Tumor-starving drugs to augment other treatments, researcher says Folkman enthusiastic about study that backs therapy's effectiveness

August 25, 1998|By Jonathan Bor | Jonathan Bor,SUN STAFF

A researcher who runs one of the nation's most closely watched cancer labs said yesterday that two new drugs that shrink tumors by starving them of their blood supply will likely be used to augment older therapies before they will be used alone.

Dr. Judah Folkman, whose experiments touched off a media frenzy and a surge of interest on Wall Street earlier this year, said he was encouraged by studies at the University of Chicago that showed one of the drugs dramatically improved the effectiveness of radiation on cancerous mice.

"No matter which therapies you use -- chemotherapy, radiotherapy, immunotherapy, gene therapy -- the drugs will improve them," Folkman said after giving a presentation to the annual meeting of the Institute of Human Virology in Baltimore.

The seven-day conference, which concludes Saturday, has drawn an international audience of about 1,000 scientists -- most of them engaged in AIDS and cancer research. The meeting was been organized by Dr. Robert Gallo, who directs the 2-year-old virology institute on the campus of the University of Maryland, Baltimore.

Folkman has spent almost three decades showing, in various ways, that tumors survive and spread by stimulating the growth of blood vessels that supply them with the nourishment they need. Last November, his laboratory reported that two new drugs destroy tumors in mice by depriving them of an adequate blood supply.

In mid-May, a news report suggested that the drugs -- endostatin and angiostatin -- were emerging as possible cures, causing a brief surge of media excitement followed by more cautionary reports emphasizing that experimental results in mice are often hard to reproduce in humans.

Folkman says it could be at least a year before EntreMed, a Rockville biotechnology firm which has the license to produce the drugs, has manufactured enough to supply "a small number of patients" in the first clinical trials. Once trials begin, it could be several years before the drugs wind their way through various levels of experimentation and -- in the best scenario -- prove themselves as drugs suitable for widespread use.

None of this has diminished Folkman's enthusiasm.

Declaring it a "landmark" study, Folkman said he was encouraged by the University of Chicago experiments that showed that angiostatin combined with radiation shrank tumors in mice far more effectively than radiation alone.

Folkman said the one-two punch, if applied to humans, could bring about faster remissions while sparing patients the harsh side effects of radiation.

Even if the drugs are eventually approved for human use, it could be several years more before doctors use them alone rather than in combination with older therapies.

"Historically in medical practice, when you introduce something new, you don't dare give up on what you've got," he said.

More than 20 angiogenesis inhibitors are already in small clinical trials, but Folkman characterized them as older drugs that either slow or arrest the growth of tumors.

Pub Date: 8/25/98

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