Survey shows that more than one third of claims in advertisements are not supported by cited studies
Advertisements for psychiatric drugs - including many top-selling antidepressants - often make claims that are either misleading or impossible to verify, according to a new US study seen by Chemistry World .
Psychologist Glen Spielmans of Metropolitan State University, St Paul, Minnesota, and colleagues analysed adverts aimed at medical professionals in four prominent US journals - including the New England Journal of Medicine, one of the most widely-read journals in the world.
Roughly half of the adverts featured citations to primary research papers to support their claims. Yet when the team checked, they found that over a third (35 per cent) of the claims were not supported by their cited sources.
’The sources are provided by the companies themselves, so it’s pretty easy to cherry pick one study that backs up their claim,’ Spielmans told Chemistry World. ’Despite that, many of the cited sources did not support the advertising claims.’
Examples include Shire’s adverts for manic depression drug Equetro (carbamazepine). Shire sold the drug to Validus Pharmaceuticals in September 2007, but an ad by Shire in 2005 claimed Equetro was an effective treatment for both manic and ’mixed’ episodes - when patients experience mania and depression at the same time. However, Spielmans’ team found that neither of the two references cited in the ads [2,3] supported the idea that mixed episode patients treated with the drug fare better than those receiving placebo.
42 out of the 53 ads (nearly 80 per cent) the researchers examined made at least one claim the team couldn’t substantiate. 27 made a claim that was not supported by the data source cited by the ad. A further 15 contained claims that couldn’t be verified by the team - usually because the ads provided no sources of data to back up their claims, or made claims that could not be verified because drug firms either failed to respond to the researchers’ requests for trial data, or refused to supply it.
Six out of nine pharmaceutical companies - including GlaxoSmithKline, Pfizer, AstraZeneca and Shire - did not reply to the researchers, while Wyeth refused to send trial data.
’In these cases, we have to take their word [that their claims were supported by scientific evidence], which, personally, I would think is not a wise idea,’ says Spielmans. Only Janssen Pharmaceutica - makers of schizophrenia drug Risperdal (risperidone) - and medical device firm Cyberonics sent relevant studies to back up their claims.
Antidepressants are the most prescribed drugs in the US, notching up $13.5 billion in US sales and $20.6 billion worldwide in 2006. Yet despite the scale of the business, Spielmans believes the US Food and Drug Administration (FDA) - which can require firms to correct misleading or false advertisements - does not have enough staff to review adverts adequately.
Spielmans claims that just 21 FDA officials at the agency’s Division of Drug Marketing, Advertising, and Communications were charged with reviewing over 39,000 adverts aimed at doctors in 2005. ’When I saw how many ads they have to review, it was mind boggling,’ he says. He believes medical journals should also take more responsibility for the adverts they run.
Spielmans says his findings contradict the pharmaceutical industry’s contention that drug ads serve to educate doctors about the benefits and risks of drugs. ’Education would typically be based on evidence,’ he notes. ’If it’s not based on evidence, it’s not education.’
Responding to the findings, Ken Johnson, senior vice-president of the Pharmaceutical Research and Manufacturers of America (PhRMA) trade association, said, ’Federal safeguards are in place to help assure that the advertising and promotional material disseminated by America’s pharmaceutical research companies in US publications is accurate and well-substantiated. America’s pharmaceutical research companies may only disseminate promotional materials for FDA-approved indications, as noted on the pharmaceutical labelling.’
The FDA has strict regulations for promotions, he added - and has the power to take action if it finds claims are not accurate or well-substantiated. An FDA spokesperson told Chemistry World that they were unable to comment on the claims.
1 G I Spielmans et al, J. Nerv. Ment. Dis., 2008, 196, 267
2 R H Weisler et al, J Clin Psychiatry, 2005, 66, 323
3 R H Weisler et al, J Clin Psychiatry, 2004, 65, 478