cal determinations. In addition, the study evaluated adverse
events and tolerability associated with the two preparations
used on the back.
This five-week, open-label single-center study enrolled 20
healthy adults (≥18 years old) who were free of acne but had
high P. acnes populations on their backs (at least 10,000 colonies
per cm2). Subjects were screened to ensure that none were
using any form of topical or systemic antibiotics within four
weeks prior to enrollment. They were instructed not to use any
antimicrobial topical products (e.g., soaps, medicated shampoos,
Key inclusion criteria included: healthy, adult male and/or
female volunteers 18 years of age and older; all females
must be using an acceptable method of contraception;
subjects willing to refrain from using antimicrobial topical
products (shampoos, soaps, acne preparations). Key exclusion
criteria included: any volunteer who exhibited any skin
disorders of an acute or chronic nature including psoriasis,
eczema, etc.; use of topical or systemic antibiotics within
the previous four weeks; females who were pregnant, planning
a pregnancy or breastfeeding.
Each subject was treated once daily with BP (5.3%) emollient
foam during the first two weeks at the study center under
supervision by a technician on weekdays and unsupervised
at home over the weekends. The area treated was from just
below the scapulae to the shoulders. A cherry tomato-sized
amount of foam was spread over this area. Subjects received
no treatment in week 3 to allow bacterial re-growth. Subjects
were subsequently instructed to apply BP (8%) wash to the
same area treated with the foam for two weeks when showering,
referring to the package insert (i.e., wash until a full lather
develops, rinse and pat dry using once daily the first week and
twice daily the second week if more than one shower a day
is needed). No specific instructions regarding the amount of
wash product were given.
Quantitative bacteriologic cultures using a modified Williamson
and Kligman16,17 scrub technique were obtained from the upper
back at baseline and weeks 1, 2, 4, 5 and 6. Colony forming
units (CFU) of P. acnes were counted at a dilution that contained
between 10 and 100 CFU. Total densities of P. acnes (log10 CFU
per cm2) were calculated and reported.
Cutaneous tolerability assessments were carried out during
the first two weeks and at the weekly visits during the last two
weeks of the study. Local signs and symptoms (scaling, dryness,
erythema, itching and stinging) were assessed on a four
point scale where 0=none, 1=mild, 2=moderate and 3=severe.
Nineteen out of 20 subjects were evaluable.
At baseline, the mean P. acnes count was log base 10 6.43±0.27
per cm2. Total P. acnes counts were reduced by 1.93 log after one
week of treatment, and by 2.1 log after two weeks of treatment
with BP (5.3%) emollient foam.
One week after discontinuation of the BP (5.3%) emollient foam
the mean P. acnes count was log base 10 (log10) 5.81±0.73 per
cm2, a statistically lower value than at baseline indicating a substantative
effect of the BP (5.3%) emollient foam. Total P. acnes
counts showed no reduction from this new baseline after one
or two weeks treatment with BP (8%) wash (Figures 1 and 2,
and Table 1).
No serious adverse events were reported with either treatment.
No erythema, dryness, scaling or burning were observed or re-