Search

Purpose: The overall impact of hydroxyurea (HU) or pipobroman treatments on the long-term outcome of patients with polycythemia vera (PV) has not been assessed in randomized studies. We report final analyses from the French Polycythemia Study Group (FPSG) study, which randomly assigned HU versus pipobroman as first-line therapy in 285 patients younger than age 65 years., Patients and Methods: The full methodology has been described previously. FPSG results were updated with a median follow-up of 16.3 years. Statistical analysis was performed by using competing risks on the intention-to-treat population and according to main treatment received., Results: Median survival was 17 years for the whole cohort, 20.3 years for the HU arm, and 15.4 years for the pipobroman arm (P = .008) and differed significantly from that in the general population. At 10, 15, and 20 years, cumulative incidence of acute myeloid leukemia/myelodysplastic syndrome (AML/MDS) was 6.6%, 16.5%, and 24% in the HU arm and 13%, 34%, and 52% in the pipobroman arm (P = .004). Cumulative myelofibrosis incidence at 10, 15, and 20 years according to main treatment received was 15%, 24%, and 32% with HU versus 5%, 10%, and 21% with pipobroman (P = .02)., Conclusion: Data from this unique randomized trial comparing HU with another cytoreductive drug in PV showed that (1) survival of patients with PV treated with conventional agents differed from survival in the general population, (2) evolution to AML/MDS is the first cause of death, (3) pipobroman is leukemogenic and is unsuitable for first-line therapy, and (4) incidence of evolution to AML/MDS with HU is higher than previously reported, although consideration should be given to the natural evolution of PV.

Background: Myeloproliferative disorders are characterized by clonal expansion of normal mature blood cells. Acquired mutations giving rise to constitutive activation of the JAK2 tyrosine kinase has been shown to be present in the majority of patients. Since the demonstration that the V617F mutation in the exon 14 of the JAK2 gene is present in about 90% of patients with Polycythemia Vera (PV), the detection of this mutation has become a key tool for the diagnosis of these patients. More recently, additional mutations in the exon 12 of the JAK2 gene have been described in 5 to 10% of the patients with erythrocytosis. According to the updated WHO criteria the presence of these mutations should be looked for in PV patients with no JAK2 V617F mutation. Reliable and accurate methods dedicated to the detection of these highly variable mutations are therefore necessary., Methods/findings: For these reasons we have defined the conditions of a High Resolution DNA Melting curve analysis (HRM) method able to detect JAK2 exon 12 mutations. After having validated that the method was able to detect mutated patients, we have verified that it gave reproducible results in repeated experiments, on DNA extracted from either total blood or purified granulocytes. This HRM assay was further validated using 8 samples bearing different mutant sequences in 4 different laboratories, on 3 different instruments., Conclusion: The assay we have developed is thus a valid method, adapted to routine detection of JAK2 exon 12 mutations with highly reproducible results.

Key Clinical Message: Although uncommon, clinicians should be aware that polycythemia vera may be masked due to hemolysis. The report of such associations could help them in clinical practice to establish an early and accurate diagnosis that may be challenging in atypical presentations of myeloproliferative neoplasms. Although uncommon, clinicians should be aware that polycythemia vera may be masked due to hemolysis. The report of such associations could help them in clinical practice to establish an early and accurate diagnosis that may be challenging in atypical presentations of myeloproliferative neoplasms. [ABSTRACT FROM AUTHOR]