A US Alzheimer’s drug trial which slowed clinical decline by over a third has been welcomed as “incredibly encouraging” by Alzheimer’s Research UK.

The phase 3 trial of the Alzheimer’s drug donanemab by pharmaceutical company Eli Lilly slowed clinical decline in 35% of participants compared with a placebo and resulted in 40% less decline on the ability to perform activities of daily living.

Nearly half (47%) of the participants on donanemab (compared to 29% on placebo) had no clinical progression after one year.

Dr Susan Kohlhaas, executive director of research & partnerships at Alzheimer’s Research UK, said: “This is incredibly encouraging, and another hugely significant moment for dementia research. A second drug for Alzheimer’s has been shown to slow people’s cognitive decline in a rigorous phase 3 trial.  We’re now on the cusp of a first generation of treatments for Alzheimer’s disease, something that many thought impossible only a decade ago.

“The treatment effect is modest, as is the case for many first-generation drugs, and there are risks of serious side effects that need to be fully scrutinised before donanemab can be marketed and used. However, this news underlines the urgency of preparing the NHS to make these treatments available should regulators deem them safe and effective. People should be really encouraged by this news, which is yet more proof that research can take us ever closer towards a cure.”