(pan-i-TOO-moo-mab) 

Trade Name: Vectibix

Panitumumab is the generic name for the trade name drug Vectibix. In some cases, health care professionals may use the trade name Vectibix when referring to the generic drug name Panitumumab.

Drug Type:

Panitumumab is classified as a "monoclonal antibody" and "signal transduction inhibitor" by binding to epidermal growth factor receptors (EGFR).

What Panitumumab Is Used For:

Panitumumab is used to treat colorectal cancer that has spread.  It is used to treat colon cancers that express EGFR and disease that has gotten worse either on or following fluoropyrimidine, oxaliplatin and irinotecan containing chemotherapy regimens.

If a drug has been approved for one use, physicians may elect to use this same drug for other problems if they believe it may be helpful.

How Panitumumab Is Given:

Panitumumab is given through an infusion into a vein (intravenous, IV).  An infusion pump is used to give the Panitumumab.

The amount of Panitumumab that you will receive depends on many factors, including your height and weight, your general health or other health problems, and the type of cancer or condition you have. Your doctor will determine your exact dosage and schedule.

Side Effects:

Important things to remember about the side effects of Panitumumab:

• You will not get all of the Panitumumab side effects mentioned below.
• Panitumumab side effects are often predictable in terms of their onset, duration, and severity.
• Panitumumab side effects are almost always reversible and will go away after therapy is complete.
• There are many options to minimize or prevent Panitumumab side effects.
• There is no relationship between the presence or severity of side effects and the effectiveness of the medication

The following Panitumumab side effects are common (occurring in greater than 30%) for patients taking Panitumumab:

• Skin reactions (including redness, acneform dermatitis, itching, or rash).
• Low level of magnesium in the blood (hypomagnesemia).

These are less common side effects (occurring in about 10-29%) for patients receiving Panitumumab:

• Fatigue
• General deterioration
• Abdominal pain
• Nausea
• Diarrhea
• Vomiting
• Swelling in hands or feet
• Cough
• Dry skin
• Inflammation of the bed of the fingernails
• Eye irritation (conjunctivitis, increased tears, irritation)

A serious but rare side effect of panitumumab is potential for a severe infusion reaction (including allergic reaction, chills, fever, and bronchospasm) causing difficulty breathing.  This will be monitored carefully during the infusion.  If you feel short of breath, let your health care provider know immediately.  If signs of reaction occur, the infusion is stopped.

Panitumumab may impair fertility (the ability to conceive) in women of childbearing potential.  The effects of Panitumumab on male fertility are unknown.  You should discuss this with your health care professional.

Not all side effects of Panitumumab are listed above.  This list includes common and less common side effects for those taking Panitumumab. Side effects that are very rare -- occurring in less than about 10 percent of patients -- are not listed here. But you should always inform your health care provider if you experience any unusual symptoms.

When to contact your doctor or health care provider:

Contact your health care provider immediately, day or night, if you should experience any of the following symptoms:

• Shortness of breath.
• Fever or chills during the infusion.

The following symptoms require medical attention, but are not an emergency. Contact your health care provider within 24 hours of noticing any of the following:

• Nausea (interferes with ability to eat and unrelieved with prescribed medication)
• Vomiting (vomiting more than 4-5 times in a 24 hour period)
• Diarrhea (4-6 episodes in a 24-hour period)
• Extreme fatigue (unable to carry on self-care activities)
• Swelling of the hands or feet
• Severe rash (causing pain, itching or drainage)
• Eye irritation

Always inform your health care provider if you experience any unusual symptoms.

Precautions:

• Before starting Panitumumab treatment, make sure you tell your doctor about any other medications you are taking (including prescription, over-the-counter, vitamins, herbal remedies, etc.). Do not take aspirin, products containing aspirin unless your doctor specifically permits this.
• Do not receive any kind of immunization or vaccination without your doctor’s approval while taking Panitumumab.
• Inform your health care professional if you are pregnant or may be pregnant prior to starting Panitumumab. Pregnancy category C (use in pregnancy only when benefit to the mother outweighs risk to the fetus).
• For both men and women: Use contraceptives, and do not conceive a child (get pregnant) while taking Panitumumab. Barrier methods of contraception such as condoms are recommended. Discuss with your doctor when you may safely become pregnant or conceive a child after therapy.
• Avoid exposure to sun while taking Panitumumab.  Use sunscreen, hats and protective clothing.  Sunlight make worsen skin reactions.
• Do not breast feed while taking Panitumumab.

