Pegylated Interferon Alfa-2b Versus Interferon Alfa Therapy in Adult Essential Thrombocythemia

Inclusion Criteria: * ≥18 years old. * Male or Female. * Diagnosis of essential thrombocythemia according to the 2016 World Health Organization criteria. * Those who have not use interferon within 4 weeks before the first medication. * Patients with indications for cytoreductive therapy. * Men and women with reproductive potential, as well as all women with menopause less than 2 years, must agree to use acceptable contraceptive methods until 28 days after the last dose of study drug, and women must agree not to breastfeed during the study period. * Voluntary written informed consent. Exclusion Criteria: * Resistance, or intolerance, or any contraindications to interferon. * Patients with active thrombosis or active bleeding. * Neutrophil count \< 1.0x10\^9/L. * Hemoglobin \< 11g/dL for male, or \< 10g/dL for female. * Poor control of thyroid dysfunction. * Patients with a prior malignancy within the last 3 years. * Patients with severe cardiac or pulmonary dysfunction. * Severe renal damage (creatinine clearance \< 30 ml / min). * Severe liver dysfunction (ALT or AST \> 2.5×ULN). * Patients with hepatitis B virus, hepatitis C virus replication or HIV infection. * Patients with a history of drug / alcohol abuse (within 2 years before the study). * Patients that have participated in other experimental researches within one month before enrollment. * History of psychiatric disorder. * Any other circumstances that the investigator considers that the patient is not suitable to …