Jueves 11 de Abril de 2002, Ip nš 12

Drug stabilizes cancer growth minus side effects
Por Rhonda Rowland

The drug phenoxodiol was given to patients with a variety of cancers that failed standard chemotherapy drugs in a study done by the Ohio-based Cleveland Clinic.

"I am encouraged that this drug appears to have so few side effects," said Dr. Ronald Bukowski, director of experimental therapies at the Cleveland Clinic's Taussig Cancer Center. "We hope to get to the point where we can give patients enough medicine for it to be effective.

"There was no shrinkage in tumors in any of the patients, but some of the tumors stabilized, meaning they appeared to stop growing."

Results of the study were released this week at the annual meeting of the American Association for Cancer Research in San Francisco.

Phenoxodiol appears to work by inhibiting an enzyme that is vital for cancer growth. With the drug interfering with this enzyme rather than directly attacking cells, normal healthy cells are left untouched, reducing side effects.

However, patients in the study did experience some nausea and fatigue.

Phenoxodiol belongs to a relatively new class of drugs known as signal transduction inhibitors, all designed to switch off certain cancer processes.

"This is a hot area in cancer," said Dr. Graham Kelly, chairman of Marshall Edwards Inc., a pharmaceutical firm that is developing the drug. "Other drugs in this category that are in early studies are not necessarily showing a response. The trick is to know which switch is important for which cancers."

Phenoxodiol was discovered by Novogen Ltd., Marshall Edwards' Australian parent company.

Since the success of the cancer drug Gleevec, which works in the majority of patients with a common type of leukemia called CML, scientists have been trying to find other agents that selectively destroy cancers.

"Gleevec was designed specifically for CML. It's a designer drug," Bukowski said. "They knew what the illness was and what would stop it and designed a drug to do just that. This new drug was not developed with any one cancer in mind, and researchers are not sure which type it will help best."

In addition to the Cleveland Clinic study, phenoxodiol is also being tested in Australia in a range of cancers, including kidney, pancreatic, lung, prostate, colon and melanoma.

"We are not curing disease or putting people into remission," Kelly said. "The important thing is we're getting a response, and we have yet to learn how to use the drug properly.

"We have to figure out the best dose, and when we get those answers, I think we'll get a marked response."

Kelly said signal transduction inhibitors may be more effective in prolonging life and slowing tumor growth if they are used together in so-called "drug cocktails."

In studies, phenoxodiol is administered intravenously for six weeks. The drug is continued if the patient shows a positive response.

The next phase of study will begin within six months and will include at least 20 patients with each type of cancer being investigated.


  09/04/2002. CNN.