The significant cardiovascular risks linked to Vioxx could have been identified nearly four years before the anti-inflammatory medication was taken off the market, a new study has concluded, but consumers and physicians didn't have access to such information at the time.

"We need comprehensive, transparent, independent access to clinical-trial data in order to do a much better job of making this information available to the public," said the study's lead author, Dr. Joseph S. Ross, an assistant professor of geriatrics and palliative medicine at New York's Mount Sinai School of Medicine.

In research published in the Archives of Internal Medicine, Ross and his colleagues analyzed 30 studies, 12 of which were not available to the public when Vioxx was on the market and have only become available because of lawsuits filed by consumers who said they were harmed by the drug. The studies, which involved more than 20,000 people, showed an increased risk of heart attacks, strokes and hypertension among people taking Vioxx.

The nonsteroidal anti-inflammatory medication was withdrawn from the market in 2004 when the risk became public. But concerns about Vioxx's effects on the heart were expressed by the Food and Drug Administration even before it was approved in 1999. And, as early as June 2001, when many of the 30 studies were completed, the evidence showed a 35% increase in the risk of a cardiovascular event or death among users.

Some medical experts expressed concerns about Vioxx, which generated billions of dollars annually in sales, before it was finally withdrawn. But those warnings were lost in a blizzard of direct-to-consumer marketing from the drug's maker, Merck & Co., said the authors of a commentary accompanying the study.

"The Vioxx story really highlights the difference between marketing and informing," said Dr. Lisa M. Schwartz and colleagues of the Veterans Affairs Outcomes Group. "If physicians and patients had had the facts, it would have taken an alchemist, not a marketing department, to turn this lemon into gold."

Merck officials disagreed with the study's conclusions, saying in a statement released Monday that the Mount Sinai investigators used unreliable methods to assess data. "The first time Merck observed a difference in a placebo-controlled study was when it learned the results . . . in September 2004," the statement said.

New government regulations enacted since the Vioxx controversy require public disclosure of study results on both efficacy and safety within 12 to 24 months of completion. But there are some loopholes in the program, Ross said. For example, manufacturers only have to report summaries of the clinical trials, not individual reports of side effects.

He said the new research points out how difficult it can be for consumers to make good choices when selecting prescription drugs.

shari.roan@latimes.com