Below is an instruction from Human. Write a response.
    ### Instruction:
    What are the treatments for Polycythemia Vera ?
    ### Response:
    The purpose of treatment for polycythemia vera is to reduce the number of extra blood cells. Treatment of polycythemia vera may include the following:             -  Phlebotomy.     -  Chemotherapy with or without phlebotomy.     -  Biologic therapy using interferon alfa or pegylated interferon alpha.
    