Dosage, Preparation, and Administration

Recommended weight-based dosage and schedule1

  • ENHERTU is always given as a monotherapy
Graphic depicting the dosing schedule for ENHERTU. 5.4 mg/kg IV once every 3 weeks (21-day cycle.) 90 minutes initial infusion, if well tolerated, 30 minutes subsequent infusions. Graphic depicting the dosing schedule for ENHERTU. 5.4 mg/kg IV once every 3 weeks (21-day cycle.) 90 minutes initial infusion, if well tolerated, 30 minutes subsequent infusions.
  • ENHERTU mBC dosage (5.4 mg/kg) may differ from other approved indications

Until disease progression or unacceptable toxicity

  • Do not substitute ENHERTU for or with trastuzumab or ado-trastuzumab emtansine
  • Slow or interrupt the infusion rate if the patient develops infusion-related symptoms
  • Permanently discontinue ENHERTU in case of severe infusion reactions
  • Premedication: ENHERTU is moderately emetogenic, which includes delayed nausea and/or vomiting. Administer prophylactic antiemetic medications per local institutional guidelines for prevention of chemotherapy-induced nausea and vomiting

Dosage forms and strengths

  • For injection: 100 mg of ENHERTU as a white to yellowish white lyophilized powder in a single-dose vial for reconstitution and further dilution
  • Please see below for Preparation for Administration instructions

Downloadable Resource for You:

    ENHERTU Dosing, Preparation, Administration
    and Infusion Guide

Recommended dose reductions for ENHERTU for adverse reactions1

  • Management of adverse reactions may require temporary interruption, dose reduction, or treatment discontinuation of ENHERTU per dose modifications provided in the tables below
  • Do not re-escalate the ENHERTU dose after a dose reduction is made
  • If a planned dose is delayed or missed, administer as soon as possible; do not wait until the next planned cycle. Adjust the schedule of administration to maintain a 3-week interval between doses. Administer the infusion at the dose and rate the patient tolerated in the most recent infusion
Dose reduction schedule Metastatic breast cancer
starting dose 5.4 mg/kg
First dose reduction 4.4 mg/kg
Second dose reduction 3.2 mg/kg
Requirement for further dose reduction Discontinue treatment

Dose modifications for adverse reactions1

Adverse reaction Severity Treatment modification
Interstitial Lung Disease (ILD/Pneumonitis) Asymptomatic ILD/pneumonitis
(Grade 1)
  • Consider corticosteroid treatment as soon as ILD/pneumonitis is suspected
  • Interrupt ENHERTU until resolved to Grade 0, then:
    • If resolved in 28 days or less from date of onset, maintain dose
    • If resolved in greater than 28 days from date of onset, reduce dose one level (see table above)
Symptomatic ILD/pneumonitis (Grade
2 or greater)
  • Permanently discontinue ENHERTU
  • Promptly initiate corticosteroid treatment as soon as ILD/pneumonitis is suspected
Neutropenia Grade 3 (less than 1.0 to 0.5 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 2 or less, then maintain dose
Grade 4 (less than 0.5 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 2 or less
  • Reduce dose by one level (see table above)
Febrile Neutropenia Absolute neutrophil count of less than
1.0 x 109/L and temperature greater than 38.3°C or a sustained temperature of 38°C or greater for more than 1 hour
  • Interrupt ENHERTU until resolved
  • Reduce dose by one level (see table above)
Thrombocytopenia Grade 3 (platelets less
than 50 to 25 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 1 or less, then maintain dose
Grade 4 (platelets less
than 25 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 1 or less
  • Reduce dose by one level (see table above)
Left Ventricular Dysfunction LVEF greater than 45% and absolute decrease from baseline is 10% to 20%
  • Continue treatment with ENHERTU
LVEF 40% to 45% And absolute decrease from baseline is less than 10%
  • Continue treatment with ENHERTU
  • Repeat LVEF assessment within 3 weeks

And absolute decrease from baseline is 10% to 20%
  • Interrupt ENHERTU
  • Repeat LVEF assessment within 3 weeks
  • If LVEF has not recovered to within 10% from baseline, permanently discontinue ENHERTU
  • If LVEF recovers to within 10% from baseline, resume treatment with ENHERTU at the same dose
LVEF less than 40% or absolute decrease from baseline is greater than 20%
  • Interrupt ENHERTU
  • Repeat LVEF assessment within 3 weeks
  • If LVEF of less than 40% or absolute decrease from baseline of greater than 20% is confirmed, permanently discontinue ENHERTU
Symptomatic congestive heart failure (CHF)
  • Permanently discontinue ENHERTU
Adverse
reaction 		Severity Treatment modification
Interstitial Lung Disease
(ILD/Pneumonitis) 		Asymptomatic
ILD/
pneumonitis
(Grade 1)
  • Consider corticosteroid treatment as soon as ILD/pneumonitis is suspected
  • Interrupt ENHERTU until resolved to Grade 0, then:
    • If resolved in 28 days or less from date of onset, maintain dose
    • If resolved in greater than 28 days from date of onset, reduce dose one level (see table above)
Symptomatic
ILD/
pneumonitis
(Grade 2
or greater)
  • Permanently discontinue ENHERTU
  • Promptly initiate corticosteroid treatment as soon as ILD/pneumonitis is suspected
Neutropenia Grade 3
(less than 1.0
to 0.5 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 2 or less, then maintain dose
Grade 4
(less than
0.5 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 2 or less
  • Reduce dose by one level (see table above)
Febrile Neutropenia Absolute neutrophil count of less than 1.0 x 109/L and temperature greater than 38.3°C or a sustained temperature of 38°C or greater for more than 1 hour
  • Interrupt ENHERTU until resolved
  • Reduce dose by one level (see table above)
Thrombocytopenia Grade 3 (platelets less than

