Pardanani, Animesh

Abstract Abstract 5158 Background: Vitamin D insufficiency is commonly observed in clinical practice. Observational studies have suggested an association of vitamin D insufficiency with increased risk of cancer development. Further, vitamin D insufficiency has been associated with poorer prognosis in solid tumors as well as hematologic malignancies, including non-Hodgkin lymphoma and chronic lymphocytic leukemia. In this study, we examined the clinical and prognostic correlates of low plasma levels of 25-hydroxyvitamin D (25[OH]D), which reflects whole-body vitamin D stores, in a cohort of myeloproliferative neoplasm (MPN) and myelodysplastic syndrome (MDS) patients. Methods: We studied a total of 409 patients: 247 (60%) had primary myelofibrosis (PMF), 74 (18%) de novo MDS, 63 (15%) polycythemia vera (PV) and 25 (6%) essential thrombocythemia (ET). Inclusion criteria required availability of archived plasma, bone marrow aspirate and biopsy and cytogenetic information at the time of first referral to our institution. Vitamin D measurements were performed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). For the purposes of this study, plasma 25(OH)D levels <10 ng/mL indicated severe deficiency, <25 ng/mL insufficiency, and 25–80 ng/mL optimal levels. Results: Patient characteristics were as follows: (i) PMF: median age=63 years, >65 years=41%, males=68% and serum creatinine above the upper normal limit (UNL)=15%; (ii) MDS: median age=72 years, >65 years=77%, males=69% and creatinine >UNL=12%; (iii) PV median age=61 years, >65 years=37% and males=50%; and (iv) ET: median age=48 years, >65 years=10% and males=28%. Median (range) plasma 25(OH)D levels (ng/mL) were as follows: PMF 25 (0–60), PV 27 (6.8–51), ET 31 (6–50) and MDS 30 (7.7–72) (p=0.005). The proportion of patients with 25(OH)D insufficiency were: PMF 48%, PV 43%, ET 28% and MDS 28% (p=0.01). Similarly, the proportion of patients with severe 25(OH)D deficiency were: PMF 9%, PV 3%, ET 12% and MDS 1% (p=0.05). In PMF and MDS, 25(OH)D insufficiency was not significantly correlated with age (≤65 vs. >65 years), gender, red cell transfusion need, DIPSS-plus/IPSS category, hemoglobin (<10 vs. ≥10 g/dL), thrombocytopenia (<100 vs. ≥100 × 109/L), circulating blasts, unfavorable karyotype, serum creatinine >UNL, or JAK2V617F (PMF only) (p>0.05). 25(OH)D insufficiency was not predictive of inferior overall survival (OS) in PMF, MDS, PV, or ET (p>0.05). Similarly, in PMF and MDS, 25(OH)D insufficiency was not predictive of inferior leukemia-free survival (LFS) (p>0.05). Severe 25(OH)D deficiency was infrequently observed in MDS or PV patients; in PMF or ET patients, there was no prognostic impact of severe 25(OH)D deficiency on OS or LFS (p>0.05). Conclusions: Vitamin D insufficiency is relatively common in PMF, PV, ET and de novo MDS however this finding had no prognostic value for OS in the aforementioned patients. In PMF and MDS patients, low 25(OH)D levels had no clearly identifiable clinical correlates and further did not have prognostic value for LFS. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 971 Unlike the case in acute myeloid leukemia, there is limited information on the prognostic impact of IDH mutations in myelodysplastic syndromes (MDS). In the current study of 277 patients with MDS, IDH mutations were detected in 34 (12%) cases: 26 IDH2 (all R140Q) and 8 IDH1 (six R132S and two R132C). Mutational frequency was 4% (2 of 56) in refractory anemia with ring sideroblasts (RARS), 12% (16 of 130) in refractory cytopenia with multilineage dysplasia, 14% (2 of 14) in MDS-unclassifiable, 14% (6 of 42) in refractory anemia with excess blasts (RAEB)-1, and 23% (8 of 35) in RAEB-2. Normal karyotype was noted in all but one IDH1-mutated cases and 13 IDH2-mutated cases. Multivariable analysis identified