TUESDAY, Oct. 19, 2004 (HealthDayNews) -- An aspirin that is "thousands of times more powerful" than traditional forms of the drug but has no gastrointestinal side effects looks promising in animal studies, researchers say.
The drug, called nitric oxide-donating aspirin, or nitroaspirin, appears to help prevent colon cancer in mice without raising the incidence of gastrointestinal bleeding, researchers reported Oct. 19 at the American Association for Cancer Research meeting in Seattle.
Although the findings are "preliminary," the drug may be also help protect against cardiovascular disease and ease arthritis pain, said researcher Dr. Basil Rigas, chief of the Division of Cancer Prevention at SUNY Stony Brook, New York.
"My laboratory has been working with this compound for the last five years and it has two striking features -- one, it's much more potent than regular aspirin, and secondly, it's much safer," he said.
Clinical trials involving the use of nitroaspirin in 240 patients at high risk for colon polyps and colon cancer are expected to begin "over the next few months," he added.
Doctors have long known that aspirin -- a drug first discovered more than 100 hundred years ago -- prevents or treats a number of common ailments. However, aspirin, like other members of the non-steroidal anti-inflammatory (NSAID) family of drugs, tends to raise risks for gastrointestinal bleeding in long-term users.
In fact, popular cox-2 arthritis medications such as Celebrex, Bextra and Vioxx -- the last of which was recently withdrawn from the market due to increased risk of heart attack or stroke -- were successful because they relieved pain without the gastrointestinal risk inherent in other NSAIDs.
Many NSAIDs, including aspirin, also seem to help lower risks for colon cancer.
"That's actually where some of the initial data on colon cancer came from, " said Dr. Durado Brooks, director of prostate and colorectal cancer at the American Cancer Society. "People who were taking these drugs for arthritis were coincidentally noticed to have a lower likelihood to have [colon] problems."
However, with regular aspirin's gastrointestinal side effects, scientists have been busy looking for alternatives.
"It's similar to traditional aspirin, but different in one way, in that the molecule of aspirin has been modified to release nitric oxide (NO)," Rigas explained. "Nitric oxide is a very important molecule that has multiple effects within the cardiovascular system, the respiratory system and, we are finding, against cancer."
In their study, Rigas and his colleagues found that mice engineered to have a high risk of colon tumors that were given nitroaspirin daily for three weeks displayed a 59 percent reduction in tumors compared with untreated mice. And there were no signs of increased gastrointestinal toxicity compared to placebo.
The study was funded by a grant from the National Cancer Institute.
Brooks said the findings "look very promising, and it's an exciting concept." But he stressed that, "we're a long way from being able to say anything about nitroaspirin's true value, given that what we've looked at is an animal study."
He also noted that drugs that look safe in the short-term can lose their appeal when long-term data arrives.
"Remember, cox-2 inhibitors [such as Vioxx] have been used for a long time and were felt to be safe and effective -- they were a form of 'safer aspirin,' too," he said. "So who knows? Maybe somewhere down the line we may find out about the side effects of nitroaspirins. We just don't know right now."
Still, Brooks remains cautiously optimistic. The drug could well prove to be "a single agent that helps decrease the incidence of heart disease as well as decreasing colon cancer risk," he said. "It might even be a chemotherapeutic agent for someone who has a colon polyp identified -- you give them this to make it go away."
Rigas agreed the findings are preliminary, but he said the drug's potential impact could be enormous. "Our investigators have studied this for prophylaxis against heart disease, also against arthritis," he said. "It's up to 5,000 times more powerful than regular aspirin, and a lot safer."
To learn more about NSAIDS, visit the Arthritis Foundation.