Trial data on Neurontin may have been manipulated

A new paper published in the New England Journal of Medicine has accused drugmaker Pfizer of manipulating clinical data on trials of anti-seizure drug Neurontin (gabapentin). The accusations stem from a look at internal Pfizer documents exposed by a lawsuit in which author Kay Dickersin was an expert witness. She'd been asked to testify in a suit alleging that Pfizer and Parke-Davis had tried to illegally market Neurontin for off-label use.

Dickersin, who serves as a professor of epidemiology at Johns Hopkins Bloomberg School of Public Health in Baltimore, compared Pfizer internal documents to 20 trials paid for by Pfizer and subsidiary Parke-Davis. Twelve of the trials had published their results.

After making comparisons, Dickersin and colleagues found that the trials were structured in a way that could distort reports on their benefits. Rather than establishing primary and secondary outcomes for the research, and using the established primary goal to evaluate success, primary outcomes specific by the research were sometimes changed after the data came in. In other cases, Pfizer-funded researchers reported the secondary outcome as primary, or added entirely new outcomes.

Pfizer's response: "The review recently published in the New England Journal of Medicine, regarding the reporting of industry-sponsored trials for gabapentin for off-label use, was derived from a report created for litigation and coauthored by plaintiffs' expert witness, who was hired to produce opinions to support plaintiffs' arguments."

That's an interesting argument, but if the researchers were examining original data, more spin than substance. My guess is that we've far from heard the end of this issue.

To get more perspective on the controversy:
- read this HealthDay News piece [1]

Related Articles:
Pfizer pays $2.3B penalty for off-label drug marketing [2]
Pfizer sued over off-label use of Lipitor [3]
Feds charge researcher over Pfizer consulting fees [4]