The pharmaceutical companies Merck and Schering-Plough, which co-market the cholesterol drug Vytorin, "have gone into damage-control mode, taking out newspaper ads." The PR campaign follows the companies' reluctant publication of a study showing that neither of the drugs present in Vytorin "reduced the buildup of fatty plaque in arteries." The study "was completed in 2006, but Merck and Schering said they didn't release it for nearly 21 months due to the complexity of the data and their own scientific concerns." The drug companies' ads, which ran in the New York Times and USA Today, refer to the damning study as "a single study that has generated a lot of confusion." The ads stress that the drugs "have been proven to lower LDL (bad) cholesterol," but what the study showed was that Vytorin is not "any better than generic Zocor in reducing the buildup of fatty plaque." Members of Congress have called for an investigation into why the "massive advertisement campaign for Vytorin was allowed to continue," after the study was belatedly made public. (The drug makers pulled their Vytorin TV -- but not print -- ads on January 22, reports Associated Press.) Class-action lawsuits are also being filed, alleging that the drug companies "misrepresented and withheld significant information" from the Food and Drug Administration and the public.