Perjeta: How Does It Work, Uses, Side Effects

Perjeta is used in combination with other medications for the treatment of certain types of breast cancer that has already spread to other parts of the body as well. Perjeta is the brand name for the commonly used drug pertuzumab. The medication works on the surface of the cancer cells, blocking out the chemicals signals from these cells that would otherwise boost the uncontrolled growth of these cancer cells. However, most people who are treated with Perjeta experience side effects such as joint or muscle pain, rash, and chills. If you experience side effects while on Perjeta, you need to make your doctor aware of the same immediately. Read on to find out more about Perjeta and its uses and side effects.

Perjeta, the brand name for the drug pertuzumab, is used in combination with other targeted therapy medicines and with Taxotere which is a type of chemotherapy drug, for the treatment of HER2-positive metastatic breast cancer. The medication is used for the treatment of the type of breast cancer that has not been treated with Herceptin, which is a type of targeted therapy medication, or with chemotherapy yet. Perjeta was known as Omnitarg during its early studies.⁽¹⁾

Perjeta also as the approval for:

• Being used in combination with Taxotere and Herceptin before surgery for the treatment of HER2-positive, early-stage, locally advanced, or inflammatory breast cancer which has a high risk of becoming fatal or metastasizing.
• Being used in combination with chemotherapy and Herceptin after surgery for the treatment of HER2-positive, early-stage breast cancer that has a greater risk of recurrence.

However, Perjeta is not a suitable treatment option for everyone who is undergoing treatment for breast cancer. The ideal candidates for treatment with Perjeta include:

• People who have HER2-positive metastatic breast cancer. Perjeta is not ideal for those patients who have already been treated with anti-HER2 therapy or chemotherapy for the metastatic disease.
• People who have early stage HER2-positive breast cancer and have not yet undergone surgery. In these cases, cancer has to be present in the lymph nodes or has to be larger than 2 cm.
• People who have early stage HER2-positive breast cancer and have already undergone surgery, but have a high recurrence risk.
• People who have HER2-positive breast cancer that is either locally advanced or inflammatory. These people have not yet undergone surgery.

Before progressing any further, it is important to understand what exactly is HER2-positive breast cancer. This is a type of breast cancer that tests positive for the human epidermal growth factor receptor 2 (HER2). HER2 is a protein that is responsible for boosting the growth of cancer cells in the body. HER2 positive breast cancer is much more aggressive than any other types of cancer.

Additionally, metastatic breast cancer refers to breast cancer that has already spread to other different parts of the body, moving away from the original spot (breast tissues) where it initially started.⁽²⁾

Perjeta has been approved for use in the treatment of HER2-positive metastatic breast cancer, but it has to be used in combination with both Herceptin (trastuzumab) and Taxotere (docetaxel. It is also used together with Herceptin and chemotherapy in patients of HER2-positive breast cancer that is locally advanced or inflammatory, or in an early stage.

Perjeta is commonly used before surgery. It is given every three weeks to the patient as an intravenous injection. When the patient goes to get this injection, he/she is also given chemotherapy and Herceptin.

For HER2-positive metastatic breast cancer, Perjeta is usually given once every three weeks also through an intravenous infusion. Herceptin and docetaxel are also administered during the same visit to the doctor’s office.

Perjeta is also given after surgery if there is a high chance of your cancer recurring. Your doctor might also recommend using Perjeta along with Herceptin once every three weeks through an intravenous infusion.

When you have any type of cancer, these cancerous cells start to grow in an uncontrolled fashion. Perjeta works on controlling this uncontrolled growth. It works on the surface of the cancer cells by blocking the chemical signals that boost this uncontrolled growth.

Genes present within your body act like an instruction manual that informs each and every cell of our body on how to grow, what type of cell to become, and also on how to behave. Genes are able to do this by ordering or passing the information to the cells to manufacture special proteins that will cause the cell to perform a certain activity, for example, cell growth, repair, or rest.

