(5;12). Of the 108 (57%) patients screened for presence of an occult T-cell clone (PCR for TCR gene rearrangement), 14 (13%) tested positive. (iii) Survival and risk of disease transformation: At a median follow of 21 months (range <1-174), 56 (30%) deaths were recorded; MN/eo 23 (64%), IH 25 (22%), PDGFRA- or PDGFRB-rearranged myeloid neoplasm 3 (18%), CEL-NOS 3 (50%), and T-cell/eo 2 (14%). The combined median survival was 95 months: MN/eo 34 months, CEL-NOS 13 months, IH 151 months, PDGFRA- or PDGFRB-rearranged myeloid neoplasm and eosinophilia associated with an abnormal lymphocyte clone (not reached) (p<0.01; Figure). Transformation to acute leukemia was seen in 4 patients (2 with PDGFRA- or PDGFRB-rearranged myeloid neoplasm, and 1 each with CEL-NOS and IH) (p<0.01). Conclusions In a major tertiary center in the United States, the two major causes of hypereosinophilia were secondary (46%) and idiopathic (32%). Regarding the former, autoimmune diseases and parasitic infections were the most and least frequent causes, respectively. Cases with clonal eosinophilia were predominantly male while the sex ratio was more balanced in the other subcategories. Among primary hypereosinophilia, survival was the worst in clonal eosinophilia not associated with the imatinib-sensitive PDGFR mutations. Additional data regarding clinical characteristics, laboratory findings, and treatment outcome of idiopathic hypereosinophilia patients will be presented at the meeting. Disclosures: Pardanani: TargeGen: Research Funding; Cytopia: Research Funding.

Abstract Abstract 3918 Poster Board III-854 BACK GROUND We have previously demonstrated that the myeloproliferative neoplasms (MPNs) of primary myelofibrosis (PMF), polycythemia vera (PV), and essential thrombocythemia (ET) can lead to weight loss, splenomegaly and constitutional symptoms (Cancer 2007;109:68–76). Additionally we have demonstrated that hypocholesterolemia in MPN patients is associated with decreased survival (Blood 2007;110:a2548). Given that current JAK2 inhibitor trials are demonstrating the ability to reverse MPN associated splenomegaly (Haematologica 2009;94(Suppl 2)439 a1088) and cachexia (Blood 2008;112(11):a1760) we sought to determine the baseline natural history for these variables in patients treated prior to the JAK2 inhibitor era. METHODS We analyzed the Mayo MPN database for patients (not treated with JAK2 inhibitors) with information on disease prognosis, presentation, therapies, height and weight at diagnosis, and outcomes. Additionally, when available, we analyzed additional weights during the clinical course, the body mass index (BMI- (weight/(height*height)), spleen size, and peripheral blood studies including lipids. Results: Patients 783 patients with MPNs (followed for a median of 51 months (range 1-871 months); 60% having expired) were identified for the analysis (PV=158, ET=255, PMF=370) with 541 (69%) having a weight at the time of diagnosis, the remainder had a weight obtained a median of 7.8 months after diagnosis. Additionally, 508 patients (65%) had a weight value available from 1–3 additional time points during the course of their disease. Corresponding measurements of splenomegaly, or absence thereof, were noted in 766 cases (98%). Lipid panels (obtained within 18 months of diagnosis) were available in 264 patients. Results by MPN disease type are listed in the Table. Impact on prognosis Univariate analysis of variables discussed which negatively impacted survival included the subtype of MPN (not surprisingly worse for PMF p<0.001), weight loss of greater than 10% during the course of follow-up (P<0.001), or development of splenomegaly of >10 cm below the left costal margin (p=0.004) whereas hypocholesterolemia was significant only for the subset of PMF patients (P=0.03). The IWG-MRT International Prognostic Score (IPSS - Cervantes et. al. Blood 2009) was the only variable prognostically relevant in multivariate analysis (P<0.001). Conclusions Progressive splenomegaly, weight loss, and hypocholesterolemia are common across all MPNs but are most prognostically detrimental in PMF. Ongoing and future trials of JAK2 inhibitors will answer whether reversal of these latter hypercatabolic and proliferative manifestations of disease will improve outcomes for MPN patients. Disclosures: No relevant conflicts of interest to declare.

