Neovastat is derived from the cartilage of the dogfish shark.

By Charlene Laino

MSNBC

March 2001

NEW ORLEANS, March 26 - Patients with advanced kidney cancer given an extract of shark cartilage lived twice as long as would be expected if they hadn't taken the fishy concoction, a small pilot study shows. And three patients - all of whom failed to respond to all standard cancer treatments and probably would have died within eight months - are still alive 31 months after treatment began, researchers said.

THE EXTRACT, a product made from the cartilage of the common dogfish shark that is prepared differently than the shark cartilage pills sold in some natural food stores and over the Internet, is also showing promise in patients with advanced lung and blood cell cancers, said principal investigator Dr. Gerald Batist, a cancer doctor at McGill University in Montreal. Its anti-cancer fighting properties: four chemicals that are what scientists called anti-angiogenesis factors - substances that literally starve the lifelines of tumors, he said. The product, known as Neovastat, is among the most promising entries into the fashionable field of anti-angiogenesis agents, said Dr. William Li, clinical instructor of medicine at Harvard and head of the non-profit Angiogenesis Foundation in Cambridge, Mass. The development of anti-angiogenesis drugs capped a 30-year research process that began when Dr. Judah Folkman of Harvard Medical School had the hypothesis in the 1970s that tumors cannot grow or spread without a steady blood supply to feed them. By developing drugs that block the formation of new vessels, Folkman reasoned, you would eliminate the flow of blood to tumors, much like chopping a plant off at its roots. And without nutrients, tumors, like plants, would be prevented from growing much bigger than a pinhead.

In the past few years, dozen of anti-angiogenesis drugs have entered clinical trials, although none has yet been approved for use as an anti-cancer agent in the United States. But Pierre Falardeau, vice president of scientific affairs at Aeterna, which manufactures the shark cartilage extract, said if all goes as planned, the drug could be available by prescription within a year or two. The drug is "extremely interesting and promising," said Li, a former student of Folkman's. "This the first anti-angiogenesis agent to show a statistically significant - that is, not due to chance - increase in survival in a group of critically ill patients." Extending survival is the Holy Grail of this class of drugs, Li explained. "Of the more than 50 agents in clinical trials, Neovastat is among the elite dozen that have made it to the final stages of human testing and the first to actually show improved survival." Neovastat is also noteworthy for its triple mode of action against the growth of new blood vessels to feed a tumor, he said. The drug blocks a growth factor that signals tumor cells to recruit new blood vessels, inhibits an enzyme needed for cancer cells to invade new tissue, and stimulates cancer cell death, according to Li.

CARTILAGE THE KEY Shark cartilage was originally studied as it was thought that sharks don't develop cancer and thus must contain anti-cancer agents. Ironically, even though it's since been shown that sharks do develop cancer after all, cartilage was found to be a rich source of anti-angiogenesis factors, Falardeau said.

"The cartilage can be from any species - chickens, fish, whatever," he said. "But sharks are a good source because they are abundant in waters worldwide and widely fished for their meat, with the cartilage normally discarded." The spines of about 100 dogfish sharks are needed to treat one cancer patient for one year, according to Falardeau. The cartilage is crushed up and purified into a liquid that is then frozen. The patient thaws the pint-sized drink - described as "fishy" tasting - before drinking it twice a day. In preparing Neovastat, the researchers use a patented biochemical method to treat the cartilage in such a way that it releases the anti-angiogenesis factors.

STUDY DETAILS

The study, presented here Monday at the annual meeting of the American Association for Cancer Research, enrolled 22 patients with advanced kidney cancer that had spread to other parts of the body and could not be helped by any conventional therapy. Surgery to remove the kidney had failed to stop the cancer from spreading and neither radiation nor chemotherapy successfully killed off remaining cancer cells. Advertisement

Eight patients treated with a low dose of the drug lived an average of 7.1 months, compared to 16.3 months for 14 patients receiving a higher dose. For a patient with this advanced cancer who does not respond to standard treatments, the expected survival time is approximately eight months, Li said. On the basis of the results, all surviving patients have since been given the higher dose: Three are still alive, including one who had developed a tumor on her head that completely disappeared. No significant side effects were observed in the patients. The trial was funded by Aeterna. The National Cancer Institute found the results promising enough that it is funding a larger study in patients with lung cancer, Falardeau said. Trials are also underway in patients with multiple myeloma, a cancer of the blood.

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