Enhertu (fam-trastuzumab deruxtecan-nxki) is a brand-name prescription medication. The Food and Drug Administration (FDA) has approved it to treat certain types of cancer that contain human epidermal growth factor receptor 2 (HER2). Enhertu is approved for use in adults.
Specifically, Enhertu is used to treat:
- HER2-positive breast cancer that can’t be surgically removed or has spread to other areas of the body
- HER2-positive stomach or esophagus cancer that has spread to other areas of the body
Enhertu belongs to a group of medication called antibody-drug conjugate. There’s currently no generic version of Enhertu.
Enhertu comes as a powder that’s mixed into a solution. The solution is given as an IV infusion by your doctor or another healthcare professional.
Your doctor may only recommend Enhertu after you’ve already tried other medications to treat your cancer that did not work.
Dosage summary
The following chart summarizes Enhertu’s dosage. Your doctor will determine the dosage that’s best for you.
| Condition | Form | Dosage | Strength | Frequency |
| Breast cancer | powder that’s mixed into a solution for IV infusion | 5.4 milligrams per kilogram of body weight* (mg/kg) | 100 mg | every 3 weeks |
| Stomach or esophageal cancer | 6.4 mg/kg | every 3 weeks |
* One kg is about 2.2 pounds (lb).
For information about the dosage of Enhertu, including its strengths and how to take the drug, keep reading. For a comprehensive look at Enhertu, see this article.
Below is information about Enhertu and its typical dosages for certain types of cancer.
Enhertu form
Enhertu comes as a powder that’s mixed into a solution. The solution is given as an IV infusion by your healthcare professional at your doctor’s office or clinic.
Enhertu strength (100 mg)
Enhertu comes in one strength: 100 milligrams (mg).
Typical dosages
Your doctor will recommend the best dosage for you. They may adjust it over time to reach the amount that’s right for you. Your doctor will ultimately prescribe the smallest dosage that provides the desired effect.
If you have additional questions about Enhertu dosing, such as the maximum dose or the best dosage for you, talk with your doctor.
The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.
Dosage for stomach cancer
The dosage of Enhertu for stomach cancer is based on your body weight. The recommended dosage of Enhertu is 6.4 mg per kilogram of body weight (mg/kg). (One kg is about 2.2 pounds [lb].) So, if you weigh 70 kg (about 154 lb), your dose would be 448 mg. You’ll receive this dose of Enhertu once every 3 weeks.
You’ll continue receiving Enhertu treatment until you develop side effects from the medication that cause you to need to stop taking it, or until your cancer worsens.
Dosage for esophageal cancer
For esophageal cancer, your dose of Enhertu is based on your body weight. The recommended dosage is 6.4 mg/kg. So, if you weigh 70 kg (about 154 lb), your dose of Enhertu would be 448 mg. You’ll receive your dose of Enhertu once every 3 weeks.
You’ll continue receiving Enhertu treatment until you develop side effects from the medication that cause you to need to stop taking it, or until your cancer worsens.
Dosage for breast cancer
To treat breast cancer, your dosage of Enhertu is based on your body weight. The recommended dosage is 5.4 mg/kg. So, if you weigh 70 kg (about 154 lb), your dose of Enhertu would be 378 mg. You’ll receive your dose of Enhertu once every 3 weeks.
You’ll continue receiving Enhertu treatment until you develop side effects from the medication that cause you to need to stop taking it, or until your cancer worsens.
Long-term treatment
Enhertu is meant to be a long-term treatment. If you and your doctor determine that Enhertu is safe and effective for you, you’ll likely take it long term. In some cases, such as if you have serious side effects from Enhertu or if your cancer worsens, your doctor may recommend that you stop taking Enhertu.
The Enhertu dosage your doctor prescribes will depend on several factors. These include:
- the type of cancer you have
- your weight
- if you have side effects with Enhertu treatment
Other medical conditions you have can also affect your Enhertu dosage.
Dosage adjustments
In some cases, your doctor may recommend adjusting your dosage of Enhertu if you’re experiencing side effects during your treatment. These side effects can include:
- lung problems
- neutropenia (low white blood cell levels)
- febrile neutropenia (fever with low white blood cell levels)
- low platelet count (platelets are cells that help blood clot)
- heart problems
In these cases, your doctor may decrease your dosage to try to lower the possibility of side effects occurring. If you have severe side effects, your doctor may recommend that you stop treatment with Enhertu and try a different medication.
Enhertu comes as a powder that’s mixed into a solution. The solution is given as an IV infusion by your healthcare professional at your doctor’s office or clinic. (An IV infusion is an injection given over a period of time.)
You’ll get your first dose of Enhertu over 90 minutes to be sure that you don’t have any side effects from the drug. Then, after your first dose, your Enhertu infusions will only take 30 minutes. If you develop side effects during your treatment with Enhertu, your infusion may be slowed down and may take longer.
If you have questions about how Enhertu is given, talk with your doctor.
If you miss your dose of Enhertu, reschedule your appointment to get your dose as soon as possible. Then, adjust your schedule so you’re continuing to receive doses every 3 weeks. Do not skip a dose of Enhertu.
To help make sure that you don’t miss an appointment for your dose of Enhertu, try using a medication reminder. This can include setting an alarm or using a timer. You could also download a reminder app on your phone.
The dosages in this article are typical dosages provided by the drug manufacturer. If your doctor recommends Enhertu for you, they’ll prescribe the dosage that’s right for you. If you have questions about the dosage of Enhertu that’s right for you, talk with your doctor.
Besides learning about dosage, you may want other information about Enhertu. These additional articles might be helpful to you:
- More about Enhertu. For information about other aspects of Enhertu, refer to this article.
- Side effects. To learn about side effects of Enhertu, see this article. You can also look at the Enhertu prescribing information.
- Drug comparison. Find out how Enhertu compares with Herceptin and Tykerb.
- Details about your condition. For details about cancer, see our cancer hub. To learn more about breast cancer, you can refer to our breast cancer hub and list of related articles.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.