Ziftomenib (also known as KO-539) is a Menin-MLL (KMT2A) inhibitor medication. It is being studied for treating patients who have acute myeloid leukemia (AML) that has either come back after previous treatment or has not responded to treatment. This medication works by targeting specific genetic changes in leukemia cells, particularly in patients who have certain mutations like NPM1 or KMT2A rearrangements. It is also being studied in patients who have acute lymphoblastic leukemia (ALL) with specific genetic changes.

Acute Myeloid Leukemia (AML) – A blood and bone marrow cancer that affects the myeloid cells, which normally develop into various types of blood cells. In AML, the bone marrow produces abnormal white blood cells that do not function properly and multiply rapidly. These abnormal cells build up in the bone marrow and blood, leaving less room for healthy blood cells. The disease can progress quickly, causing a decrease in normal blood cell production, including red blood cells, white blood cells, and platelets. AML can occur in both children and adults, though it is more common in older adults. The condition may develop as a new disease or can emerge from other blood disorders.

Acute Lymphoblastic Leukemia (ALL) – A blood cancer that affects lymphoid cells, which normally develop into white blood cells called lymphocytes. In ALL, immature lymphoid cells multiply rapidly and abnormally in the bone marrow, preventing the production of normal blood cells. These abnormal cells, called lymphoblasts, crowd the bone marrow and can spread to other parts of the body. The disease typically develops quickly, affecting the body’s ability to produce normal blood cells. ALL is more common in children but can occur at any age.