Grassley, R-Iowa, asked the company, based in New Jersey, and DesignWrite, a medical writing company, to provide details including payment for the articles on Prempro and the involvement of doctors who signed them, The New York Times reported.
Members of Grassley's staff released documents showing that Wyeth had been recruiting ghost writers for Prempro in the late 1990s. At least one article was published after a federal study in 2003 showed Prempro might increase the risk of breast cancer.
"Any attempt to manipulate the scientific literature, that can in turn mislead doctors to prescribe drugs that may not work and/or cause harm to their patients, is very troubling," Grassley said in a letter to Bernard Poussot, Wyeth's chairman and chief executive.
Grassley says Wyeth executives prepared outlines for ghost-written articles, and then arranged the writing and found scientists to put their names to them. Wyeth has been accused of using similar tactics in the past with two weight-loss drugs, and Merck has similarly been tied to such tactics with its painkiller, Vioxx, the newspaper said.