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Switching Botulinum Toxin A Products for Patients with Upper Limb Spasticity or Cervical Dystonia: A Review of Clinical Effectiveness

Last updated: February 9, 2018
Project Number: RC0960-000
Product Line: Rapid Response
Research Type: Drug
Report Type: Summary with Critical Appraisal
Result type: Report

Question

  1. What is the clinical effectiveness of switching botulinum toxin A products for patients with upper limb spasticity?
  2. What is the clinical effectiveness of switching botulinum toxin A products for patients with cervical dystonia?

Key Message

No literature was identified that assessed the clinical effectiveness of switching botulinum toxin A products for patients with upper limb spasticity. One systematic review (ONA to ABO), one randomized controlled trial (ABO to ONA), and two nonrandomized studies (ABO to INCO and ONA to INCO) assessed the clinical effectiveness of switching botulinum toxin A products for patients with cervical dystonia. These studies assessed the effects of switching in stabilized patients who had previously responded to treatment. They did not assess a switch in therapy due to secondary failure or adverse effects. Overall, it was generally found that efficacy of botulinum toxin A products was similar following the switch, in terms of functional outcomes and treatment duration. Based on non-randomized studies, similar treatment duration was observed with ONA and INCO at a 1:1 conversion ratio and with ABO and INCO at a conversion ratio of 4:1. However, the systematic review found that for the switch from ONA to ABO, some differences were noted in Tsui Scores, Toronto Western Spasmodic Torticollis Rating Scale, and treatment duration at higher conversion ratios (1:4). An RCT that assessed a switch from ABO to ONA found no statistical differences in functional outcomes (Tsui Scores, Toronto Western Spasmodic Torticollis Rating Scale) four weeks after the switch at conversion ratios of 1:3 and 1:1.7.