presence of mutant IDH1 (p=0.0004; HR 4.0, 95% CI 1.9–8.8), revised International Prognostic Scoring System (IPSS-R) risk category (p<0.0001), and red cell transfusion need (p=0.002) as independent predictors of inferior survival (Figure 1). In a similar multivariable analysis, mutant IDH1 was the only variable associated with shortened leukemia-free survival (p=0.001; HR 7.0, 95% CI 2.3–20.8). The presence of IDH2 R140Q did not affect overall (p=0.54) or leukemia-free (p=0.81) survival (Figure 2). The current study suggests a powerful adverse prognostic effect for mutant IDH1 in MDS. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 2806 Background: A high degree of prognostic certainty is required to recommend or discourage high risk treatment procedures in primary myelofibrosis (PMF). The Dynamic International Prognostic Scoring System (DIPSS-plus) uses eight risk factors to predict overall survival (OS) in PMF: unfavorable karyotype, peripheral blood (PB) blast count ≥1%, platelet count <100 × 109/L, white blood cell count (WBC) >25 × 109/L, hemoglobin level <10 g/dL, red blood cell transfusion need, constitutional symptoms, and age >65 years (Gangat et al. JCO 2011;29 :392). The presence of four or more of these risk factors defines high-risk disease. purpose: The purpose of the current study was to enhance the prognostic weight of some of the DIPSS-plus risk factors with the intent to identify one or two parameters that can reliably predict death in the first two years of disease. Methods: An updated Mayo Clinic database of 884 karyotypically-annotated patients with PMF was used. Calculations of 2-year mortality rates and variables considered for prognostic value were from time of referral to the Mayo Clinic. Cytogenetic risk categorization per DIPSS-plus was further refined to capture additional prognostic information from monosomal karyotype (MK) (Vaidya et al. Blood 2011;117 :5612) and inv(3)/i(17q) abnormalities (Caramazza et al. Leukemia 2011;25 :82). Receiver operating characteristic (ROC) analysis was employed to define best discriminant levels. Results: To date, 564 (64%) deaths have been documented. Each one of the aforementioned DIPSS-plus risk factors was associated with a 2-year mortality rate that ranged from 42% (PB blast count ≥1%) to 60% (unfavorable karyotype). High-risk disease per DIPSS-plus was associated with 57% two-year mortality. The only risk factors that were associated with >80% two-year mortality were MK (n =19) and inv(3)/i(17q) abnormalities (n =8) and both were associated with significantly worse survival, compared to other unfavorable karyotype (n =102): HR (95% CI) of 5.1 (3.1−8.4) and 3.9 (1.7−8.8), respectively. ROC analysis identified PB blast counts of 2% and 9% (AUC 0.62) and WBC of 43 × 109/L (AUC 0.66) as best discriminant levels for predicting 2-year mortality; OS was significantly worse in the presence of PB blast >9% (HR 4.1, 95% CI 2.8–6.1) vs. 2% to 9% (HR 1.8, 95% CI 1.5–2.2) vs. <2%; the corresponding 2-year mortality rates were 73%, 46% and 25%. OS was also significantly worse in the presence of WBC ≥40 × 109/L (HR 2.8, 95% CI 2.2–3.6) vs. 26–39 × 109/L (HR 1.6, 95% CI, 1.2–2.1) vs. <26 × 109/L; the corresponding 2-year mortality rates were 63%, 42% and 28%. Two-year mortality rates exceeded 80% in the presence of any two of the following: PB blast count >9%, WBC ≥40 × 109/L or unfavorable karyotype other than MK or inv(3)/i(17q). Conclusions: A greater than 80% 2-year mortality in PMF is predicted by the presence of MK, inv(3)/i(17q) abnormalities, or any two of the following: PB blast >9%, WBC ≥40 × 109/L, other unfavorable karyotype. Such patients and those with high DIPSS-plus risk should be referred to allogenic stem cell transplantation earlier than later. Disclosures: No relevant conflicts of interest to declare.

