This trial adopts a multicenter, open-label, positive drug parallel control clinical trial design, planning to enroll approximately 75 MF participants. Eligible participants will be stratified and assigned in a 1:1:1 ratio to the low-dose flonoltinib maleate tablet group, high-dose flonoltinib maleate tablet group, or the ruxolitinib tablet group. Stratification factor include the Dynamic International Prognostic Scoring System (DIPSS) risk classification (intermediate-2 and high risk)
Age ≥ 18 years, no gender restrictions;
Diagnosed with primary myelofibrosis (PMF) according to WHO criteria (2016 edition) or post-polycythemia vera myelofibrosis (PPV-MF) or post-essential thrombocythemia myelofibrosis (PET-MF) according to IWG-MRT criteria;
Evaluated as intermediate-2 or high-risk myelofibrosis according to the Dynamic International Prognostic Scoring System (DIPSS) risk classification;
Expected survival ≥ 24 weeks;
Previous anticancer treatment-related toxic reactions have not recovered to grade 1 or below (excluding alopecia and conditions specified in inclusion criteria 8 and 9), or have not fully recovered from previous surgery (major surgery within 4 weeks);
Hypersensitivity, allergic to the investigational drug or its excipients;
Previous intolerance or resistance to ruxolitinib;
Use of JAK inhibitors within 4 weeks before the first dose;