Solanezumab works by preventing the formation of brain plaques that kill nerve cells and cause the loss of brain tissue.
The study, presented at the Alzheimer's Association International Conference in Washington, D.C., is the first Alzheimer's disease clinical trial to employ delayed-start methodology.
In this instance, delayed-start methodology involved randomly separating patients into two separate groups. One group was treated with solanezumab for 18 months while the other received a placebo. After 18 months, the placebo group then began treatment with the drug. This "delayed-start period" then ran for a further 2 years.
"This new analytical method enabled us to assess if solanezumab had an effect that is consistent with slowing progression of disease by modifying the underlying disease progression, which, up until now, has not been studied," states study author Hong Liu-Seifert, PhD.
Alzheimer's disease is a fatal neurological disease that can lead to dementia and progressive memory decline. Experts believe that around 5.3 million Americans are affected by the disease.
Damage occurs when proteins build up in the brain, forming structures known as plaques. These plaques block the connections between nerve cells, ultimately killing the cells and leading to the loss of brain tissue.
Solanezumab is one form of treatment being studied as a potential therapy for patients with mild forms of Alzheimer's disease. It works by binding to proteins called amyloid-beta, allowing them to be cleared before they build up and form plaques in the brain.
The results come from the secondary analysis of data produced by three studies. EXPEDITION and EXPEDITION2 were identical phase 3 randomized, double-blind placebo-controlled trials lasting for 18 months. EXPEDITION-EXT was the name given to the delayed-start period, in which the placebo groups began treatment with solanezumab.
A total of 581 patients with mild Alzheimer's disease completed the study - 295 from the early-start group and 286 from the delayed-start group.
Benefit in starting treatment 'earlier rather than later'
The researchers found that differences in cognition and function between the two groups were preserved at both 108 weeks (28 weeks after the delayed-start period commenced) and 132 weeks (52 weeks after the delayed-start period commenced). These differences were deemed statistically significant.
As it was, the results indicated that patients who had the start of treatment delayed were unable to "catch up" with patients whose treatment began earlier, suggesting that the treatment may slow the progression of the disease rather than just reducing symptoms.
"The results support the potential benefit of starting treatment with solanezumab earlier rather than later in disease progression, and suggest there is persistence of treatment effect even after the delayed-start patients are given the drug," says co-author Dr. Paul Aisen, Director of the Alzheimer's Therapeutic Research Institute at the University of Southern California, San Diego.
Liu-Seifert, a research advisor at Eli Lilly and Company - the pharmaceutical company that manufactures the drug - states that their findings support the trial design and delayed-start analysis plan for the next stage of the trials - EXPEDITION3 - for which the final patient is expected to be seen in October 2016.
The findings of the study are to be published in the journal Alzheimer's & Dementia: Translational Research & Clinical Interventions.
Earlier this month, Medical News Today reported on a study in which a new DNA repair mechanism was discovered that could lead to new ways to treat and prevent disorders such as Alzheimer's disease.
In the study, researchers discovered how special enzymes can detect and initiate the repair of single-strand breaks in DNA that were previously believed to be inaccessible.