Key Points Herceptin is a monoclonal antibody that attaches to proteins on some cancer cells and slows or stops the growth of the cells (see Question 1). Herceptin is used to treat HER–2 positive breast cancer (see Question 3). Some serious side effects, including heart muscle damage and allergic reactions, are associated with Herceptin (see Question 5). Herceptin is being studied in clinical trials (research studies) for the treatment of breast cancer and other types of cancer (see Question 6).

1. What is Herceptin? How does it work?

Herceptin (trastuzumab) is a monoclonal antibody. Antibodies are substances the body produces to help fight infection or other foreign particles. Monoclonal antibodies are made in the laboratory, and some are designed to attack specific cancer cells.

Herceptin targets cancer cells that “overexpress,” or make too much of, a protein called HER–2 or erb B2, which is found on the surface of some cancer cells. Herceptin attaches to the HER–2 positive cancer cells and slows or stops the growth of the cells. Herceptin is used only to treat breast cancers that are HER–2 positive. HER–2 positive cancers overexpress the HER–2 protein or have amplification (too many copies) of the HER–2 gene.

Approximately 20 to 30 percent of breast cancers overexpress HER–2. These tumors tend to grow faster and are generally more likely to recur (come back) than tumors that do not overproduce HER–2.

2. How are tumors tested for HER–2?

The amount of HER–2 protein in the tumor is measured in the laboratory using a test called immunohistochemical (IHC) analysis. The results of the test are measured on a scale from 0 (negative) to 3+ (strongly positive). Patients with tumors that are 3+ on the IHC test are most likely to benefit from Herceptin therapy; those with tumors that are 0 or 1+ are unlikely to benefit from this treatment. Patients with tumors that are 2+ often have an additional test, called fluorescence in situ hybridization (FISH), to determine whether the tumor is HER–2 positive. FISH measures the number of copies of a gene. Tumors with too many copies of the HER–2 gene as determined by the FISH test are considered positive.

3. How is Herceptin used in the treatment of cancer?

Herceptin is approved by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic breast cancer (breast cancer that has spread to other parts of the body) that is HER–2 positive. The FDA approved Herceptin after two clinical trials (research studies) with women whose metastatic breast cancers produced excess amounts of HER–2 demonstrated that Herceptin was safe and effective.

In 2005, the results of four clinical trials showed that Herceptin is also effective in the treatment of early-stage breast cancer that overexpresses HER–2. In all four studies, women who received Herceptin and chemotherapy lived longer and had significantly less chance of the breast cancer coming back than patients who received chemotherapy alone.

4. How is Herceptin given? What are some of the common side effects of Herceptin?

Herceptin is given by infusion (a method of putting fluids, including drugs, into the bloodstream). The first dose of Herceptin is usually given over a 90-minute period, and the nurse or doctor watches the patient for signs of side effects. If the patient tolerates this dose well, smaller maintenance doses can be given over a 30-minute period.

Side effects that most commonly occur during the first treatment with Herceptin include fever and/or chills. Other possible side effects include pain, weakness, nausea, vomiting, diarrhea, headaches, difficulty breathing, and rashes. These side effects generally become less severe after the first treatment with Herceptin.

Patients who receive Herceptin along with chemotherapy may experience side effects that are different from those of patients who take Herceptin by itself. For example, anemia (a condition in which the number of red blood cells is below normal) and infection, primarily mild upper respiratory infection, have been seen more often in patients given Herceptin with chemotherapy compared with those receiving Herceptin alone. Patients should discuss any concerns about the side effects of treatment with their doctor. The doctor may be able to make suggestions for managing side effects.

5. Can Herceptin cause any serious side effects?

Yes. Herceptin can cause heart muscle damage that can lead to heart failure. Heart failure is a serious condition in which the heart cannot pump enough blood throughout the body. Symptoms of heart failure include shortness of breath, difficulty breathing, and swelling of the feet or lower legs.

Herceptin can also affect the lungs, causing severe or life-threatening breathing problems that require immediate medical attention.

In addition, Herceptin can cause hypersensitivity (allergic) reactions that can be severe or life-threatening. Symptoms of a reaction include a drop in blood pressure, shortness of breath, rashes, and wheezing. Most patients who experience hypersensitivity reactions do so when the drug is being given or within 24 hours after treatment.

Because of these potentially life-threatening side effects, doctors evaluate patients carefully for any heart or lung problems before starting treatment. Doctors and nurses also monitor patients closely during treatment. Patients who develop any problems during or after treatment should call the doctor immediately or go to the nearest emergency care facility.

