A US drug company says it has created the first therapy that could slow Alzheimer's disease, and it is now ready to bring it to market.
Currently, there are no drugs that can do this - existing ones only help with symptoms.
Biogen says it will soon seek regulatory approval in the US for the "groundbreaking" drug, called aducanumab.
It plans to file the paperwork in early 2020 and has its sights on Europe too.
Approval processes could take a year or two. If successful, the company aims to initially offer the drug to patients previously enrolled in clinical studies of the drug.
The announcement is somewhat surprising because the company had discontinued work on the drug in March 2019, after disappointing trial results.
But the company says a new analysis of a larger dataset of the same studies shows that higher doses of aducanumab can provide a significant benefit to patients with early Alzheimer's, slowing their clinical decline so they preserve more of their memory and every day living skills - things that the disease usually robs.