50 to 25 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 1 or less, then maintain dose
Grade 4
(platelets less than
25 x 109/L)
  • Interrupt ENHERTU until resolved to Grade 1 or less
  • Reduce dose by one level (see table above)
Left Ventricular Dysfunction LVEF greater than 45% and absolute decrease from baseline is 10% to 20%
  • Continue treatment with ENHERTU
LVEF 40% to 45% And absolute decrease from baseline is less than 10%
  • Continue treatment with ENHERTU
  • Repeat LVEF assessment within 3 weeks
And absolute decrease from baseline is 10% to 20%
  • Interrupt ENHERTU
  • Repeat LVEF assessment within 3 weeks
  • If LVEF has not recovered to within 10% from baseline, permanently discontinue ENHERTU
  • If LVEF recovers to within 10% from baseline, resume treatment with ENHERTU at the same dose
LVEF less than 40% or absolute decrease from baseline is greater than 20%
  • Interrupt ENHERTU
  • Repeat LVEF assessment within 3 weeks
  • If LVEF of less than 40% or absolute decrease from baseline of greater than 20% is confirmed, permanently discontinue ENHERTU
Symptomatic congestive heart failure (CHF)
  • Permanently discontinue ENHERTU

Toxicity grades are in accordance with NCI-CTCAE v.5.0.

ENHERTU preparation for administration

In order to prevent medication errors, check the vial labels to ensure that the drug being prepared and administered is ENHERTU and not trastuzumab or ado-trastuzumab emtansine.1

Reconstitute and further dilute ENHERTU prior to intravenous infusion. Use appropriate aseptic technique.1

ENHERTU is a hazardous drug. Follow applicable special handling and disposal procedures.1,2

Reconstitution1

Reconstitution1

  • Reconstitute immediately before dilution
  • More than one vial may be needed for a full dose. Calculate the dose (mg), the total volume of reconstituted ENHERTU solution required, and the number of vial(s) of ENHERTU needed
  • Reconstitute each 100 mg vial by using a sterile syringe to slowly inject 5 mL of Sterile Water for Injection, USP into each vial to obtain a final concentration of 20 mg/mL
  • Swirl the vial gently until completely dissolved. Do not shake
  • Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. The solution should be clear and colorless to light yellow. Do not use if visible particles are observed or if the solution is cloudy or discolored
  • If not used immediately, store the reconstituted ENHERTU vials in a refrigerator at 2ºC to 8ºC (36ºF to 46ºF) for up to 24 hours from the time of reconstitution, protected from light. Do not freeze
  • The product does not contain a preservative. Discard unused ENHERTU after 24 hours refrigerated

Dilution1

Dilution1

  • Dilute the calculated volume of reconstituted ENHERTU in an intravenous infusion bag containing 100 mL of 5% Dextrose Injection, USP. DO NOT use Sodium Chloride Injection, USP. ENHERTU is compatible with an infusion bag made of polyvinylchloride or polyolefin (copolymer of ethylene and polypropylene)
  • Gently invert the infusion bag to thoroughly mix the solution. Do not shake
  • Cover the infusion bag to protect from light
  • If not used immediately, store at room temperature for up to 4 hours including preparation and infusion, or in a refrigerator at 2ºC to 8ºC (36ºF to 46ºF) for up to 24 hours, protected from light. Do not freeze
  • Discard any unused portion left in the vial

Administration1

Administration1

  • If the prepared infusion solution was stored refrigerated (2ºC to 8ºC [36ºF to 46ºF]), allow the solution to reach room temperature prior to administration. Cover the infusion bag to protect from light
  • Administer ENHERTU as an intravenous infusion only with an infusion set made of polyolefin or polybutadiene
  • Administer ENHERTU with a 0.20 or 0.22 micron in-line polyethersulfone (PES) or polysulfone (PS) filter
  • Do NOT administer as an intravenous push or bolus
  • Cover the infusion bag to protect from light during administration
  • Do not mix ENHERTU with other drugs or administer other drugs through the same intravenous line
  • First infusion: Administer infusion over 90 minutes
  • Subsequent infusions: Administer over 30 minutes if prior infusions were well tolerated

Please click here for full Prescribing Information, including Boxed WARNINGS, and click here for Medication Guide.

See Warnings and Precautions
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IV, intravenous; LVEF, left ventricular ejection fraction; mBC, metastatic breast cancer; NCI-CTCAE, National Cancer Institute–Common Terminology Criteria for Adverse Events.