INCB018424, an Oral, Selective JAK2 Inhibitor, Shows Significant Clinical Activity in a Phase I/II Study in Patients with Primary Myelofibrosis (PMF) and Post Polycythemia Vera/Essential Thrombocythemia Myelofibrosis (Post-PV/ET MF).

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 558-558 ◽  
Author(s):  
Srdan Verstovsek ◽  
Hagop Kantarjian ◽  
Animesh Pardanani ◽  
Deborah Thomas ◽  
Jorge Cortes ◽  
...  

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.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3851-3851 ◽  
Author(s):  
Srdan Verstovsek ◽  
Zeev Estrov ◽  
Jorge E. Cortes ◽  
Deborah A. Thomas ◽  
Gautam Borthakur ◽  
...  

Abstract Abstract 3851 Background: Myelofibrosis (MF) is a myeloproliferative neoplasm associated with splenomegaly, debilitating symptoms, cytopenias and progressive bone marrow fibrosis. Survival in MF is poor, and effective therapy is lacking. Ruxolitinib (INCB18424) is a JAK1 and JAK2 inhibitor with established clinical benefit in patients (pts) with MF (Verstovsek S. J Clin Oncol 29: [suppl; abstr 6500], 2011) by reducing spleen size and improving MF symptoms & quality of life. Objective: Aim was to identify potential correlates of overall survival (OS) of MF pts receiving ruxolitinib. This study was based on a subset analysis of an open-label single-arm phase I/II trial (INCB18424–251; NCT00509899). Methods: 158 adult pts with primary or secondary MF were enrolled in the parent trial; most received ruxolitinib at doses of 10–25 mg PO twice daily. This updated analysis focuses on 107 pts enrolled at MDACC: 63 were high, 34 intermediate (int)-2 and 10 int-1 risk, according to the International Prognosis Scoring System (IPSS), and assesses their survival and correlates thereof. For log-rank survival analysis, events were censored at the later of last dose, last visit, or last follow-up date. Results: Efficacy and safety findings of the parent trial have been published (Verstovsek S. N Engl J Med 363:1117, 2010): ruxolitinib treatment led to a rapid and sustained reduction in splenomegaly and improvements in MF symptoms; anemia and thrombocytopenia were the most common adverse events. After a median follow-up of 32 months, 58 of 107 pts (54%) were still receiving therapy. The corresponding overall survival (OS) was 69% (33 pts died, none due to therapy-related reasons: 14 while on therapy/within 30 days (d) of discontinuation (dc), and 19 off-study). Accounting for deaths occurring on the study, the 2-yr actuarial survival of int-2 and high-risk pts was 92% and 88%, respectively. However, the 2-yr survival of 13 int-2 and 21 high-risk pts who had discontinued therapy and were subsequently followed was 32% and 21%, respectively. MF transformed to acute leukemia in 9 pts: 5 while on therapy/within 30 d of dc, and 4 off-study; the transformation rate was 0.036/pt years. Pts with normal baseline cytogenetics did not have better survival than those with aberrations (Hazard ratio [HR]=1.52; p=0.24). However, pts with a baseline bone marrow fibrosis score of 2 had greater survival than those with a score of 3 (HR=2.21; p=0.031). Other evaluable baseline pt characteristics (gender, age, anemia, WBC and splenomegaly, did not affect survival. Surprisingly, high-risk pts (per either IPSS or dynamic IPSS [DIPSS]) did not have significantly worse survival than int-2 pts. Importantly, reduction in palpable spleen length while on ruxolitinib was noted to be the most robust predictor for survival: pts who had a ≥50% reduction in spleen size (n=62) had significantly prolonged survival vs. those with a <25% reduction (n=20) (Fig. 1; HR=4.94; p<0.0001). Conclusions: Most MDACC pts with advanced MF in the phase I/II ruxolitinib study are still receiving therapy, demonstrating an OS of 69% after a median of 32 months. The 2-yr survival of pts who remained on therapy was 3–4-fold greater than those who discontinued therapy. Among baseline pt characteristics, only a lower bone marrow fibrosis score correlated with better survival. Conversely, achievement of ≥50% reduction in spleen size while on ruxolitinib resulted in greater survival (vs. <25% reduction). Our data suggest that the most important factors that influence survival of MF pts receiving ruxolitinib are continuous active therapy and a degree of the spleen response, not pt pretherapy characteristics. Disclosures: Verstovsek: Incyte Corporation: Research Funding.


