Controversy About Lack of Placebo Group Decline in Alzheimer's Clini...(said. Based on our analysis the mostrel...),Health

Scientific Review of Donepezil Trials Shows Slowing Rates of Placebo Group Decline

Professor Roy Jones, Director of RICE -- The Research Institute for the Care of Older People, based at the Royal United Hospital in Bath, England, and colleagues conducted a meta-analysis using individual patient data from randomized, double-blind, placebo-controlled studies of donepezil (Aricept) for Alzheimer's between 1990 and 1999. The work stemmed from discussions and analyses undertaken through an expert working group initiated and funded by Eisai and Pfizer, makers and marketers of donepezil.

"Our results indicate that patients with Alzheimer's entering the later clinical trials appear to be experiencing a slower rate of decline in memory and thinking processes," Jones said. "These observations are potentially important for the future design of clinical trials in people with Alzheimer's. For example, it may be necessary to conduct longer duration research studies -- more than 24 weeks -- to ensure any effects of treatment can be fully evaluated."

Data were available from 3,403 patients who participated in 13 randomized, double-blind, placebo-controlled Alzheimer trials. Data were grouped according to the year of initiation of the trials. Group 1: studies initiated in 1990-1994; Group 2: studies initiated in 1996-1999. This cut-off was associated with the timing of donepezil registration. Changes from baseline MMSE and ADAS-cog scores up to week 24 were compared between groups 1 and 2 for placebo only, and then between donepezil and placebo.

Decline on the MMSE from baseline to week 24 was significantly greater among placebo patients in group 1 (-1.28 points) compared with group 2 (-0.56 points; P = 0.024). Placebo decline on
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