Glaxo's Tykerb helps some breast cancer patients

GlaxoSmithKline's new breast cancer pill Tykerb might help prevent the growth of tumors in some people with a hard-to-treat form of the disease, U.S. researchers reported on Sunday.

The addition of Tykerb to standard chemotherapy treatment failed to help most breast cancer patients, the researchers told a meeting of the American Society of Clinical Oncology.

However, it did increase survival in those patients who were HER2-positive, a type of breast cancer that spreads more quickly and accounts for a quarter of cases, they said.
Dr. Angela Di Leo of Sandro Pitigliani Hospital in Prato, Italy, and colleagues examined data from a Phase III trial of 580 breast cancer patients whose cancer had spread and were either negative or untested for HER2 and who were resistant to Roche Holdings' Herceptin, generically known as trastuzumab.

Tykerb, known generically as lapatinib, given along with standard chemotherapy, did not work for most patients. But an analysis of 91 patients who were later identified as HER2-positive and who had not been treated with cancer drug Herceptin showed the combination therapy halted tumor growth for three months.

"This sets the stage for a comparison study of Herceptin plus chemotherapy against Tykerb plus chemotherapy," said UCLA hemotologist-oncologist Richard Finn, one of the investigators of the study.

Finn said researchers are starting to look at Tykerb to treat HER2-positive breast cancer patients at an earlier stage in their disease.

Tykerb, approved in recent months in the United States and Switzerland for breast cancer, is being tested for other types of cancer. It is central to Glaxo's push into cancer medicine, the fastest-growing and most profitable area in the drug market.

Researchers also presented Phase II data using Tykerb to treat 241 patients whose breast cancer had spread to the brain -- a problem for 30 percent to 40 percent of women who are HER2-positive.

After six months, tumors shrank by at least 50 percent in just 7 percent of patients, while about a fifth had less than a 50 percent reduction. The trial's goal had been to shrink the tumors by at least half in 10 percent to 20 percent of patients.

"This is not a home run, but the effect was real and I think we can build on it," said Dr. Nancy Lin of Harvard Medical School, an investigator in the Glaxo-funded study.

Tykerb is a pill and is more convenient than Roche Holding's and Genentech's $1.8 billion-a-year seller Herceptin, which must be injected.

Breast cancer is the fifth-deadliest cancer worldwide, causing more than 500,000 deaths a year, according to the World Health Organization. It kills 40,000 people a year in the United States alone.