Tykerb enters a growing family of oral cancer treatments

When a patient visits most physicians, they get a few diagnostic tests and walk out with a prescription. And oncology is headed in that direction.

In March, the Food and Drug Administration approved Tykerb, a new drug that joins a small, but growing, family of oral drugs to treat cancer. There are about a half dozen oral drugs on the market that treat cancer, with more in clinical trials.

“Oral drugs have always been the preferred method of treatment,” said Dr. Chainarong Limvarapuss, oncologists at Sutter Solano Cancer Center in Vallejo. “These treatments tend to be easier for the patient.”

Tykerb was just approved on March 13, and Dr. Limvarapuss already has a couple of patients on the drug. “It has been tolerated well,” he said.

About 20 percent of oncology drug sales are in oral form, and growing at a rate of 25 percent a year, said Gena Cook, vice president of sales and marketing for OTN, a specialty mail order pharmacy in South San Francisco.

Tykerb is only available through the mail from one of about 13 specialty pharmacies across the country, said Sarah Alspach, manager of product communications at GlaxoSmithKline, the maker of Tykerb.

The specialty pharmacies are the best method of distribution for these new drugs because they have a coordinated model of care that follows up with the patient on the phone to make sure they are taking the medication appropriately.

As a result, 94 percent of patients who get their drugs from a specialty pharmacy are in compliance with the medication directions, compared with 54 percent of patients who get their drugs from the local retail pharmacy, Cook said, quoting independent research.

Tykerb (lapatinib) was approved for use in combination with capectabine (Xeloda), another cancer drug for patients with advanced, metastatic breast cancer cells that exhibit HER2 proteins.

The combination treatment is indicated for women who received unsuccessful prior therapy of other cancer drugs, including an anthracycline, a taxane, and trastuzumab (Herception), according to the FDA.

Every year, there are between 8,000 and 10,000 women who die from metastatic HER2 positive breast cancer each year, according to the American Cancer Society. A small percentage of these women who don’t respond to other treatments will get Tykerb.

“For now, the drug has a relatively limited market,” said Dr. Limvarapuss.

While the patient population for this drug is small, it’s still expected to generate big revenue for GSK. The once-a-day pill will cost nearly $35,000 a year for patients. Analyst forecast that Tykerb could reach blockbuster status with sales of $1.5 billion in five years.
The oral form of cancer therapies costs less than the more traditional chemotherapy that is delivered intravenously, such as Avastin and Tarceva that can run as much as $100,000 for an annual supply.

There hasn’t been a problem getting private insurance to pay for the drug. And GSK has set up a system to help physicians get information about the drug, and assistance for patients who don’t have health insurance coverage. The number is 1-866-4-Tykerb, said Alspach.
Tykerb is a new molecular entity that works through multiple pathways to deprive tumor cells the signals that cause them to grow. Other drugs attack the HER2 protein on the outside of the cell, however, Tykerb is a small molecule that enters the cell and blocks the function of this and other proteins.

Tykerb was approved after positive results from a randomized clinical trial in about 400 women with advanced or metastatic breast cancer that was also HER2 positive.

Half the women in the trials received Tykerb with capecitabine and half received capecitabine alone. The group of patients who received the combination drug had significant improvement compared with patients who received only capeciabine, according to the FDA.

Tykerb could have other applications. In February, GSK entered the drug into clinical trials on head and neck cancer. “And we are looking at a number of options in breast cancer,” said Alspach.

Oral drug treatments are more appealing to patients because there are fewer side effects since the oral drugs can be more efficient with attacking the cancer cells rather than healthy cells. And the treatment can be done at home, rather than in the physician’s office, said Dr. Limvarapuss

The current success of oral drugs to treat cancer will foster more interest to develop of additional oral cancer treatments in the future, said Dr. Limvarapuss.

Troy May is the editor of Bay Area Oncology News. You can reach him at tmay@BaOncologyNews.com.

—By Troy May

Posted on April 23, 2007 11:27 AM