Tretinoin Causes Less Discomfort than Adapalene/Benzoyl Peroxide Gel

ORLANDO — Tretinoin gel microsphere 0.04% delivered by pump caused significantly less discomfort than a combination of adapalene 0.1% and benzoyl peroxide gel 2.5%.

The potential for irritation when using localized retinoids for acne can reduce patient compliance; the tretinoin gel microsphere formula (Retin-A Micro) was designed to encapsulate the active ingredient to reduce irritation, said Dr. James J. Leyden emeritus professor of dermatology at the University of Pennsylvania, Philadelphia.

Dr. Leyden and colleagues designed a split-face study to compare skin irritation from daily application of one pump of 0.04% tretinoin gel microsphere medication (TGM) with a pea-sized amount of adapalene gel 0.1%/benzoyl peroxide 2.5% gel (ADA-BPO). The results were presented in a poster at the Orlando Dermatology Aesthetic and Clinical Conference.

The researchers enrolled 170 patients aged 18-40 years with acne vulgaris and Fitzpatrick skin types I, II, or III; 155 patients completed the study. The patients were instructed to apply the two regimens (one to each side of their face) daily for 3 weeks.

Although both agents were well-tolerated by most patients, TGM was associated with better tolerance of dryness, erythema, burning, stinging, and itching.

The patients applied the products at the study center under supervision on weekdays and unsupervised at home on weekends. Expert graders evaluated the patients each weekday for erythema and dryness on a scale of 0 to 8. They also recorded the patients' assessments of itching, burning, or stinging on a scale of 0 to 4. The graders were blinded to which product was on which side of the patients' faces.

The pattern of erythema was similar for both treatments, but the TGM was associated with significantly less erythema than ADA-BPO on day 3 of the study based on daily assessment, and this difference continued until the study's end. Dryness was significantly less on the TGM side, compared with the ADA-BPO side starting on day 3 of daily assessment.

Patients reported significantly less burning and stinging on the TGM side of the face, compared with the ADA-DPO side starting on day 2 of daily assessment and day 3 of cumulative assessment. Patients also reported significantly less itching on the TGM side, compared with the ADA-DPO side starting on day 2 of daily assessment and day 3 of cumulative assessment.

"The pump delivery system facilitates improved patient education and more accurate dosing, and may have the potential to improve patient compliance," the researchers noted.

The study was supported by Ortho Dermatologics, manufacturer of Retin-A Micro. Dr. Leyden has been an adviser, investigator, or consultant for multiple pharmaceutical companies. Several study coauthors are employed by Johnson & Johnson.

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