Getting the PHESGO injection

Unlike other cancer medicines—like PERJETA (pertuzumab) or Herceptin (trastuzumab), which are given by infusion through an IV or port—PHESGO is given by injection, like a "shot".

Since it’s an injection under the skin, PHESGO does not require a port.

PHESGO is always given by a healthcare professional just under the skin of the thigh. At each appointment, the injection alternates between the left and the right thigh.


Injection time

The first dose of PHESGO takes about 8 minutes to inject. After that, doses take about 5 minutes to inject.

Your healthcare team will wait at least 30 minutes after the first dose, and at least 15 minutes after each following dose, to check for any reactions. If side effects occur, your healthcare provider may slow, delay, or stop your treatment.


Treatment schedule

Depending on your condition, your healthcare team will determine the treatment plan that’s right for you. You can also explore what your treatment schedule might look like here:

What if I miss an injection?

If you miss a dose of PHESGO, DO NOT WAIT until your next treatment. Contact your doctor or nurse right away and work with them to reschedule the treatment you missed.


“With PHESGO not requiring a port, I feel less like someone living with cancer”


Watch Jen’s story to hear more about her experience with HER2+ breast cancer and PHESGO.

Photograph of Jen, a woman with HER2+ breast cancer, looking out at a lake

Tips for treatment days

A pair of shorts

Dress for ease

Wear loose shorts or a skirt for your appointment so your healthcare provider can easily access your thigh for injection. It’s a good idea to bring a blanket, too, to stay warm.

Talking to a nurse

Take advantage of 1-on-1 nurse time

During injection, you’ll have your healthcare provider’s undivided attention, so it’s a good idea to come prepared with questions to ask about your treatment and progress. You can also talk about how you’re feeling and about any side effects you may be experiencing.

Real PHESGO stories

See how real people reacted to being diagnosed with HER2+ breast cancer and what getting treatment with PHESGO means to them.

Important Safety Information & Uses

What is PHESGO?

PHESGO is a prescription medicine approved for use in combination with chemotherapy for:

  • use prior to surgery (neoadjuvant treatment) in adults with HER2+, 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+ early breast cancer that has a high likelihood of coming back.

PHESGO is also approved for use in combination with docetaxel in adults who have HER2+ 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.