The Retrospective Evaluation of the Dose of IncobotulinumtoxinA and OnabotulinumtoxinA for the Clinical Management of Cervical Dystonia and Blepharospasm: TRUDOSE Pilot Study (P7.065)

Abstract

Objective: To evaluate dose utilization and injection intervals of onabotulinumtoxinA and incobotulinumtoxinA for treatment of CD and blepharospasm in clinical practice. Background: Limited data exists on the comparative real-world doses of onabotulinumtoxinA and incobotulinumtoxinA in cervical dystonia (CD) and blepharospasm. Methods: Retrospective medical records review in Norway and UK for patients with a primary diagnosis of idiopathic CD or blepharospasm. Patients received onabotulinumtoxinA for at least 2 years prior to switching to incobotulinumtoxinA and received treatment for at least 2 years post switch. Abstracted data included dose, reason for switching, injection visit date and adverse events. Paired t-test was used to test for within subject differences in total annual dose and average inter-injection interval. Results: Thirty-nine patients (25 CD; 14 Blepharospasm) qualified and collectively received 530 injections over the 4-year observation period. Reasons for switching were tender/financial. Average number of injections per patient was 5.97 (onabotulinumtoxinA) and 7.61 (incobotulinumtoxinA) over identical time periods pre and post switch. CD average annual dose per patient year for onabotulinumtoxinA and incobotulinumtoxinA was 444.7U (SD=236.3U) and 536.3U (SD=306.9U) (p =.007), respectively and 50.4U (SD=50.6U) and 64U(SD=53.2U) (p =.002) for blepharospasm, respectively. Average total dose ratios of incobotulinumtoxinA:onabotulinumtoxinA were 1.21 for CD and 1.27 for blepharospasm. Inter-injection intervals for all patients were 15.8 weeks (onabotulinumtoxinA) and 14.4 weeks (incobotulinumtoxinA weeks)(p=.005). Inter-injection intervals for CD were 15.6 weeks (onabotulinumtoxinA) and 14.5 weeks (incobotulinumtoxinA) (p=.062); for blepharospasm, inter-injection intervals were 16.3 weeks (onabotulinumtoxinA) and 14.2 weeks (incobotulinumtoxinA)(p=.041). No SAE’s reported. Conclusions: Results suggest that the utilization of onabotulinumtoxinA and incobotulinumtoxinA for CD and blepharospasm are not equivalent. Data show a trend for increased dose utilization with incobotulinumtoxinA post-switch, suggesting the incobotulinumtoxinA: onabotulinumtoxinA ratio may be >1 after switching and dosing should be based on individual patient needs and not a specific dose ratio. Although some of our results did not reach statistical significance, this is likely due to the small sample size. Study Supported by: Allergan Inc.

Disclosure: Dr. Tzoulis has received personal compensation for activities with Allergan Inc., Merz Pharma, and Novartis. Dr. Kent has received research support from Allergan Inc. Dr. Robertson has received personal compensation for activities with Allergan Inc. Dr. Maltman has received personal compensation for activities with Allergan Inc. as an employee. Dr. Purdy has received personal compensation for activities with Allergan Inc., Salix, and Astellas. Dr. Purdy has received research support from Allergan Inc., Salix, and Astellas. Dr. Magar has received personal compensation for activities with Allergan Inc., Salix, and Astellas. Dr. Magar has received research support from Allergan Inc., Salix, and Astellas.