Li, Chin Yang

Abstract BACKGROUND. Several studies have recently reported on the occurrence of a JAK2 V617F mutation in myeloid cells from the majority of patients with polycythemia vera (PV). The clinical relevance of this novel observation is currently under study. Similarly, there is limited information regarding the correlation of JAK2 V617F mutational status and neutrophil PRV-1 transcript level in PV, secondary polycythemia (SP) and other myeloproliferative disorders (MPD). METHODS. In a single institutional study, mutation screening for JAK2 V617F was performed in DNA derived from archived blood granulocytes from 63 consecutive patients with PV in whom current diagnostic criteria were strictly applied and diagnosis confirmed by bone marrow histology. Concomitant quantitative analysis of neutrophil PRV-1 expression was performed in 28 of the 63 patients and the results of both JAK2 V617F and PRV-1 analysis in these 28 patients were compared with those from another 22 patients with essential thrombocythemia (ET), 10 with myelofibrosis with myeloid metaplasia (MMM), 19 with SP, and 11 healthy volunteers. RESULTS. The 63 patients with PV were followed for a median of 33 months (range 3–324) from the time of initial diagnosis. During this period, 3 patients have died including 2 from acute myeloid leukemia (AML). Disease transformation into either AML or MMM has occurred in 2 and 4 patients, respectively. The median time from diagnosis to the time of mutation analysis was 12 months (range 0–306). JAK2 V617F was detected in 58 of the 63 patients with PV (92%; homozygous in 21%). The clinical phenotype of the 5 patients with wild-type allele was otherwise typical for the disease. A statistical comparison between JAK2 V617F heterozygotes (n=45) and homozygotes (n=13) in PV did not reveal significant associations in regards to age, gender, leukocyte or platelet count at diagnosis, disease duration, or the incidences of thrombosis or bleeding. However, JAK2 V617F homozygotes, compared to their heterozygote counterparts, displayed significantly higher hemoglobin level at diagnosis (p=0.001), increased incidence of pruritus (69% vs. 38%; p=0.04), and a higher rate of fibrotic transformation (23% vs. 2%; p=0.009). The overall (homozygous) JAK2 V617F mutational frequencies in the other study patients with ET, MMM, SP, and healthy controls were 55% (0%), 30% (0%), 0%, and 0%, respectively. The corresponding figures for increased PRV-1 expression in these patients were 18%, 20%, 21%, and 9% as compared to 89% in PV. In patients with either ET or MMM, the likelihood of detecting JAK2 V617F was significantly higher in the presence of an increased PRV-1 expression (83% vs. 38%; p=0.05). Similarly, in patients with PV, homozygous as compared to heterozygous JAK2 V617F correlated with higher levels of PRV-1 expression (p=0.07). CONCLUSIONS. The current clinical study demonstrates a mutant allele dose effect on erythrocytosis, PV-characteristic clinical features, and granulocyte PRV-1 expression in PV. Furthermore, compared to the PRV-1 assay, mutation screening for JAK2 V617F displayed greater specificity in distinguishing PV from SP.

Abstract Post-polycythemic (PPMM) and post-thrombocythemic (PTMM) myeloid metaplasia are consensually referred to as secondary myelofibrosis (sMF). Prognostic variables in sMF are not as well defined as they are for agnogenic myeloid metaplasia (AMM). Such information is particularly crucial for management decisions in transplant-eligible patients. Accordingly, we examined the prognostic impact of several clinical and laboratory variables in 66 young patients (age < 60 years) with sMF including 37 with PPMM and 29 with PTMM. Multivariate analysis of parameters other than cytogenetics identified older age (p=0.02), anemia (hemoglobin level < 10 g/dL; p=0.007), and PPMM (p=0.009) as independent risk factors for shortened survival. However, when such analysis was restricted to patients in whom cytogenetic studies were performed (n=31), the presence of unfavorable cytogenetic abnormalities (i.e. clones other than 20q- and 13q-) became the one and only adverse prognostic factor for survival (p=0.001). Figure Figure The prognostic value of cytogenetics was independent of the Dupriez prognostic score (p=0.003). Figure Figure A similar analysis in a temporal cohort of 50 age-matched patients with AMM also identified unfavorable cytogenetics as an independent predictor of poor survival along with thrombocytopenia and anemia. The current study suggests an important prognostic role for cytogenetics in both de novo and secondary myelofibrosis.

