By Natalie Grover
ZURICH/LONDON (Reuters) -Roche's experimental Alzheimer's drug crenezumab failed to meaningfully slow or prevent cognitive decline in people at risk of a rare, inherited form of the disease, the Swiss drugmaker said on Thursday.
The failure marks another blow to the hypothesis that targeting toxic protein plaque known as beta amyloid in the brain is a viable approach to arresting the progression of Alzheimer's disease.
Roche had hoped to prove crenezumab, which is designed to block beta amyloid, could prevent the memory-robbing disease if given before symptoms emerged.
The lengthy study involved 252 people from an extended family in Columbia diagnosed with autosomal dominant Alzheimer's disease (ADAD) caused by a specific gene mutation. They were enrolled before they showed any signs.
Participants were randomised to receive regular infusions of crenezumab or placebo over five to eight years. On Thursday, Roche said that although small numerical differences favoured crenezumab, the effects were not statistically significant.
Roche's shares slipped more than 1% in afternoon trading.
Crenezumab was discovered by fellow Swiss drug developer AC Immune, but Roche was in charge of its development via a licence agreement. The drug previously failed a pair of phase III studies evaluating its use in the early stages of Alzheimer's.
The field targeting the fatal brain disease - which affects an estimated 55 million globally - is littered with high profile failures. Drugs designed to target Alzheimer's have nearly always stumbled in trials.
Adoption of the first new Alzheimer's treatment in nearly 20 years, made by rival U.S. drugmaker Biogen Inc (NASDAQ:BIIB), spectacularly underwhelmed after the U.S. health regulator gave the green light to the treatment without clear evidence of patient benefit, driven in part by the lack of options for the most common form of dementia.
Roche, which recently suffered a key cancer drug setback, has its own keenly-watched Alzheimer's prospect. Late-stage data on the drug, gantenerumab, is expected later this year.
But the company has sought to temper expectations around high-risk, high-reward product.
"Everyone knows Alzheimer's research is a very risky type of research," Chairman Christoph Franz told Reuters last month.