Tretinoin gel offers another option for photodamage

National report - Tretinoin microsphere gel (TMG) 0.1 percent (Retin-A Micro, OrthoNeutrogena) is a safe and effective treatment for improving the clinical signs of moderate-to-severe photoaging, reported Jonathan S. Weiss, M.D., at the 63rd Annual Meeting of the American Academy of Dermatology.

Although the efficacy of tretinoin 0.02 percent and 0.05 percent in emollient cream preparations has been established in well-designed clinical trials, outcomes achievable with TMG 0.1 percent have not been specifically investigated. To address that gap in knowledge, Dr. Weiss and his colleague Joel Shavin, M.D., designed a prospective, randomized, double-blind, vehicle-controlled trial enrolling 44 females and one male with Fitzpatrick skin phototypes I-III and photodamage severity of 4 or greater on scale of 0 (none) to 9 (severe).

After six months, overall photodamage severity was significantly improved in subjects using TMG 0.1 percent nightly but not in the vehicle group, and the difference in change from baseline between TMG and vehicle was also statistically significant. Whereas about 85 percent of women using TMG benefited with a one- or two-grade improvement in photodamage severity, only about 25 percent of controls were considered to have achieved any positive change in severity grade.

The treatment was well-tolerated, and although irritation was more common with tretinoin versus vehicle, no patient discontinued the study because of local side effects.

"These results indicate that, similar to other formulations of tretinoin that have been studied, this preparation appears to be efficacious in ameliorating the signs of photodamage. In addition, TMG 0.1 percent appears to be as well or better tolerated than other retinoids we have tested or prescribed for the treatment of photodamaged skin," he comments.

"Based on these results, TMG 0.1 percent can be considered as another tretinoin option for treatment of photodamage. This formulation may be better tolerated by some patients, and so it may be a good entry point into tretinoin therapy for photodamage in some individuals," Dr. Weiss adds.

Dr. Weiss and Dr. Shavin are in private practice in Snellville, Ga., and are co-directors of Gwinnett Clinical Research Center, a private clinical research organization.

The two treatment groups in their study were well-matched at baseline with respect to their demographic characteristics and the severity of their overall photodamage and of the individual clinical signs. Efficacy evaluations also included assessment of the changes in severity of photoaging clinical signs, including tactile roughness, mottled hyperpigmentation, fine wrinkling, coarse wrinkling, sallowness and lentigines, and their results corroborated the benefits of TMG treatment noted in the overall severity evaluation. While there were significant improvements in tactile roughness, mottled hyperpigmentation, sallowness and lentigines in both groups after six months, the changes in mottled hyperpigmentation, sallowness and lentigines were greater in the TMG group. In addition, only TMG was associated with a significant improvement in fine wrinkling.

"The improvement noted in the vehicle arm of this study is common in controlled studies of topical treatment for photoaging, since patients generally undertake a total skincare regimen including use of emollients and sunscreens. Some of the improvements are likely due to those adjuvant measures, and those achievable benefits reinforce the importance of undertaking double-blind, controlled studies," Dr. Weiss says.

With 12 months of TMG treatment, coarse wrinkling was also significantly improved, while women who had been using TMG for just six months showed significant benefits in their other clinical signs of photodamage. The benefits of TMG were also seen in patient self-assessments of overall appearance and feel of the skin as well as in investigator's global evaluation of clinical response.

About 30 percent of patients in each group reported some adverse event. With the exception of cutaneous irritation, the types and frequencies of those adverse events were generally similar in both groups.

Disclosure: The study was investigator-initiated and designed. Dr. Weiss and Dr. Shavin received financial support for the study from OrthoNeutrogena. Dr. Weiss has served as a consultant to OrthoNeutrogena. Neither Dr. Weiss nor Dr. Shavin has a direct financial interest in OrthoNeutrogena.