This study tests a medicine called nuvisertib for myelofibrosis (MF), a blood cancer that causes scar tissue in the bone marrow. The study is split into three groups depending on past treatments. Each group checks if nuvisertib works differently. Some patients will take nuvisertib alone, while others will take it with another medicine like ruxolitinib or momelotinib.

Participants must have a confirmed diagnosis of myelofibrosis and meet specific health criteria. For example, they should have a certain number of blood cells, proper liver and kidney function, and a life expectancy of at least six months. People with certain health issues, like severe heart problems or other types of cancer, cannot join.

• **Study Length**: Exact duration not specified, but involves multiple cycles.
• **Visits Needed**: Regular visits for monitoring and assessments.
• **Risks**: Potential side effects like heart issues or liver problems.

Participants need to consider potential risks and benefits before joining. This study is important for patients who haven’t responded well to other treatments.