Cautious response to Alzheimer’s drug claims

There has been a cautious response to claims that a drug treatment given to patients in the early stages of Alzheimer's disease has been able to slow its progress.

Patients on the drug solanezumab saw an average 34 per cent reduction in mental decline compared with those who had not yet started the drug, the study suggested.

Details of the US study were released yesterday at the Alzheimer’s Association International Conference in Washington, DC.

Research support groups responded enthusiastically to the news and the findings were described as “an exciting step forward” by Dr Doug Brown, head of research at the US Alzheimer’s Society.

The response was far more muted among researchers and clinicians working with Alzheimer's. "I would be cautious about this; this is not going to have any immediate impact on our treatment for dementia and Alzheimer's," said Prof Declan McLoughlin, research professor in psychiatry at Trinity College Dublin and a consultant at St Patrick's University Hospital, Dublin.

Alzheimer’s disease is a progressive, fatal neurodegenerative condition. The incidence of Alzheimer’s has been rising worldwide because people are living longer.

There are about 48,000 people living with dementia in Ireland, with Alzheimer’s the cause in most patients.

There has been a major international effort for many years to find a successful treatment that could slow down, halt or counter the progress of the disease, but there has been very limited progress.

The condition is linked to the buildup of plaques in the brain, made of proteins that form but do not dissolve away. They build-up over time, damaging or killing brain cells.

The researchers have concentrated on two approaches to treatment, one involving getting rid of the plaques, the other developing drugs that counter the memory loss caused by the disease.

Plaques targeted

Solanezumab, developed by US drug company Eli Lilly, works by targeting the plaques, using the body’s immune system to attack the proteins and reduce them.

The company organised a trial involving 1,300 patients in 2012, but despite showing early promise the trial was a failure. The researchers went back, however, and sifted the data in a “secondary analysis”. They presented details of this analysis at the meeting in Washington. It showed the drug performed best among patients in the early stages of the disease. Eli Lilly immediately started another trial assessing this, with results due by the end of 2016.

“The original study was not designed to find out [effects of early treatment], this was a secondary look,” said Prof McLoughlin.

He was also uncertain about the claimed 34 per cent reduced mental loss. “They believe this is statistically significant, but it is not necessarily clinically significant. We need to see that the statistical significance translates into meaningful functional improvement or a substantial slowing down of the progression of the disorder. It will take many years to confirm it has a disease-modifying effect,” he said.

Prof John Hardy of University College London said: "These reports are good news in the same way that a forecast of sunny weather at the weekend is good news. It raises hopes for good weather, but it does not mean good weather is a certainty."