BMA Concise Guide to Medicine & Drugs

Trastuzumab

Brand name Herceptin

Used in the following combined preparations None

QUICK REFERENCE

Drug group Anticancer drug

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Trastuzumab belongs to a group of drugs known as monoclonal antibodies and is used in the treatment of early and advanced breast cancer and stomach cancer. Produced synthetically, it is similar to antibodies that occur naturally to fight infection, and it attacks cancer cells in a similar way.

Around one breast cancer in five involves cancer cells with excessive amounts of a protein called HER2 on their surface. HER2 stimulates the growth of these cancer cells, making the tumours aggressive and fast growing.

Trastuzumab blocks the HER2 protein on the cancer cells, destroying them. Therefore, to see whether treatment would be appropriate, it is necessary for tests to be carried out to confirm the presence of HER2.

Trastuzumab may be given on its own or in combination with other treatments. It is given by intravenous infusion, either weekly or every three weeks.

INFORMATION FOR USERS

Trastuzumab is prescribed only under close medical supervision, taking account of your present condition and medical history.

How taken/used Intravenous infusion, subcutaneous injection.

Frequency and timing of doses Every 1–3 weeks. Infusions are usually given over a 90-minute period.

Adult dosage range As advised by doctors, according to your bodyweight.

Onset of effect Not known.

Duration of action Up to 24 weeks.

Diet advice None.

Storage Not applicable. The drug is not normally kept in the home.

Missed dose The drug is administered in hospital under close medical supervision. If for some reason you miss your dose, contact your doctor as soon as possible.

Stopping the drug Discuss with your doctor. Stopping the drug prematurely may lead to worsening of the underlying condition.

Exceeding the dose Overdosage is unlikely since treatment is carefully monitored and supervised.

POSSIBLE ADVERSE EFFECTS

Infusion reactions such as fever and shivering are common, especially with the first infusion. Other common effects include nausea, vomiting, diarrhoea, weakness, abdominal pain, and muscle and joint pain. Discuss with your doctor if any of these are severe. Trastuzumab may also cause heart failure. If you experience wheezing, breathlessness, cough, palpitations, chest pain, dizziness, flu-like symptoms, swelling of the lips or face, or an itchy rash, notify your doctor immediately; the drug should also be stopped if lip or facial swelling, itchy rash, or wheezing occur.

INTERACTIONS

Doxorubicin and other anticancer drugs There is an increased risk of heart failure when these are given with trastuzumab.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You are allergic to trastuzumab.

· You have breathing difficulties.

· You have had heart failure, coronary artery disease, or high blood pressure.

· You have ever had chemotherapy before, especially with doxorubicin.

· You are pregnant or planning pregnancy.

· You are taking other medicines.

Pregnancy Not recommended.

Breast-feeding Not advised during treatment with trastuzumab and for six months after stopping.

Infants and children Not recommended under 18 years. Safety not established.

Over 60 No special problems.

Driving and hazardous work No known problems. However, if you have fever or shivering (infusion reaction) do not undertake such activities until symptoms subside.

Alcohol No known problems.

PROLONGED USE

Serious problems are rare.

Monitoring Treatment is under specialist supervision; patients are usually observed for at least six hours after the start of treatment and for two hours after subsequent treatments. Heart function should be assessed regularly during treatment.