Abstract BACKGROUND: Information regarding risk factors for leukemic transformation (LT) in primary myelofibrosis (PMF) is limited, although both leukocytosis and abnormal cytogenetics have previously been implicated. The current retrospective study examines clinical variables at diagnosis as well as specific treatment modalities for their effect on LT in PMF. METHODS: Diagnoses of PMF and LT were based on World Health Organization criteria. In addition, study inclusion required availability, for review, of bone marrow histology and clinical data obtained at or within 6 months of diagnosis but prior to treatment intervention. Statistical methods used were standard and included Cox regression analysis of leukemia-free survival (LFS). RESULTS: A master database of PMF patients seen at the Mayo Clinic from 1976 through 2006 was queried to identify 311 patients who fulfilled the aforementioned stipulated criteria for study inclusion; median age was 57 years and 41% were females. At presentation, 30% of the patients displayed a hemoglobin level (Hgb) of < 100 g/L, 20% a leukocyte count of < 4 or > 30 x 109/L, 18% a platelet count of < 100 x 109/L, 12% an absolute monocyte count (AMC) of ≥ 1 x 109/L, 28% hypercatabolic symptoms and 35% a peripheral blood (PB) blast percentage of ≥ 1; 27 patients (9%) had a PB blast percentage of ≥ 3. Dupriez prognostic scoring system distribution for high, intermediate, and low risk disease was 30 (10%), 94 (30%), and 187 (60%) patients. Among 182 and 139 evaluable patients, 74 (41%) and 80 (58%) displayed cytogenetic abnormalities and JAK2V617F, respectively. At a median follow-up of 27 months (range 0–282), 27 cases (9%) of LT were documented at a median time from diagnosis to LT of 26 months (range 0.8–266). Effect of clinical and laboratory variables at diagnosis on leukemic transformation By univariate analysis, LFS was negatively affected by anemia (p=0.04), leukocytosis (p=0.04), PB monocyte count ≥ 1 x 109/L (p=0.02), platelet count of < 100 x 109/L (p=0.004), hypercatabolic symptoms (p=0.03) and PB blast percentage of ≥ 3 (p<0.0001); LFS was not affected by PB blast percentage of > 1 but < 3 (p=0.49). By multivariable analysis, significance was sustained only for PB blast percentage of ≥ 3 (p = 0.0002) and platelet count of < 100 x 109/L (p = 0.02) with hazard ratios (HR) of 5.8 and 2.8 and 95% confidence intervals (CI) of 2.3–14.6 and 1.2–6.6, respectively. The presence of JAK2V617F did not affect LFS (p=0.98). Effect of specific treatment on leukemic transformation By univariate analysis, LT was significantly associated with history of splenectomy (p=0.01) and treatment with erythropoiesis stimulating agents (ESA; p=0.004), danazol (p=0.007), and androgens (p=0.03) but not with hydroxyurea (p=0.17), interferon alpha (p=0.95), thalidomide (p=0.26) or other drugs. On multivariable analysis, significance was sustained for both ESA (p = 0.005; HR 3.1, CI 1.4–6.8) and danazol (p = 0.01; HR 3.4, CI 1.3–8.5), even when the aforementioned prognostic indicators at diagnosis were added as covariates to the multivariable model. CONCLUSIONS: The current study identifies PB blast percentage of ≥ 3% and platelet count of < 100 x 109/L, at presentation, as independent risk factors for LT in PMF. Unexpectedly, the study also revealed an association between LT and treatment history with ESA or danazol. These observations are intriguing, considering recent reports on the possible harmful effects of ESA in certain solid tumors.

