Clinical Relevance of Treatment With OnabotulinumtoxinA in Patients With Cervical Dystonia: Results From the CD Probe Study (P3.016)

Objective: To explore minimal clinically important change perceived by patients as beneficial by the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) using data from the Cervical Dystonia Patient Registry for Observation of OnabotulinumtoxinA Efficacy (CD PROBE) study. Background: Although ≥10-point or ≥30% difference has been reported for defining clinically important change, there is no validated definition of clinically meaningful response to onabotulinumtoxinA treatment for CD. Design/Methods: CD PROBE is a multicenter, prospective clinical registry that recruited CD patients from 88 US sites. CD patients who were new to botulinum toxin therapy or had not received it for ≥16 weeks and were deemed suitable for onabotulinumtoxinA received 3 cycles of drug. Changes from baseline in TWSTRS scores were correlated with clinical improvement as assessed by the Patient or Clinical Global Impression of Change (PGIC/CGIC) scales. The model was discriminated using logistic regression; good discrimination was defined as ≥70% correct classification of PGIC or CGIC based on TWSTRS scores. We report on the 479 patients who completed the study. Results: Mean TWSTRS score significantly decreased from baseline to final visit (39.2 to 27.1, P Conclusions: Change in total TWSTRS score correlated well with patient- and clinician-based evaluations (PGIC and CGIC, respectively) of onabotulinumtoxinA-treated patients with CD. These results approximate definitions of response used in other studies. Study Supported by: Allergan plc, Dublin, Ireland Disclosure: Dr. Mari has nothing to disclose. Dr. Dashtipour has received personal compensation for activities with Abbvie, Cynapsus, Teva, Impax, UCB, IPSEN, Allergan plc, Lundbeck, Merz, and US WorldMeds. Dr. Jankovic has received personal compensation for activities with Adamas Pharmaecuticals, Inc; Allergan, Auspex Pharmaceuticals, Inc; Lundbeck Inc; Teva Pharmaceutical Industries Ltd as a consultant. Dr. Jankovic has received research support from Adamas Pharmaceuticals, Inc; Allergan, Inc; Biotie Therapies, CHDI Foundation; Civitas/ Acorda Therapeutics; Dystonia Medical Research Foundation; Huntington Study Group; Kyowa Haako Kirin Pharma, Inc.; Lundbeck Inc.; Medtronic; Merz Pharmaceuticals; Michael J. Fox Foundation for Parkinson Research; National Institutes of Health; Neurocrine Biosciences; NeuroDerm Ltd; Parkinson9s Foundation; Parkinson Study Group; Pfizer; Prothena Biosciences Inc.; Psyadon Pharmaceuticals, Inc.; Revance Therapeutics, Inc.; Sangamo BioSciences, Inc.; St. Jude Medical; Teva Pharmaceutical Industries Ltd. Dr. Adler has received personal compensation for activities with Adamas Pharmaceuticals, Cynapsus Lundbeck, and Merz Pharma as a consultant. Dr. Adler has received royalty payments from Springer. Dr. Schwartz has received personal compensation for activities with MedNet Solutions, Inc. as an employee. Employee of Allergan,,,,Yes, stock in Allergan,Yes, stock in Allergan,