Abstract Background: In both polycythemia vera (PV) and essential thrombocythemia (ET), aspirin and/or hydroxyurea therapy provide adequate protection from thrombosis but not from disease transformation into acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) or myelofibrosis (MF). In designing clinical trials with new drugs, including the use of small molecule JAK2 inhibitors, in either ET or PV, it is important to identify patients who are at a higher risk of early transformation into AML/MDS/MF as well as those in whom the long-term risk of these complications is too low to justify exposure to experimental drugs with unknown short-term and long-term toxicity profile. Methods: Information on an institutional database of 1061 patients with either PV (n=458) or ET (n=603) was updated in July of 2007. The World Health Organization criteria were used for diagnosis of PV, ET, AML, MDS, and MF. Two different approaches were used to assess both early and overall risk of AML/MDS/MF development in both ET and PV. In the first approach, three distinct groups were delineated and their presenting features compared; group A was comprised of patients who have remained AML/MDS/MF free after a minimum follow-up of 20 years whereas groups B and C included patients who developed either AML/MDS or MF, respectively, in the first decade of their disease. In the second approach, prognostic factors for AML/MDS/MF-free survival were examined among the entire cohort of 1061 patients. Results : In ET, the number of patients that fulfilled the above-mentioned criteria for inclusion in groups A, B, and C were 40, 12, and 8; the three groups displayed significant differences in the prevalence, at diagnosis, of lower than normal hemoglobin level (8% vs. 58% vs. 38%; p=0.0004), male sex (18% vs. 58% vs. 50%; p=0.01), and arterial thrombosis at diagnosis (p=0.03), respectively. However, only the former two remained significant during multivariable analysis that included age as a covariate. In PV, the number of patients in groups A, B, and C were 23, 18, and 12; the only difference between the three groups was the association between group B and leukocytosis (p=0.02). Cox regression analysis of the entire 1061 ET/PV patients cohort, including 65 AML/MDS/MF events in ET and 36 AML/MDS events in PV, confirmed the inferior AML/MDS/MF-free survival in ET associated with lower than normal hemoglobin and AML/MDS-free survival in PV associated with leukocytosis (Figure). Conclusion : The current study identifies PV patients with leukocytosis as being the most appropriate and ET patients without anemia as the least appropriate for consideration of participation in experimental drug treatment trials. Figure Figure Figure Figure

Abstract Background: The recent discovery of JAK2V617F, as an activating mutation in the majority of patients with myeloproliferative neoplasms, has spurred development of JAK2-selective small molecule inhibitors for the treatment of these diseases. TG101348 is a potent (enzyme IC50=3 nM) and selective (35- and 334-fold selectivity over JAK1 and JAK3, respectively) orally bioavailable JAK2 inhibitor that is effective in treating a murine model of Polycythemia vera (PV) (Cancer Cell. 2008 13:311). TG101348 selectively inhibits growth of hematopoietic colonies harboring V617F, MPLW515K, or JAK2 exon 12 mutations (Leukemia. 2008 Mar 20, Epub). Methods: A Phase I dose-escalation study of TG101348 is ongoing for patients with high- or intermediate-risk (with symptomatic disease) primary myelofibrosis (PMF) and post-PV or post-essential thrombocythemia (ET) myelofibrosis (Cancer.2007109:2083). TG101348 was administered orally once daily in 28-day cycles in cohorts of at least 3 patients. Additional eligibility criteria included absolute neutrophil count of ≥1 × 109/L and platelet count of ≥50 × 109/L, but a JAK2 mutation was not required. Primary objectives were determination of safety and tolerability, as well as pharmacokinetic behavior of TG101348. The secondary objectives were evaluation of treatment response (Blood.2006108:1497), pharmacodynamic activity, and drug effect on V617F allele burden and plasma cytokine levels. The spleen response was documented as change in palpable spleen tip from the costal margin. For patients achieving less than a complete remission after 3 cycles of treatment at their initial dose, step-wise escalation was permitted at each cycle if a cohort had been shown to have tolerated that dose. Results: Fifteen patients (9 males; median age=66 years; range=53 to 79 years) have been