This is a randomized, double-blind, placebo-controlled, parallel group, multi-center trial of two doses of daxibotulinumtoxinA (DAXI) for injection (high-dose; low-dose in adult subjects with isolated (primary) cervical dystonia (CD).

Approximately 300 subjects, recruited from approximately 80 study centers in the United States (US), Canada, and Europe will be randomized to DAXI for injection high dose, DAXI for injection low dose, or placebo group, respectively. Subjects will be stratified by treatment center and history of prior treatment with botulinum neurotoxin (BoNT).

Inclusion Criteria:

• Adults, 18 to 80 years of age
• Meets diagnostic criteria for isolated CD (idiopathic; dystonic symptoms localized to the head, neck, shoulder areas) with at least moderate severity at Baseline (Day 1), defined as a TWSTRS-total score of at least 20, with at least 15 on the TWSTRS-Severity subscale, at least 3 on the TWSTRS-Disability subscale, and at least 1 on the TWSTRS-Pain subscale

Exclusion Criteria:

• Cervical dystonia attributable to an underlying etiology, (e.g., traumatic torticollis or tardive torticollis)
• Predominant retrocollis or anterocollis CD
• Significant dystonia in other body areas, or is currently being treated with BoNT for dystonia in areas other than those associated with isolated CD
• Severe dysphagia (Grade 3 or 4 on the Dysphagia Severity Scale) at Screening or Baseline (prior to study treatment)
• Any neuromuscular neurological conditions that may place the subject at increased risk of morbidity with exposure to BoNT, including peripheral motor neuropathic diseases (e.g., amyotrophic lateral sclerosis and motor neuropathy, and neuromuscular junctional disorders such as Lambert-Eaton syndrome and myasthenia gravis)
• Previous treatment with any BoNT product for any condition within the 14 weeks prior to Screening
• Botulinum Neurotoxin Type A (BoNTA), except the investigational daxibotulinumtoxinA, treatment-experienced subjects who had suboptimal or no treatment response to the most recent BoNTA injection for CD, as determined by the investigator, or history of primary or secondary non-response to BoNTA injections, known to have neutralizing antibodies to BoNTA; or have a history of botulinum toxin type B (rimabotulinumtoxinB [Myobloc/Neurobloc]) injection for CD due to non-response or suboptimal response to BoNTA

Double Blinded