2010 ◽  
Vol 28 (11) ◽  
pp. 1856-1862 ◽  
Author(s):  
Farhad Ravandi ◽  
Jorge E. Cortes ◽  
Daniel Jones ◽  
Stefan Faderl ◽  
Guillermo Garcia-Manero ◽  
...  

Purpose To determine the efficacy and toxicity of the combination of sorafenib, cytarabine, and idarubicin in patients with acute myeloid leukemia (AML) younger than age 65 years. Patients and Methods In the phase I part of the study, 10 patients with relapsed AML were treated with escalating doses of sorafenib with chemotherapy to establish the feasibility of the combination. We then treated 51 patients (median age, 53 years; range, 18 to 65 years) who had previously untreated AML with cytarabine at 1.5 g/m2 by continuous intravenous (IV) infusion daily for 4 days (3 days if > 60 years of age), idarubicin at 12 mg/m2 IV daily for 3 days, and sorafenib at 400 mg orally twice daily for 7 days. Results Overall, 38 (75%) patients have achieved a complete remission (CR), including 14 (93%) of 15 patients with mutated FMS-like tyrosine kinase-3 (FLT3; the 15th patient had complete remission with incomplete platelet recovery [CRp]) and 24 (66%) of 36 patients with FLT3 wild-type (WT) disease (three additional FLT3-WT patients had CRp). FLT3-mutated patients were more likely to achieve a CR than FLT3-WT patients (P = .033). With a median follow-up of 54 weeks (range, 8 to 87 weeks), the probability of survival at 1 year is 74%. Among the FLT3-mutated patients, 10 have relapsed and five remain in CR with a median follow-up of 62 weeks (range, 10 to 76 weeks). Plasma inhibitory assay demonstrated an on-target effect on FLT3 kinase activity. Conclusion Sorafenib can be safely combined with chemotherapy, produces a high CR rate in FLT3-mutated patients, and inhibits FLT3 signaling.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5247-5247
Author(s):  
Ri ta Barone ◽  
Clementina Caracciolo ◽  
Rosario di Maggio ◽  
Giovanni Fazio ◽  
Luciana d’Angelo ◽  
...  

Abstract The association between Polycythemia Vera (PV) and thrombosis is multi-factorial involving the complex interaction between activated leukocytes, platelets and endothelium. Recent reports have postulated that PV patients may over express adhesive molecules on red cell surface, likely by JAK2 mutation (Wautier M et al. Blood.2007;110(3):894–901). This process activates endothelium with production of vascular growth factors and other mechanisms leading to atherosclerosis. Aortic Stenosis (AS) is the commonest valvular heart disease in western countries; its pathogenesis is mainly related to a degenerative process sharing many characteristics with atherosclerosis. At the present is not known whether patients with PV are at high risk of developing AS. Objective of the study. We perform a case-control study for evaluating rate of AS and its correlation with blood cells count and mutational status in patients with PV. Materials and methods. Prevalence of AS among PV patients have been compared with control patients matched for age, cardiovascular risk factors (hypertension, hyperlipidemia, diabetes, smoke and alcohol abuse) and coexisting cardiac diseases (i.e. heart failure). Diagnosis of PV has been posted accordingly to PVSG criteria. Diagnosis and severity of AS has been posted by echocardiography: stenosis with a valve area <1.0 cm2 has been considered severe. Results. Over a period of 18 months we recruited 43 PV patients (28 males and 15 females) and 74 controls. No differences were found in regard of the above cited characteristics; median age was 66.7 among PV patients and 68.2 among controls. The average duration of PV was 5.7 years with an average follow-up of 2.5 years. Most of the PV patients were on antiplatelet/anticoagulant therapy (27/43, 62.7%) and have been treated with cytoreductive therapy. Twelve (27.9%) had a thrombotic event before PV diagnosis; 4 (9.3%) developed thrombosis during the follow-up (median 1.3 years). A moderate/severe AS was found in 11 PV patients (25.6%) in comparison to 4 (5.4%) in control group (P= 0.023), thus giving a Relative Risk of 4.7. Among PV patients, the multivariate analysis did not show any correlation regarding JAK2 V617F mutational status, duration of disease, previous thrombosis, cytoreductive therapy and other common cardiovascular factors. Comparison of laboratory findings is reported in Table 1; a not significant trend was demonstrated in favor of patients with elevated hematocrit (>55%). Conclusions. Our study clearly shows that PV patients carry a fourfold risk of developing AS, without a clear association with blood cell alterations or previous thrombosis. Whether high prevalence of AS may be related to expression of adhesive molecules on red cells or altered share stress is currently under investigation. Table 1. Comparison of laboratory findings between PV patients with and without AS Laboratory parameter* PV patients with AS (11) PV patients without AS (32) Relative Risk P value *At diagnosis Legend: PV (Polycythemia Vera), AS (Aortic Stenosis) White blood cell×109/L (mean± SD) 9520 ± 1230 12.900 ± 2120 0.73 .078 Hemoglobin, g/dL (mean ± SD) 17.5 ± 1.3 17.1 ± 1.2 1.02 .088 Hematocrit, % (mean ± SD) 56.2 ± 0.6 51.1 ± 0.8 1.1 0.06 Platelets × 109/L(mean ± SD) 415.9 ± 43 353 ± 55 1.1 0.76 JAK2 V617F, n/N (%) 11/11 (100%) 31/32 (97%) - -


