New Documents Raise Questions About Merck’s Knowledge of Vioxx Risk; Mercury Levels in Vaccines
Previously undisclosed documents show that Merck was preparing to conduct a large-scale cardiovascular study of its COX-2 inhibitor Vioxx in 2002 but canceled the trial as it was about to begin, the New York Times reports. The trial, which was slated to produce data by March 2004, "may have provided answers about Vioxx's risks even earlier if patients had shown ill effects," according to the Times.
Merck pulled Vioxx from the market in September 2004 over concerns about cardiovascular effects. The study would have involved 20,000 patients with acute coronary syndrome, in which patients experience chest pain from cardiovascular disease. Although the plan was "briefly cited" in a 176-page document recently submitted to FDA, the company never disclosed how close the trial came to starting or how extensively it was planned, the Times reports.
Documents reviewed by the Times show that by early 2002, Merck had contacted outside researchers to oversee the trial, approached AstraZeneca to supply anti-ulcer medication to ease possible side effects and prepared a 70-page protocol for trial conduct. However, in mid-March 2002, Merck executives halted the study days before researchers had planned to submit their protocol to FDA.
Merck said in a statement on Monday that it decided not to conduct the trial because it involved "high-risk" patients. "[W]e continued to ask ourselves and our consultants whether this was the right study to definitively answer" the question of whether Vioxx increased cardiovascular risks, Merck said, adding, "We ultimately decided not to conduct that particular study."
According to the Times, work on the planned trial was stopped at the same time that Merck and FDA were "concluding lengthy and heated negotiations" concerning Vioxx's label after an earlier trial indicated that the drug might increase risks for cardiovascular problems. However, Merck said that the talks had no bearing on its decision to not conduct the trial (Meier, New York Times, 2/8).
In related news, the Los Angeles Times recently obtained a seven-page 1991 Merck memo stating that six-month-old children who were given Merck vaccines on schedule would receive mercury doses up to 87 times higher than maximum daily consumption guidelines for mercury from fish.
According to the memo, written by Dr. Maurice Hilleman to the president of Merck's vaccine division, "When viewed this way, the mercury load appears rather large." The memo continues, "The key issue is whether thimerosal, in the amount given with the vaccine, does or does not constitute a safety hazard. However, perception of hazard may be equally important."
Thimerosal is an antibacterial compound that is nearly 50% ethyl mercury, a neurotoxin. In 1999, FDA released a report showing high-level mercury exposure from pediatric vaccines. By 2002, thimerosal -- which some contend is related to the development of autism in children -- had been eliminated from almost all vaccines. An Institute of Medicine committee in May 2004 concluded that evidence "favors rejection of a causal relationship" between vaccines and autism.
The Merck memo was provided to the Los Angeles Times by James Moody, a lawyer who works with advocacy groups on vaccine safety issues. Moody said the memo provides "the first hard evidence the companies knew -- or at least Merck knew -- that the children were getting significantly more mercury" than guidelines recommended. Merck would not discuss the memo, citing pending litigation (Levin, Los Angeles Times, 2/8).