Abstract Background: The occurrence of an activating JAK2 mutation (JAK2 V617F) has been reported in a variable proportion of patients with bcr/abl-negative myeloproliferative disorders including myelofibrosis with myeloid metaplasia (MMM). In the current study, we report mutational frequencies in each of the 3 MMM variants as well as examine the prognostic relevance of the mutation in a large group of patients from a single institution. Methods: Mutation analysis for JAK2 V617F was performed in DNA derived from peripheral blood mononuclear cells (PBMC) from all study patients (n=157). Concomitant analysis was also performed in DNA derived from purified granulocytes (n=57), CD34-positive cells (n=25), and T cells (n=19). Genomic DNA was amplified by PCR and fluorescent dye chemistry sequencing was performed using the same primers used for amplification. Results: The study cohort included 157 consecutive patients with MMM including 117 with agnogenic (AMM), 22 with post polycythemic (PPMM), and 18 with post thrombocythemic (PTMM) myeloid metaplasia. The overall detection rate for JAK2 V617F in PBMC was 51% (homozygous in 5.7%) and was significantly (p=0.0002) higher in PPMM (91%; homozygous in 18%) compared to either AMM (45.3%; homozygous in 2.6%) or PTMM (38.9%; homozygous in 11.1%). In AMM (n=117), the presence of JAK2 V617F was significantly associated with an older age at diagnosis (p=0.03), and a history of both thrombosis (p=0.01) and pruritus (p=0.005). No other statistical associations were evident and the presence of the mutation did not predict leukemic transformation. Furthermore, multivariate analysis for overall survival of patients with AMM identified only age and the Dupriez prognostic score as independent prognostic factors; JAK2 V617F had no prognostic significance. Finally, the mutation was not found in T cells and its detection rate in either granulocytes or CD34-positive cells was similar to that in PBMC. Conclusion: JAK2 V617F is a myeloid lineage-specific event, its incidence in MMM is significantly higher with an antecedent history of polycythemia vera, and its presence in AMM does not affect prognosis but is associated with PV-characteristic clinical features.

Abstract BACKGROUND: THAL has been used as immunomodulatory therapy alone (Tefferi et. al. Blood 200;96:4007), or with steroids (Mesa et al. Blood2003;101:2534), in patients with primary myelofibrosis (PMF). Clinical benefit has been limited to improvements in cytopenias and/or splenomegaly. However, major histologic remissions of intramedullary manifestations of disease have not typically been observed. The mechanism of action of THAL in MF remains uncertain, and may involve cytokine inhibition or immunomodulation. We have previously observed increased numbers of CD8+ T lymphocytes on marrow trephines of patients who responded to THAL, and hypothesized that alterations in the T-cell distribution and population may provide insight into an immunomodulatory response and correspond to subsequent response in PMF patients. Methods: We analyzed a cohort of PMF patients who had received THAL therapy (alone or in combination with corticosteroids) from our institution and analyzed their clinical course and response to THAL therapy. Marrow trephines were evaluated in a systematic fashion (CYL in a blinded fashion to clinical course) for cellularity and degree of reticulin fibrosis (0–4+). Subsequently, megakaryocytes were assessed for quantitative (increased, decreased, or normal) and qualitative (size (large or small) and presence or absence of morphologic dysplasia). T cells were assessed by immunohistochemical staining for CD8 with an emphasis on number of T cell clusters per trephine, and the pattern of those clusters (large vs. small). Finally, an estimation of numbers of T cells per high power histology field was conducted in 3 distinct areas, and an average per marrow trephine obtained. All histologic features were then compared with PMF prognostic scores, and labs at presentation. Amongst those who received THAL, baseline histology was compared to response and in those patients with serial marrows longitudinal changes were assessed. Results: A cohort of 140 patients with PMF was analyzed, 65 having received THAL along the course of their illness (53 (82%) along with prednisone) and 75 from a comparison group who never received THAL. Patients from both groups had similar PMF prognostic scores and presentations. Comparison of baseline histologic features demonstrated that individuals with a baseline increases in T cell numbers (>100 per high power field) were significantly more likely to subsequently respond to THAL therapy (p<0.01). Additionally, analysis