Switchover study of onabotulinumtoxinA to incobotulinumtoxinA for facial dystonia

Importance: When making a cost-saving it is important to ensure there is no loss of efficacy.

Background: Clinical effectiveness and efficiency of incobotulinumtoxinA compared to onabotulinumtoxinA in facial dystonia is unclear. Our aim is to evaluate switching from onabotulinumtoxinA to incobotulinumtoxinA in the treatment of essential blepharospasm (EB), hemifacial spasm (HFS) and aberrant facial nerve regeneration (AFR).

Design: A retrospective study of a prospective, single-masked switchover audit from onabotulinumtoxinA to incobotulinumtoxinA.

Participants: Twenty essential EB, 12 HFS and six AFR patients.

Methods: A switchover from stable onabotulinumtoxinA to incobotulinumtoxinA using a 1:1 unit ratio and contemporaneous efficacy measures. Two nurse injectors performed the injections over a period of 6 years. Each masked patient received three onabotulinumtoxinA and three incobotulinumtoxinA over a minimum of 2 years.

Main outcome methods: At each visit, a blepharospasm disability score (BDS), Jankovic score (JS), subjective improvement (SI), duration of maximum effect (DME) and complications were recorded. A cost comparison per unit dose was made.

Results: Twenty EB, 12 HFS and six AFR received 114 onabotulinumtoxinA and 114 incobotulinumtoxinA treatments. Both brands had similar efficacy, but SI (P < .01) and DME (P < .05) were higher in the HFS group with incobotulinumtoxinA. Complications included bruising (two onabotulinumtoxinA, one incobotulinumtoxinA) and ptosis (three onabotulinumtoxinA, zero incobotulinumtoxinA). OnabotulinumtoxinA was 33% pricier.

Conclusion and relevance: Switching from onabotulinumtoxinA to incobotulinumtoxinA did not result in an inferior outcome for the treatment of facial dystonia and led to a cost-saving for the department.