The report, published in the Journal of the American Medical Association, alleges Merck employees served as ghostwriters for clinical trial and review articles about the drug rofecoxib, which is marketed as Vioxx.

"Recent litigation related to rofecoxib provided a unique opportunity to examine guest authorship and ghostwriting, practices that have been suspected in biomedical publication but for which there is little documentation," Dr. Joseph S. Ross of Mount Sinai School of Medicine, New York, and colleagues said in the JAMA report.

Another study in JAMA alleges Merck was slow to give the U.S. Food and Drug Administration a complete data about deaths from heart attack and strokes in a clinical trial of Vioxx, the report said.

Merck said many of the comments made in the report are "false, misleading or lack context."

"We are disappointed that such false and misleading statements about Merck from trial lawyers have made their way into a medical journal," Dr. Peter S. Kim, president of Merck Research Laboratories, said Tuesday in a statement.