A centralized Institutional Review Board, Chesapeake Research Review, Inc., reviewed and approved the protocol and informed consent forms, and written informed consent was obtained from all 99 subjects at seven U.S. sites before study participation. The study was conducted in accordance with Good Clinical Practices and principles that have their origins in the Declaration of Helsinki.
Depressed, distensible facial acne scars (scars disappearing completely with manual perilesional skin stretching) were targeted for treatment in this study. Evaluators were provided with a pictorial and descriptive guideline outlining the acne scarring morphology (depressed and distensible) considered for autologous fibroblast treatment.16
Healthy subjects with facial acne scarring on both cheeks were enrolled in the study. To meet eligibility, subjects’ depressed distensible acne scars on both cheeks had to be evaluator rated as moderate or severe on a novel, validated 5-point acne scar assessment scale (Table
). Subject ratings of the appearance of each cheek were required to be very dissatisfied or dissatisfied (Table
). Subjects were excluded if they had hypertrophic acne scarring or numerous icepick acne scars in the treatment area, had undergone aesthetic procedures (e.g., fractional or traditional ablative/non-ablative laser resurfacing, subcision, microdermabrasion, chemical peels) to the treated area within the past 12
months, or had ever previously received dermal fillers in the treated area. Subjects with a history of heavy smoking, alcohol or drug abuse, or steroid treatment were excluded because these attributes may be associated with limited cell expansion in vitro.17
Prescription topical treatments, such as retinoids or topical antibiotics, were discontinued for 2
weeks before the first injection and disallowed for the duration of the study. Enrolled subjects underwent three postauricular full-thickness (epidermis, dermis, fat) skin punch biopsies to harvest autologous fibroblasts. The cosmetically inconspicuous postauricular mastoid area was chosen because of its sun-protected nature. Biopsy sites were closed using 5–0 fast-absorbing chromic gut suture or with thin adhesive strips. The 3-mm punch biopsy specimens (times 3) were immediately placed into a sterile vial containing transport medium. The vials were then transported in a biocontainer with ice packs on the day of harvest overnight to Fibrocell Technologies, Inc. (Exton, PA), where the fibroblasts were isolated, cultured, and expanded over a several-week period as described previously.18
In a split-face design, the cheeks of each subject were randomized to receive autologous fibroblasts (10–20 million cells/mL) or vehicle control (dye-free, protein-free cell culture medium) injected into the high papillary dermis at a maximum dose of 2
mL per treatment, administered as approximately 0.1
, with a minimum treatment area of 9
(). Immediately before the injections, the treatment area on the cheek was anesthetized with topical lidocaine anaesthetic cream for 30 to 60
minutes. Most commonly, 4% lidocaine cream was employed, although some sites used a compounded formulation of benzocaine 20%, tetracaine 10%, and lidocaine 4%. The injections were made into the papillary dermal plane, using an insulin hub-less syringe with a 28G needle (Becton, Dickinson and Company, Franklin Lakes, NJ) so as to create a wheal and transient blanching of the skin surface with each injection. Injections were directed underneath the individual scar lesions, in addition to the perilesional area, to achieve a “field” treatment effect. The intent of injection was to introduce the live cells into the scarred area and surrounding skin within the confines of the papillary dermis, with the assumption that the cells would disperse into the surrounding dermis. Achieving a degree of correction, as commonly employed in techniques with dermal fillers (e.g., full correction or overcorrection), was not the endpoint, because the liquid cell suspension was not designed for immediate volumetric improvement. Wheals created at each injection point usually disappeared within hours after injection. After injection, small ice packs were used to reduce any stinging or discomfort, and subjects were instructed on a strict 7-day post-treatment regimen, including the use of only bland moisturizer and sunscreen. The use of make-up or topical cosmeceuticals was not allowed for 1
week after treatment. Subjects received three treatments to each side of the face 14
Validated Physician Evaluator 5-point Acne Scar Assessment Scale
Subject Acne Scar Self-Assessment Scale
Efficacy and safety evaluations were performed 1, 2, 3, and 4
months after the third treatment. The co-primary efficacy end point required that subject cheeks be considered to have responded based on the subject and evaluator acne scar assessment of treatment response to be counted as a treatment success. For the subject acne scar assessment, a responding cheek was defined as a cheek with a 2-point improvement on the subject acne scar assessment. The acne scar assessment scale is a 5-point scale (very dissatisfied
–1, somewhat satisfied
+1, very satisfied
+2).The scale is a modification of the scale used by Cohen and Holmes 19
A 5-point evaluator live acne scar assessment scale was developed and validated (0
very mild, 2
severe) for use in live assessment of subjects to detect clinically meaningful changes in acne scar severity over time. The scale was used with an associated photo guide demonstrating acne scar appearance associated with each grade. Scale evaluation studies (conducted separately from and before the interventional clinical study described here) demonstrated the validity of the scale in detecting a 1-point improvement in scar appearance. Dermatologists with experience in treating acne scars were consulted during scale development to ensure the clinical meaningfulness of a 1-point improvement.
A responding cheek was defined as a cheek with a 1-point improvement on the evaluator live acne scar assessment scale. Evaluators were blinded to the treatment each cheek had received. The study required that the physician performing the treatment injections not be the physician performing the subject evaluations to eliminate any potential for bias based on the injection.
Photographs were taken of each subject at baseline and 2, 3, and 4
months after the third treatment using photographic equipment and procedures designed to ensure reproducible positioning and lighting of subjects. An independent panel of three board-certified dermatologists assessed change from baseline in the appearance of acne scarring using a 5-point scale (–2
much worse, –1
no change, +1
much improved). Post-treatment photographs were graded compared with baseline photographs for each cheek at each time point. The independent photographic reviewers (IPR) were blinded to the treatment each cheek had received and viewed the photographs with respect to the time of the follow-up (at 1, 2, 3, and 4
The statistical analysis compared the autologous fibroblast-treated and placebo-treated sides of the face. The primary efficacy comparisons were performed separately (in different rooms) for the co-primary endpoints (subject and evaluator assessments). Success was defined as statistically significant (p
.05, two-sided) results for the subject and evaluator assessments. For each endpoint and time point, the McNemar paired test of proportions was used to test the null hypothesis for the subject and evaluator assessments. The Wilcoxon signed-rank test was used to assess the comparative difference in scar appearance for autologous fibroblast– and placebo-treated cheeks for each of the three independent reviewers.
Assessments of safety included the incidence of treatment-emergent adverse events (AEs), vital signs, and physical examination assessments throughout the study period.