Orlistat: Assessment of Adverse Events in Protocols, Clinical Study Reports, and Published Papers

Orlistat: Assessment of Adverse Events in Protocols, Clinical Study Reports, and Published Papers

Last Updated on August 30, 2016 by Joseph Gut – thasso

Orlistat II
Orlistat (Xenical)

August 30, 2016 – The present article which just appeared in August 2016 issue of  PLOS Medicine illustrates how the inaccurate and biased to say the least the assessment and the reporting of adverse drug reactions by pharmaceutical companies throughout study protocols, investigators brochures, clinical trial reports which eventually wind up in regulatory submission documents, and in published clinical trial report scan be in the quest to let appear the risk to benefit ratio of a clinical development candidate as favourable as ever possible. While the article analyses all data available to the public (some of them only after requesting them under Freedom of Information Acts)  in the case of Orlistat, a anti-Obesity medication available under the trade names of Xenical in most countries as a prescription drug or Alli as an over the counter (OTC) product, at least in the UK and the US. For a patient, it is probably an illusion to believe that practices discussed and revealed in the present article have not been or are not followed anymore in the course of the clinical development of other product, even today. Patients, regulators, physicians, prescribers, providers, and the public at large should simply be aware of this.


Find here below the referenced to the article in question, which makes for a very interesting and rather revealing reading:

Schroll JB, Penninga EI, Gøtzsche PC

PLoS Med. 2016 Aug;13(8):e1002101

PMID: 27529343


BACKGROUND: Little is known about how adverse events are summarised and reported in trials, as detailed information is usually considered confidential. We have acquired clinical study reports (CSRs) from the European Medicines Agency through the Freedom of Information Act. The CSRs describe the results of studies conducted as part of the application for marketing authorisation for the slimming pill orlistat. The purpose of this study was to study how adverse events were summarised and reported in study protocols, CSRs, and published papers of orlistat trials.

METHODS AND FINDINGS: We received the CSRs from seven randomised placebo controlled orlistat trials (4,225 participants) submitted by Roche. The CSRs consisted of 8,716 pages and included protocols. Two researchers independently extracted data on adverse events from protocols and CSRs. Corresponding published papers were identified on PubMed and adverse event data were extracted from this source as well. All three sources were compared. Individual adverse events from one trial were summed and compared to the totals in the summary report. None of the protocols or CSRs contained instructions for investigators on how to question participants about adverse events. In CSRs, gastrointestinal adverse events were only coded if the participant reported that they were “bothersome,” a condition that was not specified in the protocol for two of the trials. Serious adverse events were assessed for relationship to the drug by the sponsor, and all adverse events were coded by the sponsor using a glossary that could be updated by the sponsor. The criteria for withdrawal due to adverse events were in one case related to efficacy (high fasting glucose led to withdrawal), which meant that one trial had more withdrawals due to adverse events in the placebo group. Finally, only between 3% and 33% of the total number of investigator-reported adverse events from the trials were reported in the publications because of post hoc filters, though six of seven papers stated that “all adverse events were recorded.” For one trial, we identified an additional 1,318 adverse events that were not listed or mentioned in the CSR itself but could be identified through manually counting individual adverse events reported in an appendix. We discovered that the majority of patients had multiple episodes of the same adverse event that were only counted once, though this was not described in the CSRs. We also discovered that participants treated with orlistat experienced twice as many days with adverse events as participants treated with placebo (22.7 d versus 14.9 d, p-value < 0.0001, Student’s t test). Furthermore, compared with the placebo group, adverse events in the orlistat group were more severe. None of this was stated in the CSR or in the published paper. Our analysis was restricted to one drug tested in the mid-1990s; our results might therefore not be applicable for newer drugs.

CONCLUSIONS: In the orlistat trials, we identified important disparities in the reporting of adverse events between protocols, clinical study reports, and published papers. Reports of these trials seemed to have systematically understated adverse events. Based on these findings, systematic reviews of drugs might be improved by including protocols and CSRs in addition to published articles.

Print Friendly, PDF & Email

Ph.D.; Professor in Pharmacology and Toxicology. Senior expert in theragenomic and personalized medicine and individualized drug safety. Senior expert in pharmaco- and toxicogenetics. Senior expert in human safety of drugs, chemicals, environmental pollutants, and dietary ingredients.