Sirhan, Shireen

Abstract Abstract 178 Background: CYT387 is a potent and selective small molecule inhibitor of JAK 1 and JAK 2 which is in clinical development for the treatment of myelofibrosis. Previously reported preliminary results from a phase I/II multicenter study demonstrated improvements in splenomegaly and constitutional symptoms as well as in RBC transfusion requirements. Enrollment has been completed and all subjects have now reached a minimum of 9 months on study. Updated safety and efficacy results are presented. Methods: Subjects with high or intermediate-risk primary myelofibrosis (PMF) and post-polycythemia vera (post-PV) or post-essential thrombocythemia (ET) myelofibrosis were enrolled. Following an initial dose expansion phase, subjects were treated in a 9 month core study at an initial dose of 150 mg QD, 300 mg QD or 150 mg BID. Continued treatment with CYT387 was permitted in an extension phase for subjects who maintained at least stable disease. Responses were assessed by International Working Group (IWG) criteria with transfusion independence response defined as achieving a minimum 12 week transfusion-free period. Results: Enrollment of 166 subjects was completed at 6 study sites. Initial doses included 52 subjects at 150 mg QD, 60 subjects at 300 mg QD and 42 subjects at 150 mg BID. An additional 12 subjects were enrolled in other dose groups (100 mg QD, 200 mg QD, 400 mg QD) during the initial dose escalation phase. The median duration (range) of follow-up is 16.1 months (0.7 to 31.0 months). Durable transfusion independence responses were observed in more than half of the RBC transfusion dependent subjects with a maximal transfusion-free period exceeding 2 years and ongoing. In addition, the percentage of all subjects requiring RBC transfusions substantially decreased over the treatment period. Treatment with CYT387 resulted in rapid and sustained reductions in splenomegaly with a maximal response duration approaching 2 years. The majority of subjects reporting constitutional symptoms at baseline experienced complete resolution or marked improvement by 6 months with measurable improvement within the first month of therapy. Higher transfusion independence and spleen response rates were seen in the 300 mg dose group compared to the 150 mg QD or 150 mg BID dose groups. For the first 60 consecutively enrolled subjects for whom the most mature data is available, the median follow-up period (range) is 21.5 months (2.9–31.0 months). The anemia and spleen response rates in these subjects, per IWG-MRT, were 59% and 48%, respectively; among 33 of these subjects who were RBC transfusion dependent by IWG-MRT criteria, 70% achieved a minimum 12-week period without transfusions with a maximal transfusion-free period of greater than 2 years and ongoing. While 90% of subjects reported at least one treatment-related AE, the majority were reported as Grade 1. The most common treatment-related AEs were thrombocytopenia, peripheral neuropathy, dizziness, diarrhea, nausea, and headache. Treatment-related peripheral neuropathy was sensory, with almost all events reported as Grade 1. The most common Grade 3–4 treatment-related AEs included thrombocytopenia and hyperlipasemia. Only 5% of subjects reported treatment-related AEs resulting in study drug discontinuation. There were no treatment-related deaths. Conclusions: CYT387 has proven safe and well tolerated even with prolonged administration for over 2.5 years. Treatment with CYT387 results in clinical improvement by effecting a rapid, meaningful and durable reduction of splenomegaly and the achievement of sustained RBC transfusion independence in a substantial number of subjects. CYT387 is also effective in improving constitutional symptoms. These results support the development of CYT387 at a dose of 300 mg QD for the treatment of myelofibrosis. Final analyses of safety and efficacy will be available at the time of the meeting. Disclosures: Pardanani: Bristol-Myers Squibb: Clinical trial support, Clinical trial support Other; YM BioSciences: Clinical trial support, Clinical trial support Other; Sanofi-Aventis: Clinical trial support Other. Off Label Use: Data from the ongoing Phase-1/2 study of CYT387 use in myelofibrosis treatment will be described. Gotlib:YM Biosciences: Research Funding. Gupta:Celgene: Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; YM Biosciences: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi-Aventis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Roberts:YM BioSciences: clinical trial support Other. Wadleigh:Incyte: Membership on an entity's Board of Directors or advisory committees. Sirhan:Novartis: Consultancy, Honoraria. Bavisotto:YM BioSciences: Consultancy. Kawashima:YM BioSciences: Employment. Kowalski:YM BioSciences: Employment.

