1. Too Much of a Good Thing
Herceptin is a biologic drug developed because of information that scientists learned about the HER2 gene and breast cancer. HER2 genes are present in many cells in our body. These genes tell our cells to make HER2 protein, which helps them grow and divide. People with HER2 positive breast cancer have too many HER2 genes in their cells. In these people, the HER2 genes cause cancer cells to grow and divide quickly. About 1 in 4 people with breast cancer have HER2 positive cancer, a very aggressive form of the disease.
2. The Magical Monoclonal Antibody
Antibodies are proteins that fight foreign agents in our bodies. Monoclonal antibodies, produced in a laboratory, contain millions of a single antibody programmed to attack a particular target. Herceptin is a monoclonal antibody that shuts off the HER2 gene in cells so that the cancer cells stop growing.
3. Take the Test
A test conducted on the tumor removed during surgery determines if your breast cancer is HER2 positive. If so, your doctor will probably recommend Herceptin after surgery, along with chemotherapy. Herceptin slows the growth of HER2 positive breast cancer. Most people with HER2 positive breast cancer get Herceptin for one year. Patients receive the drug through an infusion in their doctor's office. For the first 12 weeks, you go in for an infusion every week, and then you get an infusion every 3 weeks for the next several months.
4. Herceptin and Your Heart
Some people call Herceptin a wonder drug, but it can damage the heart and affect its ability to pump correctly. About 1 in 4 people who receive Herceptin for 1 year go on to develop heart problems. However, since the drug is so effective and the heart problems are treatable with medication, most doctors consider this an acceptable risk. On the other hand, people with a type of heart disease known as left ventricular cardiac dysfunction should not receive Herceptin because the drug can cause congestive heart failure. In rare cases, Herceptin can also cause lung problems. Your doctor will perform tests on your heart and lungs before recommending Herceptin.
5. A Note About Safety
There are side effects caused by Herceptin. It can affect your red and white blood cell counts, which can increase your risk of infection. It can also drastically lower your blood pressure, in which case your doctor might take you off the medication. There are also annoying, but not as serious, flu-like symptoms like fever, headache, increased cough and tiredness. About two out of five women taking Herceptin report these symptoms, but they are usually worse at first and get better over time.
