How does this medication work? What will it do for me?

Trastuzumab emtansine belongs to the group of cancer-fighting medications known asantineoplastics. Specifically, it belongs to the group of antineoplastics known as targeted antibodies. It is used to treat HER2-positive breast cancer which has recurred or continued to grow after being treated with other medications.

Trastuzumab emtansine works by slowing or stopping the growth of cancer cells in your body and causing the death of tumour cells.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?

Powder for reconstitution for infusion

When reconstituted according to manufacturer's instructions, each single-use vial containing sterile powder for concentrate for infusion solution is designed to give 20 mg/mL of trastuzumab emtansine. Non-medicinal ingredients: polysorbate 20, sodium hydroxide, succinic acid, and sucrose.

How should I use this medication?

The recommended adult dose of trastuzumab emtansine varies according to body size. It is generally calculated as 3.6 mg per kilogram of body weight. Depending on how well this medication is tolerated, your doctor may reduce the dose to reduce the severity of side effects.

Trastuzumab emtansine is usually injected into a vein through a site on the skin that has been prepared for this purpose. The first dose is often scheduled to be given over a ninety minute period. If the side effects are well tolerated, the next doses may be given over 30 minutes, once every 3 weeks. Your doctor will want you to stay in the clinic after the infusion, for at least as long as the infusion takes to be administered. This is to ensure that any side effects experienced due to the administration of the medication can be treated immediately. The total number of infusions that you will receive depends on your response to the treatment.

Trastuzumab emtansine is always given under the supervision of a doctor.Very careful handling of this medication is required. It is always administered in a hospital or similar setting with access to sterile equipment for preparation.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important this medication be given exactly as recommended by your doctor. If you miss an appointment to receive trastuzumab emtansine, contact your doctor as soon as possible to reschedule your appointment.

This medication will be stored at the hospital or clinic where you receive the infusion.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you are allergic to trastuzumab emtansine or any ingredients of the medication.

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • abdominal pain
  • constipation
  • diarrhea
  • dizziness
  • dry mouth
  • fatigue
  • headache
  • increased blood pressure
  • inflammation or sores in the mouth
  • itchiness
  • loss of sensation of taste
  • muscle or joint pain
  • nausea
  • prickling, tingling, or numbness in the arms or legs
  • trouble sleeping
  • vomiting
  • weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • redness or irritation at the infusion site
  • signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
  • signs of bleeding (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
  • signs of bleeding in the stomach (e.g., bloody, black, or tarry stools, spitting up of blood, vomiting blood or material that looks like coffee grounds)
  • signs of breathing problems (e.g., shortness of breath, dry cough, wheezing, or tightness in chest, fast or irregular breathing)
  • signs of heart failure (e.g., shortness of breath, fatigue, swelling in legs, ankles, feet)
  • signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
  • signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)
  • vision changes

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Allergic reaction: Trastuzumab emtansine may cause severe allergic reactions during or soon after the infusion. The symptoms of this reaction can include flushing, difficulty breathing, fever, chills, low blood pressure, rapid heartbeat or wheezing. If you experience any of these symptoms, notify your doctor immediately. Your doctor will likely want you to stay at the clinic for a period of time after the infusion, so you can be monitored for these effects.

Birth Control: This medication is harmful to a developing baby if it is taken during pregnancy. Women who may become pregnant should use two different forms of birth control while being treated with trastuzumab emtansine and for at least 6 months after completing treatment with this medication.

Bleeding: Trastuzumab emtansine may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Severe decreases in platelets seems to occur more often in patients with Asian heritage.

Heart function: This medication can weaken the heart muscles and make it difficult for the heart to pump a normal amount of blood out with each heartbeat. This can then cause symptoms of congestive heart failure. If you experience signs of congestive heart failure, such as difficulty breathing at rest or lying down, swelling of legs, ankles or wrists or you feel tired more easily than usual, contact your doctor as soon as possible.

Interstitial Lung Disease: Rarely, trastuzumab emtansine can cause swelling and irritation in the tissues of the lungs, making it difficult to breathe. If you experience any shortness of breath, dry cough or unexpected weight loss, contact your doctor as soon as possible.

Liver function: Trastuzumab emtansine may reduce liver function and can cause liver failure. If left untreated, this liver failure can be fatal. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Pregnancy: This medication can cause deformities and possibly death to the developing baby if it is used by the mother during pregnancy. Trastuzumab emtansine should not be used during pregnancy due to the risk of harm to the baby. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if trastuzumab emtansine passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children less than 18 years of age.

What other drugs could interact with this medication?

There may be an interaction between trastuzumab emtansine and any of the following:

  • abciximab
  • anthracycline anti-cancer medications (e.g., daunorubicin, doxorubicin, idarubicin)
  • atazanavir
  • azathioprine
  • "azole" antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • belimumab
  • boceprevir
  • clozapine
  • conivaptan
  • corticosteroids (e.g., budesonide, dexamethasone, hydrocortisone, fluticasone, prednisone)
  • cyclosporine
  • delaviridine
  • digoxin
  • grapefruit juice
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • leflunomide
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • medications to treat cancer (e.g., carboplatin, cyclophosphamide, doxorubicin, ifosfamide, vincristine)
  • nefazodone
  • pimecrolimus
  • tacrolimus
  • vaccines
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.