Similar Rate of Thrombosis in Essential Thrombocythemia and Polycythemia Vera Patients after Stratification for JAK2 V617F Allele Burden.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1745-1745
Author(s):  
Alessandra Carobbio ◽  
Guido Finazzi ◽  
Elisabetta Antonioli ◽  
Paola Guglielmelli ◽  
Alessandro M. Vannucchi ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Vascular Complications ◽  
Jak2 V617f ◽  
Similar Rate ◽  
Wild Type ◽  
Allele Burden ◽  
Real Time Quantitative Pcr ◽  
Venous Thromboembolic

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

Sequential Analysis By Next Generation Sequencing of 18 Genes in Polycythemia Vera and Essential Thrombocythemia Reveals a Association Between Mutational Status and Clinical Outcome after 3-Year Follow-up

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2808-2808
Author(s):  
Damien Luque Paz ◽  
Aurelie Chauveau ◽  
Caroline Buors ◽  
Jean-Christophe Ianotto ◽  
Francoise Boyer ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Jak2 V617f ◽  
Primary Myelofibrosis ◽  
Jak2 V617f Mutation ◽  
Poor Prognostic Factor ◽  
Disease Evolution ◽  
Allele Burden ◽  
V617f Mutation

Abstract Introduction Myeloproliferative neoplasms (MPN) are molecularly characterized by driver mutations of JAK2, MPL or CALR. Other somatic mutations may occur in epigenetic modifiers or oncogenes. Some of them have been shown to confer a poor prognosis in primary myelofibrosis, but their impact is less known in Polycythemia Vera (PV) and Essential Thrombocythemia (ET). In this study, we investigated the mutational profile using NGS technology in 50 JAK2 V617F positive cases of MPN (27 PV and 23 ET) collected at the time of diagnosis and after a 3 year follow-up (3y). Patients and Methods All patients were JAK2 V617F positive and already included in the prospective cohort JAKSUIVI. All exons of JAK2, MPL, LNK, CBL, NRAS, NF1, TET2, ASXL1, IDH1 and 2, DNMT3A, SUZ12, EZH2, SF3B1, SRSF2, TP53, IKZF1 and SETBP1 were covered by an AmpliseqTM custom design and sequenced on a PGM instrument (Life Technologies). CALR exon 9 mutations were screened using fragment analysis. Hotspots that mutated recurrently in MPN with no sequencing NGS coverage were screened by Sanger sequencing and HRM. A somatic validation was performed for some mutations using DNA derived from the nails. The increase of a mutation between diagnosis and follow-up has been defined as a relative increase of twenty percent of the allele burden. An aggravation of the disease at 3y was defined by the presence of at least one of the following criteria: leukocytosis >12G/L or immature granulocytes >2% or erythroblasts >1%; anemia or thrombocytopenia not related to treatment toxicity; development or progressive splenomegaly; thrombocytosis on cytoreductive therapy; inadequate control of the patient's condition using the treatment (defined by at least one treatment change for reasons other than an adverse event). Results As expected, the JAK2 V617F mutation was found in all patients with the use of NGS. In addition, we found 27 other mutations in 10 genes out of the 18 genes studied by NGS (mean 0.54 mutations per patient). Overall, 29 of 50 patients had only the JAK2 V617F mutation and no other mutation in any of the genes analysed. No CALR mutation was detected. Nine mutations that were not previously described in myeloid malignancies were found. The genes involved in the epigenetic regulation were those most frequently mutated: TET2, ASXL1, IDH1, IDH2 and DNMT3A. In particular, TET2 mutations were the most frequent and occurred in 20% of cases. There was no difference in the number or in the presence of mutations between PV and ET. At 3y, 4 mutations appeared in 4 patients and 15 out of 50 patients (9 PV and 6 ET) were affected by an allele burden increase of at least one mutation. At 3y, 24/50 patients suffered an aggravation of the disease as defined by the primary outcome criterion (16 PV and 8 ET). The presence of a mutation (JAK2 V617Fomitted) at the time of the diagnosis was significantly associated with the aggravation of the disease (p=0.025). Retaining only mutations with an allele burden greater than 20%, the association with disease aggravation is more significant (p=0.011). Moreover, a mutation of ASXL1, IDH1/2 or SRSF2, which is a poor prognostic factor in primary myelofibrosis, was found in 8 patients, all having presented an aggravation of their disease (p=0.001). Only 4 patients had more than one somatic mutation other than JAK2 V617F and all of them also had an aggravation at 3y (p=0.046). In this cohort, appearance of a mutation at 3y was not associated with the course of the disease. Conversely, the increase of allele burden of at least one mutation was associated with an aggravation (p=0.019). Discussion and conclusion Despite the short follow-up and the limited number of patients, this study suggests that the presence of additional mutations at the time of the diagnosis in PV and TE is correlated to a poorer disease evolution. The increase of mutation allele burden, which reflects clonal evolution, also seems to be associated with the course of the disease. These results argue for a clinical interest in large mutation screening by NGS at the time of the diagnosis and during follow-up in ET and PV. Disclosures Ugo: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: ASH travel.

