Inclusion Criteria:  Adults ≥ 18 years (or based on the legal age of the territory) Diagnosed of primary myelofibrosis, post-PV and post-ET myelofibrosis according to the WHO 2016 classification Bone marrow reticulin fibrosis grade of 0-1 or low/intermediate-1 risk according to DIPSS Compensated liver function defined as: bilirubin ≤ 1.5 x upper limit normal (ULN); alanine aminotransferase (ALT) ≤ 2 x ULNor aspartate aminotransferase (AST) ≤ 2 x ULN; prothrombin time versus control <3 seconds at screening Glomerular filtration rate ≥ 50 mL/min (by MDRD equation or Cockcroft-Gault formula) Men and women of childbearing potential must agree to perform contraception until 28 days after the last dose of ropeg. Women must avoid breast-feeding during the study. Able to give a written informed consent and fully comply to the requirements of the study.  Exclusion Criteria:  Prior or current use of IFNα preparations for PMF or secondary MF. Prior use of IFNα for antecedent PV or ET is allowed provided that the time from the last dose of IFNα to recruitment is > 4 weeks. Patients currently on other investigational therapy (ies) Contraindications or hypersensitivity to IFNα preparations History of organ transplantation Pregnant or lactating women Documented autoimmune disease at screening Infection with human immunodeficiency virus (HIV) Active and uncontrolled infections with hepatitis B virus (HBV) and hepatitis C virus (HCV). Please note that patients on antiviral therapy with undetectable HBV DNA and HCV RNA may be recruited. Evidence of severe retinopathy including but not limited to macular degeneration, diabetic retinopathy and hypertensive retinopathy. History of clinically significant neuropsychiatric conditions including but not limited to depression and epilepsy. Clinically significant neuropsychiatric conditions including but not limited to depression and epilepsy. Presence of other active malignancies within three years prior to the time of recruitment. History of malignant disease, including solid tumours and haematological malignancies (except basal cell and squamous cell carcinomas of the skin and carcinoma in situ of the cervix that have been completely excised and are considered cured) within the last 3 years. Evidence of alcohol or drug abuse within 6 months