At the ASCO Meeting in May 2005 the results of three clinical trials showed convincingly that Herceptin is a useful addition to chemotherapy in preventing breast cancer recurrence for women who have tumours that are Her2-positive. These results were subsequently published in the New England Journal of Medicine. Updates at ASCO in June 2006 show that Herceptin also prolongs survival. The trials have only been conducted since the year 2000 so reliable long-term data are awaited.
So far there seems to be little in the way of side-effects, although a decline in heart function occurs in around 4% of women. There is a possibility that this effect on the heart muscle may not be entirely reversible on cessation of Herceptin, but permanent clinical effects are rare so far.
There were two American studies: the National Surgical Adjuvant Breast and Bowel Project (NSABP) study began enrollment in March 2000 and had 2,085 patients. The North Central Cancer Treatment Group (NCCTG) study enrolled its first patient in June 2000 and had 3,406 patients. Both studies were supported by the US National Cancer Institute. The joint interim analysis presented at ASCO this was based on data from 3,351 patients. Each of the studies was a randomized, controlled trial that evaluated the combination of anthracycline and cyclophosphamide (AC) followed by paclitaxel chemotherapy, with or without Herceptin, using different treatment schedules of paclitaxel in women with Her2-positive breast cancer.
Australian women took part in another of these trials, the "HERA" (HERceptin Adjuvant) Trial, conducted by Roche and the Breast International Group (BIG). This was a large-scale, 39-country study which compared 12 months or 24 months with observation in patients with Her2 positive tumours who had finished their adjuvant chemotherapy and radiotherapy. An interim analysis at ASCO shows a significant reduction in breast cancer recurrences for women who had Herceptin, but it is too early to look at survival outcomes. It is also too early to know if 12 months or 2 years treatment is better.
It seems likely that patients who were randomised on this trial to observation may be eligible to have Herceptin. Any of my patients who are so eligible will be contacted by our team at Westmead, but if you are concerned and were a part of this trial you can contact Sonia Byrne RN at soniabr@westgate.wh.usyd.edu.au or 02-9845-8935. There is no evidence that having Herceptin more than 9 months after diagnosis has any benefit, so I would advise any of you who are in that bracket to relax.
PLEASE NOTE: Do NOT be alarmed if you had Her2 positive breast cancer and you did not receive this drug. The improvements are RELATIVE. When the press reports say "it improves survival by 49%" this does not mean you will live twice as long! Let's say, 90% of women were going to be alive and free of breast cancer at 10 years, then about 94% would be alive and free of breast cancer if they had the treatment. The most important part of your preventative strategy remains the chemotherapy, radiotherapy and, if indicated, the hormone therapy, (like tamoxifen).
At the ASCO Meeting in June 2006 evidence was presented showing that Herceptin prolongs life in certain women with Her2 +ve tumours who are given it after completing adjuvant chemotherapy. The Australian government has now announced that Herceptin will be reimbursed on the PBS for this indication from September 1st. Roche are offering free Herceptin to eligible women up to that time. I will be contacting those patients of mine who I think should consider this option, but those who are in doubt or have questions should contact my secretary, Annette Arkell 02-9845-8089. You can read all about the relevant trials, and more about Herceptin and how it works HERE

There are some preliminary results from a relatively small Finnish study suggesting that a shorter duration of Herceptin (9 weeks) may be sufficient, but this evidence is preliminary.