of megakaryocyte morphology demonstrated that those patients in which megakaryocytes were atypical for PMF (i.e. small) were significantly more likely to have thrombocytopenia and were less likely to respond to THAL (p=0.05). Independent assessment of the prognostic value of these individual histologic features upon survival failed to reveal any direct impact upon survival by Kaplan-Meier Analysis. Table 1. Comparison of Histologic Features in 140 patients with Myelofibrosis Group Cell Fibrosis ≥3 Meg Numbers Meg Size T Cell clusters T-Cells (per HPF) >100 Tcells (per HPF) Control (N=75) 72% (10–100) 33% 91% Increased 21% Small 4 (0–16) median 80 (13–258) 37% THAL ALL (N=65) 60% (5–95) 62% 79% Increased 38% Small 3 (0–14) median 93 (20–500) 43% -THAL Responders (N=28) 60% (5–95) 56% 82% Increased 22% Small (p=0.05) 5 (0–10) median 113 (45–198) 61% (p<0.01) -THAL Non Responders (N=37) 60 (5–95) 67% 76% Increased 48% Small 3 (0–14) median 70 (20–500) 26% A subgroup of patients who received THAL (N=12) had a second post therapy marrow available for analysis for comparison of THAL effects upon the marrow, although the numbers were small, there was no statistically significant differences upon histologic parameters analyzed including cellularity, degree of fibrosis, megakaryocyte morphology, or T cell clustering or numbers. Inclusion of prednisone in the regimen had no impact on histologic prognostic observations. Conclusions: THAL therapy for MF patients can be associated with significant clinical benefit for cytopenias and splenomegaly, and interestingly patients with increased marrow T-cell populations at baseline have a clear increased likelihood of response. Although this analysis is unable to gauge mechanism, it would suggests a greater potential for immunomodulation in patients with a robust T-cell population. Additionally, analysis of megakaryocytes suggests the presence of small megakaryocytes may in contrast represent a more resistant phenotype of disease with more thrombocytopenia and THAL resistance.

Abstract Background: Current therapy in adult systemic mastocytosis (SM) includes observation alone, topical therapy for cutaneous disease, symptomatic non-cytoreductive therapy and cytoreductive therapy. The latter involves several drugs whose individual merit in the treatment of SM has not been well characterized. Patients and Methods: Diagnosis of SM was according to the 2001 WHO criteria (World Health Organization Classification of Tumours of Hematopoietic and Lymphoid Tissues, p 1–351. Lyon, France: IARC Press; 2001). Response to cytoreductive therapy was assessed by consensus criteria (Eur J Clin Invest.2007;37:435). The study population was selected from a series of 342 adult SM patients referred to our institution and seen between 1964 and 2008. KITD816V mutation analysis was performed by DNA sequencing. Results: A total of 134 study patients received treatment that included at least one cytoreductive drug as either first-line (n=105) or second-line (n=29) therapy. Interferon-alpha with or without prednisone (n=58), hydroxyurea (n=43), imatinib mesylate (n=42) and 2-chlorodeoxyadenosine (n=26) were the most frequently used cytoreductive agents accounting for 120 of the 134 study cases; the remaining 14 patients received other cytoreductive drugs, none of which were effective. i. Interferon-alfa (IFN-a) with or without prednisone IFN-a with or without prednisone (24 and 34 patients, respectively) was given to 12 patients with indolent SM (ISM), 14 aggressive SM (ASM), and 32 SM with associated clonal hematological non-mast cell lineage disease (SM-AHNMD). For all 58 patients receiving therapy, complete (CR), major (MR), and partial (PR) response/regression were achieved in 3, 7, and 14 patients, respectively, for an overall response rate (ORR) of 41%. ORR in ISM, ASM, and SM-AHNMD was 50%, 43%, and 38%, respectively. Median duration of response was 12 months (range, 1–117 months). Anemia and elevated ESR were significantly associated with inferior ORR; 29% vs. 56% (p=0.04) and 14% vs. 57% (p=0.01), respectively. BM detection of KITD816V did not appear to affect response rates (p=0.4). ii. Hydroxyurea (HU) HU was given to 2 ASM, 40 SM-AHNMD and 1 mast cell leukemia (MCL) patients. The drug was used as first-line therapy in 30 patients. MR and PR were achieved in 1 and 8 SM-AHNMD patients, respectively (ORR=21%). Median duration of response was 37 months (range, 5–84 months). iii. Imatinib mesylate (IM) in patients with SM and associated eosinophilia IM was given to 22 SM patients who had associated eosinophilia (SM-eos): 2 had ISM, 2 ASM, and 18 SM-AHNMD. The drug was used as first-line therapy in 9 patients. Ten