A new drug to treat advanced aggressive breast cancer that no longer responds to other drugs received approval from the US Food and Drug Administration (FDA) this week.
Tykerb (GlaxoSmithKline’s brand name for lapatinib) is a new targeted anti-cancer drug taken in pill form with Xeloda (Roche’s brand name for capecitabine, another anti-cancer chemotherapy drug) for patients with advanced, metastatic breast cancer that is HER2-positive and has stopped responding to anthracyclines, taxanes, and Herceptin (Genentech’s US, and Roche’s European brand name for trastuzumab).
Tykerb (known as a new molecular entity, NME) inhibits stimulation of HER2 and EGFR receptors and reduces cellular growth signals that promote tumour progression, invasion and metastases (where the cancer moves to other organs). Like Herceptin, it leaves healthy cells alone and targets only tumour cells.
Tykerb differs from Herceptin, which is a monoclonal antibody that acts on cells from the outside. Tykerb is small enough to go inside cells to disrupt intra-cellular growth promoting signals.
Because of this different action, Tykerb works in some HER2-positive breast cancers that are no longer responding to Herceptin.
Tykerb was tested on 399 women with advanced or metastatic, HER2-positive breast cancer whose disease had progressed after treatment with Herceptin and other drugs. Half took Tykerb with Xeloda and half took Xeloda alone. According to the drug manufacturer, the combination group showed a statistically significant delay in disease progression with an increase of median time to progression from 18.6 to 27.1 weeks.
The tumour response rate was also higher in the group that took Tykerb.
The FDA says it is too early to assess the survival rate. This will come as a disappointment to many for whom the survival rate is the most important factor in their treatment decision.
In terms of side effects Tykerb appears to present lower risk for heart problems compared to Herceptin. A small percentage of the patients in the trial experienced a generally reversible decrease in heart function which can cause shortness of breath.
The most common side effects of Tykerb include diarrhea, nausea, vomiting and rash as well as numbness, tingling, redness, swelling and discomfort in the hands and feet.
The FDA advises patients to talk to their doctor about potential side effects, including interactions with other drugs and medical conditions such as heart and liver problems.
The FDA has approved Tykerb for use in combination with Xeloda. Both drugs are in pill form and can be taken orally.
According to the FDA, Tykerb will be available in tablets of 250 mg and should be taken as an undivided dose of 1,250 mg once a day for 21 days and with Xeloda on the first 14 days of a 21 day cycle.
The American Cancer Society estimates 180,000 new cases of breast cancer are diagnosed in the US each year, and 8,000 to 10,000 American women die from metastatic HER2-positive breast cancer each year.
Tykerb is GlaxoSmithKline’s tradename for lapatinib in the US. In Europe, where approval is pending, the drug will be marketed under the name Tyverb.
Click here for more medical information on breast cancer (breastcancer.org).
Written by: Catharine Paddock
Writer: Medical News Today