INTRODUCTION
Acne vulgaris is a common, easily recognized skin condition
that affects adolescents and adults in all races and
ethnicities. In published single-center and national practice
surveys, acne vulgaris was the most common dermatologic
disorder observed among black patients in the Unites States, (ie,
individuals of African ancestry with Fitzpatrick skin types [FST] IV
through VI).1-3 Overall, it is believed that the pathogenesis of acne
is similar in all races and ethnicities, but racial, ethnic, and skin
type variations in clinical features, potential exacerbating factors
and sequelae of acne vulgaris have been described.4,5 Acne vulgaris
in black skin is frequently associated with postinflammatory
hyperpigmentation (PIH), which can be a sequela of the acne itself
or a complication of treatment (ie, secondary to irritation).4,5
PIH results from inflammatory mediators which stimulate melanogenesis
- a phenomenon that is more common in darkly pigmented
skin types due to greater melanocyte reactivity.4,5 In acne
vulgaris, PIH typically results at sites of clinically inflamed lesions
(ie, papules, pustules, cysts); however, it is plausible that subclinical
inflammation may also contribute to pigment alterations.4,5
Due to the heightened potential for PIH in darker skin types, it is
important to treat their acne with effective therapies that target
and minimize the acne-associated inflammation and the causes
thereof. 4,5 It is also important to keep in mind the tolerability profile
of the chosen therapies.4,5
Adapalene, a synthetic retinoid, and benzoyl peroxide, an effective
antimicrobial agent, are currently available at concentrations of 0.1% and 2.5%, respectively, as a fixed dose combination
gel (Epiduo® Gel, Galderma Laboratories, L.P.; adapalene-BPO)
for the treatment of acne. Adapalene-BPO targets the primary
pathogenic factors of acne: proliferation of Propionibacterium
acnes, abnormal keratinocyte differentiation, sebum production
and accumulation, and most importantly for this population,
inflammation.6,7 Three multicenter, randomized, double blind,
parallel-group, placebo controlled studies involving 3,855 subjects
have established the safety and efficacy of adapalene-BPO
in the treatment of acne for all skin types.8,9,10 An analysis of
pooled data from these 3 studies evaluated whether subjects
with skin of color were more sensitive to irritation from topical
acne treatment than other skin types; specifically, if the tolerability
of adapalene-BPO gel treatment was different in subjects
with FST I through III versus FST IV through VI.11 In that analysis,
adapalene-BPO was not associated with a higher incidence of
any signs or symptoms of irritation in subjects with higher FST.3
The analysis discussed here was conducted based on data from
these 3 studies, to investigate the safety and efficacy of adapalene-
BPO in subjects who self-identified their race as black.
METHODS
Study Design
The 3 studies included in this analysis had similar objectives
and designs. They were multicenter, randomized, double-blind,
parallel-group, active and vehicle-controlled studies. The efficacy
and safety of the adapalene 0.1%–BPO 2.5% combination
