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Drug authorisations: too few patients involved in trials

Evaluation of new drugs prior to marketing authorisation is inadequate to ensure patient safety.

How many people have been exposed to a new drug before a marketing authorisation has been granted? The authors of a study analysed centralised European marketing authorisations granted between 2000 and 2010.

According to this study, the 161 new drugs authorised for non-rare diseases during this period were tested on around 1700 persons on average. 56% of the drugs were tested on fewer than 2000, and 13% on fewer than 500 persons. For drugs designed for long-term use, the numbers involved in the trials were generally a little higher: 2340 persons on average. But only 30% of these drugs were tested for at least 6 months on over 1000 patients.

According to the authors of the study, the number of patients involved in pre-marketing authorisation trials is insufficient to evaluate the drugs’ efficacy and long-term harms.

Due to lax regulations, all too often the medicines agencies accept third-rate evaluations: no comparison with the reference drug, evaluation against surrogate outcome measures, etc.

The low number of participants in the trials is another example of the drug companies’ low evaluation standards. At the expense of patients who are exposed to the risk of harmful effects about which little is known or which are not even suspected during the trials.

Post-authorisation monitoring cannot replace a high-quality initial evaluation. Patient protection requires stringent pre-marketing evaluation. The legislation relating to clinical trials should be moving in this direction, not the opposite.

©Prescrire 1 October 2014

"Premarketing trials: too few patients" Prescrire Int 2014; 23 (153): 251. (Pdf, free).

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