enrolled in the study to date – 10 with PMF (8 V617F+) and 5 with post-PV MF (all V617F+). The median follow-up to date is 13 weeks (range 1–28). Treatment was discontinued in 1 patient, in cohort 1, on the 2nd day of dosing after it was discovered that the patient had baseline QTcF prolongation (Grade 1). In the remaining 14 patients, no dose-limiting toxicities or other significant non-hematological adverse events have been observed to date. The pharmacokinetic parameters of TG101348 in plasma were well characterized following single daily oral doses of 30 mg, 60 mg, 120 mg or 240 mg. Dose-proportional pharmacokinetics were observed following single and multiple doses of TG101348. Treatment response data are as follows: Cohort 1 (starting dose=30 mg; 3 patients; median follow-up=26 weeks): 2 of the 3 patients had improvement in constitutional symptoms including fatigue, night sweats and pruritus. No other benefits were noted. These patients have now been dose escalated to either 120 or 240 mg/day. Cohort 2 (starting dose=60 mg; 3 patients; median follow-up=18 weeks): 1 patient had a 40% decrease in spleen size (18 to 10 cm). All 3 patients have now been dose escalated to 120 or 240 mg/day. Cohort 3 (starting dose=120 mg; 3 patients; median follow-up=13 weeks): 2 of the 3 patients reported improvement in constitutional symptoms including fatigue, night sweats, and pruritus. 1 patient had a 25% decrease in spleen size (28 to 21 cm). 2 patients have been dose escalated to 240 mg/day. Cohort 4 (starting dose=240 mg; 3 patients; median follow-up=8 weeks): 1 patient developed Grade 3 anemia (baseline Grade 1) at the end of the first cycle. 1 patient reported decreased fatigue. All 3 patients have experienced a 20 to 53% reduction in spleen size; baseline measurements were 10, 13, and 17 cm. Cohort 5 (starting dose=360 mg; 2 patients; median follow-up=1 week). Both patients had decreased splenomegaly within 1 week of therapy, including 1 with disappearance of palpable splenomegaly from a baseline of 20 cm; this patient also reported significant improvement in constitutional symptoms. Conclusions: Preliminary findings indicate that TG101348 is well tolerated in patients with myelofibrosis. Although it is too early to make valid conclusions, a decrease in spleen size has been noted at higher dose levels. Similarly, improvement in constitutional symptoms has been reported by some patients. Updated results on current and future patients, including data on pharmacokinetics, pharmacodynamics, and changes in V617F allele burden and plasma cytokine levels will be presented at the meeting.

Abstract Background : Current prognostication in primary myelofibrosis (PMF) utilizes international prognostic scoring systems that rely on clinical parameters that are sensitive to day-to-day variations and subjective interpretation. Recent studies in PMF have disclosed important prognostic information attached to additional cytogenetic details (Blood. 2011;118:4595) and somatic mutations, including CALR and ASXL1 (NEJM. 2013;369:2379; Leukemia. 2013;27:1861). Methods : PMF diagnosis and definition of blast transformation (BT) were according to World Health Organization criteria (Blood. 2009;114:937). Cytogenetic analysis and reporting was done according to the International System for Human Cytogenetic Nomenclature (Cytogenetic and genome research. 2013. Prepublished on 2013/07/03 as DOI 10.1159/000353118). Previously published methods were used for analyses of CALR, JAK2, MPL and other prognostically-relevant mutations, including ASXL1, SRSF2, EZH2 and IDH(Leukemia. 2014;28:1472). Results : The training set included 964 Mayo Clinic patients (median age 65 years; 62% males) in whom informative karyotype or mutation information was available; cytogenetic information was available in 903 (94%) cases, JAK2/CALR/MPL mutational status in 532 (55%), ASXL1 in 425 (44%), SRSF2 in 434 (45%), IDH1/2 in 376 (39%) and EZH2 in 268 (28%). DIPSS-plus (JCO. 2011;29:392) risk distribution was high in 37% of patients, intermediate-2 in 37%, intermediate-1 in 15% and low in 11%. We used a revised risk stratification for cytogenetics (see accompanying ASH 2014 abstract) to distinguish four distinct cytogenetic risk categories: very high (monosomal karyotype, inv(3), i(17q), -7/7q-, 11q or 12p abnormalities; n=67), high (complex non-monosomal, two abnormalities not included in very high risk category, 5q-, +8, other autosomal trisomies except +9, and other sole abnormalities not included in other risk categories; n=164), intermediate (sole abnormalities