It is a revelation that caused a stir, around a disease currently affecting 900,000 people in France. On July 21, the American scientific journal Sciencepublished an investigation in which it suspects the French researcher Sylvain Lesné of having falsified a study concerning Alzheimer’s.
Published in the magazine Nature in 2006 – and cited more than 2,200 times in the scientific literature – the latter demonstrates the role of beta-amyloid 56 (AB*56) protein in cognitive decline. Sylvain Lesné’s results are in line with the so-called “amyloid cascade” theory, advanced in the 1990s. According to this theory, the first stage of the disease is linked to the accumulation of beta-amyloid proteins, which form plates between nerve cells in the cerebral cortex.
One hypothesis among others
These suspicions of fraud, which are currently being verified by the journal Nature, can they call into question twenty years of research on Alzheimer’s disease? Sylvain Lesné explained that he had injected the AB*56 protein into rats, after having purified it. A feat, as these molecules are very unstable and difficult to isolate. “To my knowledge, no scientist has managed to reproduce the results of this study, so this revelation, if it turns out to be true, will not change much,” assures Philippe Amouyel, Director General of the Alzheimer Foundation.
“We cannot question thousands of studies on the subject because only one may prove to be manipulated”, abounds Bertrand Fougère, geriatrician at the University Hospital of Tours. Especially since the mechanism of the disease is still unclear. “The amyloid cascade hypothesis has real arguments, but there are others, which involve, for example, the tau protein”says the specialist.
Debates around treatment
If the article of Science is also commented on is that it also denounces a scientific fraud concerning a drug under development. Several works on Simufilam, a treatment supposed to intervene on the amyloid cascade and developed by the company Cassava Sciences, are indeed pinned there.
If the company rejects the accusations, at least five of the studies carried out by its researchers have already been retracted by the scientific journals in which they had been published. In August 2021, a request was also sent to the American health agency (FDA) by an American citizen, for it to suspend clinical trials on this drug, without success.
Scientific integrity in question
“These stories of fraud illustrate the pressure researchers and health authorities are putting on each other to find a cure,” analyzes Bernard Meunier, emeritus research director at the CNRS, specialist in Alzheimer’s. “Publications are important for the reputation of researchers, especially the youngest. This can increase the temptation to embellish studies,” complete Philippe Amouyel, for who “discussions about scientific integrity need to take place in the research community”.
Regarding Simufilam, the director general of the Alzheimer Foundation wants to be reassuring: “There are a lot of molecules that are currently being tested, and this one is not the most anticipated. As for the uncertainty around treatments, the situation is not new. » In 2021, for example, the FDA gave the green light to the marketing of aducanumab, a monoclonal antibody developed by Biogen, targeting the amyloid protein. The European Medicines Agency had refused it, considering that the benefit had not yet been demonstrated.
What alter the hope of one day finding a cure? “With each debate, the process is slowed down, concludes Bertrand Fougère. But at the same time, it gives a real dynamic to research. »