April 11, 2002: Merck Adds a Warning about Cardiovascular Risk to Vioxx Label

After six months of negotiations, Merck and the FDA finally agree on the text for a warning about Vioxx’s cardiovascular side effects that will be added to the drug’s label. The FDA had wanted to include a clear message that Vioxx increases the risk of heart problems since the current version of the label includes no information about such risks. An excerpt from the FDA’s originally proposed text reads: “VIOXX should be used with caution in patients at risk of developing cardiovascular thrombotic events… . The risk of developing myocardial infarction in the VIGOR study was five-fold higher in patients treated with VIOXX 50 mg (0.5 percent) as compared to patients treated with naproxen (0.1 percent).…” The FDA also wanted to include a graph showing that the risk of heart problems increases with continued exposure to the drug. Merck objected to the FDA’s proposals. It insisted that a description of the cardiovascular risks be included in the “Precaution” section of the label, instead of the more severe “Warning” section, as proposed by the FDA. The company also wanted to include results from several disparate clinical studies that had been conducted prior to the drug’s release. These are the same tests that are cited in the “Cardiovascular Card” that Merck sales people show to doctors (see April 28, 2000). But the FDA objected, telling the company that the studies were “trials of different design, size, and duration, using different doses of VIOXX and different comparators” and therefore did not provide useful data for determining the drug’s cardiovascular risk. The FDA eventually concedes to several of Merck’s requests. The final text of the warning is included in the “Precaution” section of the label, as Merck wanted, and does not include the graph that had been requested by the FDA. The text of the cautionary statement is also watered down. The section summarizing the results of the VIGOR study (see March 2000) and two other studies states: “The significance of the cardiovascular findings from these 3 studies (VIGOR and 2 placebo-controlled studies) is unknown.” [Merck, 2001; US Food and Drug Administration, 1/30/2002 ; US Food and Drug Administration, 2005; Office of Representative Henry A. Waxman, 5/5/2005, pp. 16-19 ]