Efficacy and Safety of Incobotulinumtoxin A for the Correction of Glabellar Lines Among Patients With Skin Types IV to VI

April 2015 | Volume 14 | Issue 4 | Original Article | 350 | Copyright © April 2015

Brooke A. Jackson MDa and Mark R. Vogel MAb

aSkin Wellness Center of Chicago, Chicago, IL
bSan Francisco, CA

BACKGROUND: Despite the frequent use of botulinumtoxin A (BoNTA) in non-Caucasian patients, safety and efficacy has not been well characterized in persons with darker skin.
OBJECTIVE: To investigate the efficacy and safety of incobotulinumtoxin A [Xeomin® (XEO)] for the correction of glabellar lines among non-Caucasian patients with Fitzpatrick skin types IV to VI.
METHODS: This open-label, single-center, post-marketing study treated 29 patients with Fitzpatrick skin types IV to VI with moderate to severe glabellar frown lines. Evaluation at day 0 included standardized photographs and patient and investigator assessments. Post evaluation, XEO was administered at 5 intramuscular injection sites with equal aliquots of 4 units per 0.1 mL. Photographs and assessments were repeated at days 30 and 90.
RESULTS: Response to treatment was defined as a 1 or more point improvement in patient and investigator assessments. At day 30, 100% (n = 29; 95 C.I. 0.87, 1.00; P< .001) responded to treatment. At day 90, 69% (n=20; 95% C.I. 0.52, 0.83; P= .42) responded to treatment. The safety profile was similar to previously reported trials with BoNTA.
CONCLUSION: The efficacy and safety of XEO among patients with skin types IV to VI is similar to that among persons with fairer skin.

J Drugs Dermatol. 2015;14(4):350-353.


As with other organs of the body, the skin undergoes changes with aging. Unlike other organs, however, the skin is visible and, usually, an easy indicator of a person’s age. In fact, several studies have concluded that facial attributes such as skin uniformity are among the most important factors in estimating a person’s age.1-3 Signs of facial aging, such as rhytides and folds, can be caused by photoaging, smoking, facial expressions, and environmental factors. To address the aging face, numerous cosmetic procedures are available.
Of these cosmetic procedures, treatment with botulinum toxin Type A (BoNTA) for the correction of hyperdynamic wrinkles is the most common, with more than 3 million procedures performed each year.4 BoNTA, as well as other cosmetic procedures, are commonly used in patients of various ethnicities; in 2012, non-Caucasians constituted 21% of all cosmetic procedures. 4 Despite the use of BoNTA among patients with skin of color, the number of these patients enrolled in clinical trials does not reflect the percentage of patients with skin of color in the population who receive cosmetic correction with toxin. Several studies have investigated the use of the first two BoNTA products – onabotulinumtoxin A [Botox® (BTX); Allergan, Irvine, CA] and abobotulinumtoxin A [Dysport® (DYS); Medicis Aesthetics, Scottsdale, AZ] – in non-Caucasian populations.5, 6 However, the latest BoNTA product, incobotulinumtoxin A [Xeomin ® (XEO); Merz North America, Greensboro, NC] has not been widely reported in these populations to date.
It is important to understand the safety and efficacy of BoNTA products in non-Caucasian patients, as the skin of those individuals with Fitzpatrick skin types IV to VI may age differently than the skin of individuals with fairer skin. Studies that have investigated skin types IV to VI suggest that the protective pigmentation of types IV to VI may cause the effects of photodamage to occur 10 to 20 years later, often with less severity, than those with types I to III.7-11 Premature aging can occur in types IV to VI but typically will manifest as midfacial aging instead of the photodamage that is characteristic of lighter skin.12 Because of this difference in response, persons with darker skin types potentially may be more responsive to BoNTA than Caucasians (by achieving greater change from baseline on glabellar severity ratings). In studies of BTX and DYS specifically, African Americans, who constituted nearly 20% of the study population, had a higher response rate to DYS than the general population.13 These results were consistent with those of Brandt and colleagues. The 51% of non-Caucasian subjects in the trial demonstrated a higher proportion of response to DYS than the Caucasian subjects demonstrated.5
XEO was studied in Caucasians and non-Caucasians in 2 pivotal trials in 16 clinical sites in the United States and Canada. These studies, which supported the approval of XEO in the United States in 2011, are commonly referred to as GL-1 and GL-2; a total of 547 patients were enrolled in these studies and were primarily Caucasian (89% and 65%, respectively).14 In