A Study to Compare Dysport® and Botox® in the Treatment of Cervical Dystonia

A Double Blind, Randomized, Multi-center, Cross-over Study to Demonstrate the Non-inferiority of Dysport® in Comparison With Botox®, Assuming a Bioequivalence Ratio of 2.5:1 Units, in the Cervical Dystonia

1. to examine the non-inferiority of Dysport in the clinical efficacy and safety in comparison with Botox®, assuming a bioequivalence ratio of 2.5:1 units, in the treatment of Cervical dystonia.
2. double blind, randomised, multi center, crossover study

1. Prospective, randomized, head-to-head, double-blind, cross-over study.
2. Total patients: A group 51, B group 51
3. Study duration: 16 + 4 + 16 weeks. Eligible patients will be randomised at baseline to receive either Dysport® or Botox® and monitored at weeks 2, 4, 8, 12, 16 weeks. After 4 weeks of wash out period, then the patients get the other treatment (i.e, Patients who have got Dysport will be then administered with Botox)
4. Compare the TSUI change score from baseline to 4 weeks after injection.

Inclusion Criteria:

• Patients ≥ 18 years of age of both genders,
• Cervical dystonia
• symptoms with a minimum duration of 18 months,
• Negative pregnancy test in sexually active women,
• Able to participate in the study (understand goals of botulinum toxin A treatment and sign Informed Consent Form).

Exclusion Criteria:

• Patient with cervical contractures
• Known significant underlying dysphasia
• Patients who have received botulinum toxin treatment within the past 4 months.
• Contraindication to botulinum toxin treatment
• Any disease that might affect neuromuscular function (Myasthenia Gravis, Eaton-Lambert syndrome, ALS …)
• Patients who have received oral anti-spasticity medication, phenol therapy, myotomy or denervation surgery, deep brain stimulation for cervical dystonia,
• Patients who required more than 500 units of Dysport or 200 units of Botox.
• Any concomitant treatment that could interfere with the action of botulinum toxin,
• Subjects having participated within the last 3 months or currently participating in an investigational drug study,
• Pregnancy,
• Lactation.