Understanding possible side effects with PHESGO

Side effects may occur during treatment with PHESGO. It’s important to know what side effects may happen and what to watch out for during your treatment with PHESGO. Talk to your doctor about any and all side effects you experience, even if you think they are minor.


Most serious side effects of PHESGO

  • PHESGO may cause heart problems, including those without symptoms (such as reduced heart function) and those with symptoms (such as congestive heart failure)
  • Receiving PHESGO during pregnancy can result in the death of an unborn baby and birth defects
  • PHESGO may cause serious lung problems
  • Other possible serious and sometimes fatal side effects of PHESGO therapy include:
    • Worsening of low white blood cell counts caused by chemotherapy
    • Severe allergic reactions (hypersensitivity reactions/anaphylaxis) and administration-related reactions

Most common side effects of PHESGO and tips you can try

The most common side effects of PHESGO when given with chemotherapy as part of an early breast cancer regimen are hair loss, nausea, diarrhea, low levels of red blood cells, and weakness.

The most common side effects of PHESGO when given with docetaxel for treatment of breast cancer that has spread to other parts of the body (metastatic) are diarrhea, hair loss, low levels of white blood cells with or without fever, nausea, feeling tired, rash, and damage to the nerves (numbness, tingling, pain in hands/feet).

Learn what to watch out for and get tips for certain side effects below.

Remember, the tips mentioned below may not work for everyone. Be sure to talk with your doctor before trying any of these tips.

Hair loss (also called alopecia) may happen on any part of the body. It may happen suddenly or a little at a time, and may cause the hair to become thin, dry, or dull.

Some tips you can try:
  • Use a mild shampoo, and try not to wash your hair every day
  • Avoid perming, curling, straightening, or blow-drying with high heat
  • Apply a broad-spectrum sunscreen to the scalp, or cover the scalp with a sun-protective hat or scarf when outside

Nausea is when you feel sick to your stomach. This can lead to vomiting—when you throw up.

Some tips you can try:
  • Try relaxation techniques, such as deep breathing or thinking of a positive image or scene, to distract you from feeling sick to your stomach
  • Choose foods that are nutritious and avoid foods that are greasy, fried, salty, sweet, or spicy
  • If the smell of a food bothers you, try cooling it down before eating it

When you have diarrhea, it means you have loose or watery bowel movements that happen 3 or more times in a day.

Some tips you can try:
  • Drink plenty of clear, noncarbonated fluids, and consider using electrolyte replacement drinks, such as sports drinks
  • Choose nutritious foods, rather than foods that are greasy, fatty, or spicy
  • Eat small, frequent meals of foods that are easy to digest, such as rice or applesauce
  • Eat foods high in potassium, such as bananas or potatoes

A low red blood cell count (also called anemia) means that parts of the body may be getting less oxygen. This can lead to symptoms like weakness or feeling tired.

Some tips you can try:
  • Eat foods high in iron, such as spinach, lean beef, and lentils
  • Eat foods high in vitamin B12, such as liver, salmon, or fortified cereal

A low white blood cell means you have a weakened immune system or are “immunocompromised.” You are at a higher risk of getting sick from a virus or other infections.

Some tips you can try:
  • Wash your hands frequently and have the people you spend time with do the same
  • Avoid large crowds of people, as germs can spread easily through coughing and sneezing
  • Be extra cautious when outdoors. Avoid swimming or wading in lakes, streams, and ponds, wear bug repellent and long sleeves and pants to avoid mosquito bites, and wear gloves while gardening to avoid cuts or scrapes

A lack of physical strength or energy that may affect your balance or movement.

Some tips you can try:
  • Don’t overdo it, and get enough rest
  • Exercise by taking short walks, if your doctor approves. This may help improve your sleep and energy levels

Fatigue is a feeling of being tired or exhausted that may affect your ability to perform normal activities.

Some tips you can try:
  • Be physically active each day, if your doctor approves. This may help improve your appetite, strength, and weight
  • Participate in activities during the time of day when you have more energy
  • Do the most important tasks first

An area of irritated or swollen skin. Many rashes are itchy, red, painful, and irritated.

Some tips you can try:
  • Pat the skin dry (instead of rubbing) after a bath or shower
  • Wear loose clothes to avoid rubbing and irritating the rash

Sensations of discomfort can occur when there’s damage to the nerves that send signals from the brain to parts of the body.

Some tips you can try:
  • Good nutrition, including foods rich in thiamine, protein, and antioxidants
  • Taking medications as directed by your doctor
  • Physical or occupational therapy may be helpful
Looking for more support?

