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Drug safety

The need to assess the safety of drugs revealed itself following the therapeutic accidents at the beginning of the 20th century that we could even qualify as tragedies such as for the thalidomide case. The studies - required by the state - to assess the safety of a drug evolve according to new discoveries and are harmonized by an international organization called ICH (international Conference on Harmonization). This international harmonization ensures the scientific and medical value of studies and prevents their repetition. The same approach exists for veterinary drugs with an international organization called VICH.

The safety assessment studies, also called toxicology studies are mainly conducted on animals because they are the only models capable of reproducing the effects of a product on a whole organism. The animal species selected are chosen for their ability to best predict the possible side effects. Most of the time, those are rodents, but also rabbits, dogs or primates. Depending of the intended use of the drug, International recommendations will specify the necessary studies, the animal species, the number of animals, the drug doses, the way of administration and for how long. The number of animals used for drug safety testing represents about 5% of all animals used in research in France.

The tests used in toxicology are the safest possible, taking into account the scientific knowledge. They protect patients in clinical trials and are used for the drafting of the drug instruction leaflets (contra-indications, warnings, precautions, drug interactions). While very effective, the safety assessments are not perfect. Ideally, we would like to have faster tests (some current tests can last several years), cheaper tests and that do not use animals. The toxicology studies would also ideally predict the rare side effects that are only detected in patients, once the product is on the market. For all those reasons, the ICH comes together several times a year to update any recommendations, taking into account any new scientific or medical discoveries.

It is also good to be aware that the quality control of biological drugs (vaccines, serums, blood derived products, or tissue samples) is still mainly carried out in vivo. Indeed, on one hand the complexity of the products doesn’t often allow the use of physicochemical analysis methods to test for the quality, but on the other hand their biological origin imposes additional specific controls to avoid the risk of contamination by infectious agents. All this means that animal tests are required. These tests, which need to be repeated for each manufacturing batch, use in France over 20% of all animals used for research. However, whenever it’s possible, researchers use alternative methods. For example, the Novo Nordisk lab that specializes in biological medicines succeeded after 30 years of research and efforts to completely eliminate in vivo testing for the control of its products.