Care During Chemotherapy and Beyond

Pertuzumab, Trastuzumab and Hyaluronidase

(per TU zoo mab, tras TU zoo mab, & hye al yoor ON i dase)

Trade Name(s): Phesgo ®

Pertuzumab/trastuzumab/hyaluronidase is the generic name for the trade name drug Phesgo. In some cases, health care professionals may use trade name or the generic name when referring to the drug.

Drug Type: Pertuzumab, trastuzumab, and hyaluronidase is a targeted therapy. This medication is classified as an antineoplastic agent and anti-HER2 monoclonal antibody (For more detail, see “How Pertuzumab, trastuzumab, and hyaluronidase Works” below).

What This Drug Is Used For

  • Early Breast Cancer
    • Used in combination with chemotherapy in adults with HER2+, locally advanced, inflammatory, or early stage breast cancer (EBC).
    • In combination with chemotherapy occurring after surgery in HER2+ adults with high risk of recurrence.
  • Metastatic Breast Cancer
    • Used in combination with docetaxel for HER2+ adults with metastatic breast cancer who have not received prior anti-HER2 therapy or prior chemotherapy in the metastatic setting.

Note: 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 Pertuzumab, Trastuzumab and Hyaluronidase Is Given

  • Injected subcutaneously by a healthcare professional into the patient’s thigh
    • Alternate between left and right thighs and allow 2.5 cm between previous injection site.
    • Look for healthy skin void of redness, swelling, moles, tattoos or any other scar tissue.
  • Initial (loading) dose (15 mL injection)
    • Inject over 8 minutes
    • Observe patient for 30 minutes following the injection
  • Maintenance dose (10 mL injection)
    • Inject over 5 minutes
    • Observe patient for 15 minutes following the injection if the patient had no reaction to previous infusions.
  • Missed dose:
    • If ≤ 6 weeks since previous dose, administer maintenance dose.
    • If o If ≥ 6 weeks since previous dose, administer initial dose followed by maintenance dose 3 weeks later.

Side Effects

Important things to remember about the side effects of Pertuzumab, trastuzumab, and hyaluronidase:

  • Most people will not experience all of the side effects listed.
  • Pertuzumab, trastuzumab, and hyaluronidase side effects are often predictable in terms of their onset, duration, and severity.
  • Most side effects will improve after therapy is complete.
  • There are many options to minimize or prevent the side effects of pertuzumab, trastuzumab, and hyaluronidase.

The following side effects are common (occurring in greater than 30%) for patients taking pertuzumab, trastuzumab, and hyaluronidase:

These are less common side effects (occurring in 10-29%) for patients receiving pertuzumab, trastuzumab, and hyaluronidase:

These are rare serious side effects for patient receiving pertuzumab, trastuzumab, and hyaluronidase:

Not all side effects are listed above. 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:

  • Fever of 100.4º F (38º C) or higher, chills (possible signs of infection), dizziness, nausea, vomiting, diarrhea, urticaria, angioedema, breathing problems of chest pain.

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)
  • Unusual bleeding or bruising
  • Black or tarry stools, or blood in your stools
  • Blood in the urine
  • Pain or burning with urination
  • Extreme fatigue (unable to carry on self-care activities)

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


  • Before starting Pertuzumab, trastuzumab, and hyaluronidase 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.
  • Pertuzumab, trastuzumab, and hyaluronidase has been known to have an increased risk of neutropenia when administered with any myelosuppressive chemotherapy.
  • Inform your health care professional if you are pregnant or may be pregnant prior to starting this treatment. This drug must not be given to a pregnant woman or a woman who intends to become pregnant. If you become pregnant while taking Pertuzumab, trastuzumab, and hyaluronidase , stop taking the medication immediately and call your doctor for further instructions.
  • Pertuzumab, trastuzumab, and hyaluronidase has been known to cause embryo-fetal toxicities for up to 7 months post injection. In femals of reproductive potentential, effective contraception should be used during therapy and for 7 months after the last dose.

Self-Care Tips

  • Drink at least two to three quarts of fluid every 24 hours, unless you are instructed otherwise.
  • You may be at risk of infection so try to avoid crowds or people with colds, and report fever or any other signs of infection immediately to your health care provider.
  • Wash your hands often.
  • Use an electric razor and a soft toothbrush to minimize bleeding.
  • Avoid contact sports or activities that could cause injury.
  • To reduce nausea, take anti-nausea medications as prescribed by your doctor, and eat small, frequent meals.
  • Follow regimen of anti-diarrhea medication as prescribed by your health care professional.
  • Eat foods that may help reduce diarrhea (see managing side effects - diarrhea).
  • Avoid sun exposure. Wear SPF 30 (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.
  • Get plenty of rest.
  • Maintain good nutrition.
  • Remain active as you are able. Gentle exercise is encouraged such as a daily walk.
  • 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.

Monitoring and Testing While Taking Pertuzumab, Trastuzumab and Hyaluronidase

  • You will be checked regularly by your doctor while you are taking Pertuzumab, trastuzumab, and hyaluronidase 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 orther orders (such as your kidneys and liver) may also be ordered by your doctor.
  • Cardiac studies to assess Left Ventricular Ejection Fraction (LVEF), may be ordered

How Pertuzumab, Trastuzumab and Hyaluronidase Works

Cancer is a disease caused by changes, also known as mutations, in DNA that change the way cells grow and divide. Cancer cells can be destroyed using many different types of medications that work in very different ways. Examples of medications that destroy cancer cells include cytotoxic chemotherapy, targeted therapy, immunotherapy, and antibody-drug conjugates.

The immune system uses antibodies to protect the body against foreign substances. An antibody is a protein that sticks to a specific type of protein called an antigen. When an antibody finds an antigen, it triggers the immune system to destroy the cells that have the antigen. Researchers can create antibodies in a lab that target specific antigens like ones found on cancer cells. These antibodies created in a lab are called monoclonal antibodies.

Monoclonal antibodies target specific differences in the cancer cells than normal cells. Since monoclonal antibodies have a specific target on cancer cells, they may cause less toxicity to healthy cells. Each type of monoclonal antibody 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.

Phesgo® contains two separate monoclonal antibodies, trastuzumab and pertuzumab. Previously, trastuzumab and pertuzumab were used separately or in combination to provide anti-cance r treatment. Phesgo® combined these two separate monoclonal antibodies into a single injection for use.

Trastuzumab and pertuzumab are monoclonal antibodies that both target a protein called HER2 on cancer cells; however, they bind to different sites on the protein. When bound, these agents work together to inhibit cancer cell growth and cause cancer cell death.

The addition of hyaluronidase-zzxf to the combination medication allows for both trastuzumab and pertuzumab to be absorbed more readily into the bloodstream. It does not have any anti-cancer effects.

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. is designed to provide the latest information about chemotherapy to patients and their families, caregivers and friends. For information about the 4th Angel Mentoring Program visit