High Alert Medication: This medication bears a heightened risk of causing significant patient harm when it is used in error.

Genetic Implications: Genetic Implications


Trade Name(s)

  • Herceptin Hylecta
  • Herceptin SC Canadian Trade name

Ther. Class.


Pharm. Class.

monoclonal antibodies


  • Genetic implication  Human epidermal growth factor receptor 2 (HER2)-overexpressing node-positive or node-negative breast cancer (as part of one of the following regimens: doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel; or docetaxel and carboplatin) (as adjuvant therapy).
  • Genetic implication HER2-overexpressing node-positive or node-negative breast cancer (to be used alone after multimodality anthracycline-based therapy) (as adjuvant therapy).
  • Genetic implication HER2-overexpressing metastatic breast cancer (as first-line therapy) (in combination with paclitaxel).
  • Genetic implication HER2-overexpressing metastatic breast cancer in patients who have already received ≥1 other chemotherapy regimens for metastatic disease (as monotherapy).


Trastuzumab:  Genetic implication A monoclonal antibody that binds to  HER2  sites in breast cancer tissue and inhibits proliferation of cells that overexpress  HER2  protein Hyaluronidase:  Acts locally by depolymerizing hyaluronan, which increases permeability of the SUBQ tissue.

Therapeutic Effect(s):

Regression of breast cancer and metastases.


Absorption: 77% absorbed following SUBQ administration.

Distribution: Minimally distributed to tissues.

Metabolism and Excretion: Unknown.

Half-life: Unknown.

TIME/ACTION PROFILE (plasma concentrations)

SUBQUnknown1–4 daysUnknown


Contraindicated in:

  • OB:  Pregnancy.

Use Cautiously in:

  • Pulmonary disease or extensive tumor involvement of lungs (↑ risk of pulmonary toxicity);
  • Dyspnea at rest (↑ risk of hypersensitivity reaction);
  • Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
  • Rep:  Women of reproductive potential;
  • Pedi:  Safety and effectiveness in children not established;
  • Geri:  Older adults may have ↑ risk of cardiac dysfunction.

Exercise Extreme Caution in:

Pre-existing cardiac dysfunction.

Adverse Reactions/Side Effects


Derm: alopecia, flushing, rash, erythema, pruritus, skin discoloration

EENT: epistaxis

GI: ↓ appetite, abdominal pain, constipation, diarrhea, dyspepsia, nausea, stomatitis, vomiting, ↑ liver enzymes

GU: menstrual abnormalities, urinary tract infection.

Hemat: anemia, leukopenia, NEUTROPENIA

Local: injection site pain

MS: arthralgia, myalgia

Neuro: dizziness, dysgeusia, headache, peripheral neuropathy, insomnia


Misc: fatigue, fever, HYPERSENSITIVITY REACTIONS (including anaphylaxis and angioedema)

* CAPITALS indicate life-threatening.
Underline indicate most frequent.



  • Concurrent administration of myelosuppressive  chemotherapy drugs  may worsen degree of neutropenia.
  • Concurrent  anthracycline  (daunorubicin,  doxorubicin, or  idarubicin ) therapy may ↑ risk of cardiotoxicity; if possible, avoid anthracycline-based therapy for up to 7 mo after stopping trastuzumab hyaluronidase.


Do not substitute with or for ado-trastuzumab emtansine. Dosage and route of administration is different from trastuzumab.

SUBQ (Adults): Trastuzumab 600 mg/hyaluronidase 10,000 units every 3 wk for 52 wk or disease recurrence, whichever occurs first (for adjuvant therapy) or until disease progression (for metastatic disease).


