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January 2019

Early-Phase Randomized Clinical Trials—Expectations vs Hard Reality

Author Affiliations
  • 1Department of Neurology, Mayo Clinic, Rochester, Minnesota
JAMA Neurol. 2019;76(1):15-16. doi:10.1001/jamaneurol.2018.3301

The randomized clinical trial reported by Sha et al1 in this issue of JAMA Neurology explores a novel and unconventional approach to Alzheimer disease (AD) therapeutics. The authors hypothesize that circulating factors found in the blood of young people might address some of the neurodegenerative consequences of AD or associated neurodegeneration. They originally tested the idea in mice2 and found that in heterochronic parabiosis (which they define as a “surgical union of 2 organisms of different ages”2(p1326)) or infusion of intravenous plasma from young to old mice, they could partially restore “molecular and behavioral disease-related deficits”2(p1326) in mice with AD transgenes. They were not able to isolate the specific substance in the young blood product that was the active therapeutic, but the molecular changes suggested that whatever the active substance was entered the brain.