Pill Said to Slow Breast Cancers
September 19, 2006 RALEIGH, N.C. (The New York Times News Service) -- GlaxoSmithKline has asked federal regulators to approve its promising breast cancer drug, Tykerb.
The drug, which was discovered by GSK biologists and chemists in Research Triangle Park, would give doctors a weapon against an aggressive and advanced type of breast cancer that has grown resistant to existing treatments.
"This is a big advance," said Dr. Neil Spector, a cancer drug researcher at Duke University.
But Tykerb's real promise lies in its potential to be used earlier, before the cancer spreads, Spector said.
"It's a whole new ballgame when you get into the early, maintenance treatment," he said.
Additional testing would be needed before researchers know the drug's full potential. And it could be mid-March before the Food and Drug Administration approves the pill, if it does, and longer still before the drug could be on the market.
Doctors aren't the only ones excited about Tykerb's potential.
Analysts project that the drug will become a blockbuster seller, with more than $1 billion in annual sales.
The British drug maker, which has a U.S. headquarters in RTP, is also investigating Tykerb as a possible treatment for head and neck cancers.
About 210,000 cases of breast cancer are diagnosed in the United States every year, according to the American Cancer Society.
In about 90 percent of the diagnoses, the cancer is in an early stage.
Tykerb targets a cancer known as HER2 positive, because it uses a protein inside the cell, called HER2, to shut down the cell's mechanism to die. As a result, the cell starts dividing rapidly.
About one-third of all breast cancers are HER2 positive.
Chemotherapy doesn't work well on HER2 positive breast cancer.
The best medicine available is Herceptin, a drug made by Genentech.
It generated $747 million in sales last year, about 56 percent more than in 2004.
But Herceptin must be given intravenously and has been shown to cause heart damage in 15 percent to 20 percent of patients.
Spector said that Herceptin's risk of heart failure is a concern, especially with younger women diagnosed with HER2 positive breast cancer.
"The hope is that pills like Tykerb may not have the same heart damage as Herceptin," he said.
Known side effects of Tykerb are diarrhea, nausea, vomiting and rash.
GSK cut short final testing of Tykerb this summer and offered the drug to all 324 participating women because the drug was working so well.
Early results from the clinical trial showed that the women who took Tykerb in combination with Xeloda went 8 months without having their tumors grow or spread to other parts of their bodies. The women who received only Xeloda experienced a delay of 4 months.
GSK has asked the FDA to approve Tykerb as a treatment to be given in combination with Xeloda. Herceptin is given in combination with an intravenous chemotherapy drug.
"This filing is the result of many years of tremendous research and development work by the scientists at GSK," said Dr. Paolo Paoletti, who oversees the company's cancer drug research.
"It is truly an outstanding milestone, especially for the many thousands of women who are facing the devastating effects of advanced breast cancer."
The FDA has granted Tykerb fast-track status, which it reserves for drugs that treat serious diseases and fill an unmet medical need. Under fast-track status, the regulatory review usually takes about six months.
At the end of the review, GSK will find out whether the FDA rejected or approved its request to make Tykerb available, or whether regulators need more information to decide.
Copyright 2006 The New York Times News Service. All rights reserved.
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