of the 22 patients with SM-eos were known to harbor the FIP1L1-PDGFRA fusion mutation and all responded to IM (ORR=100%). None of 5 FIP1L1-PDGFRA-negative SM-eos patients had a response to IM. In the remaining 7 patients with unknown mutation status, 4 patients had a response to IM (1 CR, 1 MR, and 2 PR). iv. IM in patients with SM not associated with eosinophilia IM was administered to 20 SM patients without associated eosinophilia (7 ISM, 2 ASM, 10 SM-AHNMD, and 1 MCL). Response was documented in 4 (20%) patients (1 CR, 1 MR, and 2 PR) including 1 with ISM, 2 with ASM and 1 with SM-AHNMD. Median duration of response was 19.5 months (range, 9–69 months). Two patients developed interstitial pneumonitis. v. 2-Chlorodeoxyadenosine (2-CdA) 2-CdA was given to 10 ISM, 3 ASM, and 13 SM-AHNMD patients; the drug was used as first-line therapy in 8 patients. CR, MR and PR were achieved in 1, 7, and 4 patients, respectively (ORR=46%). ORR in ISM, ASM, and SM-AHNMD was 50%, 33%, and 46%, respectively. Median duration of response was 11 months (range, 3–74 months). Presence of leukocytosis (WBC > 10 x 109/L), monocytosis (absolute monocyte count > 0.9 x 109/L) or circulating immature myeloid cells was significantly associated with inferior response; 13% vs. 61% (p=0.02); 11% vs. 69% (p=0.006) and 0% vs. 71%, (p=0.001), respectively. Response was not affected by BM detection of KITD816V (p=1.0). Conclusions: Both IFN-a and 2-CdA are reasonable treatment options, with comparable efficacy, for symptomatic SM including the subcategories of ISM, ASM and SM-AHNMD. IFN-a response was significantly better in the absence of anemia or elevated ESR. 2-CdA response was similarly better in the absence of leukocytosis, monocytosis or circulating immature myeloid cells. The therapeutic value of IM was limited to FIP1L1-PDGFRA-positive disease.

Abstract BACKGROUND: The potential risks of tumor growth promotion and thromboembolism associated with erythropoietin (Epo) therapy warrant cautious use of erythropoiesis stimulating agents (ESA). Recent data suggest a surprising and significant association between ESA use and increased incidence of leukemic transformation in primary myelofibrosis (PMF) (data from an analysis separately submitted for American Society of Hematology meeting, 2007). It is prudent, therefore, to avoid unnecessary ESA exposure in PMF, especially in patients with low likelihood of treatment response. METHODS: Diagnosis of PMF was based on World Health Organization criteria. Study inclusion required availability of treatment history with ESA and adequate follow-up. We excluded patients who were receiving hemoglobin-improving agents concomitantly with an ESA, such as prednisone, androgens, danazol, or thalidomide. Transfusion dependency was defined by a history of minimum 2 units of red blood cell transfusions in a 1-month period for a hemoglobin < 8.5 g/dL, not associated with bleeding. An adequate treatment response was defined as a minimum 2.0 g/dL increase in hemoglobin level or becoming transfusion-independent over a minimum 1-month period. RESULTS: A master database of PMF patients seen at the Mayo Clinic from 1976 through 2006 was queried to identify 43 patients (median age 67 years; 35% females) treated with ESAs and in whom adequate follow-up was available to determine response. Prior to ESA treatment, median hemoglobin was 9.2 g/dL (range 7.0–11.9), and 16 (37%) were red blood cell transfusion-dependent. In 25 patients, pre-treatment serum Epo level was available (median 34 mU/mL; range 2–323). Among the 43 study patients, 16 (37%) were previously treated with other PMF-specific therapies, and 18 (42%) were receiving cytoreductive treatment concurrent with an ESA. Overall, 23% of patients (10 of 43) responded to treatment with ESA. The response rate was 0% (0 of 16) in the transfusion-dependent group compared to 37% (10 of 27) in the transfusion-independent group (p=0.007). Among the transfusion-independent patients, the proportion of ESA responders was significantly higher in the presence of a baseline hemoglobin level < 10 g/dL prior to treatment (p=0.009). ESA response was not correlated with baseline serum Epo level in the context of either all 43 study patients (p=0.68) or the 27 transfusion-independent patients (p=0.39). ESA response was not affected by PMF-specific treatment history (p=0.46), use of concurrent cytoreductive therapy (p=0.28), cytogenetic findings (p=0.62), JAK2V617F presence (p=0.69) or its allele burden at time of initial PMF diagnosis (p=0.16). CONCLUSIONS: Clear benefit of ESAs in PMF is limited to red blood cell transfusion-independent patients and those with baseline hemoglobin levels less than 10 g/dL.