JAK2 (V617F)-Positive Essential Thrombocythemia and Polycythemia Vera Are Different Expressions Of a Genotypic/Phenotypic Continuum

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1592-1592
Author(s):  
Elisa Rumi ◽  
Daniela Pietra ◽  
Chiara Elena ◽  
Ilaria Casetti ◽  
Emanuela Sant 'Antonio ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Median Time ◽  
Essential Thrombocythemia ◽  
Cumulative Incidence ◽  
Mutant Allele ◽  
Clinical Phenotype ◽  
Jak2 V617f ◽  
Wild Type ◽  
Allele Burden ◽  
Wbc Count

Abstract Background About 95% of patients with polycythemia vera (PV) and 60-70% of those with essential thrombocythemia (ET) carry the unique JAK2 (V617F) mutation. Previous observations suggest that JAK2 (V617F)-positive ET and PV form a biological continuum, in which the degree of erythrocytosis is determined by physiological and genetic factors. Aims In this work, we studied the natural history of JAK2 (V617F)-positive ET and PV with the aim of establishing whether the two disorders indeed represent different phenotypic expression of a genotypic/phenotypic continuum. Methods We identified 1269 patients diagnosed with ET or PV at our Division between 1980 and 2012, for whom at least one DNA sample was available. The JAK2 (V617F) mutation was assessed using allele-specific quantitative PCR. As patients carrying JAK2 exon 12 or MPL mutations were excluded, the final study population included 1214 patients, 719 of whom with ET (463 JAK2 mutated, 256 JAK2 wild-type) and 495 with PV. Results I: presenting features The clinical phenotype of ET patients at diagnosis differed according to JAK2 mutational status. JAK2 mutated ET presented with older age at diagnosis, higher hemoglobin (Hb) level and white blood cell (WBC) count, lower platelet (PLT) count and erythropoietin level compared to JAK2 wild-type ET (Wilcoxon rank-sum test: P<.001 in all comparisons). The median V617F allele burden was significantly lower in JAK2 mutated ET than in PV (18.4% vs 43.4%, P<.001). A mutant allele burden greater than 50% was observed in 2% of patients with JAK2 mutated ET and 41.5% of those with PV (Fisher exact test: P<.001). In both JAK2 mutated ET and PV, the mutant allele burden was directly related to WBC count and Hb level. Results II: PV evolution Evolution to PV was observed in 53 JAK2 mutated ET patients (incidence 95% CI: 1.4-2.4 per 100 p-years) vs none of the 256 JAK2 wild-type ET (incidence 95% CI: 0-0.2 per 100 p-years), resulting in a significantly different occurrence. The median time to PV evolution was 54 months (range 3.5-220). The cumulative incidence of PV evolution in JAK2 mutated ET patients at 15 years was 28.8% (95% CI: 20.7-37.3; Figure 1). PV evolution was significantly associated with higher JAK2 allele burden at diagnosis (Cox regression HR=1.04, P<.001). Based on the hypothesis that PV patients might have had a silent “pre-PV phase”, we did an ad hoc search for any complete blood count (CBC) collected before diagnosis. Among PV patients, 177 (36%) had a previous CBC, collected at a median time of 22 months (range 1-305) before PV diagnosis. A normal CBC was observed in 15% of patients; the remaining subjects showed thrombocytosis (≥450 x 109/L) and/or leukocytosis (≥10 x 109/L) and/or erythrocytosis. The median time to PV onset was significantly shorter in patients showing at least one CBC abnormality than in those with normal CBC (24 vs 48 months, P=.011). Results III: clinical course The median follow-up was 5.1 years (range, 0-32 years). JAK2-mutated ET and PV did not differ in terms of cumulative incidence of thrombosis (25.3% vs 33.7% at 15 years, P=.35; Figure 2A) and had similar overall survival (OS) (90.3% vs 82.6% at 15 years, P=.29; Figure 2B). Conversely, JAK2 wild-type ET showed a better OS in comparison with both JAK2 mutated ET (P=.028) and PV (P=.004) and a lower incidence of thrombosis (12.7% at 15 years) than JAK2 mutated ET (P=.002) and PV (P<.001). A similar cumulative incidence of disease progression (leukemia and myelofibrosis) was observed in JAK2 mutated (11.7% at 15 years) and JAK2 wild-type ET (12.1% at 15 years), whereas a higher cumulative incidence was observed in PV (26% at 15 years; P=.011 and P=.007 when compared with JAK2 mutated ET and JAK2 wild-type ET respectively). Conclusions This study supports the hypothesis that JAK2 mutated ET and PV are different expressions of a genotypic/phenotypic continuum, in which the mutant allele burden contributes to determine the clinical phenotype. The risk of progression from JAK2 mutated ET to PV is about 2% per year. This work was supported by grant #1005 from Associazione Italiana per la Ricerca sul Cancro (AIRC) “Special Program Molecular Clinical Oncology 5x1000” to AGIMM (AIRC-Gruppo Italiano Malattie Mieloproliferative - http:www-progettoagimm.it). Disclosures: No relevant conflicts of interest to declare.

