Ofering a look at the way drug manufacturers influence scientific research, US researchers said Wednesday, a review of internal company documents indicate Pfizer Inc. in order to expand Neurontin, its epilepsy drug market, intentionally altered or omitted unfavourable study findings.

As a general rule, clinical trials answer specific, pre-determined scientific questions, however, comparing Pfizer documents and published studies on Neurontin for conditions other than epilepsy, researchers found 8 out of 20 study reports failed to make it into medical journals.

Further, it was revealed that Pfizer, the world’s biggest drug manufacturer changed the answer to the main scientific question in 8 of the 12-studies published, from the original design of the study.

Kay Dickersin, whose study appears in the New England Journal of Medicine said a lot of primary outcomes were shifted around, between protocol planning and study reporting.

All of the studies funded by Pfizer, showed how off-label uses of the drug worked for migraine or pain sufferers. The US Food and Drug Administration (FDA) approved neurontin a decade ago for treating seizures and pain caused by shingles, but not for any other conditions. Its potential side effects include suicidal tendencies and depression.

Doctors are free to prescribe approved drugs as they deem fit, however, while companies cannot market drugs for anything but what they have been approved for, they are permitted to hand- out study reprints from medical journals to show how they work in patients with different problems.

Dickersin procured the documents, when she appeared as an expert witness in the lawsuit against Pfizer, with the drug manufacturer paying $430-million in 2004 for settling the lawsuit over illegal promotion of Neurontin.

Last year, Pfizer was sued once again for off-label marketing practices, holding back negative study results, including changing the pattern of its trials for producing more favourable results.

According to the report, when primary findings were unfavourable in a company-funded study, negative results were usually buried and positive findings highlighted, without disclosing the switch.

However, Pfizer disputes the report’s conclusions saying, it never ‘attempted to mislead the medical community about the effectiveness’ of the drug for certain uses.