Self-Care Tips:

• Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
• Wash your hands often.
• To reduce nausea while taking Panitumumab, take anti-nausea medications as prescribed by your doctor, and eat small, frequent meals.
• Avoid sun exposure. Wear SPF 15 (or higher) sunblock and protective clothing.
• In general, drinking alcoholic beverages should be kept to a minimum or avoided completely. You should discuss this with your doctor.
• If you experience symptoms or side effects, be sure to discuss them with your health care team. They can prescribe medications and/or offer other suggestions that are effective in managing such problems.
• In general, drinking alcoholic beverages should be kept to a minimum or avoided completely. You should discuss this with your doctor.
• Get plenty of rest.
• Maintain good nutrition.
• If you experience symptoms or side effects while taking Panitumumab, be sure to discuss them with your health care team. They can prescribe medications and/or offer other suggestions that are effective in managing such problems.

Monitoring and Testing:

You will be checked regularly by your doctor while you are taking Panitumumab to monitor side effects and check your response to therapy. Periodic blood work to monitor your complete blood count (CBC) as well as the function of other organs (such as your kidneys and liver) may also be ordered by your doctor.

How Panitumumab Works:

Targeted therapy is the result of about 100 years of research dedicated to understanding the differences between cancer cells and normal cells. To date, cancer treatment has focused primarily on killing rapidly dividing cells because one feature of cancer cells is that they divide rapidly. Unfortunately, some of our normal cells divide rapidly too, causing multiple side effects.

Targeted therapy is about identifying other features of cancer cells. Scientists look for specific differences in the cancer cells and the normal cells. This information is used to create a targeted therapy to attack the cancer cells without damaging the normal cells, thus leading to fewer side effects. Each type of targeted therapy works a little bit differently but all interfere with the ability of the cancer cell to grow, divide, repair and/or communicate with other cells. Modern targeted therapy types include the use of monoclonal antibodies and anti-angiogenesis drugs, both of which are described in greater depth here.

The different types of targeted therapies are defined in three broad categories. Some targeted therapies focus on the internal components and function of the cancer cell. The targeted therapies use small molecules that can get into the cell and disrupt the function of the cells, causing them to die. There are several types of targeted therapy that focus on the inner parts of the cells. Other targeted therapies target receptors that are on the outside of the cell. Therapies that target receptors are also known as monoclonal antibodies. Anti-angiogenesis drugs target the blood vessels that supply oxygen to the cells, ultimately causing the cells to starve.

Researchers agree that targeted therapies are not a replacement for traditional therapies. Targeted therapies involve production of components such as monoclonal antibodies or anti-angiogenesis drugs may best be used in the short term, combination with traditional therapies. More research is needed to identify which cancers may be best treated with targeted therapies such as monoclonal antibodies or anti-angiogenesis drugs and to identify additional targets for more types of cancer.

Using Monoclonal Antibodies as Targeted Therapy

Monoclonal antibodies are a relatively new type of "targeted" cancer therapy. Antibodies are part of the immune system. Normally, the body creates antibodies in response to an antigen (such as a protein in a germ) entering the body. The antibodies attach to the antigen in order to mark the antigen for destruction by the body's immune system. In the laboratory, scientists analyze specific antigens on the surface of cancer cells (target) to determine a protein to match the antigen. Then, using protein from animals and humans, scientists work to create a special antibody that will attach to the target antigen. An antibody will attach to a matching antigen like a key fits a lock. This technology allows treatment to target specific cells, causing less toxicity to healthy cells. Monoclonal antibody therapy can be done only for cancers in which antigens (and the respective antibodies) have been identified.

Panitumumab is a targeted therapy that targets and binds to the epidermal growth factor receptors (EGFR) on the surface of the cell. EGFR is found on the surface of many normal and cancer cells.  By binding to these receptors, Panitumumab blocks an important pathway that promotes cell division this results in inhibition of cell growth and apoptosis (cell suicide).  Panitumumab is believed to work when the tumor cells test positive for expression of EGFR.

Note: We strongly encourage you to talk with your health care professional about your specific medical condition and treatments. The information contained in this website is meant to be helpful and educational, but is not a substitute for medical advice.

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