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4107-4107 ◽  
Author(s):  
Yohei Nakaya ◽  
Haruna Naito ◽  
Junko Homan ◽  
Seishi Sugahara ◽  
Tatsuya Horio ◽  
...  

Abstract Abstract 4107 A somatic point mutation of Janus Kinase 2 (JAK2) tyrosine kinase (JAK2 V617F) has been shown to occur at a high frequency in myeloproliferative neoplasm (MPN) patients. JAK2 V617F is a constitutively activated kinase that activates the JAK/STAT signaling pathway and dysregulates cell growth and function. These findings suggest that the inhibition of aberrant JAK2 activation has a therapeutic benefit. Our novel JAK2 inhibitor, NS-018, is highly active against JAK2 with an IC50 value of less than 1 nM, and it has 30–50-fold selectivities for JAK2 over other JAK-family kinases such as JAK1, JAK3 and Tyk2. We determined the X-ray structure of JAK2 in complex with NS-018. An Asp-Phe-Gly (DFG) motif is located at the N-terminus of the activation loop and regulates ATP binding. The resolved X-ray structure showed that NS-018 bound to JAK2 in the “DFG-in” active conformation. A molecular modeling study indicated that NS-018 would hardly bind to JAK2 in the “DFG-out” inactive conformation. In accordance with the structural analysis, NS-018 preferentially suppressed the growth of bone-marrow cells expressing activated JAK2. Thus, NS-018 reduced in a dose-dependent manner the number of erythroid colony-forming units (CFU-E) derived from bone-marrow cells taken from JAK2 V617F transgenic mice, but had only a limited effect on the number of colonies from wild-type mice (Figure A). NS-018 had no effect on the number of granulocyte-macrophage colony-forming units (CFU-GM) from either mouse strain. Furthermore, NS-018 showed potent antiproliferative activity against Ba/F3 cells expressing JAK2 V617F with an IC50 value of <100 nM but showed only minimal cytotoxicity against most other hematopoietic and non-hematopoietic cell lines (IC50 >3 μ M). In a mouse Ba/F3-JAK2 V617F leukemia model, NS-018 significantly prolonged survival during repeated oral administrations at 6.25 mg/kg bid and reduced splenomegaly at doses as low as 1.5 mg/kg bid. NS-018 was well tolerated at dosages of more than 100 mg/kg bid. In conclusion, NS-018 is a potent JAK2 inhibitor which preferentially inhibits an activated form of JAK2 and has potent in vitro and in vivo efficiency in preclinical studies. NS-018 is expected to be suitable for the treatment of MPN caused by aberrant JAK2 activation and its effectiveness will be verified by early-phase clinical investigations in the near future. JAK2 V617F preferential inhibition of erythrocyte colony growth Bone-marrow cells were collected from femurs of JAK2 V617F transgenic mice and same-strain BDF1 wild-type mice. (a) To detect CFU-E colonies, cells were treated with NS-018 in semisolid methylcellulose containing erythropoietin (EPO) and cell clusters were counted after incubation for two days. (b) To detect CFU-GM colonies, cells were treated with NS-018 in semisolid methylcellulose containing EPO, interleukin-3 (IL-3), IL-6 and stem cell factor and colonies were counted on day 7. Disclosures: Nakaya: Nippon Shinyaku Co., Ltd: Employment. Naito:Nippon Shinyaku Co., Ltd: Employment. Homan:Nippon Shinyaku Co., Ltd: Employment. Sugahara:Nippon Shinyaku Co., Ltd: Employment. Horio:Nippon Shinyaku Co., Ltd: Employment. Niwa:Nippon Shinyaku Co., Ltd: Employment. Shimoda:Nippon Shinyaku Co., Ltd: Research Funding.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3838-3838 ◽  
Author(s):  
Animesh Pardanani ◽  
Jason Gotlib ◽  
Catriona Jamieson ◽  
Jorge E. Cortes ◽  
Moshe Talpaz ◽  
...  

