Studies for Weight-Loss Drug Underreported Adverse Events

Reporting on some of the clinical studies conducted for a popular prescription weight-loss drug that is now available over-the-counter (OTC) downplayed the side effects and potential harms associated with the medication, according to a new review.

The drug, orlistat, was approved in the US in 1999 and marketed by Roche, the developer, as Xenical. In 2007, GlaxoSmithKline won approval to market orlistat as an OTC drug called Alli, which is available at drugstores today.

Danish researchers examined documents relating to trials conducted in Europe that helped to support its approval there. Just like in the US, pharmaceutical companies must report adverse events seen in trials to regulatory authorities in clinical study reports (CSRs).

The team received CSRs for 7 placebo-controlled trials involving orlistat that enrolled a total of 4,225 participants. But they found problems. For example, instructions to trial investigators stated that gastrointestinal side effects were only to be recorded if the patient found them “bothersome.”

Most of the time, the results are published in scientific journals for a wider audience to see. However, the researchers found that the journal articles frequently underreported the adverse effects and events that were detailed in the CSRs, they reported in PLOS Medicine.

In fact, only between 3% and 33% of the adverse events outlined in the CSRs made it into the published articles.

The researchers conceded that their analysis only involves one drug that was initially approved in Europe in the 1990s, and trial reporting in journals may have improved since then. But they also call for more transparency in clinical trial reporting.

“Based on these findings, systematic reviews of drugs might be improved by including protocols and CSRs in addition to published articles,” the authors conclude.


Jonathan Block

Jonathan Block

Jonathan Block is an associate editor at BioCentury, which provides news and information about the biotechnology and pharmaceutical industries. Prior to joining BioCentury in 2019, Jonathan worked for MedShadow as content editor. He has been an editor and writer for multiple pharmaceutical, health and medical publications, including The Pink Sheet, Modern Healthcare, Health Plan Week and Psychiatry Advisor. He holds a BA from Tufts University and is earning an MPH with a focus on health policy from the CUNY Graduate School of Public Health & Health Policy.


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