Abstract Since the identification of the JAK family of intracellular tyrosine kinases and their downstream signaling partners, the STATs (Signal Transducers and Activators of Transcription), evidence has accumulated that activation of JAK signaling pathways can contribute to proliferation and survival of cancer cells. A direct link to oncogenesis was made when an activated form of JAK2 (JAK2 V617F) was identified in the majority of patients with myeloproliferative disorders (MPDs) including approximately half of patients with myelofibrosis (MF). Introduction of this JAK2 mutation into the bone marrow of mice induced erythrocytosis [Wernig et al. (2006) Blood107:4274] supporting JAK2 as a relevant target for treatment of myeloproliferative disorders. We have identified a novel small molecule inhibitor of JAK2, XL019, which may prove to have utility in treating MPDs. XL019 is a potent and reversible inhibitor of the JAK2 enzyme, with a Ki of 2 nM, and shows excellent selectivity (minimum of 50-fold selectivity against >120 protein kinases tested including other JAK family members). XL019 downregulates STAT signaling in cell lines expressing both wild type and activated forms of JAK2. IC50s for inhibition of STAT5 phosphorylation by XL019 ranged from 623 nM (HEL92.1.7) to 3398 nM (KG-1) in tumor cell lines. XL019 showed increased potency in primary human erythroid cells in vitro, where the IC50 for inhibition of EPO-stimulated phospho-STAT5 was 64 nM. XL019 inhibits proliferation in cell lines harboring activated or overexpressed JAK2, including certain lines derived from patients with Hodgkin’s Lymphoma (L-1236, 928 nM IC50), AML (MV4-11, 992 nM IC50), essential thrombocythemia (SET-2, 386 nM IC50), and erythroleukemia (HEL92.1.7, 6777 nM IC50). Preclinical single-dose pharmacodynamic studies demonstrate a potent effect of XL019 on JAK-STAT signaling in HEL92.1.7, CFPAC-1 and DU 145 xenograft tumors. Twice daily dosing (bid) led to substantial tumor growth inhibition in the DU145 and HEL models (maximum tumor growth inhibition of 86% and 60%, respectively), accompanied by increases in tumor cell apoptosis (4 – 4.4 fold increase) and decreases in tumor microvasculature (44% reduction in DU 145 xenograft tumors). Based on these encouraging data, XL019 is being evaluated in subjects with primary or post PV/ET MF in a Phase I dose escalation study, which has completed enrollment of the first cohort. The primary objectives of this study are to determine the safety and tolerability of XL019 when administered orally once daily for 21 days in 28 day cycles. Secondary objectives include determination of the pharmacokinetics and pharmacodynamics of XL019, and to evaluate response using the International Working Group for MF consensus response criteria. We have developed a flow-based mechanistic assay for JAK2 activity, which measures GM-CSF-stimulated phospho-STAT5 in peripheral granulocytes in whole blood samples. Additional pharmacodynamic assessments for this study include JAK2 V617F allele burden, erythropoietin-independent colony formation, cytokine levels, and changes in bone marrow histology. Our initial findings regarding the pharmacokinetics, pharmacodynamics, tolerability and efficacy of XL019 in MF patients will be presented.

Abstract Abstract 5154 Background Recent clinical trials with JAK or mTOR inhibitors in primary myelofibrosis (PMF) have identified pruritus as one of the most treatment-responsive disease traits. However, little is known about the prevalence of pruritus in PMF or its clinical and laboratory correlates. Methods The study population was selected among a consecutive series of patients with PMF seen at the Mayo Clinic and in whom bone marrow histologic and cytogenetic information was available for re-review. JAK2, MPL and IDH mutation status and plasma cytokine levels (IL-1b, IL-1RA, IL-2R, IL-6, IL-8, IL-10, IL-12, IL-13, IL-15, TNF-α, G-CSF, IFN-α, IFN-γ, MIP-1a, MIP-1b, HGF, IP-10, MIG, MCP-1 and VEGF) were recorded where available. Overall and leukemia-free survival analyses were performed from time of referral to the Mayo Clinic. Results I: Prevalence of pruritus and other baseline information Among 566 consecutive patients with PMF (median age 62 years; 368 males), the presence (n=90) or absence (n=146) of pruritus was documented in 236 patients. The prevalence of pruritus was 38% when considering only those patients in whom pruritus history was documented (n=236), and 16% when all study patients (n=566) were considered regardless of whether or not the absence of pruritus was documented in their history. Among the 90 patients with pruritus, it was severe