Myeloid Metaplasia

The goal of this clinical trial is to learn which of three different doses of Flonoltinib Maleate taken by mouth daily works best to treat adult patients with myelofibrosis in whom the most common approved therapy has failed to adequately control the disease. It will also learn about the safety of the three different daily doses of Flonoltinib Maleate. The main questions it aims to answer are: Which dose is the best at controlling the symptoms and signs of organ damage caused by myelofibrosis? What medical problems do participants have when taking the three different doses of Flonoltinib Maleate? Researchers will compare the three different doses of Flonoltinib Maleate to see which dose is best to treat patients with myelofibrosis. Participants will: Take Flonoltinib Maleate every day for as long as it seems to be of benefit to them in terms of controlling myelofibrosis. Visit the clinic for checkups and tests after giving fully informed written consent confirming that they would like to consider entering the study. Visit the clinic for checkups and tests when on the study once every 2 weeks for the first 2 months, every 4 weeks after that, and when coming off study therapy. Keep a diary of their symptoms.