title: Repeated OnabotulinumtoxinA Treatment of Glabellar Lines at Rest Over Three Treatment Cycles.
abstract: BACKGROUND
  OnabotulinumtoxinA has demonstrated the ability to eliminate mild glabellar lines at rest; however, less is known regarding the effect of repeat treatment on more severe lines at rest.
  
  
  OBJECTIVE
  To assess the effect of repeated onabotulinumtoxinA treatment for reduction of glabellar lines at rest.
  
  
  METHODS
  Subjects 18 to 75 years old with at least mild glabellar lines at rest, as assessed by the validated Facial Wrinkle Scale (FWS) with photonumeric guide (score ≥ 1), received 3 treatments of 20 U onabotulinumtoxinA 4 months apart (N = 225). "Response" was defined as elimination of glabellar lines at rest (FWS score = 0) at any time point (Days 7, 30, 60, 90, and 120). Effect of treatment cycle on response was analyzed using repeated measures logistic regressions (p < .05).
  
  
  RESULTS
  Most subjects were female (85%) and white (88%) (age range: 35-54 years). The likelihood of significant response was as follows: for all subjects combined (odds ratio [OR]: 1.31), for subjects with mild resting lines at baseline (OR: 1.49), and for older women (≥55 years) with mild resting lines at baseline (OR: 2.22). Of all subjects, 76% responded after 1 treatment, and 45% responded in all 3 cycles.
  
  
  CONCLUSIONS
  Subjects repeatedly treated with onabotulinumtoxinA showed progressive improvement in glabellar lines at rest.
authors.affiliation: Departments of *Dermatology and Skin Science, and †Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada; ‡Private Practice, Boca Raton, Florida; §Department of Clinical Development, Allergan plc, Irvine, California; ¶Department of Neurology, University of California, Irvine, California.
authors.forename: Alastair
authors.initials: A
authors.lastname: Carruthers
authors.forename: Jean
authors.initials: J
authors.lastname: Carruthers
authors.forename: Steven
authors.initials: S
authors.lastname: Fagien
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Lei
authors.forename: Julia
authors.initials: J
authors.lastname: Kolodziejczyk
authors.forename: Mitchell F
authors.initials: MF
authors.lastname: Brin
mesh_terms: D000328:Adult; D000367:Age Factors; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage*; D003357:Cosmetic Techniques; D004334:Drug Administration Schedule; D005260:Female; D005546:Forehead; D006801:Humans; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage*; D012146:Rest; D019233:Retreatment; D015595:Skin Aging
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A