This study will test an experimental drug called ZE74-0282 in people with certain blood disorders caused by a specific mutation called JAK2 V617F. The main goals are to find the right dose level, to see how safe and tolerable different doses are, how the drug moves through the body, and whether it shows early signs of anti-tumor activity. Participants will receive ZE74-0282 in one of several dose groups. The study is open-label, meaning both the doctor and the participant know which treatment is given. It will take place at multiple centers across different countries. Blood tests and regular check-ups will be done to monitor side effects and measure the effect on the disease.