Bevacizumab: Effects, Uses & Risks

Bevacizumab is among the agents used to treat cancer. It is a humanized monoclonal antibody.

What is bevacizumab?

Bevacizumab is among the agents used to treat cancers, such as breast cancer. Bevacizumab is considered an important therapeutic agent for cancer. The active ingredient is used to treat various types of cancer, including breast cancer, colorectal cancer, pancreatic cancer and prostate cancer. Bevacizumab was approved in 2005. Thus, the monoclonal antibody is one of the more recent treatment agents. However, the drug has been used with considerable success to date. In addition to the treatment of cancer, other indications are also conceivable. For example, the drug is sometimes administered against age-related macular degeneration of the eyes.

Pharmacologic action

Cancer is among the most insidious diseases of the present. Thus, it results in uncontrolled growth of the body’s cells. As it progresses, the cancer cells displace the healthy tissue more and more, which eventually leads to the development of a malignant (malignant) tumor. Unlike ordinary cells, cancer cells keep dividing. In some tumors, the cancer cells split off and spread, so that they can reach other organs via the lymphatic system or the bloodstream and damage them as well. In such cases, physicians speak of daughter tumors or metastases. In this way, the cancer spreads increasingly throughout the body and, in the final stage, ultimately leads to the death of the patient. In order for the tumor to grow, it is dependent on an independent blood supply. Thus, it needs a lot of oxygen and nutrients for its rapid growth. For this purpose, the tumor produces the messenger substance VEGF. This binds to a receptor, resulting in the formation of blood vessels. Bevacizumab is used to combat the growth of the tumor. The antibody, which is produced by genetic engineering, blocks the receptors so that the VEGF messenger can no longer bind to them. In this way, the formation of blood vessels can be stopped. This property makes bevacizumab an angiogenesis inhibitor. Because the supply of nutrients and oxygen stops, the cancer tumor eventually stops growing. An additional effect of bevacizumab is the sealing of blood vessels, which prevents fluid from leaking into neighboring tissue and prevents the formation of edema (water retention in the body). Bevacizumab is also effective in the human eye. For example, the substance in the retina prevents the growth of troublesome blood vessels. The same applies to the accumulation of water retention in the macula. Bevacizumab is administered by infusion. In this way, the drug enters the bloodstream immediately and spreads through the organism at a high rate. Because bevacizumab has a protein structure, its gradual breakdown can be carried out throughout the body.

Medical application and use

Bevacizumab is used for the therapy of various cancers. For example, the drug is administered in combination with chemotherapy for colon cancer or rectal cancer. The drug is also suitable for the initial treatment of breast cancer associated with metastases when used with the cytostatic drug paclitaxel or capecitabine. Together with chemotherapy, bevacizumab is also used against bronchial cancer. In this case, however, the field of application is limited to advanced daughter tumors that are no longer operable. Other cancers that can be treated with the monoclonal antibody include carcinomas of the fallopian tubes, ovaries or peritoneum, as well as kidney cancer, prostate cancer and lung cancer. Experimentally, bevacizumab can also be administered to treat vascular neoplasms in the retina of the eye. The substance is used to treat macular edema or age-related macular degeneration (AMD). For this purpose, the physician injects the bevacizumab into the vitreous body of the eye, which leads to a growth stop and sometimes even to a decrease of the harmful blood vessels. However, since bevacizumab has not yet been approved for ophthalmic treatments, its use has so far been off-label. Bevacizumab may only be administered by qualified medical personnel. The recommended dose is 5 to 15 milligrams per kilogram of body weight.Administration is at three-week intervals as part of an infusion that lasts about 90 minutes.

Risks and side effects

About ten percent of all patients suffer adverse side effects after taking bevacizumab. The most common are diarrhea, constipation, nausea, vomiting, fatigue, feelings of weakness, high blood pressure, eye disorders, intestinal bleeding, nosebleeds, headaches, rhinitis, fever, discoloration of the skin, skin dryness, skin inflammation, or even gastrointestinal rupture. Furthermore, abscesses, abdominal pain, anemia, fainting, infections, muscle weakness, breathing difficulties, dehydration or listlessness are within the realm of possibility. In the worst cases, a heart attack or stroke may be imminent. Extensive inflammation of the eye may occur. If the patient’s immune system is already weakened, there is a risk of soft tissue infection. The therapy must then be stopped immediately. If the patient is hypersensitive to bevacizumab, the drug should not be used. The same applies to hypersensitivity to human or animal antibodies or if metastases are present in the brain. The use of bevacizumab must also be avoided during pregnancy, as animal studies have shown considerable damage to the newborns. Likewise, the treatment of children and adolescents should be refrained from, as there are not yet sufficient data for their therapy. Interactions between bevacizumab and other drugs are also conceivable. For example, joint use of the substance with other anticancer agents such as sunitinib should be avoided because of the risk of changes in small blood vessels.