Abstract Abstract 3838 Background: SAR302503 (SAR503, formerly TG101348), a potent, oral JAK2-selective inhibitor was studied in a Phase I/II trial for the treatment of patients with high- or intermediate-risk primary, post-polycythemia vera (PV) and post-essential thrombocythemia (ET) myelofibrosis (MF). SAR503 was administered orally once daily in 28-day cycles. Eligibility criteria included platelet count of ≥50 × 109/L. Interim safety and efficacy data from this study up to April 2010 have been previously published (JCO 2011, 29(7):789–796). The aim of this presentation is to report updated safety and efficacy of ongoing patients as well as an analysis of the JAK2V617F allele burden in this cohort. Results: Overall, 59 subjects (median age 64 years) were treated. Forty four patients had PMF, 12 post-PV MF and 3 post-ET MF; 86% were JAK2 V617F-positive. Median palpable spleen size was 18 cm at study enrollment. Twenty eight patients were treated in the dose-escalation cohort (30–800 mg administered as a single daily dose); thirty one patients were treated at the MTD (680 mg) in the dose confirmation cohort. 43/59 patients (73%) completed 6 cycles of treatment and continued treatment on the extension study. Currently, 22 patients (37%) remain on treatment with a median number of 28.5 cycles (24–41 range) and a median of last dose of 440 mg/day. Safety: Treatment-emergent toxicities in cycle 1–6 have been previously reported; toxicities were dose-dependent and generally alleviated with dose-reduction. Five patients discontinued treatment beyond cycle 6 for treatment-related adverse events: thrombocytopenia, depression, mental status changes, creatinine elevation and subdural hematoma. For the subgroup of patients with a baseline platelet count between 50–100 × 109/L (n =13; median 73, range 51–94); the platelet count at defined times points during follow up was: cycle 3; median 50, range 21–138 (p=0.09) and cycle 6; median 47, range 13–85 (p=0.01). Despite 7 of the 13 patients being treated at ≥680 mg/day, only 2 instances of Grade 4 thrombocytopenia were noted in this group Spleen response: As previously reported, spleen responses were seen early, usually within first 3 cycles, with half or more patients in each dose level ≥240 mg/day showing a durable ≥50% decrease in palpable spleen size. Spleen size (mean, median, range, and proportion with ≥50% reduction) at the following time points was: Baseline (n=58; 18.33cm, 18cm, 4–38cm, NA) ; 6 months (n=57; 9.05cm, 9cm, 0–30cm, 54.4%;) 12 months (n=42; 8.55cm, 9cm, 0–28cm, 66.7%) 18 months (n=36; 8.03cm, 8.5cm, 0–33cm, 52.8%); 24 months (n=31; 8.10cm, 8cm, 0–30cm, 54.8%,) 30 months (n=18; 6cm, 7.5cm, 0–16cm, 61.1%,and) 36 months (n=9; 5.89cm, 3cm, 0–16cm, 66.7%). JAK2V617F allele burden: We previously reported a significant decrease in JAK2V617F allele burden at the end of cycles 6 and 12. A durable decrease was also demonstrable after 24 cycles of treatment (n =21; median 9%, range 0–100%) relative to baseline (n =51; median 20%, range 3–100%) (p=0.03). Similarly, for patients with JAK2 V617F allele burden >20% at baseline; there was a significant decrease after cycle 24 (n =12; median 21%, range 6–100%) relative to baseline (n =23; median 60%, range 23–100%) (p=0.03). Conclusions: SAR503 is safe and efficacious treatment with long term effect on spleen size and JAK2V617F allele burden in patients with high- and intermediate-risk myelofibrosis. Additional follow up information will be updated at the time of meeting. Disclosures: Jamieson: Wintherix: Equity Ownership; Pfizer Oncology: Research Funding; Celgene: Research Funding; Novartis: Honoraria. Gao:Sanofi-Aventis: Employment. Zhang:Sanofi-Aventis: Employment. Neumann:Sanofi-Aventis: Employment.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 793-793 ◽  
Author(s):  
Srdan Verstovsek ◽  
Hagop M. Kantarjian ◽  
Zeev Estrov ◽  
Jorge E. Cortes ◽  
Deborah A. Thomas ◽  
...  

