An Alzheimer's update: New drugs, new insights, new hope
- The Alzheimer's Association International Conference (AAIC) convened on Saturday in Washington, D.C., and attendees are anticipating updates from Eli Lilly about solanezumab and from Biogen about aducanumab. Researchers are also exploring the merits of combo therapy.
- Both solanezumab and aducanumab reduce amyloid plaque in the brain and both are being tested on subjects with mild cognitive impairment (MCI) - the earliest stage of Alzheimer's disease (AD).
- There has been a great deal of failure in development efforts in this therapeutic area in the last 20 years, but this year's focus on combination therapies, early intervention, and the revival of the anti-amyloid plaque theory are giving rise to an invigorated sense of hope.
By now, we know the stats well: An estimated five million Americans have AD, and the number is rapidly growing. By 2040, if things continue unabated, about 28 million people will have AD, and the costs will consume one quarter of the entire Medicare budget. And despite years of failures and billions of dollars spent, researchers continue to look for a treatment that actually addresses the underlying pathology of AD, versus simply treating the symptoms.
Enter this year's biggest news stories - solanezumab and aducanumab. Lilly will be presenting new data on salanezumab, which was found ineffective in 2012 studies focusing on patients with mild-to-moderate AD. The difference this year is that Lilly will be focusing on treatment effects in patients with MCI (the earliest form of AD). Of interest is the crossover study design in which patients who took solanezumab from the start of the study were compared with those who started on placebo and later switched to solanezumab. Assuming that there are differences in the brains and cognitive changes in those patients, this may prove that solanezumab actually affects the underlying pathology of AD.
With respect to Biogen's aducanumab, the excitement is palpable, because in March, aducanumab became the first experimental drug to significantly reduce beta-amyloid in the brain and simultaneously slow impairment in MCI patients. The focus here will be on dosing. Earlier researchers found that of the three dose ranges tested (1 mg, 3 mg, 10 mg), only the 3- amd 10-mg doses elicited a response in terms of reducing amyloid plague burden and improving cognitive function; however, the 10-mg dose led to brain swelling. Now Biogen is hoping to hit the sweet spot with a 6-mg dose with the goal of maximizing efficacy and avoiding the brain swelling.
All told, this year's Alzheimer's Association International Conference (AAIC) looks to be very promising, with a combination of new approaches, such as being more careful when selecting patients for trials to make sure they have AD-related dementia, with various drugs and combination approaches to therapy.