A Prospective, Neurophysiologic Comparative Study to Assess the Efficacy and Duration of Effect of IncobotulinumtoxinA and AbobotulinumtoxinA in the Treatment of Crow’s Feet

November 2015 | Volume 14 | Issue 11 | Original Article | 1291 | Copyright © November 2015

Anastasia Saybel MD,a Ada Artemenko MD PhD,b Sergei Nikitin MD PhD,c and Alexei Kurenkov MD PhDd

aClinic Ideal, Laser Technologies Centre, Moscow, Russia
bScientific Research Department of Neurology, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
cInstitute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia
dDepartment of Psychoneurology, Federal State Budgetary Institution “Scientific Centre of Children Health”, Russian Academy of Medical Sciences, Moscow, Russia

This randomized, rater-blind, split-face study compared the safety and efficacy of incobotulinumtoxinA and abobotulinumtoxinA for the treatment of crow’s feet. Nine units of incobotulinumtoxinA were administered to the lateral periorbital region of one side of the face and 27 units of abobotulinumtoxinA to the other in healthy subjects (aged 35–55 years) with moderate-to-severe crow's feet at rest (2–3 points on the 5-point Merz Aesthetics Scale [MAS]). Investigators assessed efficacy using the MAS, while subjects assessed using a 9-point global assessment scale. Secondary objectives included electromyography to assess muscle activity before injection and at 2 weeks, 4 months, and 6 months afterwards. Twenty women were enrolled and 18 completed the study. At rest and maximum smile, at each time point, the mean wrinkle scores were significantly lower (P≤ 0.05) than baseline for both treatments. No differences were noted between treatments. Responder (≥ 1-point improvement from baseline) rates for both products were 100% and 83% at 2 weeks and 4 months post-treatment, respectively. At 6 months post-treatment, responder rates were 67% and 61% for incobotulinumtoxinA and abobotulinumtoxinA, respectively. For both, the maximum changes in electromyography parameters were observed 2 weeks post-treatment. A response was maintained for 6 months (P≤ 0.05 vs baseline). Both treatments were well tolerated; only mild adverse events were reported. In conclusion, for treatment of crow’s feet, incobotulinumtoxinA and abobotulinumtoxinA (1:3 dose) demonstrated comparable efficacy in terms of magnitude and longevity of effect. Both products demonstrated a high responder rate, with the response being maintained for 6 months in the majority.

J Drugs Dermatol. 2015;14(11):1291-1296.


Botulinum toxin type A (BoNT/A) formulations are used in aesthetics for the treatment of wrinkles of the upper and lower face.1,2 A temporary reduction in the severity of wrinkles is achieved owing to inhibition of acetylcholine release causing a complete blockade of cholinergic transmission at the neuromuscular junction, and thus muscle relaxation.3 The effect is temporary, with muscle function being restored following axon terminal sprouting.3
IncobotulinumtoxinA (Xeomin®/Xeomeen®/Bocouture®/XEOMIN Cosmetic™, NT 201; free from complexing proteins, Merz Pharmaceuticals GmbH, Germany) and abobotulinumtoxinA (Dysport® Ipsen, UK/Azzalure®, Galderma, Switzerland) are indicated for the treatment of glabellar frown lines,4,5 but BoNT/A formulations have also shown efficacy for the treatment of lateral periorbital wrinkles (crow’s feet).6-9
In 2009, the US Food and Drug Administration introduced product labelling to note that potency units (U) are specific to each preparation and are not interchangeable between products.10 However, in spite of this, simple ratios based on clinical experience are commonly employed in clinical practice.11,12 The literature reports dose-conversion ratios for incobotulinumtoxinA to abobotulinumtoxinA in the range of 1:2.5–1:3.8,12 In recent years, thorough guidance for practitioners on the dosage and administration of BoNT/A formulations has been provided from consensus panel statements.11,13 An international consensus committee recommends that, when using abobotulinumtoxinA for the treatment of crow’s feet (in combination with lower eyelid wrinkles), 1–2 injections are administered at the mid-pupillary line, about 2 mm below the border of the lower eyelids.13 These guidelines suggest that the injection should be very superficial, with the needle held