TY - JOUR

T1 - Rates of cognitive change in Alzheimer disease: Observations across a decade of placebo-controlled clinical trials with donepezil

AU - Jones, Roy W

AU - Schwam, Elias

AU - Wilkinson, David

AU - Waldemar, Gunhild

AU - Feldman, Howard H

AU - Zhang, Richard

AU - Albert, Kenneth

AU - Schindler, Rachel

PY - 2009

Y1 - 2009

N2 - Treatment success in Alzheimer disease (AD) trials is generally based on benefits over placebo-treated controls. Consequently, variation in rates of decline among placebo-treated patients could impact outcomes from AD trials. In the present analyses, individual patient data [baseline Mini-Mental State Examination (MMSE): 10 to 26] were pooled from randomized, placebo-controlled studies of donepezil for AD conducted during the 1990s, and grouped by initiation year-group 1: 1990 to 1994; group 2: 1996 to 1999. Changes in MMSE and Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) were compared between groups 1 and 2 for placebo, and then between donepezil and placebo. Data were available from 3403 patients in 13 trials. Group 2 (post-1995) included patients with lower baseline MMSE scores, older patients, fewer males, more comorbidity, and more concomitant medications. MMSE decline by week 24 was significantly greater among group 1 (pre-1995) placebo patients versus group 2; a similar trend was observed with the ADAS-cog. Nevertheless, donepezil-mediated treatment effects were consistent over the decade of enrollment. These analyses suggest that patients are showing slower rates of cognitive decline in more recent trials compared with older trials, although having more comorbidities. This finding may have important potential implications for future clinical trial design.

AB - Treatment success in Alzheimer disease (AD) trials is generally based on benefits over placebo-treated controls. Consequently, variation in rates of decline among placebo-treated patients could impact outcomes from AD trials. In the present analyses, individual patient data [baseline Mini-Mental State Examination (MMSE): 10 to 26] were pooled from randomized, placebo-controlled studies of donepezil for AD conducted during the 1990s, and grouped by initiation year-group 1: 1990 to 1994; group 2: 1996 to 1999. Changes in MMSE and Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog) were compared between groups 1 and 2 for placebo, and then between donepezil and placebo. Data were available from 3403 patients in 13 trials. Group 2 (post-1995) included patients with lower baseline MMSE scores, older patients, fewer males, more comorbidity, and more concomitant medications. MMSE decline by week 24 was significantly greater among group 1 (pre-1995) placebo patients versus group 2; a similar trend was observed with the ADAS-cog. Nevertheless, donepezil-mediated treatment effects were consistent over the decade of enrollment. These analyses suggest that patients are showing slower rates of cognitive decline in more recent trials compared with older trials, although having more comorbidities. This finding may have important potential implications for future clinical trial design.

U2 - 10.1097/WAD.0b013e31819cd4be

DO - 10.1097/WAD.0b013e31819cd4be

M3 - Journal article

C2 - 19561444

VL - 23

SP - 357

EP - 364

JO - Alzheimer Disease and Associated Disorders

JF - Alzheimer Disease and Associated Disorders

SN - 0893-0341

IS - 4

ER -