Abstract Abstract 793FN2 Background: Myelofibrosis (MF) is a myeloproliferative neoplasm associated with splenomegaly, debilitating symptoms, cytopenias and progressive bone marrow fibrosis that leads to early death. Patients (pts) with high-risk MF according to International Prognosis Scoring System (IPSS) have particularly poor outcome with a median survival of 2 years (yrs). No approved or effective therapy exists. Ruxolitinib is a JAK1 and JAK2 inhibitor with established clinical benefit in the treatment of pts with MF by reducing spleen size and improving quality of life. Objective: The objective of this analysis was to compare assorted outcomes of MF pts receiving ruxolitinib to those of a matched historical control group. Methods: Overall survival (OS) of 107 pts enrolled in a Phase I/II trial (INCB18424-251; NCT00509899) and followed at the MD Anderson Cancer Center (MDACC) was compared to that of 310 pts with MF identified in 3 large databases (MDACC, U. of Pavia and Hospital Niguarda cà Granda, Milano) with characteristics that would have allowed them to enroll in INCB18424-251. Thus, the pt features between the 2 groups were matched based on enrollment criteria. Among 107 ruxolitinib treated pts, 63 had high risk, 34 intermediate (int)-2 and 10 int-1 risk according to IPSS. In the control group (n=310), 165 pts had high and 145 pts int-2 risk; most pts were treated with conventional or investigational therapies during follow-up. Results: Ruxolitinib-treated pts had a median age of 66 yrs, hemoglobin (Hb) of 10.2 g/dL, WBC of 19×10^9/L, platelets of 277×10^9/L, and palpable spleen of 19 cm. Control pts had a median age of 70 yrs, Hb of 9.7 g/dL, WBC of 12×10^9/L, platelets of 265×10^9/L, and palpable spleen of 6 cm. Baseline characteristics that differed between 2 groups included: significantly more int-2 vs high-risk pts (according to both IPSS and dynamic IPSS [DIPSS]), older age and lower Hb in the controls, as contrasted to higher WBC and larger spleen in those on ruxolitinib. There were no differences between the groups with regard to male:female ratio, platelet count, and cytogenetic characteristics. With regard to OS comparison between the 2 groups, a significant difference was seen in favor of ruxolitinib (p=0.022). Indeed, 33 of 107 pts (30.8%) in the ruxolitinib group vs. 189 of 310 (60.9%) in the control group died, after a median follow-up of 32 and 22 months, respectively. The difference in OS was highly significant in the high-risk pt subgroup (p=0.006), in that 21/63 (33.3%) vs. 112/165 (67.9%) died in the ruxolitinib and control groups, respectively. In the univariate analysis, significant factors associated with longer OS were int-2 (vs. high) risk (per IPSS/ DIPSS), platelets >400×10^9/L, and age <65 years, but not gender, abnormal cytogenetics, high WBC (>25×10^9/L), anemia (Hb <10g/dL), or spleen size. In the multivariate analysis, using age and blood cell counts as continuous variables, independent significant factors for better survival were IPSS int-2 risk, younger age, higher platelets, and treatment with ruxolitinib (p=0.02; HR=0.63). Conclusions: We have identified a historical control group of pts with clinical characteristics that would have allowed them to participate in the Phase I/II study of ruxolitinib in MF. We compared their survival to 107 pts who participated in that trial, and were followed at the MDACC. The survival of pts with high-risk MF that were treated with ruxolitinib was found to be significantly longer than that of the matched control group. Further, ruxolitinib therapy was identified as an independent factor influencing better survival in the multivariate analysis. Our data suggest the potential of ruxolitinib to change the natural progression of MF pts with advanced disease. Disclosures: Verstovsek: Incyte Corporation: Research Funding.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1745-1745
Author(s):  
Alessandra Carobbio ◽  
Guido Finazzi ◽  
Elisabetta Antonioli ◽  
Paola Guglielmelli ◽  
Alessandro M. Vannucchi ◽  
...  