6. Is Herceptin still being studied in clinical trials?

Yes. Clinical trials are ongoing to test the safety and effectiveness of Herceptin for breast and other types of cancer. People interested in taking part in a clinical trial should talk with their doctor. Information about clinical trials is available from the National Cancer Institute's (NCI) Cancer Information Service (CIS) (see below) at 1–800–4–CANCER and in the NCI booklet Taking Part in Cancer Treatment Research Studies, which can be found at http://www.cancer.gov/publications on the Internet. This booklet describes how research studies are carried out and explains their possible benefits and risks. More information about clinical trials is available at http://www.cancer.gov/clinicaltrials on the NCI's Web site. The Web site offers detailed information about specific ongoing studies by linking to PDQ^®, the NCI's comprehensive cancer information database.

# # #

• National Cancer Institute Fact Sheet 7.2, Biological Therapies for Cancer: Questions and Answers ¹
  (http://www.cancer.gov/cancertopics/factsheet/Therapy/biological)
• National Cancer Institute Fact Sheet 7.49, Targeted Cancer Therapies: Questions and Answers ²
  (http://www.cancer.gov/cancertopics/factsheet/Therapy/targeted)
• Taking Part in Cancer Treatment Research Studies ³ (http://www.cancer.gov/clinicaltrials/Taking-Part-in-Cancer-Treatment-Research-Studies)

For more help, contact:

NCI's Cancer Information Service
Telephone (toll-free): 1–800–4–CANCER (1–800–422–6237)
TTY (toll-free): 1–800–332–8615
LiveHelp^® online chat: https://cissecure.nci.nih.gov/livehelp/welcome.asp

Glossary Terms

A condition in which the number of red blood cells is below normal.

A type of protein made by plasma cells (a type of white blood cell) in response to an antigen (foreign substance). Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord.

The Cancer Information Service is the National Cancer Institute's link to the public, interpreting and explaining research findings in a clear and understandable manner, and providing personalized responses to specific questions about cancer. Access the CIS by calling 1-800-4-CANCER (1-800-422-6237), or by using the LiveHelp instant-messaging service at https://cissecure.nci.nih.gov/livehelp/welcome.asp. Also called CIS.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

Treatment with drugs that kill cancer cells.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical study.

Frequent and watery bowel movements.

The amount of medicine taken, or radiation given, at one time.

Any substance, other than food, that is used to prevent, diagnose, treat or relieve symptoms of a disease or abnormal condition. Also refers to a substance that alters mood or body function, or that can be habit-forming or addictive, especially a narcotic.

A substance that flows smoothly and takes the shape of its container. Liquids and gases are fluids.

The functional and physical unit of heredity passed from parent to offspring. Genes are pieces of DNA, and most genes contain the information for making a specific protein.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Herceptin is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Herceptin is also being studied in the treatment of other types of cancer. Also called trastuzumab.

An exaggerated response by the immune system to a drug or other substance.

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

Treatment that is given to help keep cancer from coming back after it has disappeared following the initial therapy. It may include treatment with drugs, vaccines, or antibodies that kill cancer cells, and it may be given for a long time.

Having to do with metastasis, which is the spread of cancer from one part of the body to another.

A type of protein made in the laboratory that can locate and bind to substances in the body, including tumor cells. There are many kinds of monoclonal antibodies. Each monoclonal antibody is made to find one substance. Monoclonal antibodies are being used to treat some types of cancer and are being studied in the treatment of other types. They can be used alone or to carry drugs, toxins, or radioactive materials directly to a tumor.

The National Cancer Institute, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. The National Cancer Institute conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

In biology, to make too many copies of a protein or other substance. Overexpression of certain proteins or other substances may play a role in cancer development.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

To come back or to return.

A cell that carries oxygen to all parts of the body. Also called erythrocyte and RBC.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

An indication that a person has a condition or disease. Some examples of symptoms are headache, fever, fatigue, nausea, vomiting, and pain.

Treatment.

A monoclonal antibody that binds to HER2 (human epidermal growth factor receptor 2), and can kill HER2-positive cancer cells. Monoclonal antibodies are made in the laboratory and can locate and bind to substances in the body, including cancer cells. Trastuzumab is used to treat breast cancer that is HER2-positive and has spread after treatment with other drugs. It is also used with other anticancer drugs to treat HER2-positive breast cancer after surgery. Trastuzumab is also being studied in the treatment of other types of cancer. Also called Herceptin.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

To eject some or all of the contents of the stomach through the mouth.