Herceptin Hylecta (trastuzumab and hyaluronidase-oysk) is a type of targeted immunotherapy used in the treatment of HER2 (human epidermal growth factor receptor 2)-positive breast cancers. HER2-positive breast cancer cells overexpress - have excessive amounts of - the HER2 receptor protein on their surface. HER2 (previously called HER2/Neu) helps cancer cells to grow and divide quickly.

Herceptin Hylecta contains a monoclonal antibody known as trastuzumab. Trastuzumab is a HER2 inhibitor. It works by targeting and binding to HER2, which stops the cancer cells from growing and dividing. Trastuzumab initiates antibody-dependent cell-mediated cytotoxicity (ADCC), which means it gets your own immune system cells to target and kill the cancer cells that are coated with antibodies.

Herceptin Hylecta is administered over 2-5 minutes via a quick subcutaneous injection under the skin, unlike Herceptin which is an intravenous (IV) trastuzumab product that is administered via infusion into a vein or port over 30-90 minutes. The quick administration of Herceptin Hylecta is made possible by the addition of hyaluronidase, which is an enzyme that works temporarily at the injection site to facilitate the absorption of trastuzumab into the blood stream.

Herceptin Hylecta was approved by the US Food and Drug Administration (FDA) in 2019.

What is Herceptin Hylecta used for?

Herceptin Hylecta is a prescription medication used for adults with:

• adjuvant (early) HER2-positive breast cancer that is node positive (has spread to the lymph nodes) or node negative but with a feature that puts the patient at high risk of recurrence (ER/PR negative or with one high risk feature):
  • as part of a treatment regimen consisting of doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel
  • as part of a treatment regimen with docetaxel and carboplatin
  • as a single agent following multi-modality anthracycline based therapy.
• metastatic breast cancer (breast cancer that has spread):
  • in combination with paclitaxel for first-line treatment of HER2-overexpressing metastatic breast cancer
  • as a single agent for treatment of HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease.

Patients are selected for treatment based on an FDA-approved companion diagnostic for trastuzumab.

Herceptin Hylecta may cause serious side effects including:

• Heart Problems. This include heart problems - such as congestive heart failure or reduced heart function - with or without symptoms. The risk for and seriousness of these heart problems were highest in people who received both Herceptin Hylecta and a certain type of chemotherapy (anthracycline). In a study of adjuvant (early) breast cancer, one patient died of significantly weakened heart muscle. Your doctor will check for signs of heart problems before, during, and after treatment with this medication.
  
  Contact a health care 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.
• Severe lung problems including:
  • Severe shortness of breath
  • Scarring of the lungs
  • 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
    
    Your doctor may check for signs of severe lung problems when he or she examines you.
    These signs usually happen within 24 hours after receiving Herceptin Hylecta.
• Embryo-Fetal Toxicity. Herceptin Hylecta may result in the death of an unborn baby or birth defects. Contraception should be used while receiving treatment and for 7 months after your last dose of this medication. If you are or become pregnant while receiving this medication or within 7 months after your last dose, you are encouraged to report Herceptin Hylecta exposure to Genentech at 1‑888‑835‑2555.
• Exacerbation of Chemotherapy-Induced Neutropenia. Neutropenia (low white blood cell counts) can be life threatening. Low white blood cell counts were seen more often in patients receiving intravenous trastuzumab plus chemotherapy than in patients receiving chemotherapy alone in clinical trials. Your doctor may check for signs of low white blood cell counts when they examine you.
• Hypersensitivity and Administration-Related Reactions. Hypersensitivity and administration-related reactions have been reported with this medication. Serious and fatal reactions have been reported after treatment with intravenous trastuzumab products. Your doctor will monitor you for signs of these reactions. Contact your healthcare provider immediately if you experience any symptoms of hypersensitivity and administration-related reactions, including dizziness, nausea, chills, fever, vomiting, diarrhea, hives, swelling under the skin, breathing problems, or chest pain.

• Herceptin Hylecta is admistered by a healthcare professional.
• This medication is injected at an infusion center along with your other chemotherapy drugs. If you only take Herceptin Hylecta you may be able to receive injections at your doctor's office.
• Herceptin Hylecta is administered by subcutaneous injection over 2-5 minutes once every 3 weeks.
• The left and right thigh may be used for injections and ideally the alternate thigh should be used each time. New injections should be given at least 2.5 cm away from an old site. No injection should be given into areas where the skin is red, bruised, tender or hard.
• If other medicines for subcutaneous use are used during the treatment course, a different injection site should be used.
• Do not stop taking this medication without talking to your healthcare provider first.
• It may take up to 7 months for this medication to be removed from your body, so heart function checks may continue even after you've finished treatment.

The recommended dose of Herceptin Hylecta is 600 mg/10,000 units (600 mg trastuzumab and 10,000 units hyaluronidase) administered subcutaneously over approximately 2-5 minutes once every three weeks.

See full prescribing information for further details about dosing.

Do not receive Herceptin Hylectra if you are allergic to trastuzumab or any of the other ingredients in it. See below for a complete list of ingredients.

What should I tell my doctor before receiving Herceptin Hylecta?

Before receiving Herceptin Hylecta, tell your healthcare provider about all of your medical conditions including if you:

• have had heart failure, coronary artery disease or heart valve disease (heart murmurs)
• have had high blood pressure or have taken any high blood pressure medicine or are currently taking any high blood pressure medicine
• have ever had or are currently using a medicine called doxorubicin or epirubicin (medicines used to treat cancer). These medicines (or any other anthracyclines) can damage heart muscle and increase the risk of heart problems while taking medications containing trastuzumab.
• suffer from breathlessness, especially if you are currently using a taxane. Medications containing trastuzumab can cause breathing difficulties, especially when it is first given. This could be more serious if you are already breathless. Very rarely, patients with severe breathing difficulties before treatment have died when they were given Herceptin.
• have ever had any other treatment for cancer

If you miss a dose of Herceptin Hylecta, contact your healthcare provider and arrange to have it administered as soon as possible. The interval between subsequent injections should not be less than 3 weeks.

Trastuzumab, the active ingredient in this medication, may affect your ability to drive a car or operate machines. If during treatment, you experience symptoms, such as dizziness, sleepiness, chills or fever, you should not drive or use machines until these symptoms disappear.

Herceptin Hylecta can cause serious side effects:

• See 'Important information' above

The most common side effects of Herceptin Hylecta seen in patients with adjuvant breast cancer are:

• tiredness
• joint pain
• diarrhea
• injection site reaction
• upper respiratory tract infection
• rash
• muscle pain
• nausea
• headache
• swelling
• flushing
• fever
• cough
• pain in an extremity

The most common side effects of Herceptin Hylecta seen in patients with metastatic breast cancer (based on intravenous trastuzumab) are:

• fever
• chills
• headache
• infection
• congestive heart failure
• insomnia
• cough
• rash

These are not all the possible side effects of this medication.

You should contact your doctor immediately if you have any of the side effects listed above. You may report side effects to the FDA at 1‑800‑FDA‑1088 or http://www.fda.gov/medwatch. You may also report side effects to Genentech at 1‑888‑835‑2555.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Especially tell your doctor if you are prescribed an anthracycline drug after stopping Herceptin Hylecta. It is recommended to avoid anthracycline-based therapy for up to 7 months after stopping Herceptin Hylecta.