Bosutinib, recognized by its brand name Bosulif, is a specialized medication classified as a targeted therapy. It falls within a group of drugs known as tyrosine kinase inhibitors (TKIs). Its primary function involves interfering with specific processes within the body’s cells to manage certain types of cancer.
Medical Uses of Bosutinib
Bosutinib is approved for the treatment of Philadelphia chromosome-positive Chronic Myeloid Leukemia (Ph+ CML). Ph+ CML is a type of cancer that originates in the bone marrow, leading to an overproduction of abnormal white blood cells. This condition is characterized by the presence of an abnormal chromosome, known as the Philadelphia chromosome, which produces a specific protein that drives cancer cell growth.
The medication is used in adult patients who have newly diagnosed chronic phase Ph+ CML. It also serves as a treatment option for adult patients with chronic, accelerated, or blast phase Ph+ CML who have previously been treated with other therapies and either could not tolerate them or whose disease progressed.
How Bosutinib Works
The action of bosutinib centers on inhibiting an abnormal enzyme called BCR-ABL tyrosine kinase. In individuals with Philadelphia chromosome-positive Chronic Myeloid Leukemia, this enzyme is continuously active, sending signals that tell cancer cells to grow and multiply without control. This unchecked proliferation leads to the accumulation of abnormal white blood cells.
Bosutinib works by attaching to and blocking the activity of this specific BCR-ABL tyrosine kinase. Consider it like a specialized key that fits into a lock, preventing the lock from turning and activating the growth signal. By switching off this abnormal signaling pathway, bosutinib helps to slow or stop the growth of the leukemia cells. This targeted approach aims to disrupt the disease process at its source, without affecting healthy cells as broadly as conventional chemotherapy.
Administration and Dosing
Bosutinib is provided as an oral tablet. It is important that this medication be taken with food to improve its absorption into the body and to help reduce potential stomach upset. Patients should swallow the tablets whole and not crush, cut, or chew them.
A typical starting dosage for newly diagnosed chronic phase Ph+ CML is 400 mg once daily. For patients with resistant or intolerant Ph+ CML, the usual starting dose is 500 mg once daily. Patients must adhere to their doctor’s specific instructions regarding dosage and frequency. If a dose is missed, patients should not take an extra dose to make up for it; the next dose should be taken at the regularly scheduled time. Should vomiting occur shortly after taking a dose, patients should not take an additional dose but instead wait until their next scheduled dose.
Potential Side Effects
Common Side Effects
Patients taking bosutinib may experience several common side effects. Diarrhea is frequently reported and can sometimes be managed with anti-diarrhea medications as advised by a healthcare provider. Other gastrointestinal issues include nausea, vomiting, and stomach pain.
Skin rash and fatigue are also common occurrences during treatment. Some patients may experience a decrease in blood cell counts, which can include low levels of platelets (thrombocytopenia), red blood cells (anemia), or white blood cells (neutropenia).
Serious Side Effects
Less common but more severe side effects require immediate medical attention. Liver problems can occur, with symptoms such as yellowing of the skin or eyes (jaundice), dark urine, or unusual tiredness. Patients should report these signs promptly.
Fluid retention can also manifest as severe swelling, particularly around the lungs (pleural effusion) or heart (pericardial effusion), causing shortness of breath or chest discomfort. Heart problems, including changes in heart rhythm or function, are also possible. Kidney issues, indicated by changes in urination patterns or swelling, may also arise.
Important Safety Considerations
Food and Drug Interactions
Patients undergoing treatment with bosutinib must be aware of certain food and drug interactions. It is important to avoid consuming grapefruit or grapefruit juice while on this medication, as grapefruit can increase the levels of bosutinib in the body, potentially leading to increased side effects.
Several medications can also interact with bosutinib, impacting its effectiveness or increasing the risk of side effects. These include certain antibiotics, such as clarithromycin, and some antifungal medications like ketoconazole. Herbal supplements, such as St. John’s Wort, can decrease bosutinib levels, making it less effective. Patients should always inform their doctor about all prescription and over-the-counter medications, as well as any herbal products or supplements they are taking.
Required Medical Monitoring
Regular medical monitoring is important during treatment with bosutinib. Patients will undergo frequent blood tests to assess various bodily functions. These tests include monitoring liver function to detect any signs of liver damage.
Blood cell counts will also be regularly checked to ensure levels of red blood cells, white blood cells, and platelets remain within a safe range. Kidney function tests are performed to monitor kidney health. These routine tests allow healthcare providers to adjust dosing if necessary and manage potential side effects proactively, ensuring the safest and most effective treatment.