JAK2V617F Complete Molecular Remission in Long-Term Follow-up of Patients with Polycythemia Vera and Essential Thrombocythemia Treated with Ruxolitinib

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3185-3185
Author(s):  
Lisa Pieri ◽  
Alessandro Pancrazzi ◽  
Annalisa Pacilli ◽  
Claudia Rabuzzi ◽  
Giada Rotunno ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Research Funding ◽  
Jak2v617f Mutation ◽  
Prolonged Treatment ◽  
Molecular Response ◽  
Molecular Remission ◽  
Allele Burden ◽  
Jak2v617f Allele Burden

Abstract Polycythemia vera (PV) and essential thrombocythemia (ET) are myeloproliferative neoplasms (MPN) characterized by the presence of JAK2V617F mutation in >95% and 60% of patients (pts), respectively. This mutation usually affects one allele in ET while most PV pts are homozygous due to mitotic recombination. Acquisition of the JAK2V617F mutation is strongly associated with the germline 46/1 predisposition haplotype. Ruxolitinib is a JAK1/JAK2 inhibitor recently approved for myelofibrosis (MF) and under investigation in PV and ET pts intolerant or resistant to hydroxyurea. We enrolled 24 pts, 11 with PV and 13 with ET, in the phase II INCB18424-256 trial that overall included 34 PV and 39 ET pts. 21/24 pts were still on treatment at 5 years (yr), of which 19 JAK2V617F mutated. Results of the PV cohort have been reported recently (Verstovsek et al. Cancer, 2014): with a median follow up of 35 months (mo), the JAK2V617F allele burden decreased by a mean of 8%, 14%, and 22%, respectively, after 12, 24 and 36 mo. The proportion of pts who achieved a reduction ≥50 % at any time during the 1st yr, 2nd yr, and 3rd yr were 5.9%, 14.7%, and 23.5%, respectively, but no patients achieved a complete remission. In our series of pts we evaluated the JAK2V617F allele burden by two RTQ-PCR methods, according to Lippert (sensitivity, 0.8%) and to Larsen (sensitivity, 0.08%) method. We also analysed by next generation sequencing (NGS; Ion Torrent platform) a series of MPN-associated mutations including TET2, ASXL1, IDH1/2, LNK, CBL, SRSF2, EZH2 and MPL at baseline and at 5 yr of treatment in ruxolitinib treated pts who achieved a >25% JAK2V617F allele burden reduction at 5 yr (n=13/19). JAK2V617F allele burden decreased by a mean of 7%, 11%, and 19% at 12, 24 and 36 mo, and decreased further by a mean of 28% after 60 mo. Three (1 PV, 2 ET) of 19 pts (16%) achieved a 50% or greater allele burden reduction after 2 yr; no additional pts achieved this degree of allele burden reduction even in prolonged follow up. These 3 pts further improved their molecular response to a complete molecular response (CMR) after 5 yr of treatment. Their mean JAK2V617F allele burden was 46.6% at baseline, 28.3%, 16.3%, 8.7% and 0% after 1 yr, 2 yr, 3 yr and 5 yr, respectively. The JAK2 CMR was confirmed in at least one independent sample at 3 mo after first discovery. At this last timepoint, the PV pt was in complete haematological remission according to ELN criteria, the 2 ET pts were in partial remission