New Drug Shows Promise for Early-Stage Alzheimer's

One hemisphere of a healthy brain, left, is shown next to a hemisphere of a brain of a person suffering from Alzheimer's disease. REUTERS/Denis Balibouse

Researchers say solanezumab, a drug that has been evaluated in a number of Phase III trials, may be effective for treating mild to moderate Alzheimer's disease. If the drug is approved, it would be the first therapy available to patients meant to stop the progression of the disease rather than merely managing symptoms of memory loss and cognitive decline.

This week, at the annual Alzheimer's Association meeting, researchers presented an analysis of 1,322 patients who participated in either the Expedition or Expedition 2 Phase III trials conducted by Eli Lilly. The two trials lasted for 18 months. In both placebo-controlled trials, solanezumab was found to reduce memory loss and cognitive decline by more than 30 percent.

Afterward, approximately 95 percent of patients with mild Alzheimer's participated in an extension of the trial (called Expedition-Ext) that took place for three and a half years after the conclusion of the initial trials. This extension helped produce what's known as a "delayed-start" trial. In this type of study, one group of patients receives the drug, and the other takes the placebo. Study participants in the placebo group then switch from the placebo to the actual drug after the completion of the official 18-month trial. This allows the researchers to compare the effects of the drug on different timelines.

The delayed-start study model also gives researchers the opportunity to evaluate if the drug is merely treating symptoms or the disease itself. The researchers suspect long-term therapies for Alzheimer's would work slowly over time rather than immediately alleviating symptoms.

The researchers determined that patients who took the drug at the start of the Expedition and Expedition 2 trials benefited most from it. Patients in the delayed-start group didn't "catch up" with those who had been taking the drug for a longer duration. Patients who were in the placebo group showed fewer improvements in cognitive function.

This finding backs up what many Alzheimer's experts have suspected for some time: It's not only important for researchers to identify an effective drug for the disease. It's also essential to diagnose a patient early and begin treatment as soon as possible.

Heather Snyder, director of medical and scientific relations at the Alzheimer's Association, calls the study's design "uncharted territory in the field." She added that the delayed-start model is also being utilized in an ongoing Expedition 3 trial.

Snyder says that if solanezumab is most effective during the earliest stage of the disease, this may be a reason for scientists to also focus efforts on developing more effective diagnostic tools. At the meeting, a number of scientists also presented potential ways to improve rates of early diagnosis, including a test that measures levels of certain proteins in a patient's saliva, which may be an indicator of Alzheimer's.

There are currently no drugs available to treat Alzheimer's. Physicians instead focus on addressing symptoms such as agitation and loss of memory and cognitive function. Solanezumab is an antibody that blocks the development of beta-amyloid plaques in the brain, which is one of the hallmarks of the disease.

Snyder also says that scientists and physicians are beginning to observe that one drug probably isn't not enough to effectively treat and manage Alzheimer's. She added that in the future physicians will be more likely to utilize "a cocktail approach" to develop an effective treatment plan for patients. These may include drugs such as solanezumab and other medications for symptoms management.