of 20q-, 1q+ or any other sole translocation, and -Y or other sex chromosome abnormality; n=133) and low (normal or sole abnormalities of 13q- or +9; n=539). Mutational frequencies were 58% for JAK2, 25% CALR, 7% MPL, 36% ASXL1, 11% SRSF2, 5% IDH1/2 and 6% EZH2. The 131 cases with CALR mutations were further subclassified into two prognostically different groups: type 1/type 1-like (n=110) and type 2/type 2-like (n=21) (see accompanying ASH 2014 abstract). At a median follow-up time of 4.2 years for patients who are alive, 664 (69%) deaths and 70 BT (7%) were recorded. Age-adjusted multivariable analysis that included cytogenetic and mutational risk groups disclosed the following as independent predictors of shortened survival: very high risk karyotype (HR 4.2; 3 points), high risk karyotype (HR 1.9; 1 point), triple-negative (HR 2.8; 2 points), JAK2 (HR 3.1; 2 points), MPL (HR 3.1; 2 points), type 2/type 2-like CALR (HR 3.6; 2 points), ASXL1 (HR 1.9; 1 points) and SRSF2 (HR 1.9; 1 point); EZH2 (p=0.24) and IDH1/2 (p=0.68) and intermediate risk karyotype (p=0.87) were not significant. The above-mentioned significant variables and age demarcated at 60 years (2 points), were subsequently used to develop an HR-derived, genetics-based prognostic scoring system (GPSS) for 369 patients who were fully informative for both karyotype and all significant mutations: low risk (0 points; n=31), intermediate-1 (1 or 2 points; n=90), intermediate-2 (3 or 4 points; n=133) and high (5 or more points; n=115); the corresponding median survivals were >17, 9 (HR 4.7, 95% CI 1.7-13.0), 5 (HR 10.7, 95% CI 3.9-29.3) and 2.2 (HR 29.2, 95% CI 10.6-80.0) years (Figure 1). High risk GPSS was also associated with higher BT rate (HR 7.4, 95% CI 2.1-26.3). The prognostic distinction between high/intermediate-2 and low/intermediate-1 risk GPSS, in terms of both overall (median 5 vs 26.4 years; HR 7.1, 95% CI 3.3-14.9) and leukemia-free survival (median 11.6 years vs not reached; HR 9.4, 95% CI 2.2-41.0) was validated in an independent cohort of 183 patients from the University of Florence (Figure 2). Conclusions : The current study demonstrates the feasibility of genetics-based prognostic models in PMF that rely on objective parameters that are amenable to further refinement as new genetic information becomes available. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 3795 Recent studies suggest a powerful prognostic value for plasma cytokine levels in primary myelofibrosis (IL-2R, IL-8, IL-12, IL-15 and CXCL10) and large cell lymphoma (IL-2R, IL-8, IL-10, IL-12, CXCL9 and CXCL10). In order to examine the possibility of a similar phenomenon in myelodysplastic syndromes (MDS), we used multiplex ELISA to measure 30 plasma cytokines in 78 patients with primary MDS. Compared to normal controls (n =35), the levels of 19 cytokines were significantly altered. Multivariable analysis identified increased levels of CXCL10 (p<0.01), IL-7 (p=0.02) and IL-6 (p=0.07) as predictors of shortened survival; the survival association remained significant when the Cox model was adjusted for the international prognostic scoring system (IPSS), age, transfusion-need or thrombocytopenia. MDS patients with normal plasma levels of CXCL10, IL-7 and IL-6 lived significantly longer (median survival 76 months) than those with elevated levels of at least one of the three cytokines (median survival 25 months) (p<0.01). Increased levels of IL-6 were associated with inferior leukemia-free survival, independent of other prognostic factors (p=0.01). Comparison of plasma cytokines between MDS (n =78) and primary myelofibrosis (n =127) revealed a significantly different pattern of abnormalities. These observations reinforce the concept of distinct and prognostically-relevant plasma cytokine signatures in hematologic malignancies.Figure:Survival data for 78 patients with de novo myelodysplastic syndrome (MDS) stratified based on plasma levels of CXCL10, IL-7 and IL-6: (i) normal levels of all 3 cytokines (top curve), or (ii) increased (> 3 standard deviations of the normal mean level) level(s) of one or more of the aforementioned cytokines (bottom curve) (p=0.002).Figure:. Survival data for 78 patients with de novo myelodysplastic syndrome (MDS) stratified based on plasma levels of CXCL10, IL-7 and IL-6: (i) normal levels of all 3 cytokines (top curve), or (ii) increased (> 3 standard deviations of the normal mean level) level(s) of one or more of the aforementioned cytokines (bottom curve) (p=0.002). Disclosures: No relevant conflicts of interest to declare.

