 Eligible patients are randomized to be treated with the best available therapy recommended for this risk class, standard arm based on phlebotomy including administration of low-dose 100 mgdaily of acetylsalicylic acid ASA, when there are not contraindications OR Pegylated Proline-Interferon alpha-2b AOP2014 every 2 weeks in addition to the recommended available regimen experimental arm, for up to 12 months. The allocation of patients to study arms is 1:1 and stratification at randomization will be performed according to age category 50 years old or 50 years old and time from diagnosis naϊve or non-naϊve. Naive patients are defined as new cases coming to observation, diagnosed for the first time just before study entry and never treated; non-naive patients are old cases diagnosis not older than 3 years before study entry undergoing therapy with phlebotomy andor low doses of ASA. 