Examine the impact of cervical dystonia (CD) severity on presentation subtype and onabotulinumtoxinA utilization in the completer population from the CD PROBE study.

Cervical dystonia (CD) is a chronic condition in which the neck and upper shoulder muscles involuntarily contract, resulting in abnormal postures and/or movements.

Multicenter, prospective, observational registry (NCT00836017). Patients with CD treated with onabotulinumtoxinA according to standard of care at each clinician’s practice. OnabotulinumtoxinA utilization and safety data collected each session. Completers defined as patients that completed all treatment sessions and had data for all outcome measures.

Of N=1046 patients enrolled in CD PROBE, N=350 were categorized as completers. Completers (N=350) were on average 57.3 years old, 74.9% female, 94.6% White, and 60.6% naïve to botulinum toxin. 54.3% had moderate severity at injection 1, with 32.6% mild and 13.1% severe. Regardless of severity, torticollis was the most common predominant presentation subtype at injection 1 (mild: 44.7%, moderate: 55.8%, severe: 63.0%), followed by laterocollis (mild: 42.1%, moderate: 32.6%, severe: 26.1%). The median onabotulinumtoxinA dose to treat torticollis (injection 1: 160 U, injection 3: 200 U) and laterocollis (injection 1: 170 U, injection 3: 200 U) increased over time. For all severities, the median total dose increased from injection 1 to injection 3 (mild: 138 U to 165 U, moderate: 183 U to 200 U, severe: 200 U to 285 U, respectively). 81 patients (23.1%) reported 139 treatment-related adverse events; there were no treatment-related serious adverse events. No new safety signals were identified.

CD severity impacted presentation subtype frequency and onabotulinumtoxinA utilization in CD PROBE, with higher and tailored dosing observed over time and with increasing disease severity.