J Korean Ophthalmol Soc.  2020 Mar;61(3):227-234. 10.3341/jkos.2020.61.3.227.

Efficacy and Safety of Letibotulinum Toxin A for the Treatment of Essential Blepharospasm

  • 1Department of Ophthalmology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea. yswoph@hanmail.net
  • 2Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
  • 3Department of Ophthalmology, St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, Korea.
  • 4Department of Ophthalmology, Yeungnam University College of Medicine, Daegu, Korea.
  • 5Department of Ophthalmology, Dong-A University College of Medicine, Busan, Korea.
  • 6Department of Ophthalmology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
  • 7Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
  • 8Department of Ophthalmology, CHA Bundang Medical Center, CHA University, Seongnam, Korea.
  • 9Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
  • 10HanGil Eye Hospital, Incheon, Korea.
  • 11Department of Ophthalmology, Chungnam National University School of Medicine, Daejeon, Korea.
  • 12Department of Ophthalmology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea.
  • 13Myung-Gok Eye Research Institute, Department of Ophthalmology, Kim's Eye Hospital, Konyang University College of Medicine, Seoul, Korea.
  • 14Department of Ophthalmology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea.
  • 15Department of Ophthalmology, Gachon University Gil Medical Center, Incheon, Korea.


To evaluate the efficacy and safety of BOTULAX® in subjects with essential blepharospasm.
In this study, a total of 250 subjects with essential blepharospasm were enrolled at 15 investigational sites and a total of 220 subjects completed the study. The efficacy and safety were evaluated at weeks 4 and 16 after treatment compared with baseline. In total, 240 subjects were enrolled, treated with the investigational product, and evaluable for the primary efficacy assessment at week 4 after treatment; these subjects were included in the intention-to-treat (ITT) population. With the ITT set as the main efficacy set, efficacy assessment included Jankovic rating scale (JRS), functional disability score, investigator evaluation of global response and quality of life. Safety assessment including the incidence of adverse events was also performed.
In terms of the primary efficacy endpoint (i.e., change in JRS total score at week 4 after treatment from baseline [ITT set]), mean change indicated a statistically significant reduction (p < 0.0001) and demonstrated the non-inferiority of the test drug to similar drugs. In terms of the secondary efficacy endpoints, mean change in JRS total score at week 16 after treatment and mean change in functional disability score at weeks 4 and 16 after treatment both exhibited a statistically significant reduction compared with baseline (p < 0.0001 for all). Among the 249 subjects treated with the investigational product in this study, 44 (17.67%) experienced 76 treatment emergent adverse events but no serious adverse events were observed.
Based on the study results, BOTULAX® is considered to be an effective and safe treatment for essential blepharospasm.


BOTULAX®; Botulinum neurotoxin type A; Essential blepharospasm; Letibotulinum Toxin A
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