Report: FDA Study Faults Merck's Vioxx

Updated from 8:23 a.m. EDT

An unreleased Food and Drug Administration study reportedly concludes that Merck's (MRK) recently recalled arthritis drug Vioxx may have been responsible for more than 27,000 heart attacks and sudden cardiac deaths in recent years.

An FDA study covering the time of Vioxx's approval in 1999 through 2003 concluded that the health episodes could have been avoided if patients had instead used rival Pfizer's (PFE) Celebrex drug, according to a report in The Wall Street Journal.

Word of the study, which covered some 66,000 patients who had used one or the other drug, comes a week after Merck's stunning decision to voluntarily withdraw its No. 2 drug over heart safety concerns, a move that knocked 27% off the drugmaker's share price in one day.

Merck's decision, although unwelcome to investors, was seen as a highly responsible and ethical move, whose execution also received high marks by crisis management experts.

Merck shares fell $1.52, or 4.5%, to $31.91, having touched a new 52-week intraday low of $31.85 earlier in the session.

The market withdrawal came less than a month after a published FDA-sponsored study concluded that Vioxx put users at a greater risk of heart attacks than those using Celebrex. The study said people using Merck's arthritis drug had a 50% greater chance of heart attacks and sudden cardiac death.

In the past week, Pfizer has repeatedly vouched for the safety and, by implication, the superiority of Celebrex.

In issuing the withdrawal, Merck said its decision to pull Vioxx was based on new, three-year data from a clinical trial that had just become available to the company.

In a statement that day, the FDA said that the "risk that an individual patient taking Vioxx will suffer a heart attack or stroke related to the drug is very small," but said users should still contact their physicians.

In another development Wednesday, lawyers for a Texas woman filed a lawsuit against the drugmaker, charging she had to undergo open-heart surgery after using Vioxx for less than a year. Merck has already been hit with class-action lawsuits since pulling the drug.

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