Patients with mild Alzheimer's disease who took Eli Lilly and Co's experimental drug solanezumab early in the course of their disease preserved more of their cognitive and functional ability, according to new Lilly data released on 22 July.

Lilly presented new follow-up data from two large trials of the infused medicine on Wednesday at the Alzheimer's Association International Conference (AAIC) in Washington.

"In people with Alzheimer's disease one of the things that happens during the disease a normal protein called amyloid begins to accumulate in the brain. And the drugs that were presented this morning were all aimed at removing more amyloid from the brain. Many people in Alzheimer's research believe if you lower amount of amyloid in Alzheimer's brain you will moderate the course of the disease," said Alzheimer's Association Chief Medical and Scientific Officer, William Thies.

In 2012, the original 18-month studies of solanezumab, called Expedition and Expedition 2, each included about 1,000 patients with mild to moderate disease. The drug failed to slow cognitive declines or loss of abilities of daily living for the entire patient population.

But when Lilly analysed results only for mild patients, the data suggested solanezumab caused a significant 34 percent slowdown in mental decline and an 18 percent slowdown in loss of functional abilities compared to placebo, researchers said.

To better assess whether mildly impaired patients benefit from the drug, Lilly extended its two trials by another two years and only enrolled those with mild disease. Researchers continued to provide solanezumab to patients who had taken it during the studies and also allowed patients who had been given placebos to switch over to solanezumab.

Lilly had previously reported that after the first six months of the extension study, patients who had taken solanezumab all along continued to show a greater benefit than those who switched to the drug later.

"It's important because it showed a continued effect of the drug, so the drugs aren't transient," Thies said.

Should solanezumab prove successful in that 2,100-patient study of patients with mild Alzheimer's, within several years it could become the first approved drug to slow the course of the disease , Lilly officials said.