Medivation's Dimebon Improved Thinking, Memory In Alzheimer's Patients
Alzheimer's patients treated with Medivation's investigational drug Dimebon showed improvement in the key aspects of cognitive function over a one-year period compared with placebo. The improvement occurred in not only memory and language, but also in more complex functions such as awareness of time and place, and praxis -- the process of getting an idea and initiating and completing a new motor task. These clinical results were generated during a pivotal trial of Dimebon in patients with mild-to-moderate Alzheimer's disease (AD).
The data were presented today during an oral presentation at the 60th Annual Meeting of the American Academy of Neurology (AAN) by Steven H. Ferris, Ph.D., the Gerald J. and Dorothy R. Friedman Professor of Psychiatry at New York University and director of the NYU Alzheimer's Disease Center.
"The finding that Dimebon improved memory, orientation, language and praxis in Alzheimer's disease patients suggests that it provides a broad rather than a selective cognitive benefit," said Dr. Ferris. "This is an important finding given that deficits in memory and thinking are one of the hallmarks of Alzheimer's disease and cause patients and caregivers significant distress."
Dimebon Significantly Improved Cognitive Function at One Year
The data presented at the AAN Annual Meeting included results of an analysis of the 11 subdomains of the Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog), a standardized measure of cognition in patients with AD and one of two endpoints the U.S. Food and Drug Administration (FDA) has used to approve all currently marketed drugs for mild-to-moderate AD. In the study, ADAS-cog was assessed at the beginning of the study and at weeks 12, 26, 39 and 52.
Results showed that Dimebon-treated patients were significantly improved compared with placebo on 9 of the 11 ADAS-cog subdomains after one year of treatment. Benefits were observed in memory (word recall, p=0.04; word recognition, p=0.03; remembering instructions, p=0.10); orientation (p= 0.01); constructional praxis (the ability to copy simple drawings or patterns, p=0.005) and ideational praxis (the ability to perform a familiar but complex sequence of actions, p=0.006); and language (following commands, p<0.0001; naming objects, p<0.0001; word finding, p=0.005; comprehension, p=0.15; overall language, p=0.0002).
"We have recently presented a number of different findings from our first pivotal trial of Dimebon at scientific conferences, demonstrating that this investigational drug has a beneficial impact on the key aspects of Alzheimer's disease -- from behavioral symptoms to thinking and memory problems to impairments in daily function," said Lynn Seely, M.D., chief medical officer of Medivation. "Medivation is committed to rapidly developing Dimebon as a treatment for mild-to-moderate Alzheimer's disease to make it available to the millions of people who suffer from this increasingly prevalent disease, for which new treatment options are desperately needed."
Dimebon Showed Statistically Significant Benefit Versus Placebo on All Key Efficacy Endpoints
Medivation previously announced efficacy and safety results from the pivotal, 12-month, double-blind, placebo-controlled trial of Dimebon in 183 patients with mild-to-moderate AD. Dimebon improved the clinical course of Alzheimer's disease patients by causing statistically significant improvements over placebo in each of the five primary aspects of the disease -- memory, thinking, activities of daily living, behavior and overall clinical function. Significant gains over placebo were evident after as little as 12 weeks of treatment, and were maintained after both six months and a full year of treatment. In addition, after six months of treatment, Dimebon patients were significantly better on all five disease aspects than they were at the beginning of the study. The real-world impact of these data was evaluated by independent assessment, including caregiver interviews, which confirmed improvement or stabilization in 81 percent of Dimebon-treated patients after six months of treatment. Importantly, Dimebon's overall benefit compared to placebo continued to increase over time, and was larger at one year than at six months.
Dimebon was well-tolerated throughout the entire one-year treatment period. The majority of adverse events were mild, with dry mouth (18.0 percent Dimebon, 1.1 percent placebo) and depressed mood the most common events. There were significantly fewer serious adverse events in the Dimebon group than in the placebo group at one year.
Medivation is planning to initiate a second, confirmatory pivotal Phase 3 trial of Dimebon in mild-to-moderate AD in the second quarter of 2008 with the goal of completing the trial and applying for U.S. and European marketing approval in 2010. The Company is also evaluating Dimebon in an ongoing Phase 2 clinical trial in mild-to-moderate Huntington's disease. Dimebon is an orally-available small molecule that has been shown to inhibit brain cell death in preclinical models relevant to Alzheimer's and Huntington's diseases, making it a potential treatment for these and other neurodegenerative diseases.