Efficacy and Safety of Botulinum Type A Toxin (Dysport) in Cervical Dystonia: Results of the First US Randomized, Double-Blind, Placebo-Controlled Study Daniel Truong, MD, 1 * Drake D. Duane, MD, 2 Joseph Jankovic, MD, 3 Carlos Singer, MD, 4 Lauren C. Seeberger, MD, 5 Cynthia L. Comella, MD, 6 Mark F. Lew, MD, 7 Robert L. Rodnitzky, MD, 8 Fabio O. Danisi, MD, 9 James P. Sutton, MD, 10 P. David Charles, MD, 11 Robert A. Hauser, MD, 12 and Geoffrey L. Sheean, MD 13 1 The Parkinson’s and Movement Disorders Institute, Fountain Valley, California, USA 2 Arizona Dystonia Institute, Scottsdale, Arizona, USA 3 Baylor College of Medicine, Houston, Texas, USA 4 University of Miami School of Medicine, Miami, Florida, USA 5 Colorado Neurological Institute, Englewood, Colorado, USA 6 Rush University Medical Center, Chicago, Illinois, USA 7 University of Southern California, Los Angeles, California, USA 8 University of Iowa, Iowa City, Iowa, USA 9 Mount Sinai Medical Center, New York, New York, USA 10 Neurological Research Institute, Encino, California, USA 11 Vanderbilt University, Nashville, Tennessee, USA 12 University of South Florida, Tampa, Florida, USA 13 University of California, San Diego, California, USA Abstract: Botulinum toxin type A (Dysport) has been shown in European studies to be a safe and effective treatment for cervical dystonia. This multicenter, double-blind, randomized, controlled trial assessed the safety and efficacy of Dysport in cervical dystonia patients in the United States. Eighty patients were randomly assigned to receive one treatment with Dysport (500 units) or placebo. Participants were followed up for 4 to 20 weeks, until they needed further treatment. They were assessed at baseline and weeks 2, 4, 8, 12, 16, and 20 after treatment. Dysport was significantly more efficacious than pla- cebo at weeks 4, 8, and 12 as assessed by the Toronto Western Spasmodic Torticollis Rating Scale (10-point vs. 3.8-point re- duction in total score, respectively, at week 4; P  0.013). Of participants in the Dysport group, 38% showed positive treat- ment response, compared to 16% in the placebo group (95% confidence interval, 0.02– 0.41). The median duration of re- sponse to Dysport was 18.5 weeks. Side effects were generally similar in the two treatment groups; only blurred vision and weakness occurred significantly more often with Dysport. No participants in the Dysport group converted from negative to positive antibodies after treatment. These results confirm pre- vious reports that Dysport (500 units) is safe, effective, and well-tolerated in patients with cervical dystonia. © 2005 Move- ment Disorder Society Key words: cervical dystonia; spasmodic torticollis; botuli- num toxin; Dysport; clinical trial Focal dystonias are abnormal contractions of muscles leading to abnormal postures. The overactivity of mus- cles characteristic of focal dystonia is thought to be mediated by a neurophysiological disturbance in the basal ganglia and/or brainstem. 1,2 Cervical dystonia is the most common type of focal dystonia encountered in neurological practice, with a prevalence of eighty-nine affected patients per one million individuals. 3 It is char- acterized by sustained involuntary contractions of the cervical muscles, often leading to painful and disabling neck spasms and abnormal head positions. Rotation (tor- *Correspondence to: Dr. Daniel Truong, The Parkinson’s and Move- ment Disorders Institute, 9940 Talbert Avenue #204, Fountain Valley, CA 92708. E-mail: dtruong@pmdi.org Received 12 December 2003; Revised 20 May 2004; Accepted 20 July 2004 Published online 25 February 2005 in Wiley InterScience (www. interscience.wiley.com). DOI: 10.1002/mds.20403 Movement Disorders Vol. 20, No. 7, 2005, pp. 783–791 © 2005 Movement Disorder Society 783