On June 29, 2020, the U.S. Food and Drug Administration (FDA) approved the fixed-dose combination of Herceptin (chemical name: trastuzumab), Perjeta (chemical name: pertuzumab), and hyaluronidase-zzxf to treat all stages of HER2-positive breast cancer in combination with chemotherapy.
The brand name of the medicine is Phesgo, and it is given as an injection under the skin.
Hyaluronidase-zzxf is an enzyme that helps the body absorb the medicines.
Both Herceptin and Perjeta are HER2 inhibitors. They work against HER2-positive breast cancer by blocking the chemical signals that tell the cancer cells to grow.
Traditionally, Herceptin and Perjeta are given intravenously, which means they’re delivered directly into your bloodstream through an IV or a port. The first dose of both medicines takes about an hour to complete. After that, it takes 30 to 60 minutes to get each dose.
Phesgo combines fixed doses of Herceptin and Perjeta, plus hyaluronidase-zzxf, in one vial. Phesgo is injected into a person’s thigh. The first dose of Phesgo takes about 8 minutes to inject, and each dose after that takes about 5 minutes, so the time to receive each dose is much shorter than getting an intravenous infusion of the medicines.
Because it’s given as an injection, a healthcare professional can give you Phesgo in your home, avoiding a trip to a treatment center.
When a medicine is injected under the skin, it’s called a subcutaneous injection.
Phesgo can be used in combination with chemotherapy:
- before surgery to treat early-stage or inflammatory HER2-positive breast cancer
- after surgery to treat early-stage HER2-positive breast cancer with a high risk of recurrence
Phesgo also can be used in combination with Taxotere (chemical name: docetaxel) to treat HER2-positive metastatic breast cancer that has not been treated with anti-HER2 therapy or chemotherapy.
“Currently, most patients with HER2-positive breast cancer receive trastuzumab and pertuzumab at infusion centers,” Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases, said in a statement. “With a new administration route, Phesgo offers an out-patient option for patients to receive trastuzumab and pertuzumab. As part of the FDA’s ongoing commitment to address the novel coronavirus pandemic, we continue to keep a strong focus on patients with cancer who constitute a vulnerable population at risk of contracting the disease. At this critical time, we continue to expedite oncology product development. This application was approved about 4 months ahead of the FDA goal date.”
The FDA’s approval of Phesgo is based on results from the FeDeriCa study, which found that injecting Phesgo was just as effective and safe as giving Herceptin and Perjeta through an IV.
“The FDA approval of Phesgo reflects our commitment to improving outcomes for the many people living with HER2-positive breast cancer,” Levi Garraway, M.D., Ph.D., Genentech chief medical officer and head of Global Product Development, said in a statement. “Phesgo offers a treatment administration that supports the needs and preferences of individual patients, and helps to meet the increasing demand across the healthcare system for faster and more flexible treatment options.”
Phesgo side effects
Both Herceptin and Perjeta can cause side effects, some of them severe. Giving the medicines as an injection doesn’t cause any different or more severe side effects.
The most common side effects of Phesgo when given with chemotherapy to treat early-stage HER2-positive breast cancer are:
- hair loss
- low red blood cell levels
The most common side effects of Phesgo when given with Taxotere to treat metastatic HER2-positive breast cancer are:
- hair loss
- low white blood cell levels
- peripheral neuropathy (numbness, tingling, or pain in the hands and feet)
The severe side effects Phesgo may cause are:
- Heart problems: Phesgo may cause serious heart problems, including some that don’t have symptoms, such as reduced heart function, and some that do have symptoms, such as congestive heart failure. Symptoms to watch for include swelling of the ankles or legs, shortness of breath, cough, or weight gain of more than 5 pounds in less than 24 hours. Contact your doctor immediately if you have any of these symptoms. Your risk of heart problems is higher if you are receiving Phesgo in combination with anthracycline chemotherapy.
- Lung problems: Phesgo may cause inflammation of the lungs, which can be life-threatening. Symptoms include trouble breathing, cough, tiredness, and fluid in the lungs.
- Severe neutropenia: Neutropenia means you have abnormally low levels of neutrophils, a type of white blood cell. People with neutropenia have a much higher risk of getting serious infections. Your doctor will monitor your neutrophil counts while you are being treated with Phesgo.
- Injection site reactions: Because Phesgo is given as an injection, a small number of people have had reactions at the injection site, including anaphylaxis. Anaphylaxis is a severe allergic reaction that can cause hives, low blood pressure, dizziness, chills, and trouble breathing. The healthcare provider who gives you the Phesgo injection will closely monitor you for 30 minutes after your first dose. For later doses, you will be monitored for 15 minutes. Tell your doctor immediately if you have any of the symptoms of anaphylaxis.
What this means for you
If you’ve been diagnosed with early-stage or inflammatory HER2-positive breast cancer and Herceptin and Perjeta will be part of your treatment plan, you may want to talk to your doctor about Phesgo and ask if getting the medicines as an injection makes sense for your unique situation.
If you’ve been diagnosed with metastatic HER2-positive breast cancer and are deciding on first treatments for metastatic disease, you also may want to talk to your doctor about Phesgo and discuss whether an injectable form of Herceptin and Perjeta makes sense for your unique situation.
Written by: Jamie DePolo, senior editor
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