Most drugs work by blocking or interfering with the activity of a protein molecule. So the fact that the HER2 protein was present at a very high level in some breast cancer cells highlighted it as a good target for potential drugs to treat HER2 positive tumours.
Building on the research from our scientists and others around the world, Dr Mark Sliwkowski and his colleagues at the biotechnology company Genentech developed a way to target HER2 with an antibody – the same kind of molecule that Professor Gullick first used to reveal the location of HER2 in cancer cells.
The antibody blocked the receptor activity of HER2, stopping it transmitting signals into the cells that made them grow and divide. This eventually became the drug Herceptin (also known as trastuzumab).
Herceptin was approved as a drug for HER2 positive breast cancer in 1998, 10 years before Sadie got her diagnosis.
Sadie had surgery, chemotherapy and radiotherapy before she started Herceptin treatment. It wasn’t the easiest road for her to walk down, as she explains.
“The long haul began, I wrote ‘be brave, a faint heart never won the day’ on my first day of chemotherapy, but my resolve was tested as I became more and more unwell during the treatment. Would I make my daughter’s graduation and my nephew’s wedding? Both of which required photos – and I’d lost my hair!
“But as the months went by I started to look and feel a bit more normal. After all, I’d got cancer but it had not got me.”
Sadie started Herceptin treatment in 2009, getting the drug every 3 weeks. Because it can sometimes affect the heart muscle, Sadie also had heart scans to keep an eye on things. The first Herceptin delivery went as planned, at first, until Sadie started having a bad reaction to the treatment. But doctors and nurses responded quickly, and avoided any serious problems.
Sadie abseiling down the Forth Rail Bridge in South Queensferry.
“I continued on with another five treatments, together with heart scans, and all seemed to go to plan – but I started to show signs of problems with my heart, so I was taken off the drug for a three month recovery period. Then I completed my full course of Herceptin without any further difficulties. I even managed to abseil down the Forth Rail Bridge during my year of treatment!’
Researchers are working hard to make new variants of Herceptin. The next generation of treatments are being developed to make them kinder, with fewer side effects for patients.
And other research is looking at wider uses of Herceptin. It’s now used to treat HER2 positive stomach cancer patients. And there have been studies indicating that the drug might be beneficial for patients with lung cancer , pancreatic cancer and even some HER2 negative breast cancers . What’s for sure is that Herceptin will continue to benefit thousands of patients, and possibly many more in the future as we find new uses for it.
As for Sadie, this year she celebrated 5 years cancer free by once again joining the Edinburgh Race for Life.
“It was the most beautiful day and the crowds were mighty pink! Crossing the finish line I could not help but cry…but tears of joy on this occasion. The finish line banner said “We did it” ….we sure did.”
With special thanks to Sadie for sharing her story with us.
*In England and Wales between 10 per cent and 15 per cent of breast cancers in women are HER2 positive. This is based on a subset of surgically-treated breast cancer cases and so the estimate includes some adjustment by Cancer Research UK. National Cancer Intelligence Network (2011). Second All Breast Cancer Report .
Venter D.J., Tuzi N.L., Kumar S. & Gullick W.J. Overexpression of the c-erbB-2 oncoprotein in human breast carcinomas: immunohistological assessment correlates with gene amplification., Lancet, PMID: 2885574