Vioxx -- CV problems after 4 months, or 18? Posted by Rob Schneider at 05/22/06 01:35 PM

Last week, experts announced that new data from Vioxx' maker, Merck, indicated that increases in possible stroke and heart attacks may occur as early as four weeks on the drug, instead of 18 months as previous studies have shown.

A story in today's NY Times looks at how the data underlying this new announcement might be interpreted in different ways to tell different stories.

Ever since Merck pulled its arthritis painkiller Vioxx off the market in September 2004 on evidence that it could cause strokes or heart attacks, the company and its lawyers have stood by the premise that it was dangerous only to patients who took it for at least 18 months.

So it was news last week when prominent medical experts said that new data from Merck indicated that Vioxx's risks started to emerge after only four months of use. The controversy is the latest illustration of how widely open to interpretation and potential corporate pressure the results of clinical trials can be — even when reported in a leading medical journal.

According to the article, critics said the previous analysis minimized the risks of the drug:

The conclusion "makes the drug look a lot safer than it was," Dr. Steven E. Nissen, the interim chairman of cardiovascular medicine at the Cleveland Clinic, said last week after reviewing the new data. "If you wanted to construct a legal defense that says nothing happens for 18 months, this is how you would cut the data."

As it turns out, the earlier studies concluding heart and stroke problems increased after 18 months had excluded clinical trial participants who had dropped out of the study.

"People may drop out because they had chest pain and then weeks later they had a heart attack," said Dr. Alastair J. J. Wood, a drug safety expert at Vanderbilt University. Merck says it was simply adhering to the study's original design, and that the more recent chart reflects data that were not available to analyze in early 2005. It said, and some outside experts agreed, that a 14-day cutoff is frequently used in clinical trials. Indeed, they said, measuring what happens to patients long after they have stopped using a drug could minimize the measured effects of the drug.

The story discusses what happens when drug companies sponsor the studies to determine safety and effectiveness of the drugs they sell:

"The 'hand' of the study sponsor seems too evident throughout the manuscript, which is written consistently in a fashion designed to support the company's public positions," said one reviewer. Another argued that the paper "aggressively promotes the safety of up to 18 months of use of rofecoxib. This goes beyond the data of the study." Rofecoxib is Vioxx's chemical name.

In a separate story an article in the May 17 Journal of the American Medical Association raises questions of bias in industry-funded studies of cardiovascular treatments. The article concluded:

Recent cardiovascular trials funded by for-profit organizations are more likely to report positive findings than trials funded by not-for-profit organizations, as are trials using surrogate rather than clinical end points. Trials jointly funded by not-for-profit and for-profit organizations appear to report positive findings at a rate approximately midway between rates observed in trials supported solely by one or the other of these entities.

comments (1)

1 Posted by DrAJB at 05/26/06 07:21 AM

Merck's new TV ads about "caring" have a odious transparency never exceeded by any campaigns of propaganda. One might suppose that Merck hopes to avoid the demanded [confessional] media fate of Big Tobacco. I certainly hope not !