Pigmentary Disorders Academy focuses on clinical research

Key Points

Members of the PDA, representing a multinational group of experts on pigmentary disorders, gathered in Vancouver in March 2008, to review ongoing research and publication projects and to discuss plans for future endeavors.

"In the few years since the PDA was created in 2003, our group has produced a number of publications reviewing the state of the art of existing knowledge about pigmentary disorders. More recently, our projects have evolved so that we are taking a more active approach to advancing the field by conducting new research," says Amit G. Pandya, professor of dermatology, University of Texas Southwestern Medical School, Dallas.

"Currently, there is a lack of information about possible molecular differences between skin affected by melasma and normal skin.

"Various theories exist, including those suggesting there may be differences that influence responses to hormones.

"We are hoping the studies being performed will improve our understanding of the pathogenesis of melasma, and thereby help us to identify targeted treatments and identify potentially effective molecules faster," Dr. Pandya tells Dermatology Times.

The PDA members have also completed a survey study designed to gather epidemiologic information on melasma.

Other research is concentrating on methods for assessing melasma severity and responses to treatment. In this regard, the PDA recently completed a study evaluating the performance of the Melasma Area and Severity Index (MASI). A manuscript reporting the findings from this validation study and describing a modified MASI score is in preparation.

"The MASI has been used as a rating tool in clinical research for the assessment of melasma severity, but it has never been validated. Our research indicates that certain components of the MASI may not be very reliable.

"Based on our findings, we are considering a revision of the existing system to address the limitations," Dr. Pandya says.

Objective imaging techniques for evaluating skin pigmentation in patients with melasma are being assessed and compared in an ongoing study. That trial is investigating SIAscopy (Astron Clinica), RBX Technology (Canfield Imaging) and spectrophotometry, and aims to determine which provides the most reliable and accurate quantification of skin pigmentation.

"Whether we are using instruments, genetic testing or clinical evaluation, having a validated tool for rating melasma severity will allow us to determine the efficacy of therapeutic interventions in a more accurate and efficient manner," Dr. Pandya says.

Several PDA-initiated treatment studies have been recently completed. One of these evaluated the risk of atrophy in patients using the triple combination cream containing fluocinolone acetonide 0.01 percent, hydroquinone 4 percent and tretinoin 0.05 percent (Tri-Luma Cream, Galderma) for the treatment of melasma.

To investigate the possibility that there are race-related differences in therapeutic responses, a multicenter study was undertaken in Asia to compare the efficacy and safety of the triple combination cream against hydroquinone monotherapy in the treatment of melasma. And, in Brazil, a study was conducted comparing treatment of photodamage using the triple combination cream versus topical tretinoin.

The PDA is also working to create a rating scale for postinflammatory hyperpigmentation (PIH). The project is in a pilot stage using clinical images. After further refinement, the scale will be applied to live patients with multiple raters to determine its reliability, reproducibility and validity.

"Developing a standardized rating tool is important for use in studies examining the quality-of-life impact of PIH, and the efficacy of treatments for reducing the hyperpigmentation," Dr. Pandya says.

Disclosure: The PDA was established by Galderma and supported by that company through an unrestricted grant. Its members represent dermatologists from Europe, North America, South America and Asia.

Dr. Pandya is a consultant and receives funding to perform clinical research from Galderma.