Tykerb: A New Treatment for Breast Cancer
by Martha Li
published October 07, 2009
rating: (95 Ratings)
In May 2009, Health Canada approved the use of TykerbTM, a new type of therapy for breast cancer. Here is some basic information about this revolutionary drug that is providing breast cancer patients with another option in their fight against the disease.
What is TykerbTM?
TykerbTM (lapatinib ditosylate) is a small molecule that is administered orally in tablet form, and taken in combination with Xeloda® (capecitabine), an oral chemotherapy.
Who is it for?
TykerbTM is available by prescription only. It is prescribed to women with HER2-positive metastatic breast cancer, and who have already received treatment with other breast cancer therapies including an anthracycline, a taxane, and Herceptin® (trastuzumab).
How does it work?
TykerbTM is a molecular inhibitor of a type of enzyme called HER2. The TykerbTM molecule targets HER2-positive cancer cells, enters them, and prevents the cells from responding to growth signals. Since the cancer cells are unable to receive growth signals, they cease to divide, thus halting progression of the disease.
What are the advantages of TykerbTM?
While TykerbTM functions similarly to Herceptin®, the biggest difference is that TykerbTM works from inside the HER2-positive cells. TykerbTM can therefore directly target the gene that produces HER2, whereas Herceptin® is only able to target the receptor that activates the HER2 gene at the cell’s surface. Some studies also suggest that TykerbTM can potentially cross the blood-brain barrier to attack metastatic brain tumors. Another major practical advantage is that unlike Herceptin®, which must be administered intravenously, TykerbTM is taken orally in pill form, making it a much less invasive form of treatment.
What are the clinical trial results of TykerbTM?
Health Canada approved use of the drug based primarily on a study that involved women with locally advanced or metastatic HER2-positive breast cancer whose disease had progressed after being treated with anthracyclines, taxanes and Herceptin®. The study observed the effect of treating women with TykerbTM and Xeloda® compared with the effect of Xeloda® alone. The results showed that use of TykerbTM and Xeloda® together slowed the growth of HER2-positive advanced breast cancer or metastatic breast cancer significantly more than treatment with Xeloda® alone.
What are the side effects?
The most common side effects reported by patients taking TykerbTM and Xeloda® are diarrhea, vomiting, nausea, fatigue, red, painful hands and feet, and rash.
Are there any other risks associated with taking TykerbTM?
Some women may develop liver damage while taking TykerbTM. A test should therefore be administered to check the liver before and during treatment. There have also been reports of possible heart problems related to taking TykerbTM. It is essential that anyone considering taking TykerbTM speak to their doctor about all potential side effects.
NOTE: The information provided in this article does not cover all possible uses, interactions, or adverse effects for this drug. Consult your doctor for more information.
▪ Notice of Decision for Tykerb (Health Canada, 2009).
▪ GlaxoSmithKline Inc. (May 26, 2009). “New therapy option for advanced HER2 breast cancer approved in Canada”. Press release. Retrieved 2009-09-21.