Abstract Patients with Essential Thrombocythemia (ET) can be categorized as either JAK2 V617F mutated (V617F+) or wild type (V617F−). Mutated patients display multiple features resembling Polycythemia Vera (PV), with significantly higher hemoglobin level and neutrophil counts, lower platelet count, more pronounced bone marrow erythropoiesis and granulopoiesis and higher tendency to transform in PV. Presence of the mutation and/or allele burden has been variably associated with the rate of vascular complications in ET and PV, but a direct comparison between the two disorders under this respect has not been performed. To tackle this issue, we compared the rate of major thrombosis in 867 ET patients (57% were JAK2 V617F+) with that in 415 PV patients (all V617F+). The median follow-up was 4.9 (0 – 39) and 3.8 (0 – 26) years in ET and PV, respectively. High risk ET patients (age ≥ 60 years and/or previous thrombosis) received Hydroxyurea whereas the vast majority of low-risk remained untreated. PV patients were treated according to the current risk-stratified recommendations. Thrombotic episodes were recorded over time and calculated as rates % per patient/year (pt/yr). After adjusting for age, the thrombosis-free survival curves of JAK2 V617F+ and V617F− ET patients were superimposable until 10 years after the diagnosis, then they diverged so that the actuarial probability of major thrombosis in mutated ET patients reached that of PV (48% vs 55%, test for trend p=0.05). We found that JAK2 V617F+ allele burden measured by real-time quantitative PCR influenced these rates in a comparable way in both ET and PV. Actually, in JAK2 wild type ET (n=376, 43%) the rate was 1.4% pt/yr. In ET patients with JAK2 V617F+ allele burden ranging from 1 to 25% (N=190; 49%) the rate was 1.9 % pt/yr compared to 1.2 in PV patients (N=64, 19%); in the group with 26–50% the rate was 2.0 % pt/yr in ET (N=177; 45%) and 3.0 in PV patients (N=118, 36%); in cases of V617F+ allele burden greater than 50% the rate was 3.8 % pt/yr in ET (N=23; 6%) and 2.9 in PV patients (N=147, 45%). In conclusion, from this retrospective analysis, we conclude that in patients with ET harboring JAK2 V617F mutation the rate of stroke, myocardial infarction and venous thromboembolic complications is similar to that of PV patients and increases in dependence of V617F allele burden, supporting the hypothesis that ET and PV may be viewed as a continuum also in terms of vascular complications


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 97-97 ◽  
Author(s):  
Animesh D. Pardanani ◽  
Jason Gotlib ◽  
Catriona Jamieson ◽  
Jorge Cortes ◽  
Moshe Talpaz ◽  
...  

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.


PLoS ONE ◽  
2016 ◽  
Vol 11 (2) ◽  
pp. e0147426 ◽  
Author(s):  
Gloria Solano-Aguilar ◽  
Aleksey Molokin ◽  
Christine Botelho ◽  
Anne-Maria Fiorino ◽  
Bryan Vinyard ◽  
...  

Blood ◽  
2007 ◽  
Vol 109 (12) ◽  
pp. 5477-5480 ◽  
Author(s):  
Kazuyuki Matsuda ◽  
Akira Shimada ◽  
Nao Yoshida ◽  
Atsushi Ogawa ◽  
Akihiro Watanabe ◽  
...  

Abstract Of 11 children with juvenile myelomonocytic leukemia (JMML) carrying RAS mutations (8 with NRAS mutations, 3 with KRAS2 mutations), 5 had a profound elevation in either or both the white blood cells and spleen size at diagnosis. Three patients had no or modest hepatosplenomegaly and mild leukocytosis at presentation but subsequently showed a marked increase in spleen size with or without hematologic exacerbation, for which nonintensive chemotherapy was initiated. The other three patients with NRAS or KRAS2 glycine to serine substitution received no chemotherapy, but hematologic improvement has been observed during a 2- to 4-year follow up. In the third group, all hematopoietic cell lineages analyzed had the RAS mutations at the time of hematologic improvement, whereas DNA obtained from the nails had the wild type. Additionally, numbers of circulating granulocyte-macrophage progenitors were significantly reduced during the clinical course. Thus, some patients with JMML with specific RAS mutations may have spontaneously improving disease.


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