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INTRODUCTION author. The study included patients that had previously
received at least four consecutive treatments of aboBTX‑A
Neurotoxin injection accounted for more than a third of at 4‑month intervals at a stable dose, achieving 85‑90%
all nonsurgical cosmetic procedures performed in the elimination of dynamic glabellar frown lines, and who
United States in 2012. Abobotulinumtoxin A (aboBTX‑A, had expressed satisfaction with at least four consecutive
[1]
dysport) and onabotulinumtoxin A (onaBTX‑A, Botox) aboBTX‑A treatments. Patient satisfaction with aboBTX‑A
are currently the most commonly used preparations treatment was defined by the patient’s decision not to
of Clostridium botulinum toxin in the treatment of return for re‑treatments before the planned redosing
glabellar frown lines. Composed of high‑molecular weight interval of 4‑month. The study was approved by the review
protein complexes unique to the various formulations, board of University of Chicago Medical Center.
each of these neuromodulators has a slightly different Primary outcomes of this pilot study were patient
pharmacokinetic profile. The protein complex is also perceived clinical effectiveness at 2 weeks (defined as
[2]
thought to play a role in the immunogenicity of these an 85‑90% decrease in muscle activity) and percentage of
therapeutic agents, influencing tolerance to drug effect muscle activity at 3 months per surgeon assessment. The
and clinical response over time. [3] planned conversion rate was 2:1 (aboBTX‑A: incoBTX‑A)
using the established aboBTX‑A dosage for each patient
Abobotulinumtoxin A (aboBTX‑A, dysport) is a
type A botulinum toxin approved for the temporary to determine an initial incoBTX‑A dose. However, we
permitted dose adjustment per the physician’s assessment
improvement in the appearance of moderate to severe at the time of incoBTX‑A injection. The incoBTX‑A dose
glabellar lines associated with procerus and corrugator was dispersed into the corrugator and procerus muscles
muscle activity. The toxin exists in a protein complex for each patient; injection patterns were based on
[4]
approximately 500 kDa in size. Incobotulinumtoxin diagrams reviewed in the electronic medical record,
A (incoBTX‑A, xeomin), a recently approved form documenting the injection points used during prior
of botulinum toxin type A, is also indicated for the aboBTX‑A treatments.
temporary improvement in the appearance of moderate
to severe glabellar lines associated with corrugator and/ Secondary outcomes were examined via patient
or procerus muscle activity in adult patients. IncoBTX‑A questionnaires that asked subjects to report on the
[5]
differs from the other neuromodulators, including onset of effect after incoBTX‑A injection, the pain of
onaBTX‑A and aboBTX‑A, in its formulation as a purified injection versus their recollection of pain on aboBTX‑A
toxin‑free of complexing proteins. This formulation, in injections, the perceived duration of effect, and their
theory, renders incoBTX‑A less immunogenic than the overall satisfaction with the treatment session. Patients
other forms of botulinum toxin A currently available, who were not satisfied with their initial treatment dosage
permitting reproducible effects on repeat injections. were asked to return for re‑treatment at 2 weeks. All
patients were seen in follow‑up at 10‑12 weeks. At this
Although a calculated unit conversion between alternative time, glabellar and procerus activity were assessed by
neurotoxin preparations cannot be directly derived due to the treating surgeon, and the patient’s perception of the
differing manufacturing processes, the separate bacterial treatment was recorded.
strains involved, and the variations in size of the associated
complexing proteins, [2,6,7] a published clinical study as well Demographic and clinical characteristics were summarized
as the senior author’s clinical experience has shown that a using frequency counts and percentages for categorical
reliable conversion rate between aboBTX‑A (dysport) and variables and median and range for continuous variables.
onaBTX‑A (Botox) is 2.5:1. In addition, several studies Residual muscle activity at 4‑month following at least four
[8]
have concluded that a 1:1 equivalency exists between abobotulinumtoxin A treatment sessions was compared to
onaBTX‑A (Botox) and incoBTX‑A (xeomin). [9,10] muscle activity with one incobotulinumtoxin A treatment
session at 10‑12 weeks using a paired t‑test.
In our practice since 2010, the majority of patients
treated with neuromodulators receive aboBTX‑A. Given RESULTS
the potentially promising immunogenic profile of
incoBTX‑A, we were interested in determining the A total of 32 subjects were included. The majority of
[11]
correct dosage of this neuromodulator among our patient patients were female (40‑71 years old) and most had
population. Due to the uncertainty regarding conjectural received aboBTX‑A consistently for over 2 years [Table 1].
conversion between the three neurotoxin preparations, we The mean dose of incoBTX‑A administered was 17.1
sought to establish effectiveness and dosing equivalency units (± 6.1, median dose 20 units). The mean treatment
of incoBTX‑A versus aboBTX‑A within a consecutive series dose of aboBTX‑A administered was 27.6 (± 11.7, median
of 32 patients previously treated with aboBTX‑A for dose 27.5 units). The mean difference in treatment units
temporary reduction in glabellar dynamic wrinkles. was ‑10.5 (95% confidence interval, P < 0.001) [Table 2].
Among 30 patients who reported effect onset of the one
METHODS incoBTX‑A treatment, the median result was 8.5 days,
with a range of 1‑14 days [Table 1].
We conducted a prospective pilot study at a single Twenty‑nine out of 32 patients (91%) reported satisfactory
surgeon center, with all injections performed by the senior treatment effect at 2 weeks, 3 patients (9%) requested

Plast Aesthet Res || Vol 2 || Issue 1 || Jan 15, 2015 13