Lilly has suffered a huge blow after its experimental therapy for Alzheimer's disease failed in a large-scale Phase III trial, signifying the end of its development for patients with mild forms of the disease.

Things were already looking a little uncertain for solanezumab after the failure of two clinical trials involving patients with mild or moderate disease back in 2012, though an apparent benefit seen in those with mild forms led Lilly to start a new trial, EXPEDITION3, to further investigate its effect on function and cognition in this population.

Earlier this year, in a rather unusual move, Lilly changed the endpoint of the trial, demoting the co-primary endpoint of function to a secondary target. But it did stress at the time that the move was driven by "emerging scientific evidence" supporting the notion that cognitive decline precedes and predicts functional decline in Alzheimer's disease, particularly in earlier stages of the disease, and not because it has seen any study data.

However, the trial has now shown that the beta amyloid antibody failed to meet its remaining primary goal of a statistically significant slowing in cognitive decline compared to patients treated with placebo. The firm said while the data show a trend favouring solanezumab, the magnitudes of treatment differences were small.

"The results of the solanezumab EXPEDITION3 trial were not what we had hoped for and we are disappointed for the millions of people waiting for a potential disease-modifying treatment for Alzheimer's disease," said John C. Lechleiter, chairman, president and chief executive officer, Lilly. "We will evaluate the impact of these results on the development plans for solanezumab and our other Alzheimer's pipeline assets."

Lilly said it will not pursue regulatory submissions for solanezumab for the treatment of mild dementia due to Alzheimer's disease, and that the next steps for the remaining elements of the development programme have not yet been determined. Further findings from the study will be presented at the Clinical Trials on Alzheimer's Disease (CTAD) meeting in December.

The firm's stock was trading down more than 10 percent in the aftermath of the news, but David A. Ricks, Lilly's incoming chief executive and president of Lilly Bio-Medicines insisted that "Lilly has strong growth prospects without solanezumab."

"Driven by new product launches, we continue to expect to grow average annual revenue by at least 5 percent between 2015 and 2020. Over that time frame, we also expect to increase our margins and provide annual dividend increases to our shareholders," he said.

The failure of solanezumab in Alzheimer's has also thrown a further shadow of doubt over targeting amyloid plaques as a means of reducing symptoms of the disease.