Abstract Background : Controversy persists regarding diagnostic accuracy as well as added value for quantitative assessment of neutrophil PRV-1 expression in polycythemia vera (Klippel et al. Blood2003;102:3569; Tefferi et al. Blood2004;103:3547). This is partly because of limited data regarding the relationship between neutrophil PRV-1 transcript level and other laboratory parameters in polycythemia vera (PV). More information is also needed on the PRV-1 expression profile in other myeloproliferative disorders (MPD), including essential thrombocythemia (ET) and agnogenic (AMM), post-polycythemic (PPMM), and post-thrombocythemic (PTMM) myeloid metaplasia. Methods : The current prospective study involves 141 subjects, including 49 with PV, 40 with secondary or spurious polycythemia (SP), 23 with ET, 11 with AMM, 4 with PPMM, 3 with PTMM, and 11 normal controls. Peripheral blood neutrophil PRV-1 expression was quantified by real-time PCR according to published methods (Klippel et al. Blood 2003). The results were first compared among the different disease categories and controls. Subsequently, within the specific disease categories of both PV and ET, PRV-1 expression was correlated with several laboratory [leukocyte count, absolute neutrophil count (ANC), leukocyte alkaline phosphatase score (LAP) score, CD34 count, platelet count, hematocrit, serum EPO level, MCV, serum ferritin, reticulin fibrosis] and clinical (age, sex, disease duration, spleen size, thrombosis history, and presence of treatment with cytoreductive agent, aspirin, or phlebotomy) parameters. Results : The incidence of increased neutrophil PRV-1 expression was the highest in PV and PPMM (p<0.0001) while the results in the other disease categories (ET, SP, AMM, PTMM) were similar among each other and controls ( p=0.89). Table 1 Parameters Cont. (n=11) SP (n=40) PV ( n=49) ET (n=23) AMM (n=11) PPMM (n=4) PTMM (n=3) Age in years median NA 51 58 46 60 63 47 range NA 19–78 18–83 18–81 41–80 56–71 47–72 Females NA 20% 55% 65% 18% 25% 33% PRV-1/GAPDH median 1.25 1.25 1.01 1.24 1.26 1.04 1.25 range 1.14–1.43 0.99–1.41 0.83–1.28 0.9–1.44 1.08–1.43 0.93–1.11 1.23–1.27 PRV-1 ↑ 9% 15% 76% 17% 18% 100% 0% In both PV and ET, neutrophil PRV-1 expression strongly correlated with LAP score (p=0.003 and 0.04, respectively). In addition, in PV, univariate analysis revealed significant correlations between PRV-1 expression and leukocyte count, ANC, and reticulin fibrosis. On multivariate analysis, only LAP score retained its significance. Figure Figure Conclusion :The current study confirms the previously recognized close association between increased neutrophil PRV-1 expression and PV as well as suggests a similarly strong association with PPMM but not with ET, MMM, or PTMM. The study also underscores the suboptimal diagnostic accuracy of the neutophil PRV-1 assay in distinguishing PV from SP. Most importantly, the demonstrated tight correlation between PRV-1 transcript level and LAP score raises the issue of added value to currently available diagnostic tests.

