Targeted therapy for breast cancer
Targeted therapy drugs attack specific targets inside cancer cells. The drugs that are currently available do not work for all types of breast cancer. They are useful only for HER2 positive breast cancers. For early or locally advanced breast cancer, the main targeted therapy drug is trastuzumab (brand name Herceptin). Other drugs are available for advanced breast cancer.
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Trastuzumab is usually referred to by the brand name Herceptin although there are other drugs similar to trastuzumab now available in Australia. These are known as biosimilar medicines and include Herzuma, Kanjinti and Ogivri.
Herceptin works by attaching itself to HER2 positive breast cancer cells, destroying the cells or reducing their ability to divide and grow. Herceptin also encourages the body’s own immune cells to help destroy the cancer cells.
Herceptin is used together with chemotherapy. It has been shown to increase the effect of chemotherapy drugs on early breast cancer. Most people have Herceptin via a drip into a vein (infusion), but some people have it as an injection under the skin.
The first infusion takes about 90 minutes. This is called the loading dose. The following infusions take 30–60 minutes each. You will usually have a dose every three weeks, and they will continue for up to 12 months. The first four doses are given while you are having chemotherapy treatment.
Your medical team will monitor you for side effects. These are usually caused by the chemotherapy. This means that once chemotherapy finishes and you are continuing with Herceptin alone, most side effects ease. For example, hair grows back, there is no nausea or vomiting, and you no longer need regular blood tests.
Although side effects from Herceptin itself are uncommon, they can include headache, fever and diarrhoea. In some people, Herceptin can affect how the heart works, so you will have tests to check your heart function before and during treatment.
A number of new drugs have been developed and tested as additional treatments after Herceptin for people with HER2 positive breast cancer. Talk to your doctor about whether these are appropriate for you.
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Prof Bruce Mann, Professor of Surgery, The University of Melbourne, and Director, Breast Tumour Stream, Victorian Comprehensive Cancer Centre, VIC; Dr Marie Burke, Radiation Oncologist, and Medical Director GenesisCare Oncology, QLD; Dr Susan Fraser, Breast Physician, Cairns Hospital and Marlin Coast Surgery Cairns, QLD; Ruth Groom, Consumer; Julie McGirr, 13 11 20 Consultant, Cancer Council Victoria; A/Prof Catriona McNeil, Medical Oncologist, Chris O’Brien Lifehouse, NSW; Dr Roya Merie, Staff Specialist, Radiation Oncology, Liverpool Cancer Therapy Centre, Liverpool Hospital, NSW; Dr Eva Nagy, Oncoplastic Breast Surgeon, Sydney Oncoplastic Surgery, NSW; Gay Refeld, Clinical Nurse Consultant – Breast Care, St John of God Subiaco Hospital, WA; Genny Springham, Consumer.
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Targeted therapy is a type of drug treatment that attacks specific features of cancer cells, known as molecular targets, to stop the cancer growing and spreading. Other names for targeted therapy include biological therapies and molecular targeted therapy.