Merck admits Vioxx study mistake

WHITEHOUSE STATION, N.J., May 31 (UPI) -- Merck & Co. said it made a mistake in reporting that the now-withdrawn arthritis drug Vioxx caused heart problems only after 18 months of use, a report said.

The admission undermines Merck's main defense against at least 11,500 lawsuits filed against it for adverse effects from the painkiller Merck withdrew worldwide in 2004, experts told The New York Times.

Merck acknowledged Tuesday that a statistical analysis test used to reach the conclusion, published in a March 2005 New England Journal of Medicine article, did not support its theory of potential heart problems only after 18 months of continuous Vioxx use.

The test actually showed there was 7 percent chance that Vioxx posed an equally high heart attack risk before and after the 18-month window, the Times reported.

Chief scientist Dr. Peter Kim said the mistake was discovered just last week and Merck immediately notified the U.S. Food and Drug Administration and researchers.

Even so, Kim said Merck stands by its overall findings -- including that people were not at apparent risk of a heart attack if they took Vioxx less than 18 months.