In cancerous cells, there are certain abnormalities in the genes that actually tell the cell how fast and how much to grow. Many times, cancer cells also have too many copies of these abnormal genes. When there are too many copies of these abnormal genes, it is known as overexpression. In some types of gene overexpression, cancer cells start manufacturing too many of the proteins that are responsible for controlling cell growth and cell division, leading to the growth and spread of cancer.

When you have breast cancer, some of the cancer cells start to overexpress too many copies of a gene known as HER2. This HER2 gene manufactures a protein called HER2 receptor. HER2 receptors can be thought to be like the ears or antennae on the surface of all cells. These HER2 receptors are the ones that receive the signals for stimulating the growth and multiplication of cells in the body. However, breast cancer cells that have too many HER2 receptors can start to pick up too many of these growth signals and therefore start multiplying and growing too fast and too much. These breast cancer cells that overexpress the HER2 gene are known as HER2-positive.
Similar to how Herceptin, Perjeta is also a HER2 inhibitor targeted therapy. It works by attaching itself to the HER2 receptors that are present on the surface of the breast cancer cells in your body. It then starts to block the reception of growth signals. Perjeta is known to target a different part on the HER2 receptor than the parts targeted by Herceptin. This is why it is believed to work in a manner that is complementary to Herceptin. By blocking the receptor signals, Perjeta is successful in slowing down or completely stopping the growth of breast cancer. Perjeta and Herceptin are two of the most common examples of immune targeted therapy.

Apart from blocking the HER2 receptors, Perjeta is also able to fight breast cancer by activating the immune system and alerting it to start destroying the cancer cells onto which Perjeta is attached.

There are many side effects commonly associated with Perjeta. These include:⁽³⁾

• Nausea/vomiting
• Fatigue
• Diarrhea
• Increased risk of infection
• Joint or muscle pain
• Headaches
• Rashes
• Hair loss
• Low white blood cell count
• Brittle fingernails or toenails
• Change in taste
• Chills
• Loss of appetite
• Bruising
• Bleeding gums
• Stomach aches
• Swelling in legs
• Anemia
• Sore mouth
• Dizziness
• Peripheral neuropathy

You should discuss the side effects that you experience with your doctor as your doctor will be the best person to know whether what you are experiencing is anything to be concern about or it is just a simple side effect of Perjeta. Your doctor will also suggest you ways in which you can control some of these side effects.

There is also a chance that you could end up having an allergic reaction to Perjeta. If you notice any of these following symptoms, you need to call your doctor at once as these are signs of a severe allergic reaction:

• Fever
• Nausea
• Headache
• Chills
• Facial swelling
• Difficulty breathing
• Throat swelling

In case of an allergic reaction, your doctor is likely to stop the intravenous infusion of Perjeta and take care of your symptoms first.

If your doctor has started you on Perjeta, then your cardiac function will be evaluated closely throughout the treatment. Your doctor will monitor you for the following:

• Congestive heart failure, a condition in which there is fluid buildup around your heart which causes it to pump inefficiently
• Decreased left ventricular ejection fraction, a condition in which there is a decrease in the amount of blood that is being pumped out of the left ventricle of the heart
• Left ventricular dysfunction, a condition that takes place when the left ventricle starts to lose its ability to get back to a relaxed state normally.⁽⁴⁾

If you are pregnant then you must inform your doctor about your pregnancy or even if you suspect you might be pregnant. This is because Perjeta causes embryo deaths and birth defects. This is why it is necessary to discuss the risks and benefits of treatment with Perjeta during this stage.

If you are not pregnant, then keep in mind that you should avoid becoming pregnant while you are being treated with Perjeta. It is best to discuss the best form of birth control during this period with your doctor.

Perjeta is known to be a strong, but effective, medication for treating an aggressive form of breast cancer. If you are suffering from HER2-positive cancer, then there is a high chance that your doctor will proscribe you with Perjeta, but only after discussing everything related to the drug with you. Treatments that target HER2 have been proven to be highly effective that the prognosis of HER2-positive breast cancer has today become quite good.

If your doctor is prescribing Perjeta to you, then make sure to discuss any potential side effects with your doctor, both during and after the treatment.

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