March 21, 2012

Newer Anti-Psychotic Drugs May be Less Effective

(Ivanhoe Newswire) — If you´re in pain, there´s a pill for that! But it may not always be good. A new study shows clinical effectiveness of the newer form of drugs used to treat schizophrenia and other psychotic illnesses may be enhanced by a phenomenon called publication bias.

The study, led by Erick Turner from Oregon Health & Science University in Portland, shows selective reporting of research results undermines the integrity of the evidence base, which ultimately deprives clinicians of accurate date for prescribing decisions.

The authors reached these conclusions by reviewing 24 FDA-registered premarketing trials for eight second-generation antipsychotics — aripiprazole, iloperidone, olanzapine, paliperidone, quetiapine, risperidone, long-acting injection, and ziprasidone — and then comparing these trials with the results conveyed in subsequent articles in medical journals.

They found that four premarketing trials submitted to the FDA remained unpublished and that all of the unpublished trials showed negative results — three showed the new anti-psychotic had no statistically significant advantage over placebo, and in one trial the new drug was statistically inferior to a much less expensive competing drug.

In the published trials, there was some evidence that the journal articles over-emphasized efficacy of the new drug. For example, the FDA review revealed that one of the newer drugs, iloperidone, was statistically inferior to three different drugs, but this information was not mentioned in the corresponding journal articles.

On the other hand, when the authors used meta-analysis to combine trial data and compare all eight drugs to placebo, they found that publication bias had little effect on their overall apparent efficacy. Of more concern was that some negative data remain unreported, potentially misleading clinicians.

"With further studies investigating publication bias in other drug classes, a more accurate evidence base can emerge. To that end, increased access to FDA reviews has been advocated. At the present time, the FDA is not as transparent with its clinical trial data as it could be," the authors were quoted saying.

However, "it is encouraging that the FDA has convened a Transparency Task Force. If the agency fulfills its mission to increase transparency, the public health will surely benefit," they said.

SOURCE: PLos Medicine, March, 2012