Alzheimer’s disease is a progressive condition that affects areas of the brain involved in memory, cognition, judgment, language and behavior.
The Dimebon pivotal clinical study is the first Alzheimer’s disease study in which a drug has achieved statistically significant benefits of this breadth, size and duration in a one year, well-controlled trial.
Clinical Trial--A Safety and Efficacy Study of Oral Dimebon in Patients With Mild-To-Moderate Alzheimer's Disease (Currently Recruiting)
Medivation--Dimebon
18-Month Data from an Extension of a Pivotal Trial of Dimebon in Alzheimer's
In a study recently reported, Dimebon (Medivation) improved cognition and memory, activities of daily living, and behavior in a one-year placebo-controlled trial of patients with mild to moderate Alzheimer's. At ICAD 2008, Jeffrey L. Cummings, M.D., the Augustus S. Rose Professor of Neurology, and Professor of Psychiatry and Biobehavioral Sciences, at UCLA, and colleagues reported on an open-label extension of the trial to 18 months.
One hundred eighty-three (183) people with mild-to-moderate Alzheimer's were initially randomized into a six-month placebo-controlled study of Dimebon. Patients completing six months of treatment were offered the opportunity to re-consent for an additional six months of controlled treatment in their originally randomized group, followed by an open-label extension (OLE). Data presented at ICAD 2008 include only the 104 OLE participants (54 Dimebon, 50 placebo). All were given Dimebon for the OLE, not placebo, at a dose of 20 mg three times per day. Ninety-two (92) (88.5%) patients enrolling into OLE completed six months of treatment.
Patients originally receiving Dimebon for 12 months who continued on Dimebon for an additional six months in the OLE phase had preservation of function close to their starting baselines on the key signs and symptoms of Alzheimer's disease 18 months after starting the study. Patients originally on placebo for 12 months who were then crossed over to Dimebon on the OLE phase also stabilized across all key measures tested. Since these patients had declined over the previous 12 months while on placebo, they stabilized at a lower level of function than those treated with Dimebon for the full 18 months.
Dimebon was well-tolerated through 18 months. Adverse events that occurred more often with dimebon compared to placebo were dry mouth, sweating and depressed mood/sadness.
"People initially treated with placebo and then crossed over to Dimebon did not show the same level of benefit as those people who took Dimebon for the full 18 months," Cummings said. "This emphasizes the benefit of earlier treatment, and suggests the possibility that Dimebon may slow of the progression of Alzheimer's. However, open-label extensions are not that same as placebo-controlled trials, and extrapolation of the treatment results should be done with caution. Patients are being screened now for the Phase III clinical trials."
"Dimebon appears to work through a mechanism of action that is distinct from currently marketed Alzheimer's drugs. Dimebon improves impaired mitochondrial function. Mitochondria are the central energy source of all cells and impaired mitochondrial function may play a significant role in the loss of brain cell function in Alzheimer's," Cummings added.
