A promising anti-cancer drug developed by Dr. M. Judah Folkman, a Harvard Medical School professor, has passed safety testing and will go into human trials at the Mayo Clinic.

Folkman, who is Andrus professor of pediatric surgery, has researched cancer drugs for over three decades.

Researchers announced on Wednesday that it would be safe to extend human trials on Folkman's cancer-fighting drug, called 2ME2 (2-methoxyestradiol).

The drug, which can be taken as a pill, has at least one advantage over other cancer treatments. Most traditional cancer treatments--such as surgery, chemotherapy and radiation--try to kill tumor cells directly, but 2ME2 also prevents angiogenesis, the growth of new cancerous blood vessels in the body.

Folkman said that the recent advancement in the testing for 2ME2 marked an important step in the development.

"In the first phase, the question is, 'At what dose do you start to see side effects?'" Folkman said. "In the second phase, it is primarily, 'How effective is it?'"

Folkman said he could not speculate on how quickly, if ever, the drug would be widely available.

The drug works well on mice, he said, but that does not mean it will perform well in human trials.

"Many times they work well with mice and they don't work well with humans," Folkman said.

He said he believes his work will eventually have a tangible result on cancer treatment.

"We're optimistic because of the animal work," Folkman said. "We do think that angiogenesis inhibitors will be added to chemotherapy."

A Maryland company, EntreMed Inc., is funding the clinical trials of 2ME2.

Mary Sundeen, a spokesperson for Entremed, said clinical testing of 2ME2 has returned encouraging data, suggesting that the drug may be effective in fighting multiple myeloma, an aggressive type of cancer.

"The data-driven process has led us to believe the angiogenesis mechanism may make 2ME2 good for myeloma," Sundeen said. Sundeen said it showed promise in treating breast cancer.

2ME2 has received much less media attention than Endostatin, a similar drug that is injected instead of taken orally.

Endostatin appeared on the front page of the New York Times in 1998 in an article that drew a deluge of publicity to Folkman's research.

Folkman said that he is much more cautious now when he talks to the press, rejecting thousands of requests for interviews a year.

"As a physician, you have to be really careful if you over-raise expectations," Folkman said.

Folkman's laboratory at Children's Hospital has also developed Angiostatin and thalidomide--two drugs other than 2ME2 and Endostatin that also disrupt blood flow to tumor cells.

The Medical School's Associate Professor of Ophthalmology Robert J. D'Amato first discovered the 2ME2 molecule in urine, a result published about three to four years ago, according to Folkman.