Effect of 3 Commercially Available Botulinum Toxin Neuromodulators on Facial Synkinesis

Abstract

IMPORTANCE Botulinum toxin neuromodulators are an important treatment for facial synkinesis. Whether a difference in efficacy exists among the 3 different botulinum neuromodulators used in treating this condition remains unknown.OBJECTIVE To evaluate the effectiveness of 3 commercially available botulinum toxin neuromodulators in the treatment of facial synkinesis. DESIGN, SETTING, AND PARTICIPANTSIn this single-blind, 3-arm comparison randomized clinical trial, 28 patients at the Facial Nerve Center, University of Utah, Salt Lake City, were randomized to onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA treatment. Each patient was given the Synkinesis Assessment Questionnaire (SAQ) to assess severity of synkinesis before treatment and 1, 2, and 4 weeks after treatment, and improvements were compared among the groups. Data were collected from July 3, 2012, to March 31, 2015.INTERVENTIONS Botulinum toxin type A neuromodulator (onabotulinumtoxinA, abobotulinumtoxinA, or incobotulinumtoxinA) injected into synkinetic areas of the face.MAIN OUTCOMES AND MEASURES Synkinesis assessed using the SAQ (score range, 20-100; lower scores indicate less severe synkinesis) before treatment and 1, 2, and 4 weeks after treatment.RESULTS A total of 28 patients (mean [SD] age, 49.1 [18.5] years; 8 [28.6%] male and 20 [71.4%] female), with 6 patients enrolled multiple times, received 38 treatments (15 onabotulinumtoxinA, 13 abobotulinumtoxinA, and 10 incobotulinumtoxinA). No significant difference existed in baseline pretreatment SAQ scores among the 3 groups. Mean (SD) SAQ score improvement at 4 weeks was 41% (31%) for the onabotulinumtoxinA, 42% (20%) for the abobotulinumtoxinA, and 17% (18%) for the incobotulinumtoxinA groups. No significant differences were noted in SAQ score improvements among the 3 groups at weeks 1 and 2 after treatment (week 1 mean improvements of 42% in the onabotulinumtoxinA, 45% in the abobotulinumtoxinA, and 26% in the incobotulinumtoxinA groups; P = .19; week 2 mean improvements of 43% in the onabotulinumtoxinA, 46% in the abobotulinumtoxinA, and 28% in the incobotulinumtoxinA groups; P = .20). The difference in mean SAQ score improvement for abobotulinumtoxinA vs incobotulinumtoxinA from pretreatment to 4 weeks after treatment was not significant (30 vs 12 points; P = .11) despite a significant difference in mean total SAQ score for abobotulinumtoxinA vs incobotulinumtoxinA (40.34 vs 58.00; P = .02).CONCLUSIONS AND RELEVANCE AbobotulinumtoxinA had similar efficacy to onabotulinumtoxinA and incobotulinumtoxinA for the management of facial synkinesis up to 4 weeks after treatment. IncobotulinumtoxinA had significantly less effect on SAQ score improvement than onabotulinumtoxinA at 4 weeks, perhaps because of the shorter duration of action. Shorter intervals between treatments or larger doses may be required when using incobotulinumtoxinA treatment for facial synkinesis. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT03048383LEVEL OF EVIDENCE 1.

Real-World Dosing of OnabotulinumtoxinA and IncobotulinumtoxinA for Cervical Dystonia and Blepharospasm: Results from TRUDOSE and TRUDOSE II

“…We found that the dose ratio relationship between the two botulinum toxins was much more complex in the real world than was suggested by consensus panels [ 35 ] or meta-analyses of clinical trials [ 36 ], both of which concluded the botulinum toxins were equipotent and could be switched using a 1:1 conversion ratio. In this study, the incobotulinumtoxinA to onabotulinumtoxinA dose ratio was >1 across both conditions; there was considerable variability in the dose ratio and the inter-injection interval at an individual patient level, but mean dose ratios were all >1 and are consistent with the results of Kollowe and colleagues [ 18 ], Wilson [ 28 ], Thomas [ 29 ], and the preclinical studies cited above. Our results support that there is no fixed-dose ratio conversion between incobotulinumtoxinA and onabotulinumtoxinA, and consistent with the product label and recommendations from regulatory agencies, the potency units of onabotulinumtoxinA are not interchangeable with other botulinum toxin type A products [ 37 ].…”

“…With respect to its potential to treat blepharospasm, studies suggest that onabotulinumtoxinA (20 U) and abobotulinumtoxinA (60 U) significantly outperform incobotulinumtoxinA (20 U) based on dynamic strain reduction after injection into the glabella [ 28 ], and sustained improvements in facial synkinesias at week 4 [ 29 ].…”

Botulinum Toxin Type A Injection in the Treatment of Postparetic Facial Synkinesis

“…Ten studies focusing on BTX-A treatment patterns and outcomes were included in this review. Seven prospective and two retrospective observational cohort studies comparing outcome measures before and after treatment and one randomized controlled clinical trial 2,4,5,7,8,10,12–15 . Details of these studies are summarized in Table 2.…”

Switchover study of onabotulinumtoxinA to incobotulinumtoxinA for facial dystonia

“…There are several serotypes of botulinum toxin (A‐G), but only serotypes A and B are available commercially as abobotulinumtoxinA; incobotulinumtoxinA; onabotulinumtoxinA for serotype A, and rimabotulinumtoxinB for serotype B 4,5 . Many studies have been carried out in an attempt to show the superiority of one product against the other, referring to immunogenic potential, more localized spread after injection and duration of action as reasons for superiority, however, many of these studies are commercially driven and lack good randomization to definitively determine the best product 5‐8 . In contrast, studies have shown similarity in efficacy between the different preparations 9,10 .…”

“…4,5 Many studies have been carried out in an attempt to show the superiority of one product against the other, referring to immunogenic potential, more localized spread after injection and duration of action as reasons for superiority, however, many of these studies are commercially driven and lack good randomization to definitively determine the best product. [5][6][7][8] In contrast, studies have shown similarity in efficacy between the different preparations. 9,10 Cost, however, is a driver for healthcare provision, nevertheless, there is a perception from patients that the cheaper the product, the poorer the efficacy.…”