Discover HERConnection, a free support program with information, tips, and tools to help you navigate the PHESGO treatment journey.

Important Safety Information & Uses

What does PHESGO treat?

PHESGO® (pertuzumab, trastuzumab, and hyaluronidase-zzxf) is a prescription medicine approved for use in combination with chemotherapy for:

  • use prior to surgery (neoadjuvant treatment) in adults with HER2-positive, locally advanced, inflammatory, or early stage breast cancer (tumor is greater than 2 cm in diameter or node-positive). PHESGO should be used as part of a complete treatment regimen for early breast cancer. 
  • use after surgery (adjuvant treatment) in adults with HER2-positive early breast cancer that has a high likelihood of coming back.

PHESGO is a prescription medicine approved for use in combination with docetaxel in adults who have HER2-positive breast cancer that has spread to different parts of the body (metastatic) and who have not received anti-HER2 therapy or chemotherapy for metastatic breast cancer.

What are the most serious side effects of PHESGO?

PHESGO may cause heart problems, including those without symptoms (such as reduced heart function) and those with symptoms (such as congestive heart failure).

  • The risk for and seriousness of these heart problems are highest in people who received both PHESGO and a certain type of chemotherapy (anthracycline)
  • Your doctor will check for signs of heart problems before, during, and after treatment with PHESGO. Based on test results, your doctor may hold or discontinue treatment with PHESGO
  • Contact a healthcare professional immediately for any of the following: new onset or worsening shortness of breath, cough, swelling of the ankles/legs, swelling of the face, palpitations, weight gain of more than 5 pounds in 24 hours, dizziness or loss of consciousness

Receiving PHESGO during pregnancy can result in the death of an unborn baby and birth defects.

  • Birth control should be used while receiving PHESGO and for 7 months after your last dose of PHESGO. If you are a mother who is breastfeeding, you should talk with your doctor about either stopping breastfeeding or stopping PHESGO
  • If you think you may be pregnant, you should contact your healthcare provider immediately
  • If you are exposed to PHESGO during pregnancy, or become pregnant while receiving PHESGO or within 7 months following the last dose of PHESGO, you are encouraged to report PHESGO exposure to Genentech at 1-888-835-2555

PHESGO may cause serious lung problems.

  • Your doctor may check for signs of lung problems including:
    • Severe shortness of breath
    • Fluid in or around the lungs
    • Weakening of the valve between the heart and the lungs
    • Not enough oxygen in the body
    • Swelling of the lungs
    • Scarring of the lungs

Who should not receive PHESGO?

  • PHESGO should not be used in patients who are allergic to pertuzumab, trastuzumab, hyaluronidase, or to any of the ingredients in PHESGO

What are other possible serious side effects?

  • PHESGO may worsen low white blood cell counts caused by chemotherapy: Low white blood cell counts can be life threatening and were seen more often in patients receiving Herceptin® (trastuzumab) plus chemotherapy than in patients receiving chemotherapy alone. Your doctor may check for signs of low white blood cell counts when he or she examines you
  • PHESGO may cause administration-related reactions: PHESGO is given as an injection. The active ingredients in PHESGO have been associated with severe administration reactions, including hypersensitivity or anaphylaxis, which can be fatal. Talk to your doctor if you feel any symptoms. The most common symptoms include dizziness, nausea, chills, fever, vomiting, diarrhea, hives, swelling of the skin, breathing problems, or chest pain

What are the most common side effects?

The most common side effects of PHESGO when given with chemotherapy as part of an early breast cancer regimen are:

  • Hair Loss
  • Nausea
  • Diarrhea
  • Low levels of red blood cells
  • Weakness

The most common side effects of PHESGO when given with docetaxel for treatment of breast cancer that has spread to other parts of the body (metastatic) are:

  • Diarrhea
  • Hair loss
  • Low levels of white blood cells with or without fever
  • Nausea
  • Feeling tired
  • Rash
  • Damage to the nerves (numbness, tingling, pain in hands/feet)

What should I know about side effects with PHESGO?

  • Not all people have serious side effects; however, side effects with PHESGO therapy are common. It is important to know what side effects may happen and what symptoms you should watch for
  • Your doctor may stop treatment if serious side effects happen. Be sure to contact your healthcare team right away if you have questions or are worried about any side effects

You are encouraged to report side effects to Genentech and the FDA. You may report side effects to the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. You may also report side effects to Genentech at 1-888-835-2555.

Talk to a healthcare professional for more information about the benefits and risks of PHESGO. 

Please see full Prescribing Information for additional Important Safety Information, including most serious side effects.

If you cannot afford your medication, visit phesgo.com/financial-support for financial assistance information.