title: Prevalence of asymptomatic vasogenic edema in pretreatment Alzheimer's disease study cohorts from phase 3 trials of semagacestat and solanezumab.
abstract: BACKGROUND
  Cerebral vasogenic edema (VE) has been reported to occur during antiamyloid immunotherapy. VE may be associated with central nervous system pathology with blood-brain barrier disruptions; however, less is known about the prevalence of naturally occurring VE in patients with Alzheimer's disease (AD).
  
  
  METHODS
  Fluid-attenuated inversion recovery imaging sequences were obtained from four ongoing multicenter, randomized, double-blind, placebo-controlled, phase 3 trials in patients with mild-to-moderate AD. The first set of baseline scans was from patients in volumetric magnetic resonance imaging addenda in the Interrupting Alzheimer's Dementia by EvaluatiNg Treatment of Amyloid PaThologY (IDENTITY) studies examining semagacestat, a γ-secretase inhibitor (cohort 1, n = 621). The second set of baseline scans was from the EXPanding alzhEimer's Disease InvestigaTIONs (EXPEDITION) studies examining solanezumab, an anti-Aβ monoclonal antibody (cohort 2, n = 2141). Readers were blinded to patient-identifying information and future treatment. A third set of baseline scans was from the first 700 patients who underwent protocol-specified magnetic resonance imaging before randomization in the EXPEDITION studies (cohort 3). The analysis used three neuroradiologists: two performed independent primary interpretations and the third was the adjudicator. Readers were blinded to patient information, treatment, protocol, and time point.
  
  
  RESULTS
  Four cases of asymptomatic VE were detected at baseline/screening. Two VE cases were due to underlying extra-axial mass lesions. The third VE case was associated with numerous microhemorrhages in keeping with cerebral amyloid angiopathy-related inflammation or Aβ-related angiitis. The final VE case demonstrated localized sulcal fluid-attenuated inversion recovery imaging hyperintensity. No VE was detected in cohort 3 by readers blinded to patient baseline status.
  
  
  CONCLUSIONS
  VE seems to be rare at baseline in patients with AD in clinical trials, 2 of 2,762 associated with AD. Additional cohorts should be evaluated to support these findings.
authors.affiliation: Eli Lilly and Company, Indianapolis, IN, USA. carlson_christopher@lilly.com
authors.forename: Christopher
authors.initials: C
authors.lastname: Carlson
authors.forename: Wahiba
authors.initials: W
authors.lastname: Estergard
authors.forename: Joonmi
authors.initials: J
authors.lastname: Oh
authors.forename: Joyce
authors.initials: J
authors.lastname: Suhy
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Jack
authors.forename: Eric
authors.initials: E
authors.lastname: Siemers
authors.forename: Jerome
authors.initials: J
authors.lastname: Barakos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000409:Alanine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000544:Alzheimer Disease / Q000150:complications / Q000188:drug therapy* / Q000453:epidemiology; D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors*; D016229:Amyloid beta-Peptides / Q000276:immunology*; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D001381:Azepines / Q000627:therapeutic use*; D001929:Brain Edema / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*; D015331:Cohort Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D011569:Psychiatric Status Rating Scales
chemical_list: D016229:Amyloid beta-Peptides; D061067:Antibodies, Monoclonal, Humanized; D001381:Azepines; C484278:N2-((2S)-2-(3,5-difluorophenyl)-2-hydroxyethanoyl)-N1-((7S)-5-methyl-6-oxo-6,7-dihydro-5H-dibenzo(b,d)azepin-7-yl)-L-alaninamide; C550616:solanezumab; D053829:Amyloid Precursor Protein Secretases; D000409:Alanine