Abstract BACKGROUND. In primary myelofibrosis (PMF), survival from time of diagnosis is predicted by the international prognostic scoring system (IPSS), and from time of referral, by the dynamic IPSS (DIPSS) or DIPSS-plus. JAK2/CALR/MPL mutational status and presence and number of other prognostically-relevant mutations (ASXL1, SRSF2, EZH2, IDH1/2) provide IPSS/DIPSS-plus independent prognostic information. The objective in the current study was to revise IPSS, by including mutation-relevant prognostic information. METHODS. The study included 986 PMF patients divided into learning (n=588) and validation (n=398) cohorts. Previously published methods were used to screen for mutations involving JAK2,MPL, CALR, EZH2, ASXL1, IDH1/2 and SRSF2. The clinical variables assessed were those previously identified as being prognostically-relevant by IPSS or DIPSS-plus. The prognostic model (MIPSS) was developed through a stepwise selection process, based on a z-test of the regression coefficients, and its relative quality was measured by means of the Akaike information criterion. RESULTS. In the Italian learning cohort (n=588),median follow-up was 3.6years (95% CI, 0.03-30.8) for alive patients and 196 (33.3%) deaths and 67 leukemic transformations were documented. IPSS risk distribution was low in 26%, intermediate-1 in 30%, intermediate-2 in 24% and high in 20%. Mutational frequencies were approximately 63% for JAK2, 20% CALR, 6% MPL, 7% EZH2, 22% ASXL1, 2.5% IDH1/2 and 9% SRSF2. Constitutional symptoms were recorded in 28.6% of patients, splenomegaly 75% (18% >10cm from LCM) and grade 3 fibrosis 21%. Overall 252 patients were evaluable for karyotype and abnormalities were detected in 35%, including 9.5% unfavorable. Univariate analysis identified the following risk factors for inferior survival: age >60 years, constitutional symptoms, hemoglobin <100g/L, leukocytes >25x109/L, platelets <200x109/L, circulating blasts 1% or greater, splenomegaly >10cm, grade 3 fibrosis, unfavorable karyotype, triple-negativity for JAK2, MPL and CALR (TN), JAK2 or MPL mutation, and mutations in ASXL1, SRSF2, EZH2 or IDH1/2. In multivariable analysis, age >60 years, constitutional symptoms, hemoglobin <100g/L, platelets <200x109/L, TN, JAK2 or MPL mutation, ASXL1 and SRSF2 mutation remained significant; these variables were subsequently assigned the following HR-weighted adverse points: 1.5, 0.5, 0.5, 1.0, 1.5, 0.5, 0.5 and 0.5, respectively. Subsequently, four risk groups with no overlap in the 95% CI of their survival curves were delineated (Figure 1A): low (score 0-0.5); Intermediate-1 (score 1-1.5); Intermediate-2 (score 2-3.5); and high (score 4 or greater). The number of patients in each risk category, median survivals and HR and 95% CI values are included in figure 1A. Akaike information criterion indicated that MIPSS performed better than IPSS in predicting survival (1611.6 vs 1649.0). Leukemia-free survival was also predicted by high (p<0.01) and intermediate 1/2 (p<0.01) risk MIPSS. In the Mayo Clinic validation cohort (n=398), median age 63 years; males 64%,median follow-up for alive patients was 7.5 years and 271 (68%) deaths and 51 (13%) leukemic transformations were documented. DIPSS-plus risk distribution was low in 13%, intermediate-1 18%, intermediate-2 37% and high 32%. Mutational frequencies were approximately 51% for JAK2, 30% CALR, 7.5% MPL, 5% EZH2, 36% ASXL1, 5.6% IDH1/2 and 13% SRSF2. MIPSS performed equally well in this cohort, as illustrated in figure 1B, which includes number of patients in each risk category with their median survival and HR and 95% CI values. Leukemia-free survival in the Mayo cohort was also predicted by high (p<0.01) and intermediate-2 (p=0.04) risk MIPSS. Patients in the Mayo cohort were fully annotated for karyotype, which was MIPSS-independent in its prognostic value for both overall (p<0.01) and leukemia-free (p<0.01) survival. CONCLUSIONS. MIPSS addresses the mutation-relevant prognostic information gap in IPSS and performs equally well in the setting of patients seen at time of diagnosis or referral. Karyotype carries MIPSS-independent prognostic value that is recognized in an alternative GIPSS prognostic model (see accompanying ASH 2014 abstract), which complements MIPSS. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.