A new drug that could be used to treat Alzheimer’s slows cognitive decline by one third, the initial stages of a clinical trial have found, as scientists hail the “potential therapy” for the disease.

The drug donanemab, an investigational antibody therapy, is administered via an IV infusion and targets a protein found in the brains of those with Alzheimer’s disease.

A trial involving 272 patients with early symptomatic Alzheimer’s found that donanemab contributed to a “significant slowing” of their cognitive decline compared to those who received placebo, renewing hope that researchers are closing in on therapies to fight the disease.

The two-year study, which has now concluded its second phase before entering a third and final phase, found patients’ decline was slowed by as much as 32 per cent over 18 months – a reduction researchers described as “statistically significant”.

Patients’ decline was measured with memory tests alongside assessments of how well they performed everyday activities like dressing themselves and preparing meals. 

Pharmaceutical giant Eli Lilly, which is leading the study, saw its share price soar by 14 per cent in light of the new discovery. 

Dr Daniel Skovronsky, the company’s chief scientific officer, praised the “positive results” of the trial which has provided “confidence” that donanemab could be a potential treatment for Alzheimer’s. 

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The researchers have said that they are pursuing talks with global regulators about the next steps in rolling out the drug, should the final phases also prove successful. 

The full results of the study, named Trailblazer-Alz, will be presented at a future medical congress and submitted for publication in a peer-reviewed clinical journal.

“We are extremely pleased about these positive findings for donanemab as a potential therapy for people living with Alzheimer’s disease, the only leading cause of death without a treatment that slows disease progression,” said Mark Mintun, the vice president of pain and neurodegeneration at Eli Lilly and Company. 

“With more than 30 years of dedication to finding solutions for this devastating disease, we are proud of our progress moving the field forward and advancing the science. These positive results give us hope for patients and their families,” he added.

The trial also found that donanemab helped clear amaloid plaques, a hallmark of Alzheimer’s disease, in the brain.

Six to 12 months following the treatment, the amaloid plaques were gone and did not return, said Dr. Daniel Skovronsky.

More than 850,000 people suffer with dementia in the UK, which represents one in every 14 of the population aged 65 years and over. 

At the rate of current prevalence, the charity Alzheimer’s society predicts that there will be more than 1.5 million people with dementia in the UK by 2040. 

The mortality rate for deaths due to dementia and Alzheimer’s disease significantly decreased in 2019 compared with 2018

The news of Eli Lilly’s potential breakthrough in finding an Alzheimer’s treatment follows the 2019 “turning point” by pharmaceutical company Biogen and trials of the drug aducanumab. 

Despite initially failing trials, aducanumab proved to reduce symptoms in patients and their cognitive decline by 25 per cent after 18 months.

Biogen said that these patients who took aducanumab had better cognition, memory and language and were able to live independently for longer, including performing household chores and travelling on their own.

Michel Vounatsos, Biogen’s chief executive, said that it hoped to offer patients “the first therapy to reduce the clinical decline of Alzheimer’s disease”.