Abstract Background: Immunomodulatory therapy has been shown to be of benefit for the improvement of anemia, thrombocytopenia and splenomegaly in patients with myelofibrosis (MF) initially with thalidomide (Blood2000;96:4007), and further enhanced by combination therapy with corticosteroids (Blood2003;101:2534). We sought to further enhance our previously reported efficacy of single agent lenalidomide for MF patients (Blood2006;108:1158) by combination therapy with prednisone. Methods: Symptomatic patients with MF (all with baseline anemia, hemoglobin <10g/dL or transfusion dependent) were enrolled in the single arm Phase II trial. Adequate neutrophils (>1 x 109/L) and platelets (>100 x 109/L) were required for trial entry. Lenalidomide was administered at 10 mg daily with a 3 month prednisone taper (30mg/daily, 15 mg daily, 15 mg every other day months 1,2, and 3, respectively). Patients with at least stable disease remained on single agent lenalidomide for an additional 3 months. Responses were assessed by the International Working Group for Myelofibrosis Research and Treatment (IWG-MRT) Response Criteria (Blood2006;108:1498). Results: Patients 28 patients were enrolled in the first step of the trial, and a total of 48 patients were enrolled (3 were ineligible because of proximity of prior therapy with 43 deemed evaluable). The enrolled eligible patients (56 % males) had a median age of 64 (range 18–83). At baseline, 52% were red cell transfusion dependent, and the median hemoglobin amongst those non transfusion dependent patients was 8.8 g/dL (range 5.9–12.4). By entry criteria neutrophils (median 5.1 x 109/L (range 1.0–79.4)) and platelets (median 234 x 109/L (range 40–1253)) were adequate. Therapy and Toxicity: A median of 6 cycles of therapy was administered, 10 patients received 3 months, and 25 patients the full 6 months of therapy. Premature discontinuation of therapy occurred in 19 patients; progressive disease (3), toxicity (7), patient withdrawal (5), death from disease (1), comorbidities (2), or seeking alternative therapy other (1). Myelosuppression was the main toxicity with 45% experiencing ≥ grade 3 hematologic toxicity (16%/2% and 23%/26%, grade 3/4 thrombocytopenia and/or neutropenia, respectively) and with 34% of patients having ≥ grade 3 non-hematologic toxicity. Less severe toxicities (< grade 3) were again mainly secondary to myelosuppression (34%) or gastrointestinal (i.e. diarrhea). No significant steroid induced toxicities were observed. Response: Among 43 patients eligible for response assessment the best confirmed response observed was a partial response in 11 (26%), stable disease (54%), and progression during trial in 8 (18%), 1 was not evaluable because no medication was taken. Among the latter responses improvement in anemia was seen in 9 (21%) (IWG-MRT clinical improvement (CI)-sustained normalization of hemoglobin, >2 g/dL increase, or transfusion independence for >2 months), and major reductions in spleen size in 4 (9%) (IWG-MRT CI - sustained >50% decrease). Serial marrow analysis was available in a subset which did not show any significant resolution of disease related fibrosis, hypercellularity or increased angiogenesis typical of MF. Conclusions: 1) Lenalidomide plus a corticosteroid taper was active in patients with MF primarily in those who suffer from anemia, but myelosuppression (particularly neutropenia is common) 2) Response rates observed with combination therapy are almost identical to our previously reported response rate seen with single agent lenalidomide (22% single agent, 21% in this trial), 3) Current results would suggest that given the myelosuppression observed, and rates of efficacy, thalidomide and prednisone would be first line for treating MF associated cytopenias with lenalidomide being considered second line (first line if a del(5q) present).