due to platelet count still >400x109/L: 422x109/L and 812x109/L, respectively. BM histopathology in the 2 ET pts at 5 yr, while they were in CMR, showed still evidence of megakaryocyte hyperplasia. In the PV pt, histopathology at 5 yr is pending; evaluation at 3 yr, a time when she was in complete hematologic remission and JAK allele burden had decreased from 69 to 8%, showed normalization of cellularity, megakaryocyte and myeloid lineage compared to baseline but still slight erythroid hyperplasia. All 3 pts had normal karyotype at baseline that remained unchanged thereafter. CMR for JAK2V617F was confirmed by NGS. The 2 ET pts achieving CMR did not show any additional mutations, while the PV pts presented a TET2 Y867H mutation with an allele burden of 48.9% and 52%, respectively at baseline and 5 yr. No recurrent mutations in genes other than JAK2 were found in all other examined cases at baseline or at 5 yr. In 3 informative pts, we also analysed the proportion of JAK2V617F homozygous, heterozygous and wild type clones by the method of Hasan et al (Leukemia 2013) based on allelic discrimination of 46/1 haplotype and JAK2. We found that JAK2V617F/V617F clones were reduced by a mean of 95.5%, JAK2V617F/WT showed an uneven trend with a mean reduction of 45.54% while JAK2WT/WT conversely increased (mean 61.43%) at 5 yr, suggesting that in a subset a patients who present significant reduction of VF allele burden ruxolitinib may preferentially target the homozygous clones. Until now, complete molecular remission in PV pts has been described only in patients treated with interferon. Our data suggest that a subset of pts who present a rapid and sustained reduction of the JAK2V617F allele burden under ruxolitinib may eventually reach a condition of CMR with prolonged treatment. However, similar to findings with interferon, mutations establishing clonality, such as in TET2, may still persist in patients who eventually show the disappearance of JAK2V617F mutated subclones. Disclosures Verstovsek: Incyte: Research Funding. Vannucchi:Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding.

scholarly journals Hydroxyurea does not appreciably reduce JAK2 V617F allele burden in patients with polycythemia vera or essential thrombocythemia

Haematologica ◽  
2010 ◽  
Vol 95 (8) ◽  
pp. 1435-1438 ◽  
Author(s):  
E. Antonioli ◽  
A. Carobbio ◽  
L. Pieri ◽  
A. Pancrazzi ◽  
P. Guglielmelli ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Jak2 V617f ◽  
Allele Burden

Relationship Between Granulocyte JAK2 (V617F) Mutant Allele Burden and Risk of Progression to Myelofibrosis in Polycythemia Vera: a Prospective Study of 338 Patients.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 751-751
Author(s):  
Francesco Passamonti ◽  
Elisa Rumi ◽  
Daniela Pietra ◽  
Chiara Elena ◽  
Emanuela Boveri ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Mutant Allele ◽  
Multivariable Analysis ◽  
Jak2 V617f ◽  
Continuous Variable ◽  
Free Survival ◽  
Who Criteria ◽  
Allele Burden ◽  
Risk Of Progression

