Introduction
Bosutinib (trade name: Bosulif) has been approved in Germany since March 2013 for the treatment of Philadelphia chromosome-positive chronic myeloid leukemia in adults who have had treatment before. Since May 2018, the drug has also been approved for the first-line treatment of the chronic phase in people with newly diagnosed chronic myeloid leukemia.
Chronic myeloid leukemia (CML), also known as chronic myelogenous leukemia, usually develops from a mutated chromosome called the Philadelphia chromosome. The medical term for this condition is Philadelphia chromosome-positive CML (Ph+ CML). CML is a type of bone marrow cancer in which the bone marrow makes too many granulocytes and blast cells (immature granulocytes) which then enter the blood. Granulocytes are a type of white blood cell and an important part of the immune system.
Because the condition progresses very slowly over years, it can go unnoticed for a long time. There are three phases:
Chronic phase: This phase is almost always symptom-free. That's why the condition is usually discovered by chance during routine blood examinations.
Accelerated phase: As CML progresses, blood test results get worse. Blast cell counts increase and patients look pale, feel tired and are less fit.
Blast crisis: In this far advanced phase, more and more blast cells are made in the bone marrow. This also slows down the production of red blood cells (erythrocytes) and platelets (thrombocytes). The effects of a blast crisis include susceptibility to infections, anemia, and poor blood clotting. Blast crises are life-threatening.
Bosutinib inhibits various proteins that cause bone marrow to make more granulocytes and blast cells. The aim of treatment with this drug is to stop the progression of CML in this way.