Abstract Background: Systemic mastocytosis (SM) has a varied presentation ranging from indolent forms with limited morbidity over many years to the rapidly fatal mast cell leukemia (MCL). This heterogeneity complicates clinical decision making regarding choice and timing of therapy. The aim of this study was to evaluate the prognostic value of the 2001 World Health Organization (WHO) classification of SM, and to refine risk stratification within SM sub-groups to facilitate clinical decision making. Information on KITD816V and JAK2V617F mutation analysis and clinical correlates is also provided. Methods: Patient records in the institutional electronic database from January 1976 to October 2007 were reviewed and SM patients 18 years of age or older identified; the date of diagnosis ranged from July 1964 to October 2007. Only those patients where diagnosis was confirmed by bone marrow (BM) histology were included in the analysis. KITD816V mutation analysis was performed by DNA sequencing. JAK2V617F was screened by allele-specific quantitative PCR analysis. Results: i. Clinical characteristics at presentation: A total of 342 SM patients were identified (154 female; median age at diagnosis=57 years; range 19 to 87 years). Per the 2001 WHO classification, 159 had indolent SM (ISM; median age=49 years), 41 aggressive SM (ASM; median age=65 years), 138 SM with associated clonal hematological non-mast cell lineage disease (SM-AHNMD; median age=65 years), and 4 MCL (median age=55 years) (p-value for age <0.0001). 140 (41%) patients had urticaria pigmentosa (UP) (63% with ISM; p<0.0001), 160 (47%) mast cell (MC) mediator release symptoms (69% with ISM; p<0.0001), 107 (31%) skeletal symptoms, and 142 (42%) constitutional symptoms (61% with ASM/SM-AHNMD versus 19% with ISM; p<0.0001). 123 patients (36%) had palpable splenomegaly (57% with SM-AHNMD; p<0.0001). 56 patients (16%) exhibited prominent eosinophilia (absolute eosinophil count >1500/mcl) – 31% and 22% with SM-AHNMD and ASM, respectively, versus 3% with ISM (p<0.0001); 12 of 23 patients (52%) with eosinophilia who were tested carried the FIP1L1-PDGFRA mutation. Serum tryptase (normal <11.5 ng/mL) was measured in 160 patients (47%) and almost all (96%) had an elevated level (median=64 ng/mL; range=4 to 2000 ng/mL; 33 patients had >200 ng/mL). ii. Disease course and prognostic factors After a median follow-up of 20.7 months (range=0–417), 153 deaths were recorded. 17 patients (5%) transformed to acute myeloid leukemia (AML; n=14) or MCL (n=3), most frequently with SM-AHNMD (11% versus 0% for ISM; p<0.0001). The median overall survival was 63 months (ISM=198 months, ASM=41 months; SM-AHNMD=24 months, and MCL=2 months; p<0.0001). Multivariate analysis of parameters at the time of diagnosis showed a significant and independent association between inferior survival and WHO sub-type (p<0.0001), age at diagnosis (p<0.0001), history of weight loss (p=0.01), anemia (p=0.007), thrombocytopenia (p=0.0008), hypoalbuminemia (p=0.0008), and excess BM blasts (>5%; p=0.004). A similar analysis in ISM identified anemia (p=0.04), hypoalbuminemia (P=0.002), and BM MC ≥ 30% (p=0.03) as independent predictors of inferior survival; the corresponding parameters in ASM were age at diagnosis (p=0.002) and history of weight loss (p=0.003). iii)KITD816V andJAK2V617F analysis Archived bone marrow was available in 165 patients for KITD816V and JAK2V617F analysis. By DNA sequencing, overall KITD816V detection rate was 28%: ISM 20%, ASM 29%, SM-AHNMD 33% (p=0.4). In patients with ASM (p=0.003) and SM-AHNMD (p=0.001), detection of KITD816V was associated with inferior survival. Greater than 1% (range 1–57) JAK2V617F allele burden was detected in 6 patients (4%); all belonged to SM-AHNMD including 4 with non-MC lineage myeloproliferative neoplasm. Conclusions: The current study confirms the prognostic value of the WHO subclassification of SM and identifies advanced age, weight loss, anemia, thrombocytopenia, hypoalbuminemia, and excess BM blasts as additional adverse prognostic factors. In ISM, presence of anemia, hypoalbuminemia, or BM MC ≥ 30% is associated with inferior survival. In ASM and SM-AHNMD, BM KITD816V allele burden might influence survival. JAK2V617F is rare in SM and when found, it is almost always in the context of SM-AHNMD.