Abstract Background : Current diagnosis of polycythemia vera (PV) is based on a set of clinical and laboratory criteria that were adopted more by consensus rather than because of support from systematic evidence. Accordingly, one major criterion for the diagnosis of PV requires the demonstration of increased red cell mass (RCM) as measured by radionuclide dilution methods. In order to adjust for the influence of obesity on RCM expressed in mL/kg, an expert radionuclide panel of the International Committee for Standardization in Haematology (ICHS) has recommended that the results be expressed in reference to body surface area and specific formulae for the prediction of normal values as well as guidelines for the interpretation of measured values have been proposed (J Nuclear Med1980;21:793, BJH1995;89:748). Nevertheless, there is limited data on either the performance or added value of RCM measurement, following these revised recommendations, for the diagnosis of PV in current clinical practice. Methods : The current study looks at a single institution experience with RCM measurement over the last 10 years involving patients in whom the test was performed to consider the diagnosis of PV. The study excluded patients that were previously treated with either phlebotomy or cytoreduction. Designation of diagnostic categories was based on both a retrospective and prospective analysis of clinical data, bone marrow histology, and other laboratory parameters including leukocyte count, platelet count, serum erythropoietin (EPO) level, serum B12 level, and leukocyte alkaline phospatase (LAP) score. A diagnosis of secondary polycythemia (SP) required the presence of a condition known to be associated with SP. Apparent polycythemia (AP) was represented by patients in whom the diagnosis of either PV or SP could not be made and the stability of hematocrit values was documented by serial measurements. Measurement and interpretation of RCM values were according to the aforementioned published criteria and separate analyses were performed for males and females. Results : i) Evaluation of test performance : The study cohort consisted of 105 patients (60 males; median age 62 years, range 16–89) including 25 with PV, 35 with SP, 38 with AP, and 7 with essential thrombocythemia (ET). Table 1 outlines the percentage of patients, in each disease category, whose measured values exceeded the 98–99% limits of the reference range (i.e. ±25% of the normal predicted mean for an individual patient). Table 1 Diagnosis % with increased RCM (m2) % with normal RCM (m2) % with decreased plasma volume % with increased plasma volume PV (n=25) 80 20 0 20 ET (n=7) 57.1 42.9 0 29 SP (n=35) 20 80 2.9 5.7 AP (n=38) 21.6 78.4 5.4 5.4 The results reveal that RCM measurement was neither adequately sensitive nor specific in distinguishing PV from the other disease categories. In addition, based on the aforementioned ICHS criteria, chronically contracted plasma volume appears to be an infrequent phenomenon in AP. ii) Evaluation of added value for the diagnosis of PV : Among the 19 PV patients with elevated RCM, serum EPO was measured in 17 and the results showed decreased levels in 16 (94%). Bone marrow biopsy was available for review in 9 patients and the results were consistent with PV in all instances (100%). LAP score was performed in 12 patients and 11 had LAP scores above 130 (92%). In none (0%) of the 19 patients was RCM measurement found to be vital for the diagnosis of PV. Conclusion : In the current retropsective study, RCM measurement was found to be neither diagnostically accurate nor essential for the diagnosis of PV.

Abstract Background : Neutrophil PRV-1 over-expression has been strongly associated with polycythemia vera (PV) and its quantitative measurement might complement the diagnostic distinction between PV and secondary polycythemia (Klippel et al. Blood2003;102:3569). Furthermore, the PV-specificity of the particular abnormality had been suggested by studies that demonstrated increased PRV-1 expression in post-polycythemic but not agnogenic myeloid metaplasia (Tefferi et al. Blood2003;103:3547) as well as by other studies that suggested the inevitable progression into PV of essential thrombocythemia (ET) associated with PRV-1 over-expression (Griesshammer et al. Ann Hematol2004;83:364). Still others have suggested the possibile utility of the particular assay in differentiating clonal from reactive myeloproliferation (Cilloni et al. Blood2004;103:2428). Methods : The purpose of the current study was two-fold; i) to further evaluate the specificity of neutrophil PRV-1 over expression to either PV or clonal myeloproliferation by testing the assay in atypical myeloproliferative disorders (AMPD) and ii) to evaluate eosinophil PRV-1 expression in AMPD associated with eosinophilia. In a prospective study, 13 patients with AMPD and 2 with reactive eosinophilia were evaluated for neutrophil PRV-1 expression (table 1). PRV-1 transcript quantitation was performed according to published methods (Klippel et