JAK2 V617F as a Marker for Long-Term Disease Progression and Mortality in Polycythemia Vera and its Role in Economic Modeling

Clinical Impact of JAK2V617F Allele Burden in Philadelphia-Negative Myeloproliferative Neoplasms

Objective

The impact of JAK2V617F allele burden on clinical course in Philadelphia-negative (Ph-negative) myeloproliferative neoplasms (MPNs) is not clear. We analyzed the clinical impact of JAK2V617F allele burden in a relatively large series of patients with Ph-negative MPNs and long-term follow-up.

Materials and Methods

A total of 228 patients with Ph-negative MPNs, including 118 with essential thrombocythemia (ET), 84 with primary myelofibrosis (PMF), and 26 with polycythemia vera (PV), were analyzed. The JAK2 MutaScreen assay was used to quantify JAK2V617F allele burden in genomic DNA.

Results

In PV cases, high JAK2V617F allele burden was associated with a trend towards inferior overall survival. In ET, high JAK2V617F allele burden was associated with lower hemoglobin and hematocrit levels, higher lactate dehydrogenase (LDH) levels, larger spleen size, and increased bleeding and mortality rates. In PMF, high JAK2V617F allele burden was associated with higher leukocyte counts and larger spleen size. In the entire cohort, high allele burden was associated with higher leukocyte and lower platelet counts, higher LDH levels, larger spleen size, higher percentage of bleeding events, higher death rate, and inferior overall survival.

Conclusion

Our results suggest that high JAK2V617F allele burdens are associated with more severe disease in PV and ET. In PMF, high JAK2V617F allele burdens were associated with more pronounced myeloproliferative phenotypes. In Ph-negative MPNs, high allele burdens were associated with more aggressive phenotypes. Our data with a long follow-up period support the possibility of JAK2V617F allele burden being used as a marker for predicting clinical phenotype in cases of Ph-negative MPNs.

S, R. D. JAK2 Mutation and Its Assessment in Relation to Profile of Young Polycythemia Patients in India

Purpose The main aim of this study was to detect the presence of JAK2 mutation and its assessment in relation to the clinical, hematological, and mutational profile of young patients with established polycythemia.

Methods Cross-sectional observational study was undertaken over a period of 1 year in a tertiary care center. Sixty patients were included in our study between the age 18 and 50 years with confirmed diagnosis of polycythemia vera. Reports of all the investigations including bone marrow biopsy and JAK2 mutation testing were assessed.

Results Presence of JAK2 mutation V617F was found in 38% patients, while bone marrow panmyelosis was present in 67% patients. Higher mean hemoglobin levels were observed in JAK2 mutation-positive patients, compared with those who were negative. Thrombosis-related complications were observed in five patients, all of whom were JAK2 mutation positive, while out of the 18 patients requiring phlebotomy, 15 patients were JAK2 mutation positive.

Conclusion JAK2 mutation V617F in young Indian population is seen in significantly less cases as compared with Western data, while bone marrow panmyelosis is frequently observed and thus a significant finding for diagnosing polycythemia in our setting. Median hemoglobin was greater for JAK2 mutation-positive cases and so were the phlebotomy requirements and thrombotic events occurrences. Forty-two percent patients had history of some exposure to high-altitude areas adhering to the fact that high altitude is an established risk factor for developing polycythemia and the same is reinforced by our study.

A pharmacokinetic evaluation of ropeginterferon alfa-2b in the treatment of polycythemia vera

INTRODUCTION

Polycythemia vera (PV) is a Philadelphia chromosome-negative chronic myeloproliferative neoplasm (MPN). A newly developed PV treatment option, ropeginterferon alfa-2b, contains recombinant human alfa monoisomer as an active ingredient, resulting in a novel pharmacologic profile and improved tolerability. Efficacy studies conclude remarkable long-term hematological response and sustained JAK2V617F allele burden reduction. Ropeginterferon alfa-2b compound has been approved for the treatment of polycythemia vera without symptomatic splenomegaly.

AREAS COVERED

Current clinical trials are investigating the role of ropeginterferon alfa-2b in the first-line setting of treatment for PV. The safety and efficacy results of completed trials are summarized in this review. Metabolic, pharmacokinetic issues are also discussed of ropeginterferon alfa-2b.

EXPERT OPINION

Ropeginterferon alfa-2b is a targeted therapeutic option in the treatment of PV, representing a significant improvement compared to conventional cytoreductive therapies. The single isomer entity of the recombinant human interferon alfa-2b and the mono-pegylation method imparts favorable properties to the compound. The use of ropeginterferon alfa-2b allows extended dosing interval, reduces side effects, and may increase the overall survival of PV patients by reducing the risk of progression to myelofibrosis or acute leukemia. Clinical data suggests that the compound may provide a disease-modifying option for PV patients with asymptomatic splenomegaly.