Solution for injection: trastuzumab 120 mg and hyaluronidase 2,000 units/mL


  • Conduct thorough cardiac assessment, including history, physical examination, and determination of left ventricular ejection fraction (LVEF) by echocardiogram or MUGA scan immediately before starting therapy. Determine LVEF measurements every 3 mo during and upon completion of therapy. Repeat LVEF measures at 4 wk intervals if trastuzumab hyaluronidase is held for LVEF dysfunction. Conduct LVEF measurements every 6 mo for at least 2 years following completion of therapy.  If ≥16% absolute ↓ in LVEF from pretreatment values or LVEF is below institutional limits of normal and ≥10% absolute ↓ in LVEF from pretreatment values,  hold trastuzumab hyaluronidase for at least 4 wk. Therapy may be resumed if, within 4-8 wk, LVEF returns to normal limits and absolute ↓ from baseline is ≤15%.  If persistent (>8 wk) LVEF decline or suspension of trastuzumab hyaluronidase for >3 occasions for cardiomyopathy,  permanently discontinue trastuzumab hyaluronidase.
  • Monitor patient for signs and symptoms of pulmonary toxicity (dyspnea, pulmonary infiltrates, pleural effusion, noncardiogenic pulmonary edema, pulmonary insufficiency, hypoxia, acute respiratory distress syndrome). Patients with symptomatic pulmonary disease or extensive lung tumor involvement are at increased risk. Infusion should be discontinued if severe symptoms occur.
  • Monitor for signs and symptoms of hypersensitivity reactions especially during first administration. Permanently discontinue trastuzumab hyaluronidase in patients with anaphylaxis or severe hypersensitivity reactions.

Lab Test Considerations:

Verify negative pregnancy status before starting therapy.

Genetic implication Patient selection is based on  HER2  protein overexpression or  HER2  gene amplification in tumor specimens. Assessment of  HER2  protein overexpression and  HER2  gene amplification should be performed using FDA-approved tests specific for breast cancer by laboratories with demonstrated proficiency. Information on FDA-approved tests for the detection of  HER2  protein overexpression and  HER2  gene amplification is available at:


  • High Alert: Do not confuse trastuzumab hyaluronidase (Herceptin Hylecta) with trastuzumab (Herceptin) or with ado-trastuzumab (Kadcyla).
  • Extending therapy beyond 1 yr is not recommended.
  • Before administration, check the vial to ensure that drug being administered is trastuzumab hyaluronidase and not IV trastuzumab or ado-trastuzumab.
  • SUBQ Injection should be administered by a health care professional. Solution does to not need to be diluted. Solution is colorless to yellowish and clear to opalescent; do not administer solutions that are cloudy, discolored, or contain particulate matter. Syringes are for single use only. Attach the hypodermic injection needle to the syringe immediately prior to administration to avoid clogging the needle, then adjust volume to 5 mL. Solution is compatible with polypropylene and polycarbonate syringe material and stainless steel transfer and injection needles. Solution is stable for 24 hr if refrigerated or 4 hr at room temperature; protect from light. Do not freeze or shake. Alternate injection between right and left thigh. Give new injection at least 2.5 cm from previous injection site. Avoid areas where skin is red, bruised, tender, or hard, or areas where there are moles or scars. Administer dose over 2–5 min.

Patient/Family Teaching

  • Explain purpose of trastuzumab hyaluronidase to patient.
  • Advise patients to contact a health care professional immediately if signs and symptoms of HF (new onset or worsening shortness of breath, cough, swelling of the ankles/legs, swelling of face, palpitations, weight gain >5 pounds in 24 hr, dizziness, loss of consciousness) or hypersensitivity reactions (dizziness, nausea, chills, fever, vomiting, diarrhea, urticaria, angioedema, breathing problems, chest pain) occur.
  • Rep:  May cause fetal harm (oligohydramnios, pulmonary hypoplasia, skeletal abnormalities, neonatal death). Advise females of reproductive potential to use effective contraception during and for 7 mo after last dose. Monitor women who received trastuzumab hyaluronidase during pregnancy or within 7 mo prior to conception for oligohydramnios. If oligohydramnios occurs, perform fetal testing. Advise patients to notify health care professional if pregnancy is suspected or if breastfeeding. Inform patient of  Pregnancy Pharmacovigilance Program. Patients who become pregnant during or with 7 mo of therapy should call immediately to report exposure to Genentech at 1-888-835-2555.

Evaluation/Desired Outcomes

Regression of breast cancer and metastases.