By Ed Susman
CHICAGO -- July 30, 2008 -- The experimental drug tarenflurbil, a beta amyloid-lowering agent, failed to stop the cognitive decline in patients diagnosed with mild Alzheimer's disease in a phase 3 clinical trial.
"This was the largest and longest placebo-controlled Alzheimer's disease treatment trial ever completed," said Robert C. Green, MD, Boston University School of Medicine, Boston, Massachusetts. "While this trial did not meet its endpoints, it was well designed and executed, and it provided clear answers regarding tarenflurbil's lack of efficacy and its safety."
The drug was well tolerated, Dr. Green said in his oral presentation on July 29 here at the 2008 International Conference on Alzheimer's Disease (ICAD), but it failed to distinguish itself from placebo in its primary endpoints of slowing of decline in the Alzheimer's Disease Assessment Score-cognition scale (ADAS-cog) or in the Alzheimer's Disease Cooperative Study Group-Activities of Daily Living (ADCS-ADL) score.
In both the 809-patient placebo group and in the 840 patients taking tarenflurbil 800 mg twice daily, the reduction in ADAS-cog over 18 months was 7.1 points and the decrease in ADCS-ADL was 9.8 points.
Patients were about 75 years of age in both groups and were evenly split by sex; more than 94% of patients in each group were white. Patients had been diagnosed with mild Alzheimer's disease for 20 months upon entry into the study. The Mini Mental State Examination score was 23.3 for each group, Dr. Green said.
"While the results of this trial were certainly disappointing, it doesn't mean that other amyloid-targeted therapies in the clinical trial pipeline aren't valid," said Samuel Gandy, MD, Chair of the Alzheimer's Association's Medical and Scientific Advisory Council. "There are other drugs in development that target amyloid with mechanisms of action that are different from tarenflurbil. One or more of these drugs may ultimately prove successful."
The study was supported by Myriad Pharmaceuticals.
[Presentation title: Safety and Efficacy of Tarenflurbil in Subjects With Mild Alzheimer's Disease: Results From an 18-Month Multi-Center Phase 3 Trial. Abstract O3-04-01]