Eli Lilly said its experimental Alzheimer's drug slowed cognitive decline in patients with a mild form of the disease though it failed its main trial goals, sending its shares up more than 8 per cent on hopes the treatment may still be salvaged.

The late-stage trials, known as Expedition 1 and 2, tested solanezumab in patients with mild-to-moderate Alzheimer's disease, compared with a placebo.

A secondary analysis of the results showed a statistically significant slowing of cognitive decline in patients with mild Alzheimer's disease, but not in those with moderate Alzheimer's, the company said today.

"We recognize that the solanezumab studies did not meet their primary endpoints, but we are encouraged by the pooled data that appear to show a slowing of cognitive decline," said Lilly chief executive John Lechleiter. "We intend to discuss these data

with regulatory authorities to gain their insights on potential next steps."

The results bolstered expectations the treatment may still prove viable if tested in patients either at an earlier stage of the disease, or who have yet to show symptoms.

Lilly's drug aims to reduce a toxic protein found in the brains of Alzheimer's patients, known as beta amyloid.

Pfizer Inc and Johnson & Johnson earlier this month said their similar drug, bapineuzumab, failed in late-stage trials to improve memory or thinking skills in patients with mild and moderate forms of the disease.

Sanford Bernstein analyst Tim Anderson said the results supported a theory that such treatments "probably need to be given as early as possible in the course of the disease".

Reuters