Disclaimer: This information is intended to help you understand your treatment. Always discuss your health and treatment plan with your doctor or nurse, who can answer your specific questions.
At a Glance: Quick Facts about Trastuzumab
- Generic Name: Trastuzumab
- Brand Name(s): The original formulation of trastuzumab is Herceptin®. Trastuzumab is available as a biosimilar. You can ask your healthcare provider for more information. A preparation of trastuzumab for subcutaneous administration is available under the Herceptin Hylecta™ (in the U.S.), Herceptin SC® (in Europe and other regions). A combination of trastuzumab and pertuzumab is available as Phesgo®. There are no generics of this subcutaneous preparation. Subcutaneous preparations can be administered quickly on the thigh.
- Type of Drug: Monoclonal Antibody (a type of targeted therapy)
- How It’s Given: As an infusion into a vein (intravenous [IV]) or subcultaneously (see Brand name(s))
- Common Cancers Treated: Cancers that are “HER2-positive,” most commonly breast cancer and some types of stomach (gastric) and esophageal cancer.
About Trastuzumab
- What It Is and What It’s Used For: Trastuzumab is a type of targeted therapy called a monoclonal antibody. It is not a traditional chemotherapy drug. It is specifically used to treat cancers that have high levels of a protein called Human Epidermal growth factor Receptor 2 (HER2). Your cancer will have been tested to confirm it is “HER2-positive” before you are prescribed this medication.
- How It Works: Think of HER2 as a switch on the surface of some cancer cells that tells them to grow and divide uncontrollably. Trastuzumab is designed to work like a guided missile that seeks out and attaches specifically to these HER2 switches. By attaching to them, it can block the signal telling the cell to grow and can also alert your body’s own immune system to find and destroy the cancer cell.
How You Will Receive This Drug
- Your Dosing Schedule: Trastuzumab is most often given once every three weeks. It may sometimes be given once a week. When administered once a week, each dose is one-third the dose administered once in 3 weeks. For early-stage breast cancer, treatment typically lasts for one year. For advanced cancers, you will receive it for as long as it is helping your condition.
- How is Trantuzumab Administered: Trastuzumab can be administered in two ways, offering the same medical benefit but a different experience for the patient.
- Intravenous (IV) Infusion: This is the traditional method. You will receive it at a hospital or clinic via an IV line. The very first infusion is given slowly, usually over 90 minutes, while you are monitored closely. Subsequent infusions are much shorter, typically lasting only 30 minutes.
- Subcutaneous (SC) Injection: This is a much newer and faster method. It is given as a simple injection under the skin of your thigh. The entire process takes only about 2 to 8 minutes. This formulation (e.g., Herceptin Hylecta®, Phesgo®) contains an extra enzyme that helps your body absorb the medicine quickly. This option significantly reduces time spent in the clinic.
- Important Instructions: Reactions to the medication are most common with the first dose, regardless of how it is given. Your medical team will watch you carefully during and after your first treatment
Possible Side Effects
- Most Common Side Effects:
- Infusion-Related Reactions: Symptoms like fever, chills, headache, or a rash are most common during the first treatment and are usually mild.
- Fatigue: Feeling tired or weak.
- Body Aches: Mild pain in muscles and joints.
- Diarrhea: This is usually mild. The combination of trastuzumab and pertuzumab can cause mor diarrhoea that trastuzumab alone.
- Nausea: This is also typically mild.
- Headache.
- Less Common but SERIOUS Side Effects: This drug has a boxed warning for major risks:
- Heart Problems (Cardiotoxicity): This is the most important serious side effect. Trastuzumab can weaken the heart muscle, reducing its ability to pump blood effectively, which can lead to heart failure. Your heart function will be checked before you start and at regular intervals during your treatment.
- Lung Problems: In rare cases, severe lung problems can occur.
- When to Contact/inform Your Doctor Immediately:
- Signs of Heart Problems: New or worsening shortness of breath (especially when lying down), a persistent cough, sudden weight gain, or swelling in your ankles, feet, or legs.
- Signs of a Infusion Reaction: Dizziness, trouble breathing, or swelling of the tongue or throat during a previous infusion.
- Signs of Infection: Fever over 38°C (100.4°F), chills, or a sore throat.
Important Information to Discuss with Your Doctor
- Before You Start Treatment: Tell your doctor your full medical history, especially if you have any heart conditions (like high blood pressure or valve problems) or any lung conditions.
- Pregnancy and Contraception: This drug can harm a developing fetus. Women must use effective birth control during treatment and for at least 7 months after the final dose.
- Drug and Food Interactions: Tell your doctor and pharmacist about all medicines you take, including prescriptions, over-the-counter drugs, vitamins, and herbal supplements.
Practical Tips While Taking Trastuzumab
- What to Do If You Miss a Dose: If you miss your scheduled appointment, call your doctor’s office as soon as possible to reschedule.
- Storage: This medication is handled and stored by your healthcare team.
- Follow-Up and Monitoring: The most important monitoring is for your heart. Expect to have an echocardiogram (ECHO) or a MUGA scan before you start, every 3 months during treatment, and for a period after treatment ends.
Questions to Ask Your Healthcare Team
- What is the main goal of this treatment for my cancer?
- How will my heart be monitored, and how often?
- What specific signs of heart or lung problems should I watch for at home?
- How are infusion reactions managed if they occur?
- What is the number to call if I have an urgent problem after hours?
- How long is my planned course of treatment?