Washington (AFP)

The American laboratory Biogen Thursday presented new mixed results on a drug against Alzheimer's disease that he had almost completely abandoned in March, but it is unclear whether partial results will be enough to convince the authorities to approve its placing on the market .

While research against Alzheimer's has stagnated for years, and no effective treatment exists to date, Biogen presented at a San Diego disease congress in the United States figures showing that its molecule aducanumab was reducing significantly cognitive decline in some patients in the initial phase of the disease.

The results come from two similar 18-month placebo-controlled clinical trials involving more than 3,000 patients in 20 countries.

The drug, administered monthly intravenously, did not work for everyone, but showed results when the administered dose was strong, on the cognitive decline as measured by a questionnaire (-23% compared to the placebo) or the loss of autonomy (-40%), according to a presentation that detailed all of the test results.

Biogen had surprised by announcing in October that after new data and new analyzes, he finally intended to apply for a marketing authorization for his drug, while in March, he conceded that the results were not conclusive and put an end to the tests.

Aducanumab, a monoclonal antibody, aims to dissolve the aggregates of a protein, beta-amyloid, that builds up and creates plaques in the brain tissue of Alzheimer's patients. This target is one of the three main avenues explored by research against this degenerative pathology.

After the presentation on Thursday, experts were mixed with the results, especially because the protocol was changed during testing, and because only one of the two tests, called Emerge, showed efficiency.

Others also raised the issue of significant side effects.

"As a result of the results presented today, it is not possible to be certain that people in the initial phase of Alzheimer's disease really benefit from aducanumab," said the head of the research from the Alzheimer's Society in the UK, James Pickett. "Now it's up to the regulators to look at the data and see if it has more benefits than risk for people with Alzheimer's."

In a field weary of failures, others preferred to see a glimmer of hope.

"The good news is that, given the long wait for Alzheimer's disease, aducanumab has a clear effect on important features of the disease," said Carol Routledge, Director of Research at Alzheimer's Research. UK.

The ball is in the US Food and Drug Administration's (FDA) camp, which will probably decide next year whether to approve or reject Biogen's application for marketing.

© 2019 AFP