enough to warrant specific therapy in 51 (57%) patients, was aquagenic in 29 (32%), and onset antedated PMF diagnosis in 15 (17%). All 236 patients had information on karyotype: 136 normal, 76 favorable and 24 unfavorable karyotype. Information on JAK2, MPL, and IDH mutations was available in 197 (125 positive), 147 (9 positive), and 131 (2 positive) patients, respectively. In addition, plasma levels of the aforementioned cytokines were available in 63 patients. Results II: Clinical correlates Parameters at diagnosis that were significantly associated with presence of pruritus included leukocytosis (p=0.03), absence of leukopenia (p=0.002), and absence of MPLW515 mutation (p=0.02). Borderline significance was noted for JAK2V617F positive status (p=0.08). The incidence of pruritus was 0% (0/9) vs. 41% (56/138) in MPL-mutated vs MPL-unmutated cases and 42% (52/125) vs. 29% (21/72) JAK2 mutated vs unmutated cases, respectively. No significant correlations were noted for age, DIPSS-plus scores, transfusion need, karyotype, or plasma cytokine levels. The association with leukocytosis/leukopenia was subsequently shown to be significant only in JAK2V617F-negative cases. To date, 124 deaths and 19 leukemic transformations have been documented. In JAK2-mutated cases (n=125), pruritus did not affect overall or leukemia-free survival. In JAK2-unmutated cases (n=72), a significant correlation between presence of pruritus and inferior leukemia-free survival was noted (p=0.04), and was independent of leukocytosis, thrombocytopenia or abnormal karyotype. Conclusions Pruritus accompanies PMF in a substantial proportion of patients and is more or less likely to occur in the presence of JAK2 or MPL mutations, respectively. In JAK2V617F-negative cases, PMF-associated pruritus clustered with leukocytosis and was independently associated with inferior leukemia-free survival. Disclosures: No relevant conflicts of interest to declare.

Abstract Chronic idiopathic myelofibrosis (MF) is a clonal hematopoietic disorder that leads to progressive marrow fibrosis and peripheral cytopenias. Very little is known about the role of aberrant DNA methylation in the pathobiology of this disease. Whole genome methylation was analyzed by a recently described novel method, the HELP assay (HpaII tiny fragment Enrichment by Ligation-mediated PCR; Khulan et al, Genome Res. 2006 Aug;16(8)) that uses differential methylation specific restriction digestion by HpaII and MspI followed by amplification, two color labeling and cohybridization to quantitatively determine individual promoter methylation. A whole genome human promoter array (Nimblegen) was used to determine the level of methylation of 25626 gene promoters by calculating HpaII/MspI cut fragment intensity ratio. Peripheral blood leucocytes from 9 patients with IMF were compared to 9 age-matched normal and anemic controls. Gene expression analysis was performed using 37K oligo maskless arrays using cDNA from the same samples. Methylation analysis showed that myelofibrosis samples clustered separately from normal and anemic controls when grouped by unsupervised clustering based on Pearson’s correlation coefficient. On the other hand, global gene expression demonstrated no clear cut differences between myelofibrosis and control samples suggesting that methylation profiling has greater discriminatory power when compared to conventional gene expression profiling. A high correlation (r=0.88–0.96) was observed between whole genome methylation profiles of matched sets of bone marrow and peripheral blood leucocyte samples from selected patients demonstrating that peripheral blood leucocytes can act as a valid surrogates for epigenomic analysis. Further analysis showed that genes aberrantly methylated in all myelofibrosis samples included v-myc, histone 2A, TNF, TNF Receptor1, FGF14 and others. Functional pathway analysis by Ingenuity showed that pathways involved in Inflammation and Cell signaling were the most affected by epigenetic silencing. Most interestingly, a large proportion of gene promoters were also aberrantly hypomethylated. These included genes for chemokine CXCL13, APC, IL-3, STAT2 and others. The pathways most activated by hypomethylation were involved in hematopoiesis and cell growth and proliferation demonstrating the biological validity of our analysis. Thus, our data demonstrates that myelofibrosis is characterized by distinct epigenetic aberrations that are preserved in peripheral blood leucocytes. These can be the basis of future studies on pathogenesis and diagnosis for this disease and lead to translational studies with agents targeting DNA methylation.

