BETHESDA -- The National Cancer Institute has decided to make the experimental drug taxol, which has shown promise in fighting advanced ovarian cancer, available to thousands more patients eventually through 39 cancer centers nationwide, a senior official said yesterday.
There is only enough of the scarce drug to treat 500 patients the rest of this year, said Dr. Bruce A. Chabner, director of the division of cancer treatment at NCI.
The institute wants to amass 750,000 pounds of taxol bark, he said, which is enough to treat 10,000 to 15,000 patients.
Only patients involved in controlled experiments with the drug, which is made from the bark of the Pacific yew tree, have been allowed to take it until now.
Yesterday, Dr. Chabner told the National Cancer Advisory Board, a group of experts and lay people appointed to advise the NCI, that release of the drug through the cancer centers would begin this month.
The institute's action will make any patient who has advanced ovarian cancer and meets a set of conditions eligible to try taxol at one of the 39 centers.
Taxol has not been approved by the U.S. Food and Drug Administration, but NCI has the authority to make a drug widely available if it seems to make a significant difference in the treatment of a certain cancer, said Dr. Michael J. Hawkins, chief of the institute's investigative drug branch.
"We think it's a significant advance in the treatment of cancer," Dr. Hawkins said of taxol.
NCI based its decision to release the drug widely on studies of about 120 patients with advanced ovarian cancer, Dr. Hawkins said. One of the studies was done at Johns Hopkins Hospital in Baltimore.
In about one-third of patients who improved, then relapsed under treatment with other drugs, cancers stopped growing, at least temporarily, and actually shrunk in some cases, Dr. Chabner said.
NCI is now planning to test taxol in combination with cisplatinum, a standard cancer drug, and compare the results to those of the combination of cisplatinum and cyclophosphamide, another standard treatment, Dr. Hawkins said. One drug alone usually does not bring lasting remission or a cure, he said.
nTC Taxol is thought to thwart the action of microtubules, which are important in carrying on cell division. When a cancer cell cannot reproduce, it dies, Dr. Chabner said.
An estimated 20,700 new cases of ovarian cancer are diagnosed every year in the United States, and 12,500 women were expected to die of it this year, according to the American Cancer Society. Dr. Chabner said that 5,000 of those patients would be candidates for taxol.
Ovarian cancer is often diagnosed after it has already spread beyond the ovaries because its symptoms are vague, sometimes nothing more than swelling of the abdomen.
In Maryland, Johns Hopkins Hospital is the only center that will beable to administer taxol under the new classification. To be eligible, Dr. Hawkins said, patients must meet the following conditions:
* Their cancer has spread beyond the ovaries and is no longer curable by surgery or radiation.
* They have not responded to three prior chemotherapy regimens.
* They no longer respond to cisplatinum or carboplatinum.
* The have not previously received taxol.
* They are strong enough to withstand the toxic drug -- are not bedridden, for example.
* Reversible side effects from previous treatments must have disappeared.
One member of the advisory board, Dr. Frederick F. Becker, said it is important for scientists and patients to realize that taxol "is not a panacea. This is a toxic drug." It usually reduced the number of infection-fighting white blood cells in patients, making them susceptible to infection, and can cause numbing of the hands and feet, nausea, vomiting and heartbeat irregularities, doctors said.
But Dr. Chabner and Dr. Samuel Broder, the institute's director, both said it can be an important treatment for some women with advanced ovarian cancer.
And Dr. Chabner said the institute is impressed enough with the drug that researchers plan to test it eventually on all types of cancer.