How bevacizumab works
Bevacizumab is a monoclonal antibody that targets VEGF (vascular endothelial growth factor). In this way, its interaction with its binding site (receptor) is prevented. As a result, the formation of new blood vessels (angiogenesis) is inhibited, slowing tumor growth.
While normal (healthy) cells eventually lose their ability to divide, this is not the case with cancer cells. The cells of the tumor are “immortal”, which means that they can divide again and again.
For growth, each tumor requires its own blood supply, since it needs a particularly large amount of nutrients and oxygen – transported by the blood – for rapid tissue proliferation. To this end, it independently produces large quantities of the messenger substance VEGF, which, after binding to its receptor, promotes the local formation of blood vessels.
Absorption, degradation and excretion
Bevacizumab is administered directly into the bloodstream by means of an infusion. The active substance is then rapidly distributed throughout the body. Because bevacizumab has a protein structure, it can be slowly broken down anywhere in the body. After about 18 to 20 days, the amount of antibody has decreased by half.
When is bevacizumab used?
The areas of application (indications) for bevacizumab include a wide variety of types of malignant tumors, including:
- Breast cancer (mammary carcinoma)
- Lung cancer (bronchial carcinoma)
- Kidney cancer (renal cell carcinoma)
- Cervical cancer (cervical carcinoma)
Outside its approved indications – i.e. in “off-label use” – bevacizumab is given for age-related wet macular degeneration. For this purpose, the active substance is injected intravitreally (directly into the vitreous body of the eye).
How bevacizumab is used
Depending on tolerability, the first infusion lasts approximately 90 minutes. If well tolerated, the infusion time can be shortened to as little as 30 minutes.
Bevacizumab is usually combined with other cancer drugs: Bevacizumab ensures that tumor growth is inhibited. Other drugs then help the tumor to die. This makes for a very sensible and effective combination in cancer therapy.
What are the side effects of bevacizumab?
In contrast to many other cancer drugs, the tolerability of bevacizumab can be classified as good.
Frequently, i.e. in one to ten percent of those treated, bevacizumab causes side effects in the form of pain at the infusion site, fatigue, weakness, diarrhea, abdominal pain and allergic reactions.
Less frequently, gastrointestinal bleeding, blood clots, hypertension, constipation and skin changes develop.
Contraindications
Bevacizumab must not be used in:
- Hypersensitivity to the active ingredient or any of the other ingredients of the drug.
- Hypersensitivity to CHO (Chinese hamster ovary) cell products (CHO cells are used to produce bevacizumab)
- Pregnancy
Drug interactions
When bevacizumab is co-administered with certain anticancer drugs (platinum compounds, taxanes), infections and certain blood count changes (neutropenias) are more common.
There is no evidence that bevacizumab impairs responsiveness.
Age Limitation
Limited data are available on the use of bevacizumab in children and adolescents under 18 years of age. Therefore, in patients in this age group, the benefit of treatment must be weighed against the individual risk by the treating physician in each case.
Pregnancy and Lactation
The active ingredient can potentially pass into breast milk (as can natural antibodies from the mother). Therefore, women must stop breastfeeding when being treated with bevacizumab and refrain from breastfeeding until six months after treatment.
How to get medicines with bevacizumab
Bevacizumab may only be administered by healthcare professionals. As a rule, the infusions are delivered directly to the physician, so that patients do not have to order or pick up the drug themselves at the pharmacy.
How long has bevacizumab been known?
In the meantime, the patent for bevacizumab has expired, and the first biosimilars (copycat products) have already been released.
