 A complete response is defined as an increase in platelet counts to 150×109L on two consecutive occasions. A clinical response is defined as an increase in the platelet count between 30×109L on two consecutive measures and no bleeding. Duration of response is considered from the day of the initial administration to the first time of relapse platelet count 30×109L or to time of analysis Patients will be evaluated each week during 4 weeks and then every month for at least 6 months. 