Disclosures: Cynthia Comella, MD: aeon Pharma (Products/Services: No) (Consultant/Advisory Board)allergan (Products/Services: No) (Consultant/Advisory Board)ipsen (Products/Services: No) (Consultant/Advisory Board)Merz (Products/Services: Yes) (Consultant/Advisory Board)Revance (Products/Services: No) (Consultant/Advisory Board)

Objective: To compare efficacy and safety of two injection schedules of incobotulinumtoxinA for treating cervical dystonia (CD).

Design: The CD Flex study (NCT01486264) was a phase IV, open-label, randomized, noninferiority study comparing 2 incobotulinumtoxinA injection schedules in subjects with CD.

Setting: The study was multicenter, with 43 sites in the US.

Participants: Botulinum toxin-responsive subjects (≥2 prior successful injections) who report acceptable clinical benefit lasting < 10 weeks were recruited.

Interventions: Eight injection cycles with incobotulinumtoxinA using two different schedules (short-flex: 8±2 weeks; long-flex: 14±2 weeks).

Main Outcome Measures: The primary endpoint was the change in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity subscale (blinded rater) 4 weeks after injection 8. Secondary endpoints included TWSTRS total and additional subscale scores. Immunogenicity was assessed in a subset of patients at baseline/post-injection 8. Safety was monitored throughout the study.

Results: 282 CD subjects were randomized (short-flex, N&#3f142; long-flex, N&#3f140), and 207 completed the study. Mean dosing was similar between groups (short-flex: 268U; long-flex: 272U); mean intervals were 54 days (short-flex) and 86 days (long-flex). Significant improvements in TWSTRS-severity from study baseline to 4 weeks after cycle 8 were observed in both the short-flex (4.1 points; P < 0.0001) and long-flex (2.4 points; P=0.002), and short-flex was noninferior to long-flex (LS mean difference=1.4 points; P=0.0693). Responder rates (≥20% improvement in TWSTRS-severity) after injection 8 did not differ significantly between groups, and secondary TWSTRS endpoints also revealed comparable efficacy. No significant differences in safety profile were observed. There was no secondary loss of treatment effect due to neutralizing antibodies among those tested.Conclusions: Injection intervals < 10 weeks for incobotulinumtoxinA are effective (and noninferior to longer intervals) for treating CD in patients with early waning of clinical benefit. Shorter intervals were not accompanied by increased adverse events or loss of treatment effect due to neutralizing antibodies.

Level of Evidence: Level I

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/injections-of-incobotulinumtoxina-at-intervals-less-than-10-weeks-are-effective-and-safe-for-cervical-dystonia-patients-with-inadequate-benefit-from-standard-injection-intervals/