Abstract Abstract 751 An identical gain-of-function mutation of JAK2 is found in about 95% of patients with polycythemia vera (PV). According to a two-step model [N Engl J Med. 2005 Apr 28;352(17):1779-90], the occurrence of JAK2 (V617F) gives rise to a clone that is heterozygous and expands to replace hematopoietic cells without the JAK2 mutation. A mitotic recombination in a hematopoietic cell that is heterozygous for JAK2 (V617F) later generates uniparental disomy and 9pLOH. The daughter cell that is homozygous for JAK2 (V617F) gives rise to a new clone that expands and replaces the previous heterozygous clone. Therefore, variable proportions of JAK2 (V617F) mutant alleles are found in myeloid cell populations from PV patients. A mutant allele dosage effect on phenotype has been described, and PV patients with high mutant allele burden have been found to have a more severe disease. Patients with post-PV myelofibrosis have the highest mutant allele burdens [median value of about 90% - Blood. 2008 Apr 1;111(7):3383-7]. Interestingly, JAK2 (V617F) activates circulating granulocytes, and by this means likely plays a role in the constitutive mobilization of CD34-positive cells into peripheral blood that characterizes the transformation of PV into post-PV myelofibrosis [Blood. 2006 May 1;107(9):3676-82]. Since all these observations may suggest that the mutant allele burden contributes to determining the myelofibrotic transformation of PV, we examined PV patients enrolled in a prospective observational cohort study. As of August 10, 2009, 338 patients diagnosed with PV according to the 2008 WHO criteria have been enrolled in this study. Of these patients, 320 (94.7%) carried JAK2 (V617F), 14 (4.1%) had JAK2 exon 12 mutations, and 4 (1.2%) did not carry JAK2 (V617F) nor exon 12 mutations despite a typical PV phenotype. Of the 320 patients carrying JAK2 (V617F), 146 were enrolled at diagnosis and 174 at follow-up. Patients were routinely treated with phlebotomy and low dose aspirin, while those at high risk for thrombosis (history of previous thrombosis and/or age greater than 60 years) were given also cytoreductive therapy. Diagnosis of post-PV myelofibrosis was based on the IWG-MRT criteria, while diagnosis of myelodysplastic syndrome or acute myeloid leukemia (AML) was done according the 2008 WHO criteria. In order to accurately assess the granulocyte mutant allele burden, we refined a previously described quantitative real-time polymerase chain reaction (qRT-PCR)-based allelic discrimination assay. This assay is now routinely calibrated using defined standards [Haematologica. 2009 Jan;94(1):38-45] and has a sensitivity equal to 0.2% mutant alleles. Within 320 JAK2 (V617F)-positive patients, the median mutant allele burden was 47% (range 1.1-100%); 167 (52%) patients had less than 50%, while 153 (48%) had more than 50% mutant alleles. PV patients at diagnosis had significantly lower mutant allele burdens than those enrolled in the study at follow-up (P = .002). During the study period, disease transformation occurred in 18 patients. Eight patients, all with more than 50% JAK2 (V617F) mutant alleles at study entry, progressed to post-PV myelofibrosis, while 10 patients developed AML. Since about half of the patients were enrolled at follow-up, survival analyses were carried out accounting for left censoring of the observation. Cox proportional hazard regression showed that the JAK2 mutant allele burden, analyzed as a continuous variable, was related to hematologic transformation-free survival (HR: 1.025, 95% CI 1.005-1.046; P = .015). By categorizing the mutant allele burden, patients with more than 50% mutant alleles had a significantly worse hematologic transformation-free survival (HR: 6.54, 95% CI 1.47-29.1; P = .013) compared with those with lower mutant allele burden. After adjusting for age in a multivariable analysis, the 50% cutoff retained statistical significance (P = .048). With respect to the risk of progression to post-PV myelofibrosis, the JAK2 mutant allele burden, considered as a continuous variable, was significantly related to myelofibrosis-free survival (HR: 1.04, 95% CI: 1.004-1.08; P = .029). In a multivariable analysis with allele burden and age as covariates, the mutant allele burden showed an independent effect on myelofibrosis-free survival (P= .038). By contrast, the risk of developing AML was not significantly related to the mutant allele burden. In conclusion, the findings of this study suggest that a high mutant allele burden represents a risk factor for progression to myelofibrosis in patients with PV. Disclosures: No relevant conflicts of interest to declare.

