A new jab for people with early-stage Alzheimer’s has failed to show it can slow down a decline in memory and thinking, according to pharmaceutical giant Roche.

The drug, gantenerumab, is an antibody medicine that held much promise as it entered phase three clinical trials.

However, Roche said the drug, which is given as an injection, could not clearly be shown to slow dementia progression in two drug trials.

While there was some progress, this was not statistically significant. This meant the drug could not be clearly shown to preserve people’s abilities in areas such as remembering, solving problems or personal care.

Previous data had shown that gantenerumab reduces brain amyloid plaque.

Abnormal levels of this naturally occurring amyloid protein clump together in the brains of people with Alzheimer’s, forming plaques that collect between neurons and disrupt cell function.

In September, another drug, lecanemab, was found to slow decline in the memory and thinking of people with early-stage Alzheimer’s.

Alzheimer’s Research UK said those findings represented a “historic moment for dementia research”.

The new clinical studies for Roche included more than 2,000 patients treated for more than two years in more than 30 countries worldwide.

Muriel De Vos, from Roche, said: “We are disappointed that the topline results from the pivotal Phase III Graduate I and II trials show that the primary endpoint of slowing clinical decline has not been met.

“However, we remain committed to transforming the lives of people with Alzheimer’s disease through our ongoing research and development of investigational medicines for different targets, types and stages of AD.”

Dr Richard Oakley, associate director of research at the Alzheimer’s Society, said: “These results today are disappointing, as we don’t currently have a drug for Alzheimer’s disease in the UK which slows down its progression.

“However, this is still an exciting time for dementia research, with promising early results from a similar drug, lecanemab, and 143 other drugs currently in clinical trials aiming to slow down the disease or help with symptoms.

“It’s so important to remember we need research into other types of dementia as these drugs are only for Alzheimer’s disease.

“We need to see the Government’s promised National Dementia Mission – to double dementia research funding – delivered urgently.

“It must drive early diagnosis, through more PET scanners and research into blood tests, so people can get access to these drugs if they become available.

“With 900,000 people in the UK currently living with dementia, we need a concerted effort into research for all types of dementia so one day we have treatments for everyone living with the condition.”