Abstract Abstract 2807 CCDC26 is a retinoic acid-dependent modulator of myeloid cell differentiation and death (Yin W et al. Oncogene 2006 :25 :3735). CCDC26 maps to chromosome 8q24.21 and germline polymorphisms in the gene have been associated with low-grade gliomas (Jenkins RB et al. Cancer Genetics 2011;204 :13), which in turn have recently been shown to frequently express IDH1 mutations (Parsons D et al, Science 2008;321 :1807). More recently, we have discovered that CCDC26 SNP associations in gliomas are primarily restricted to patients with IDH1 mutations (Jenkins et al. unpublished observations). We therefore hypothesized that germline CCDC26 SNPS might be associated with patients with myeloid malignancies that harbor IDH1 mutations (Mardis et al. NEJM 2009;361 :1058). Seventy-two IDH -mutated patients with chronic or blast phase myeloproliferative neoplasms (MPN), myelodysplastic syndromes or acute myeloid leukemia (most constituting post-MPN events) were identified: 18 IDH1 R132, one IDH2 R172 and 53 IDH2 R140. These 72 patients and a control group of 153 IDH unmutated cases with myeloproliferative or myelodysplastic neoplasms (total n =225) were genotyped for CCDC26 risk alleles associated with IDH -mutated gliomas: rs10464870, rs891835 and rs4295627. The respective minor allele frequencies (MAF) were significantly different between IDH1 (11%, 8% and 6%) and IDH2 (30%, 27% and 24%) mutated cases (p=0.037, 0.040 and 0.021; OR 3.4, 3.7 and 6.1 with 95% CI of 1.1–10.5, 1.1–13.0 and 1.3–28.9) as well as between IDH- wild type (24%, 24% and 21%) and IDH1 -mutated (11%, 8% and 6%) cases (p=0.10, 0.043 and 0.035; OR 0.42, 0.29 and 0.21 with 95% CI of 0.15–1.19, 0.09–0.96 and 0.05–0.90). The MAF values in our IDH -unmutated cases were similar to that of population-based controls. However, the direction of SNP associations in IDH1 -mutated myeloid malignancies were opposite of those seen in IDH1 -mutated gliomas. Our observations suggest a differential effect of CCDC26 genetic polymorphisms in IDH1 -mutated myeloid malignancies compared to either their IDH2 R140-mutated or IDH1 -mutated gliomas. Such differences in genomic context might contribute to hitherto seen differences in prognostic impact between IDH2 R140 vs. IDH1 R132 vs. IDH2 R172, in AML (Green CL et al. Blood Published online before print May 19, 2011, doi: 10.1182/blood-2010-12-322479). Disclosures: No relevant conflicts of interest to declare.

Abstract Background: A mutation in the Janus tyrosine kinase 2 gene (JAK2 V617F) has been recognized in Philadelphia chromosome-negative myeloproliferative disorders, including PV (∼95% of patients), ET (∼50%) and PMF (∼50%). INCB018424 is a potent and orally bioavailable selective JAK2 inhibitor with >80-fold selectivity against a broad panel of kinases, including JAK3. INCB018424 potently inhibits JAK2 V617F mediated signaling and malignant cell survival in vitro and in vivo in mice. Preclinical safety studies with INCB018424 demonstrated an excellent safety profile with no off-target toxicities. Methods: A phase I/II trial of INCB018424 given orally BID is being conducted in patients with PMF and Post-PV/ET MF. Both JAK2 V617F and JAK2 wild type patients are eligible. PK and PD data are being collected. Responses are being evaluated using the International Working Group (IWG) consensus criteria for treatment response in myelofibrosis with myeloid metaplasia, for the IWG for Myelofibrosis Research and Treatment (IWG-MRT) (Tefferi et al., Blood, 108, 1497–1503, 2006). Results: The initial dose of 25 mg PO BID resulted in a rapid and marked reduction in splenomegaly. All 3 patients in the first cohort of patients achieved a reduction in spleen size that is consistent with a clinical improvement response provided it is sustained for 8 weeks; spleen sizes of 25, 22, and 7 cm below the left costal margin have decreased to 8, 10, and 0 cm in the first month of therapy. At two months follow-up, the patient with a baseline spleen size of 22 cm is now down to 2 cm. All 3 patients also noted significant symptomatic improvement. The second cohort of 3 patients started therapy at an increased dose (50 mg PO BID) and at one week follow-up, the initial two patients (one JAK2 wild type, one JAK2 V617F) had decreases in spleen size from 22 cm to 17 cm and from 22 cm to 16 cm, respectively. No dose-limiting toxicities or other significant adverse events occurred in any patients to date. PK/PD analyses demonstrated that administration of INCB018424 resulted in plasma drug concentrations sufficient to markedly inhibit JAK2, as shown by suppression of phosphorylated STAT3 (a substrate of JAK2) in whole blood cells in all 3 patients in the first cohort. The 3 patients in the first cohort were all JAK2 V617F mutation positive: percentages of JAK2 V617F positive whole blood cells before therapy were 79%, 49% and 91%, and after one month of therapy, they were 59%, 48% and 78%, respectively. Conclusions: Initial results show marked reduction in splenomegaly and symptomatic improvement, without significant toxicity. The percentage of blood cells with JAK2 V617F mutation appears to be decreasing in patients on therapy. Updated results on current and future patients will be presented at the meeting.

