Combination strategies hasten, enhance clearing of solar lentigines

National Report - Combination therapy, featuring a newer dual-agent topical solution containing mequinol 2 percent and tretinoin 0.01 percent (Solagé,Galderma) used alone but particularly together with laser or intense pulsed light (IPL) treatment, provides an improved approach for treating solar lentigines, agree Marta I. Rendon, M.D., and Fran E. Cook-Bolden, M.D.

"Whereas cryotherapy was the mainstay in the past for clearing solar lentigines, its use can result in adverse effects, which include unacceptable hypopigmentation to superficial scarring when the freeze is too aggressive," says Dr. Cook-Bolden, clinical assistant professor of dermatology, Columbia University, and a private practitioner in New York.

Pretreat with topical The topical agent is commonly used after the surgical treatment, but it is also very helpful as a pretreatment. In the latter regimen, patients begin applying the mequinol-tretinoin product twice daily for two to four weeks before the laser, IPL or cryotherapy procedure.

Application of the mequinol-tretinoin solution is restarted about one week following the laser treatment, once the area has healed, and continues for two to four weeks or until complete clearing is achieved. If lentigines recur, patients can restart topical therapy again, and they return after three to six months to check for recurrence.

"The pigmented cells in the solar lentigines can be resistant to treatment, and the heat or trauma from physical treatment modalities can have a stimulatory effect, causing increased pigment production. Application of mequinol/ tretinoin helps to clear existing pigment and mitigates any treatment-induced melanocyte response," Dr. Cook-Bolden says.

Dual-agent monotherapy The mequinol-tretinoin product can also be used effectively as monotherapy. Evidence indicates that relative to hydroquinone, mequinol has more potent depigmenting action and is less irritating, and in the premarketing clinical trials, the mequinol-tretinoin product was significantly more effective for improving the appearance of solar lentigines on the face, hands and forearms than its vehicle or either of its active ingredients (Flesicher AB, et al. J Am Acad Dermatol. 2000;42:459-467).

In those studies that enrolled more than 1,200 subjects, the majority of patients (?55 percent) using the dual fixed-combination experienced at least moderate improvement in the appearance of the treated lesions after 24 weeks. In addition, another 25 percent of patients benefited with some improvement.

Results from another open-label study of 96 patients reported even better outcomes (Colby SI, et al. Drugs Dermatol. 2003;2:147-152). In that trial, 84 percent of facial lesions and 78 percent of forearm lesions were rated as clear or almost clear after being treated for 24 weeks with mequinol-tretinoin plus sunscreen. Investigators in the pivotal trial and the open-label study reported that lesion pigmentation improved further after treatment stopped.