Ellen Campbell -Grizzle
THE HEALTH care industry has greeted recent announcements about the drug trastuzumab (Herceptin) to treat breast cancer with muted excitement. Some experts have used superlatives such as 'revolutionary' and 'stunning' to describe the findings on the impact of the drug. Others claim that the product represents a turning point in the treatment of breast cancer.
Trastuzumab has demonstrated the capacity to hone in on cancer cells while sparing healthy ones. The drug targets diseased cells with laser like affinity and blocks the action of the protein HER2 (human epidermal growth factor receptor 2). Genentech, a San Francisco- based pharmaceutical company, received market approval for the drug from the U.S. Food and Drug Administration in September.
WHAT IS HER2?
HER2 is a protein found on normally functioning cells and has the function of regulating cell growth. However, when the protein is altered, extra HER2 receptors may be produced. This over-expression of HER2 causes increased growth and reproduction, often resulting in more aggressive breast cancer cells. Trastuzumab targets breast cancer cells that have too many copies of HER2 protein. It attaches itself to HER2 protein receptors on the surface of these cells and slows the growth and spread of tumours that have excess HER2. Herceptin has shown great promise in increasing patient survival and reducing the number of deaths from advanced breast cancer.
HERCEPTIN STUDIES
Studies were recently published in the New England Journal of Medicine. One was an international study sponsored by Roche. The others were North American studies sponsored by the National Cancer Institute and partly-funded by Genentech. The researcher followed just over 6,500 women with early stage breast cancer. In the first study, 220 women, taking standard therapy for one year, developed breast cancer again; developed other kinds of tumours or succumbed. This compared to 127 women when Herceptin was added. The two other studies produced similar results. After three years, patients on Herceptin showed a disease-free survival rate that was 12-points higher than without it.
The drug represents a major advance for treating women with breast cancer. However, doctors caution that the treatment only works for women whose breast cancer cells carry extra copies of HER2. It has a variety of side effects, some of which are potentially fatal, including heart failure.
COST OF MEDICATION
Herceptin is expensive. Even at wholesale price, a year's use is US$48,000 (J$2.9 million). This makes it unaffordable to many Jamaican women. Several pharmacies would not be able to afford to stock this drug. The high cost tag of novel pharmaceuticals is a source of continuing concern. This is the dark side on the face of optimism about new drug discovery and cures.
PREVENTION FIRST
Prevention is the least expensive option. Talk to your doctor about ways to avoid or modify your breast cancer risk factors. Consider:
A healthy diet - Be choosy about fats as certain types of fats increase oestrogen levels which in turn raise breast cancer risk. Enjoy your fibres, fruits and vegetables, savour soy and avoid additives. Wash fresh fruits and remove peels to get rid of pesticide residue.
Keep on top of your breast examinations and mammograms.
Try vitamin E if your family has a history of breast cancer. Ask your doctor or pharmacist about a dose that is safe for you.
Go slow on alcohol. Too much alcohol is linked with increased risk of breast cancer.
Ellen Campbell-Grizzle, president, Caribbean Association of Pharmacists (CAP) & director, information and research, National Council on Drug Abuse.
