A new drug which can slow down the symptoms of Alzhiemers could become available after a similar remedy was found less than a year ago.

Donanemab, manufactured by Pharmaceutical company Eli Lilly, can slow the deterioration of a patient living with the illness by about a third.

But out of the 1,734 volunteers who participated in trials, two have died, with a third falling severely ill from serious swelling in the brain.

Working in the same way as Lecanemab, a breakthrough Alzhiemer’s drug announced in November, Donanemab is similar to the antibodies inside our bodies, but the drug forms a sticky gunk from the brain, called beta amyloid.

Amyloid can be found in gaps between brain cells which form plaques, one of the core indications of Alzheimer’s.

"The decades-long battle to find treatments that change Alzheimer's disease is changing," Dr Cath Mummery, the clinical lead for the cognitive-disorders clinic at the UK's National Hospital for Neurology and Neurosurgery, told BBC News.

"We are now entering the time of disease modification, where we might realistically hope to treat and maintain someone with Alzheimer's disease, with long-term disease management rather than palliative and supportive care."

Volunteers who took part in the trial were given a monthly infusion of Donanemab until there were no more signs of the plaques in their brain cells.

Results showed the illness slowed down about 29% and by 35% in a group of patients researchers thought were more likely to respond.

The volunteers also regained an increasing amount of their daily habits, such as driving, topical conversations and hobbies.

But a third experienced swelling in the brain. In most cases the swelling was mild or not even noticeable, although two volunteers have already died from the side-effect at the time of writing.

"We are encouraged by the potential clinical benefits that Donanemab may provide, although like many effective treatments for debilitating and fatal diseases, there are associated risks that may be serious and life-threatening," Eli Lilly group vice-president of neuroscience research and development Dr Mark Mintun said.

Dr Liz Coulthard, from the University of Bristol, noted there were “significant side-effects” from the trials and minimum long-term data, but she believes Donanemab could "help people live well with Alzheimer's for longer".

The current breakthrough drugs have ensured scientists they are on the way to finding a cure for the illness.

Prof John Hardy, from UK Dementia Research Institute, discovered the method of targeting amyloid 30 years ago.

Hardy said: "This should dispel any lingering doubts about this approach” 

He added: "Having two drugs is great for competition."

Dr Susan Kolhaas, from Alzheimer's Research UK, said: "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."

But the two drugs are only effective on people with early stage Alzheimer’s, before the brain becomes too damaged, only 1-2% of people undergo scans/ spinal-fluid analysis to determine if they are living with the illness.

[ Lecanemab costs more than £21,000 per person per year ]