High Rates of Molecular Response After Long-Term Follow-up of Patients with Advanced Essential Thrombocythemia (ET) or Polycythemia Vera (PV) Treated with Pegylated Interferon-ALFA-2A (PEG-IFN-α-2A; PEGASYS)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 461-461
Author(s):  
Alfonso Quintás-Cardama ◽  
Ross Levine ◽  
Taghi Manshouri ◽  
Outi Kilpivaara ◽  
Hagop M. Kantarjian ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Essential Thrombocythemia ◽  
Covalent Attachment ◽  
Molecular Response ◽  
Molecular Responses ◽  
Allele Burden ◽  
Mutational Status ◽  
Starting Dose ◽  
Jak2v617f Allele Burden

Abstract Abstract 461 Background: The use of IFN-α in polycythemia vera (PV) and essential thrombocythemia (ET) has been hampered by poor tolerance and inconvenient dosing schedules. The covalent attachment of polyethylene glycol to IFN-α renders a molecule with prolonged serum half-life, which can be administered weekly. Objectives: We conducted a phase II study of subcutaneous PEG-IFN-α-2a (Pegasys) in 84 patients (pts) with high-risk PV (n=44) or ET (n=40). We performed high throughput mutational analysis of JAK2, MPL, TET2, and ASXL1 in all pts. Patients and Therapy: Median age was 51 years (range, 18–79), time from diagnosis to PEG-IFN-α-2a 51 months (range, 0–355), and number of prior therapies was 1 (range, 0–6), including hydroxyurea (HU; n=47), anagrelide (AG; n=26), IFN-α (n=12: 5 oral and 7 sc), imatinib (n=7), and dasatinib (n=1). PEG-IFN-α-2a was initial therapy in 16 (19%) pts (7 PV) that refused HU. JAK2V617F was detected in 19/40 (48%) ET and in 42/44 (95%) PV pts. Nine (11%) pts had abnormal cytogenetics. Initial PEG-IFN-α-2a starting dose was 450 mcg/wk, but that was modified to the current starting dose of 90 mcg/wk. Results: After a median follow-up of 40 months (range, 8–62), 66/83 (80%) assessable pts have responded. Median time to response was 4 weeks (range, 0.5–26). Complete response (CR) was achieved by 62 (75%) pts (for ET: platelets <440×109/L, in the absence of thromboembolic events; for PV: Hb <15 g/dL, no phlebotomy, disappearance of splenomegaly) whereas 4 (5%) pts (2 PV, 2 ET) had a partial response ([PR]; no phlebotomy, off HU and AG, still palpable spleen). Of 5 pts with abnormal karyotype at study entry who were evaluable for response, 2 reverted to diploid cytogenetics. JAK2V617F to total JAK2 ratio was determined by quantitative pyrosequencing assay in all 84 pts prior to PEG-IFN-α-2a. Sixty-one (73%) pts carried the JAK2V617F mutation, which was quantitated at least once on therapy in 54 (64%). Overall, 29 (54%) had >20% reduction in JAK2V617F allele burden, including 10 (19%) in whom the mutation became undetectable (complete molecular response [CMR]) and 15 (28%) who had a >50% reduction (partial molecular response). Molecular responses have not yet reached a plateau among pts with PV. We also analyzed pts for mutations in exon 12 of JAK2, MPL, and the tumor suppressors TET2 and ASXL1 to determine their impact on response to PEG-IFN-α-2a. No pts carried JAK2 exon 12 mutations. One JAK2V617F−negative pt with ET had a MPLW515L mutation, achieved CHR but did not achieve a molecular response. Full length resequencing of all exons of TET2 and ASXL1 genes identified somatic TET2 mutations in 9/71 (13%) and somatic ASXL1 mutations in 3/71 (4%) pts; we identified TET2 (3 JAK2V617F− ET, 2 JAK2V617F+ ET, 3 JAK2V617F+ PV, 1 JAK2V617F− PV) and ASXL1 (1 pt with ET JAK2V617F+, ET JAK2V617F−, and PV JAK2V617F+) mutations in PV and ET pts who were JAK2V617F–positive and negative. TET2 or ASXL1 mutational status did not impact the likelihood of achievement of JAK2 molecular responses, and there was no difference in JAK2V617F allele burden with PEG-IFN-α-2a according to TET2 or ASXL1 mutational status. One pt with baseline mutations in JAK2, TET2, and ASXL1 became JAK2V617F–negative on PEG-IFN-α-2a. Most pts had grade 1–2 toxicities but at doses ≤90 mcg/wk, grade 3–4 toxicity was infrequent. Twenty-five (30%) patients were taken off study after a median of 9 months (range, 3–36) but only 13 (15%) of them due to therapy-related toxicity: g3 neutropenia, anorexia, depression (n=3), ischemic retinopathy, g2 fatigue (n=5), dyspnea, g2 neuropathy. The remaining 59 pts are currently receiving 450 mcg/wk (n=1), 360 mcg/wk (n=1), 240 mcg/wk (n=1), 180 mcg/wk (n=2), 135 mcg/wk (n=3), 90 mcg every 1 (n=8), 2 (n=12), 3 (n=2), or 4 wks (n=1), 45 mcg every 1 (n=9), 2 (n=5), 3 (n=6), or 4 wks (n=8). Conclusion: PEG-IFN-α-2a is remarkably active and acceptably safe in advanced, previously treated PV and ET. Clinical responses are frequently accompanied by significant reduction of JAK2V617F allele burden, which becomes undetectable in a proportion of them suggesting selective targeting of the JAK2V617F clones. Quantitative analysis of ASXL1 and TET2 mutational allele burden during PEG-IFN-α-2a therapy to determine clonal evolution, and methylcellulose-based clonogenic assays in pts who achieved CMR to assess for the presence of erythropoietin independent colony formation are ongoing and will be presented. Disclosures: No relevant conflicts of interest to declare.

