Clinical trial of an inhibitor of RAGE-Aβ interactions in Alzheimer disease.
OBJECTIVE
To examine safety, tolerability, and efficacy of PF-04494700, an inhibitor of the receptor for advanced glycation end products (RAGE), in mild to moderate Alzheimer disease (AD).


METHODS
Double-blind, placebo-controlled trial at 40 academic centers (United States). Subjects with AD and Mini-Mental State Examination score 14-26 were randomized to PF-04494700 60 mg/day × 6 days, then 20 mg daily (high dose); 15 mg/day × 6 days, then 5 mg daily (low dose); or placebo, for 18 months. Clinical and laboratory measures were used to evaluate safety and tolerability. The primary efficacy measure was the Alzheimer's Disease Assessment Scale-cognitive (ADAS-cog). Secondary measures assessed clinical stage, function, behavior, MRI, and CSF biomarkers.


RESULTS
A total of 399 subjects were randomized. In a prespecified interim analysis, when 50% of subjects had completed the 6-month visit, the high dose was associated with confusion, falls, and greater ADAS-cog decline and was discontinued. A second prespecified analysis compared low-dose and placebo groups for futility and safety approximately 12 months after all subjects were randomized. This analysis met criteria for futility, and treatment was discontinued. There were no safety concerns in the low-dose group. Analyses including post-futility data showed decreased decline on the ADAS-cog in the low-dose group at month 18. Other clinical and biomarker measures showed no differences between low-dose treatment and placebo.


CONCLUSIONS
PF-04494700 at 20 mg/d was associated with increased adverse events and cognitive decline. At 5 mg/d, PF-04494700 had a good safety profile. A potential benefit for this low dose on the ADAS-cog is not conclusive, because of high dropout and discontinuation rates subsequent to the interim analyses.


METHODS
This study provides Class I evidence that in patients with AD high-dose PF-04494700 increased cognitive decline at 6 months and Class IV evidence that low-dose PF-04494700 slowed cognitive decline at 18 months.
From the Department of Neurosciences (D.G., R.G.T., P.S.A.), University of California, San Diego; Pfizer Global Research & Development (J.B., J.Y.M., J.W.K.), Cambridge, MA; Banner Sun Health Research Institute (M.N.S.), Sun City; University of Arizona (M.N.S.), Tucson; and the Department of Psychiatry (C.v.D.), Yale University, New Haven, CT.
Douglas
D
Galasko
Joanne
J
Bell
Jessica Y
JY
Mancuso
James W
JW
Kupiec
Marwan N
MN
Sabbagh
Christopher
C
van Dyck
Ronald G
RG
Thomas
Paul S
PS
Aisen
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D014150:Antipsychotic Agents / Q000627:therapeutic use*; D003072:Cognition Disorders / Q000097:blood / Q000188:drug therapy / Q000209:etiology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D017127:Glycation End Products, Advanced / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011569:Psychiatric Status Rating Scales; D013997:Time Factors; D014481:United States
D016229:Amyloid beta-Peptides; D014150:Antipsychotic Agents; D017127:Glycation End Products, Advanced