I believe what you meant is Essential thromobytosis (ET). It can be classified into different risk group, low and high. The goal is to prevent thromboembolic event, using aspirin or hydroxyurea. About 50% patients with ET have JAK2 mutation. A oral JAK inhibitor ruxolitinib was recently approved by FDA to treat myelofibrosis (end stage of ET). Several clinical study is on going to test the drug in ET before progressing to MF with promising result.