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Original Investigation
January 2019

Safety, Tolerability, and Feasibility of Young Plasma Infusion in the Plasma for Alzheimer Symptom Amelioration Study: A Randomized Clinical Trial

Author Affiliations
  • 1Department of Neurology and Neurological Sciences, Stanford University, Stanford, California
  • 2Department of Health Research and Policy, Stanford University, Stanford, California
  • 3Science37, San Francisco, California
  • 4Department of Neurosurgery, Stanford University, Stanford, California
  • 5Department of Pediatrics, Stanford University, Stanford, California
  • 6Alzheimer's Therapeutic Research Institute, University of Southern California, Los Angeles
  • 7SBGneuro Ltd, Oxford, England
  • 8Alkahest, San Carlos, California
JAMA Neurol. 2019;76(1):35-40. doi:10.1001/jamaneurol.2018.3288
Key Points

Question  Is young plasma safe, feasible, and tolerable in patients with mild to moderate Alzheimer disease dementia?

Findings  This randomized clinical trial consisted of a double-blind crossover group of 9 patients and an open-label group of 9 patients. Patients with mild to moderate Alzheimer disease dementia were able to tolerate 4 weekly infusions of young plasma.

Meaning  Safe and well tolerated in a small sample of patients with mild to moderate Alzheimer disease dementia, young plasma infusions warrant further analysis in a larger study using a double-blinded design with a placebo control.


Importance  Young mouse plasma restores memory in aged mice, but, to our knowledge, the effects are unknown in patients with Alzheimer disease (AD).

Objective  To assess the safety, tolerability, and feasibility of infusions of young fresh frozen plasma (yFFP) from donors age 18 to 30 years in patients with AD.

Design, Setting, and Participants  The Plasma for Alzheimer Symptom Amelioration (PLASMA) study randomized 9 patients under a double-blind crossover protocol to receive 4 once-weekly infusions of either 1 unit (approximately 250 mL) of yFFP from male donors or 250 mL of saline, followed by a 6-week washout and crossover to 4 once-weekly infusions of an alternate treatment. Patients and informants were masked to treatment and subjective measurements. After an open-label amendment, 9 patients received 4 weekly yFFP infusions only and their subjective measurements were unmasked. Patients were enrolled solely at Stanford University, a tertiary academic medical center, from September 2014 to December 2016, when enrollment reached its target. Eighteen consecutive patients with probable mild to moderate AD1 dementia, a Mini-Mental State Examination (score of 12 to 24 inclusive), and an age of 50 to 90 years were enrolled. Thirty-one patients were screened and 13 were excluded: 11 failed the inclusion criteria and 2 declined to participate.

Interventions  One unit of yFFP from male donors/placebo infused once weekly for 4 weeks.

Main Outcome and Measures  The primary outcomes were the safety, tolerability, and feasibility of 4 weekly yFFP infusions. Safety end point analyses included all patients who received the study drug/placebo.

Results  There was no difference in the age (mean [SD], 74.17 [7.96] years), sex (12 women [67%]), or baseline Mini-Mental State Examination score (mean [SD], 19.39 [3.24]) between the crossover (n = 9) and open-label groups (n = 9). There were no related serious adverse events. One patient discontinued participation because of urticaria and another because of an unrelated stroke. There was no statistically significant difference between the plasma (17 [94.4%]) and placebo (9 [100.0%]) cohorts for other adverse events, which were mild to moderate in severity. The most common adverse events in the plasma group included hypertension (3 [16.7%]), dizziness (2 [11.1%]), sinus bradycardia (3 [16.7%]), headache (3 [16.7%]), and sinus tachycardia (3 [16.7%]). The mean visit adherence (n = 18) was 86% (interquartile range, 87%-100%) and adherence, accounting for a reduction in the total visit requirement due to early patient discontinuation, was 96% (interquartile range, 89%-100%).

Conclusions and Relevance  The yFFP treatment was safe, well tolerated, and feasible. The study’s limitations were the small sample size, short duration, and change in study design. The results warrant further exploration in larger, double-blinded placebo-controlled clinical trials.

Trial Registration  ClinicalTrials.gov Identifier: NCT02256306