Abstract Abstract 3917 Poster Board III-853 Background Patients with Myelofibrosis (MF) suffer from significant fatigue, constitutional symptoms and splenomegaly (Mesa et. al. Cancer 2007) not improved by current therapy. The MF-SAF is a 19 item self administered instrument specific to MF associated symptoms previously validated for use at a single time point (Mesa et. al. Leukemia Research 2009). We sought to assess the performance characteristics of the MF-SAF when administered sequentially in the context of a prospective clinical trial. Methods Sequential MF patients enrolled in the prospective, uncontrolled Phase II, trial were given a 15 item modified MF-SAF to complete at enrollment, and after 15 days, 1 month, 2 months, 3 months and every 3 months thereafter. The MF-SAF was scored as previously published on a 0 (absent) to 10 (maximal) scale. Cross validation of serial change in MF-SAF scores was undertaken by comparison to objective measurements made as part of the therapeutic drug trial. Results Patients Eighty six MF patients were enrolled and had 2 or more MF-SAF instruments completed to allow for sequential analysis. Patients were of a median age (65 years), gender distribution (35 % females), and disease subtype (53 % PMF) typical for a clinical trial in MF. Baseline MF-SAF Responses: Baseline assessment of the most frequent MF abnormalities reported by patients completing the MF-SAF (see Table 1) confirmed the wide prevalence of MF associated symptoms, and their significant severity. General fatigue was the most frequent symptom cited (91%), while cough was the least frequently observed symptom (44%). 95% of patients had at least 2 symptoms present on the MF-SAF. Serial MF-SAF Changes in Response to Therapy Therapy with INCB018424 resulted in a significant and rapid reduction in MF associated symptoms with 46% to 85% of patients experiencing improvement in a given symptom. The greatest improvements in MFSAF score improvements were reported by patients experiencing abdominal discomfort, night sweats, pruritus and fever (see Table 1), and corresponded to significant improvements in the individual MF symptom scales as well as the patient's overall assessment of quality of life (QOL). Correlation of MF-SAF to Objective Changes during INCB018424 Therapy Objective measurements obtained on the INCB018424 trial included MRI measurements of splenic reduction, the six minute walk test (6MWT) for inactivity, and serial weights. Reduction in spleen size (by ≥ 35% by volume or ≥ 50% by palpable length) corresponded to improvement in MF-SAF scores of abdominal discomfort and fatigue (50% of patients, median score decrease of -1.2, and -1.8, respectively). Improvement in the 6MWT by > 50 meters was associated with a 2-fold greater improvement in inactivity score on the MF-SAF compared to subjects who improved 6MWT performance by <50 meters. Finally, improvements in weight loss and fever were corroborated by objective measurements made at physician visits on the trial. Conclusions The MF-SAF is a brief, easily self administered, MF specific instrument which was successfully administered sequentially in the conduct of a large Phase II clinical trial. The significant symptomatic improvements reported by patients in the open label trial of INCB018424 corresponded to both improvements in symptom specific scores on the MF-SAF and objective measurements. Further validation of the MF-SAF will be possible by inclusion in upcoming randomized placebo controlled trials in MF patients. Parallel trials performed in MF patients should consider use of this instrument to allow for comparisons. Disclosures: Levy: Incyte Corporation: Employment, Equity Ownership. Vaddi:Incyte Corporation: Employment, Equity Ownership. Erickson-Viitanen:Incyte Corporation: Employment, Equity Ownership. Verstovsek:Incyte: Research Funding.