The drug donanemab will be a “turning point” in the fight against Alzheimer’s because of the way it slows cognitive decline in some patients, according to a new study.
The antibody drug helps in the early stages of the disease by eliminating a protein that builds up in the brains of people with this type of dementia.
Although not a cure, experts say the research results mark the beginning of a new era in which Alzheimer’s can be treated.
In clinical trials, donanemab appears to have slowed the progression of the disease by one-third, allowing people to retain more of their daily lives and tasks, such as preparing food or enjoying a hobby.
Mike Colley, 80, is one of a dozen British patients who have taken part in the global research just published in the medical journal JAMA.
Colley receives a dose of the drug every month at a London clinic and says he is “one of the luckiest people you will ever meet.”
The antibody treatment helps in the early stage of the disease.
It only works in the treatment of Alzheimer’s and not other types of dementia such as vascular dementia.
This is because the drug is specifically designed to eliminate a protein that accumulates in the brains of Alzheimer’s patients.
Benefits and risks
Mike and his family realized he was having difficulty memorizing things and making decisions shortly before he participated in the study.
“Seeing him having trouble with information processing and problem solving was very difficult. But I think his deterioration is stabilizing,” said his son Mark.
Speaking exclusively to the BBC, Mike said, “I feel more confident with each passing day.”
Donanemab, produced by the Eli Lilly laboratory, works in the same way as lecanemab developed by Eisai and Biogen laboratories, which made headlines around the world when it was shown to slow the disease.
But despite having immense potential, these drugs are not without risk and are not a cure.
One of the possible side effects seen in the donanemab trials was inflammation of the brain, affecting nearly a third of the study participants. In most cases, the swelling resolved without causing symptoms.
But at least two volunteers died of dangerous brain inflammation.
Another Alzheimer’s antibody drug known as aducanumab was recently rejected by European regulators for safety reasons and lack of evidence that it was sufficiently effective.
What is dementia and what can be done about it?
In the donanemab trials, the researchers examined 1,736 patients between the ages of 60 and 85 with early-stage Alzheimer’s. Half of them received a monthly dose of the treatment and half received a placebo for 18 months.
Half of them received a monthly dose of the treatment and the other half received a placebo, for 18 months.
The results show that:
- Drug appears to have benefits, at least for some patients
- Those who had earlier disease and less amyloid protein in the brain had a greater benefit, in terms of clearance seen on brain scans
- Those who received the drug managed to maintain more of their daily life, being able to do things like answer the phone or engage in hobbies
- Disease progression, judging by what people could still do on a day-to-day basis, was reduced by 20-30% overall, and by 30-40% in a group of patients who the researchers thought were more likely to respond to the treatment
- There were significant side effects, and patients will need to be aware of the risks of the treatment
- Half of the donanemab patients were able to discontinue treatment after one year because they had cleared enough brain deposits
The amyloid protein is only one part of the complex picture that Alzheimer’s disease presents, and it is unclear whether the treatment will remain effective over a longer period, experts warn.
The drug’s effects may be modest, but the results provide further confirmation that removing amyloid protein from the brain can change the course of Alzheimer’s and help people affected by this devastating disease if they receive treatment at the right time, experts say.
Professor Giles Hardingham, of the UK Dementia Research Institute, said, “It is fantastic to see these results published in full. We have waited a long time for Alzheimer’s treatments, so it is really encouraging to see tangible progress continuing to be made in this field.”
Dr. Susan Kohlhaas, Alzheimer’s Research UK, said, “Today’s announcement marks another milestone. Thanks to decades of research, the perspective on dementia and its impact on individuals and society is finally changing, and we are entering a new era in which Alzheimer’s could become treatable.”
Lecanemab costs about US$27,500 in the U.S., where it is licensed.
It is unclear how much donanemab might cost and how long it might take to get approval in other countries, but Alzheimer’s experts said having two drugs available would help with price competition.
Real impact
Mike Colley turned 80 in April. At his birthday party, he surprised his family by singing “My Way” in front of 40 guests.
He told BBC News, “That’s the confidence I have now. I would never have done that even 12 months ago.”
His son Mark added: “I never thought I’d see my dad so full of life again. It was an incredible moment.”
Dr. Emer MacSweeney, medical director of Re:Cognition Health, led the donanemab trials in the UK.
“This is really significant and one of the biggest breakthroughs,” she said.