al. Blood2003;102:3569). PRV-1 gene expression was considered elevated in the presence of a PRV-1/GAPDH ratio of 1.17 or lower. Table 1 Patient Diagnosis Neutrophil PRV-1/GAPDH ratio Neutrophil PRV-1 expression 1 Chronic myelomonocytic leukemia associated with myelofibrosis 1.05 Increased 2 FIP1L1/PDGFRA-positive eosinophilic disorder 1.39 Normal 3 FIP1L1/PDGFRA-positive eosinophilic disorder 1.19 Normal 4 FIP1L1/PDGFRA-positive eosinophilic disorder 1.10 Increased 5 Biphenotypic acute leukemia with prominent blood eosinophilia 0.99 Increased 6 Hypereosinophilic syndrome with cardiac involvement 1.15 Increased 7 Hypereosinophilic syndrome with cardiac involvement 1.13 Increased 8 Hypereosinophilic syndrome with sinus involvement 1.29 Normal 9 Reactive eosinophilia associated with atopic dermatitis 1.09 Increased 10 Reactive eosinophilia associated with T cell skin lymphoma 1.22 Normal 11 Aggressive systemic mastocytosis associated with chronic myelomonocytic leukemia 1.08 Increased 12 Aggressive systemic mastocytosis associated with myelofibrosis 1.09 Increased 13 Aggressive systemic mastocytosis with circulating mast cells 1.29 Normal 14 Indolent systemic mastocytosis 1.20 Normal 15 Indolent systemic mastocytosis 1.18 Normal In addition, eosinophil PRV-1 expression was measured in 2 patients from the above cohort (patients 3 and 8) and 3 additional patients with hypereosinophilic syndrome (HES). Results : Table 1 outlines specific diagnoses as well as the corresponding neutrophil PRV-1 expression levels in all 15 patients tested (median age 54 years, range 20–74; 11 males). Eosinophil PRV-1 expression was normal in all 5 patients tested (range of PRV-1/GAPDH ratio between 1.20–1.39). Conclusion : The current study suggests that neutrophil PRV-1 over-expression is a non-specific marker of clonal myeloproliferation that is seen in a broad spectrum of both typical and atypical myeloid disorders. As has been the case in ET, only a subset of AMPD patients display the specific abnormality, thus undermining its diagnostic utility. The preliminary information from the current study does not suggest increased eosinophil PRV-1 expression in either HES or clonal eosinophilia.

Abstract Background : Thirty to 50% of patients with myelofibrosis with myeloid metaplasia display detectable bone marrow cytogenetic abnormalities at diagnosis with some(Demory et al. Blood1988;72:855, Dupriez et al. Blood1996;88:1013, Reilly et al. BJH1997;98:96) but not other studies (Cervantes et al. BJH1998;102:684, Okamura et al. Int J Hematol2001;73:194) suggesting a detrimental effect on survival. Methods : The current prospective study was conducted as a follow-up of the observations from an antecedent retrospective study that identified sole abnormalities of either 13q- or 20q- as ‘favorable’ to survival (Tefferi et al. BJH2001;113:763). All clinical and laboratory measurements, including bone marrow examination and karyotype analysis, were performed concurrently in consecutive cases of histologically confirmed MMM regardless of either duration of disease or presence of active therapy. Survival, leukemic transformation rate, and clinical progression were determined from the time of cytogenetic analysis. Results : Karyotypic analysis was successfully performed in a total of 88 patients (median age 61 years; 31 females) and the results were normal in 49 (56%) and abnormal in the remaining 39 patients with 9 (10%) displaying ‘favorable’, and 30 (34%) ‘other’ clonal abnormalities. At the time of study entry, 57 patients were not recieving any form of therapy, 18 were newly diagnosed, and the Dupriez prognostic score distributions were ‘0’ in 33 patients, ‘1’ in 35 and ‘2’ in 20 (Dupriez et al. Blood1996;88:1013). All patients were followed for a minimum of 3 years and a median of 42 months. The 3 cytogenetic categories were similar in age and gender distribution. Survival in the favorable cytogenetic group was similar to that of the normal group and significantly better than the group with other cytogenetic abnormalities (p=0.02). Figure Figure Similarly, no patient (0%) in the ‘favorable’ group transformed into acute leukemia while 6 of 30 (20%) in the ‘other’ and 5 of 49 (10%) in the normal groups did (p=0.21). In a Cox regression analysis, cytogenetic lesions other than the ‘favorable’ kind, hemoglobin below 10 g/dL, leukocytosis, hypercatabolic symptoms, increased blood blast %, blood CD 34 count above 100 x 106/L were individually associated with shortened survival. In a multivariate analysis, only hemoglobin level and leukocyte count retained their significance. Conclusion : Single chromosomal abnormalities of either 13q- or 20q- should be considered as ‘favorable’ cytogenetic lesions in MMM while other abnormalities are associated with an adverse prognosis. The current observation explains the discrepancy in the literature regarding the prognostic relevance of cytogenetic findings in MMM and warrants additional studies to determine the value of incorporating the specific information in prognostic scoring systems.