Pfizer Inc.’s antidepressant reboxetine, sold for more than a decade in Europe, is no more effective than a placebo at treating symptoms of depression, according to an analysis that included unpublished studies.
After examining unpublished data on the drug, researchers at the German Institute for Quality and Efficiency in Health Care found that published studies overestimated reboxetine’s benefit by 115 percent when compared to a dummy pill and 23 percent compared with other antidepressants, according to a report today in the British Medical Journal.
The variation between the results of the published and unpublished studies shows that pharmaceutical companies need stricter rules about disclosing the test results, the researchers said. Drugmakers must reveal study findings for products approved by the U.S. Food and Drug Administration, and European regulators are considering a similar policy.
“There’s still a regulatory gap in Europe,” Dirk Eyding, lead author of the analysis and the head of the clinical study department at a unit of the German Cancer Society, said yesterday in a telephone interview. Citing the unpublished studies, the researchers called reboxetine “an ineffective and potentially harmful antidepressant.”
Pfizer spokesman Chris Loder said in an e-mailed statement that it is reviewing the analysis in the British Medical Journal and that reboxetine is “an effective treatment option to clinicians for use in patients suffering from depressive illness/major depression and for maintaining the clinical improvement in patients initially responding to treatment."
The analysis looked at 13 studies of reboxetine involving 4,098 patients. Data on almost three-quarters of those patients had never been published, the study said.
‘‘It is not acceptable to be shown only positive data,’’ said Anthony Cleare, a psychiatrist and head of the Affective Disorders Unit at the Maudsley Hospital and Institute of Psychiatry at King’s College London, in a statement. ‘‘Clinicians treating patients with depression absolutely need the full picture in order to help their patients make the right choices about the various treatments that are available.’’
Concern that positive studies were more likely to get published in medical journals than negative ones led Congress in 2007 to pass a law creating a registry for clinical trials. The U.S. law doesn’t require disclosure of data from studies completed before Sept. 27, 2007, or on drugs rejected by regulators.
German Panel Recommendation
Pfizer turned over the data after the German institute issued a preliminary version of its report in June 2009 saying reboxetine doesn’t benefit patients, citing the volume of unpublished studies, the researchers said. The institute, a nonprofit group that provides recommendations to the country’s health insurance system, also funded today’s research. After reviewing the report, a separate panel recommended the German health system stop paying for the drug.
‘‘Pfizer discloses the results of its clinical trials to regulatory authorities all around the world,” Loder said in the statement. “These regulatory authorities carefully balance the risks and benefits of each medication, and reflect all important safety and efficacy information in the approved product labeling. ”
Reboxetine has been sold since 1997 in Germany, the U.K. and other European Union countries under the brand names Edronax, Norebox, Davedax and Vestra, the researchers said. U.S. regulators refused to approve the treatment in 2001.
The drug works differently than most antidepressants because it only blocks the reabsorption of the chemical norepinephrine, while other drugs target serotonin. Reboxetine was developed by Pharmacia Corp., which Pfizer acquired in 2003.