Abstract Background: Systemic mastocytosis (SM) sometimes coexists with an associated clonal hematological non mast cell lineage disease and such an occurrence is recognized by the 2001 World Health organization (WHO) classification system as SM-AHNMD (Leuk Res. 2001 25:603). However, SM-AHNMD has not been further stratified into prognostically relevant subgroups. This was the major objective of the current study, which also provides information on prevalence and relevance of detecting KITD816V and JAK2V617F mutations. Methods: Patient records in the institutional electronic database from January 1976 to October 2007 were reviewed and SM patients 18 years of age or older identified; the date of diagnosis ranged from July 1964 to October 2007. Only those cases where diagnosis was confirmed by bone marrow (BM) histology were included in the analysis. SM- and AHNMD-components were classified according to WHO criteria. Results: AHNMD sub-classification: Of 342 consecutive cases of SM that were screened, 138 (40%) were identified as having SM-AHNMD (median age 65 years, range 20–87). The most frequent AHNMD was chronic myelomonocytic leukemia (SM-CMML) seen in 38 (28%) patients. 23 (17%) patients had SM associated with myelodysplastic syndrome (SM-MDS), 22 (16%) with hypereosinophilic syndrome/chronic eosinophilic leukemia (SM-HES/CEL) and 33 (24%) with another myeloproliferative neoplasm (SM-MPN). The number of cases with other SM-AHNMD was much lower and included lymphoma 8 (6%), acute leukemia 3 (2%), MDS/MPN 3 (2%), and 8 (6%) cases of multiple myeloma, primary amyloidosis or chronic lymphocytic leukemia. Of the 33 SM-MPN patients, 2 had polycythemia vera, 6 essential thrombocythemia, and 2 myelofibrosis; the remaining 23 patients had an unclassified MPN in association with SM. Clinical characteristics at presentation: The combined incidence of urticaria pigmentosa (UP) was 18%, mast cell mediator release symptoms 28% and constitutional symptoms 62%. 76 patients (57%) had palpable splenomegaly. 99 patients (72%) had anemia, 18 (13%) leukopenia (43% with SM-MDS; p<0.0001) and 76 (55%) thrombocytopenia. 70 (51%) patients had leukocytosis and 63 (55%) displayed circulating immature myeloid cells (78% with CMML; p=0.001). 59 (54%) patients had elevated serum alkaline phosphatase level: SM-CMML 70%, SM-MPN 60%, SM-HES/CEL 40%, and SM-MDS 30% (p=0.01). Where evaluated, serum tryptase was elevated in 92% of the patients (median=75 ng/mL; range=4–1360). BM blasts were ≥5% in 25 patients (22%), including 48% with SM-MDS (p=0.004). 12 of 35 patients tested carried the FIP1L1-PDGFRA mutation (all had SM-HES/CEL; p<0.0001). Disease course and prognostic factors At a median follow up of 15 months (range 0–182), 99 deaths were recorded and the combined median survival was 24 months: SM-CMML 15 months; SM-MDS 15 months, SM-MPN 30 months; and SM-HES/CEL 87 months (p=0.003). Fifteen patients (11%) transformed to acute leukemia or mast cell leukemia. Multivariate analysis of parameters at the time of diagnosis showed a significant and independent association between inferior survival and SM-AHNMD sub-type (p=0.007), presence of constitutional symptoms (p=0.04), thrombocytopenia (p=0.01), presence of circulating immature myeloid cells (p=0.006), and hypoalbuminemia (p<0.0001). In SM-CMML, hypoalbuminemia was associated with inferior survival (p=0.03). KIT D816V and JAK2 V617F analysis: Archived BM was available in 88 patients for KITD816V and JAK2V617F analysis. By DNA sequencing, overall KITD816V detection rate was 33%: SM-CMML 48%, SM-MDS 21%, SM-HES 8%, and SM-MPN 45% (p=0.03). In patients with SM-HES/CEL (p=0.0009) and SM-MPN (p=0.04), detection of KITD816V was associated with inferior survival. Greater than 1% (range 5–57) JAK2V617F allele burden was detected in 6 patients (9%): 4 in SM-MPN, 1 in SM-CMML and 1 in SM-MDS. Conclusions: The WHO-defined SM-AHNMD comprises prognostically diverse subcategories among which SM-CMML is the most frequent. Survival is favorable in SM-HES/CEL and significantly worse in SM-CMML and SM-MDS. Additional independent predictors of inferior survival include constitutional symptoms, thrombocytopenia, circulating immature myeloid cells, and hypoalbuminemia. In SM-HES/CEL and SM-MPN, BM KITD816V allele burden may influence survival. JAK2V617F occurs infrequently in SM-AHNMD and when it does, it clusters with SM-MPN.

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.