Abstract
Cervical dystonia (CD) is primarily treated with botulinum toxin, at intervals of ≥ 12 weeks. We present efficacy, patient-reported outcomes (PROs), and safety in adults with CD at the last available visit after a single set of abobotulinumtoxinA (aboBoNT-A) injections versus placebo using 500 U in a 2-mL injection volume. In this 12-week, randomized, double-blind trial, patients were ≥ 18 years of age with primary idiopathic CD, had a Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) total score ≥ 20, and TWSTRS-Severity subscale score > 10 at baseline. Patients (N = 134) were randomized (2:1) to aboBoNT-A (n = 89) or placebo (n = 45), with aboBoNT-A patients treated with 500 units (U) if toxin-naïve, and 250 to 500 U based on previous onabotulinumtoxinA dose if non-naïve. Endpoints included total TWSTRS, Pain Numeric Rating Scale (NRS-Pain; 24-hour), Treatment Satisfaction Questionnaire for Medication, and other PROs for pain, depression, and global health. Results are for the intent-to-treat population, with "Week 12" (Wk12) comprising the last available post-baseline assessment (end-of-study or early withdrawal). Mean TWSTRS total scores improved from 42.5 at baseline to 35.4 at Wk12 with aboBoNT-A and 42.4 to 40.4 with placebo (treatment difference: -4.8; 95% confidence interval [CI]: -8.5, -1.1; p = 0.011). At Wk12, mean (95% CI) change from baseline in NRS-Pain was -1.0 (-1.59, -0.45) for aboBoNT-A and -0.2 (-0.96, 0.65) for placebo. AboBoNT-A demonstrated numeric improvements in other PROs. More aboBoNT-A-treated patients than patients receiving placebo reported being at least "somewhat satisfied" with treatment (60.4% vs 42.2%, respectively), symptom relief (57.0% vs 40.0%), and time for treatment to work (55.8% vs 33.3%). No new adverse events were reported. Results indicate that in patients with CD, treatment with aboBoNT-A using a 2-mL injection provided sustained improvement in the TWSTRS total score and patient-perceived benefits up to 12 weeks. Trial registration: Clinicaltrials.gov Identified: NCT01753310.
Highlights
Cervical dystonia (CD), a chronic neurologic movement disorder characterized by sustained or repetitive involuntary contractions of the neck muscles that leads to abnormal postures, represents the most common focal dystonia
Botulinum neurotoxin type A binds to receptors on peripheral cholinergic nerve endings and is internalized by receptor-mediated endocytosis. This is followed by cleavage of SNAP25, a protein needed for vesicle fusion to the presynaptic membrane, which is required for synaptosomal release of acetylcholine into the neuromuscular junction
Where patient data can be anonymized, Ipsen will share all individual participant data that underlie the results reported in this article with qualified researchers who provide a valid research question
Summary
Cervical dystonia (CD), a chronic neurologic movement disorder characterized by sustained or repetitive involuntary contractions of the neck muscles that leads to abnormal postures, represents the most common focal dystonia. The prescribing information in the US specified a 500-unit (U), 1-mL dilution regimen for AboBoNT-A administration; feedback obtained from scientific experts, community injectors, and market research studies favored use of a 500 U, 2-mL dilution This was most likely related to prior familiarity in using comparable volumes with other approved toxins in the US. An open-label extension study (NCT01753336) provided long-term safety and efficacy data, which supported the US approval of the 2-mL dilution regimen This manuscript expands on the 4-week results of the previously published placebo-controlled trial by providing exploratory data for up to 12 weeks to assess the durability of response with aboBoNT-A 500 U using a 2-mL dilution.
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