Safety and Effectiveness of Valbenazine as Adjunct Therapy to Botulinum Toxin Injections in Cervical Dystonia
The most common form of idiopathic dystonia is adult-onset cervical dystonia (CD), a focal form of dystonia affecting the muscles of the neck. CD is often associated with pain and limited range of motion, and frequently leads to reduced quality of life and disability. Effective long-term treatment options are extremely limited. Recurring botulinum neurotoxin (BoNT) injections can ease the symptoms of CD, but they frequently provide only partial relief and can be associated with intolerable side effects. Deep brain stimulation can be used to treat more severe cases of CD, but this neurosurgical procedure is invasive, on average only about 50% effective and may lead to serious adverse effects. Novel treatment approaches for CD are desperately needed to alleviate symptoms and improve the quality of life for the many who suffer from this chronic and disabling neurological disorder.
• Idiopathic CD (neck musculature first and most prominently affected)
• 18-75 years old (participants excluded if their dystonia symptoms began before age 18 as childhood-onset dystonia typically represents a genetic and/or primary generalized form of dystonia)
• Onset of dystonia ≥18 years old, no known hyperkinetic movement disorder-related genetic mutation
• Dystonia severity more than minimal and not very severe as defined by Toronto Western Spasmodic Torticollis Rating Scale-2 Motor Severity (TWSTRS-2-Severity) score ≥ 5 and ≤ 20.
• Stable on botulinum toxin injections last 90 days (BoNT dose change \<10% and patient reported stability of response over last two injection cycles)
• Stable on other neuroactive medications.