Efficacy and Safety of Pegylated Interferon Alpha-2a in Patients with Essential Thrombocythemia and Polycythemia Vera: Results after a Median 7-Year Follow-up of a Phase 2 Study

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 60-60 ◽  
Author(s):  
Lucia Masarova ◽  
Srdan Verstovsek ◽  
Keyur P. Patel ◽  
Kate J Newberry ◽  
Jorge E. Cortes ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Interferon Alpha ◽  
Essential Thrombocythemia ◽  
Research Funding ◽  
Pegylated Interferon ◽  
Molecular Remission ◽  
Molecular Responses ◽  
Pegylated Interferon Alpha ◽  
Allele Burden

Abstract Introduction: It has been previously reported that pegylated interferon alpha-2a can induce hematologic and molecular responses in patients with essential thrombocythemia "ET" and polycythemia vera "PV", but the follow up in these studies were relatively short. Objective: We present longer-term efficacy and safety results of a prospective phase II study of pegylated interferon alpha-2a in patients with ET and PV after a median follow up of 82.5 months (range, 8-107). Methods: Patients with a diagnosis of ET or PV, in a need of therapy, either newly diagnosed or previously treated, were eligible for this study. Median interferon starting dose of 180 mcg/week SQ (range, 450-90; 39% started on 90mcg/week) was modified in majority of the patients based on toxicity or lack of efficacy. Clinical and molecular responses were assessed every 3 to 6 months. Results: Among 83 enrolled patients (43 PV, 40 ET), 32 patients (39%) are still on study (but in 8 therapy is on hold: 5 due to toxicity, and 3 for financial reasons). Median age was 53 years (range, 19-78). Overall 37% of patients did not receive prior cytoreductive treatment. The overall median exposure to therapy was 87 months (range, 58-107) and was no different for patients still enrolled on the study and those who stopped study participation. Nine (28%) patients still on study are currently on a dose equal or higher than 90 mcg/week and 15 (47%) are on dose equal or smaller than 45mcg/week. JAK2 status or allele burden had no impact on achievement of response (clinical or molecular), time to response or duration of therapy. 55 of 59 (71%) JAK2V617F positive patients were evaluable for molecular response (Figure); 8 patients carried CARL mutation, 3 carried MPL and in 13 were triple negative. Median duration of hematologic and molecular response was 66 and 53 months, respectively; and directly correlated with treatment length and type of response (CMR had the longest duration of response). Overall yearly discontinuation rate were gradually decreasing for first 5 years, from 17% to 5%, and slowly increasing afterward to 10%. Of the 51 patients not on the study anymore, 27 (35% of the total) discontinued therapy primarily due to treatment toxicity. New late (≥24 months from