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Interview with an expert

Because of the sensitivity of my blog topic about preclinical testing, I was only since today allowed to put the read out of my interview with an expert online. First, Prometheus had to give their approval.

For my interview I asked professor Marina Maréchal to tell us about her experiences with animal testing. I wrote out a text that can serve as a complete summarization of my posts and I think it will give you all a clear view on the system and organs behind preclinical and to a lesser extent clinical tests.

Interview with Marina Maréchal


Marina Maréchal graduated in 1983 as a dentist and in 1987 she became a specialist in Periodontology. In this period she already did some clinical trials using students as a guinea pig. After her specialization she started a private practice in the periodontology for about 13 years. Her passion for scientific research let her apply for a PhD funded by an IDO project in cooperation with the departments of periodontology, rheumatology, MTM, Biomechanics and prosthodontics. In this collaboration Marina did in vivo experiments with rabbits as animal testing in preclinical trials. After her PhD she started working at Tigenix where she became head of Preclinical in cartilage repair. When the R&D department was shut down, she made a come-back to KU Leuven in preclinical research at Onderwijs&Navorsing, Gasthuisberg.

First steps towards animal testing

The main goals of performing preclinical trials (animal testing) is collecting data about feasibility, iterative testing and safety to define the ultimate safety profile of a new product before clinical trials start. To collect valuable data out of these preclinical experiments, it very important to design these animal experiments as if they are human clinical trials.   As logical as this statement is, the acceptation of doing an animal testing is already provided. An animal is to be treated as humanely as possible. Surgical procedures should be performed using sterile material and under aseptic conditions and using general anaesthesia. During postoperative check-ups the recovery of the animal will be followed checking the experience of pain, monitoring the body temperature, evaluation of the food intake or the occurrence of infections. This implies that the animal may not experience pain or suffer from a severe infection. If this is the case and some medical treatments (e.g. antibiotics, painkillers) do not solve the problem, humane endpoints determine if and when the animal will be sacrificed. Since sacrificing animals before the endpoint of the experiment decrease the number of data collected during the experiments, the animals will be treated as good as possible and also cage enrichment (some toys in the cage) will improve their well-being. Just like with humans, if an animal is feeling happy in general it will be healthier and the delivered data will be more useful.

Ethical commission

In vivo experiments cannot start before the ethics committee approves the experimental template of the study. An ethical commission form has to be prepared and submitted, and without any approval the study is not allowed and no test animals will be available for the study. The number of test animals and the type of animals that will be used in the study will be compared to the preliminary results and the expected results. Mostly in preclinical trials animal testing will involve two different species. One will start using some small animals such as mouse or rats, … followed by a larger animal based on which animal will give the best correlation with a human trial, such as a rabbit, pig, a goat, a sheep, a horse, … The choice of using mice, rabbits, horses or another animal for example is not only one of having the best correlation with a human setting, but safety, efficacy, ethics and money will also be important factors.

To the clinical trials

Before any treatment or product will be commercially available, three clinical test phases are necessary after the preclinical experiments. Phase I clinical trial is conducted in a small group of healthy volunteers (mostly male) to check mainly safety issues that could not yet be answered in the preclinical trials. Phase II clinical trial evaluates the efficacy and also safety issues in a selected population of patients (the target group) and includes a large patient group (around 100-500). Phase III clinical trial is performed in a real-life population (500-5000 patients) when efficacy and safety have already been established and therefor the goal will be to generate additional data on efficacy and safety in relatively large number of patients. Before clinical trials can be done, an enormous amount of preclinical data is needed to convince the ethics committee and the FAGG (in Belgium), put down in a clear document where all issues are mentioned. When one of these two authorities gives negative advice, the clinical trial is not approved. The importance of these extensive controls and the growing importance of preclinical data are demonstrated by some terrible incidents: http://en.wikipedia.org/wiki/Thalidomidehttp://en.wikipedia.org/wiki/TGN1412

Marina Maréchal

I asked her the question if she was still emotional at the moment she had to sacrifice an animal used in a preclinical trial and her reply was clear: “Doing preclinical experiments will include surgical procedures, postoperative care and sacrifice. If at a certain point  I would not feel any difficulty anymore to sacrifice an animal, I will not perform preclinical experiments anymore”.


I want to thank Marina for giving me this inside view on the whole mechanism around animal testing and especially by giving me her own perspective on this subject.


I hope you now all have a view on why animal testing is done and also how that it has to be performed. I want to thank you all for blogging together those months and for giving me your personal contribution to my topic.


Thank you,


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