Comparison of Efficacy and Safety of Two Different Types of Botulinum Toxin Type A in Moderate to Severe Cervical Dystonia

Dysphagia Incidence (difficulty swallowing) was defined as the number of patients reporting at least 1 treatment-emergent dysphagia event at any point in the study. Occurrences of dysphagia were captured as spontaneous events or were assessed during study visits using the Structured Symptom Interview (SSI) and the Dystonia Study Group Dysphagia Interview (DSGDI) for symptoms of difficulty swallowing; coughing while eating and drinking; choking while eating or drinking; or difficulty swallowing solids or liquids.

The TWSTRS assessments were conducted at each study visit. The TWSTRS is an assessment scale used to measure the impact of cervical dystonia on patients. It is comprised of 3 subscales: Severity, Disability, and Pain, each of which is scored independently. The total of these 3 comprises the TWSTRS total score which is scored from 0 (least symptoms) to 85 (worst symptoms). Higher scores indicate a greater degree of symptom severity.

Physician assessment of cervical dystonia severity. The rating was assessed on a scale of 0 to 10, with higher scores denoting greater severity: 0 represented 'No evidence of dystonia' and 10 represented 'Worst cervical dystonia ever.'

Physician evaluation of benefit from botulinum toxin type A treatment for cervical dystonia. Ratings were on a scale of +4 to -4, with higher scores denoting improvement in cervical dystonia: +4 was 'Complete abolishment of signs and symptoms (about 100% improvement)', 0 represented 'Unchanged', and -4 represented 'Very marked worsening (about 100% worse or greater).'

Patient evaluation of benefit from botulinum toxin type A treatment for cervical dystonia. Ratings were on a scale of +4 to -4, with higher scores denoting improvement in cervical dystonia: +4 was 'Complete abolishment of signs and symptoms (about 100% improvement)', 0 represented 'Unchanged', and -4 represented 'Very marked worsening (about 100% worse or greater).'

Patients were queried regarding their need for another injection of botulinum toxin type A for cervical dystonia. Patients were required to answer "How would you rate your need for another injection of botulinum toxin type A for cervical dystonia using the following scale?". The response options included 'absolutely requires injection', 'very much requires injection', 'somewhat requires injection' and 'does not require injection'.

Patients were required to assess their pain using a Visual Analog Scale in reference to their current perception of pain at that visit. This scale consisted of a line measuring 100 mm, and patients were instructed to put a mark on the line at the point that best described 'How much pain you are having right now'. Higher scores denoted higher pain intensity: 0 indicated 'No pain' and 100 indicated 'Worst possible pain'.

Physicians assessed the improvement in cervical dystonia after the study treatment compared to previous treatment(s) for each patient. Physicians were required to answer "How would you rate the benefit of the current treatment of cervical dystonia with botulinum toxin type A compared to the previous treatment using the following scale?". The response options were 'much worse', 'worse', 'somewhat worse', 'same as previous', 'somewhat better', 'better', and 'much better'.

Patients assessed the improvement in cervical dystonia after receiving the study treatment compared to previous treatment(s). Patients were required to answer "How would you rate the benefit of the current treatment of cervical dystonia with botulinum toxin type A compared to the previous treatment using the following scale?". The response options were 'much worse', 'worse', 'somewhat worse', 'same as previous', 'somewhat better', 'better', and 'much better'.