start of therapy) G3/4 toxicity occurred in 17% of patients. Among patients in complete hematologic response treatment failure due to vascular adverse event or disease transformation was seen in 5 patients each. Three patients died on study (not related to therapy or disease), and 8 after stopping participation. Mean changes in allele burden over time in JAK2 positive patients are depicted in figure. Conclusions: Although pegylated interferon alpha-2a can induce significant hematologic and molecular responses; toxicity still limits its use over longer period of time and loss of response or transformation is encountered. Table.ResponseCharacteristicsFirst responseLast responseHem Resp, N. of patients (No), (%)CHR62 (76)25 (40)aPHR4 (5)1 (25)ORR66 (79)26 (39)aMol Resp, No, (%)CMR10 (18)9 (90)PMR20 (36)5 (25)*mMR5 (9)2 (40)ORR35 (74)16 (46)SafetyAny gradeGrade≥3Overall Adverse Events (AE), No, (%)any AE83 (100)57 (67)recurrent AE74 (89)13 (16)AE subtypes, No, (%)musculoskeletal73 (88)6 (8)neurological53 (64)2 (4)psychiatric38 (46)4 (11)gastrointestinal54 (65)11 (20)LFT elevation27 (33)5 (18)skin18 (22)2 (11)infection/fever26 (31)3 (12)respiratory23 (28)2 (9)cardiovascular13 (16)3 (23)metabolic16 (19)2 (13)neutropenia37 (45)21 (57)thrombocytopenia18 (22)a1 (6)anemia36 (43)1 (3)Autoimmune toxicity, No, (%)hepatitis1 (2.5)CNS vasculitis1 (2.5)lupus nephritis1 (2.3)Sjogren sy & dermatitis1 (2.5)Vascular AE (TEE/bleeding),Unprovoked6 (7)5 (83)No, (%)Provoked4 (5)3 (75)Disease transformation, No, (%)Myelofibrosis6 (7)AML1 (1)Safety over ≥24 months**Any gradeGrade≥3New AE, No (%)3th year10 (17)4 (40)4th year6 (11)4 (67)5th year5 (10)1 (20)≥ 6th year10 (24)1 (10)**Effective sample size for patients on therapy/year: Initial number of patients at risk at the beginning of period minus half of patients censored during that period*% calculated from 19 patientsastatistically significant differences by Fisher's exact testAbbr. CMR= complete molecular remission (undetectable JAK2 allele burden), PMR= partial molecular remission (>50% decrease in allele burden), mMR= minor molecular remission (20-49% decrease in allele burden) Figure 1. Figure 1. Disclosures Off Label Use: Pegylated Interferon alfa-2a used for patients with essential thrombocythemia and polycythemia vera. Cortes:Novartis: Consultancy, Research Funding; BerGenBio AS: Research Funding; Teva: Research Funding; BMS: Consultancy, Research Funding; Pfizer: Consultancy, Research Funding; Ariad: Consultancy, Research Funding; Astellas: Consultancy, Research Funding; Ambit: Consultancy, Research Funding; Arog: Research Funding; Celator: Research Funding; Jenssen: Consultancy. Konopleva:Novartis: Research Funding; AbbVie: Research Funding; Stemline: Research Funding; Calithera: Research Funding; Threshold: Research Funding.

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