Dysport for the Treatment of OMD

Oromandibular dystonia (OMD) is an uncommon, disabling form of cranial dystonia, involving involuntary movements of the lower facial, masticatory, and lingual muscles. This can cause jaw movements including opening, closure, protrusion, retraction, or deviation. Common additional facial movements involve grimacing or lip pursing. When there is tongue involvement, it usually presents as tongue protrusion or curling. Such patients are impaired in relation to eating, speaking and swallowing

This study aims to evaluate the efficacy and safety of a low dose of Dysport® deemed tolerable during phase 1 in subjects with oromandibular dystonia (OMD).

Participants will be injected with Dysport® only, with an unblinded open-label disclosure. The safety and efficacy pf receiving Dysport® will be recorded for all subjects that undergo injection. All subjects will be examined and videotaped at the injection visit, then at 6 and 12 weeks after injection with a standardized protocol. The primary outcome will be blinded examination scores of the videos performed after the study is complete.The evaluators will be three different movement disorders experts, not otherwise involved in the study, who will review the videotaped examinations, presented in a random order, using the Global Dystonia Rating scale (GDS). Evaluators will rate the dystonia at baseline (injection visit) and 6 weeks after injection.

Inclusion criteria

• a diagnosis of primary or tardive OMD
• moderate or severe severity, defined as GDS score ≥4 in either "lower face" or "jaw and tongue" section
• capability of attending the scheduled visits
• only those who have been previously injected with onabotulinumtoxinA and responded to that treatment, and are at least 12 weeks post last injection
• Women of childbearing age need to use contraception in order to be included.

Exclusion criteria

• Existence of a systemic disease that could confound the evaluation
• previous placement of Deep Brain Stimulation electrodes to treat dystonia
• concomitant oral medications that could interfere with the action of botulinum toxin Type A (e.g., aminoglycosides)
• on an unstable dosage of any medication prescribed to treat dystonia (e.g., benzodiazepines, baclofen or anticholinergics)
• any known hypersensitivity to any botulinum toxin preparation and allergy to cow's milk protein
• immunoresistance to other forms of botulinum toxin type A
• existence of a concomitant neuromuscular disorder (e.g., Myasthenia Gravis or Lambert-Eaton syndrome, etc)
• infection at the proposed injection sites
• pregnant women
• women of childbearing age NOT on contraception
• breastfeeding women
• inability to comply with scheduled visits
• patients who had been previously injected with botulinum toxin type A but who did not respond