Botulinum Toxin in Parkinson Disease Tremor: A Randomized, Double-Blind, Placebo-Controlled Study With a Customized Injection Approach

Background: In essential tremor and Parkinson disease (PD) tremor, administration of onabotulinumtoxinA via a fixed injection approach improves the tremor, but many patients (30%-70%) develop moderate to severe hand weakness, limiting the use of onabotulinumtoxinA in clinical practice. Objective: To evaluate the safety and efficacy of incobotulinumtoxinA (IncoA) injection for the treatment of tremor in PD. Patients and Methods: In this double-blind, placebo-controlled, crossover trial, 30 patients each received 7 to 12 (mean, 9) IncoA injections into hand and forearm muscles using a customized approach. The study was performed from June 1, 2012, through June 30, 2015, and participants were followed for 24 weeks. Treatment efficacy was evaluated by the tremor subsets of the Unified Parkinson's Disease Rating Scale and the Patient Global Impression of Change 4 and 8 weeks after each of the 2 sets of treatments. Hand strength was assessed using an ergometer. Results: There was a statistically significant improvement in clinical rating scores of rest tremor and tremor severity 4 and 8 weeks after the IncoA injection and of action/postural tremor at 8 weeks. There was a significant improvement in patient perception of improvement at 4 and 8 weeks in the IncoA group. There was no statistically significant difference in grip strength at 4 weeks between the 2 groups. Conclusion: Injection of IncoA via a customized approach improved PD tremor on a clinical scale and patient perception, with a low occurrence of significant hand weakness. Trial Registration: clinicaltrials.gov Identifier: NCT02419313.