Researchers identify no difference in treatment with tretinoin vs. tretinoin precursors

Results from a randomized clinical trial showed no significant difference in efficacy between topical tretinoin precursors and treatment with tretinoin 0.02%.

“Retinoids are broadly accepted as the criterion standard for topical management of photodamage-improving the fine wrinkles and dyspigmentation characteristic of photodamaged skin,” Anna L. Chien, MD, of the department of dermatology at The Johns Hopkins School of Medicine in Baltimore, and colleagues wrote. “One of the major deterrents to their topical use, however, is the associated local skin irritation, such as erythema, pruritus, stinging, burning and scaling.”

The researchers noted that while cosmeceutical products containing retinol and retinyl esters are available over the counter and may provide results comparable with prescription-grade tretinoin, it remains unclear which of the purported effects of retinoids is responsible for the clinical efficacy of tretinoin or its precursors.

To evaluate the efficacy of topical tretinoin precursors (TTP) compared with tretinoin retinoic acid (RA) in treating moderate to severe facial photodamage, Chien and colleagues analyzed results from 20 patients who completed an entire course of treatment, all of whom were white women.

Based on Griffiths measurements of photoaging at week 24, the researchers found no significant different between the two treatments. However, patients treated with RA exhibited erythema more often during the course of treatment compared with the TTP group (difference, –0.53; 95% CI, –0.88 to –0.17).

“We next were interested in which molecular targets best correlate with improvements in photodamage,” Chien and colleagues wrote.

They found that patients who used TTP exhibited decreases in Griffiths photodamage score by week 24 compared with baseline (median difference, –1; 95% CI, –2 to 0), whereas those in the RA group did not show any significant difference.

“Based on this clinical analysis, we predicted that analogous pairwise comparisons of potential biomarkers should reveal significant and consistent changes in mRNA expression, at least with TTP treatment,” the researchers wrote.

Chien and colleagues noted that, given the limitation of a small population size, TTP use would still benefit from further investigation in larger, more diverse cohorts where parametric methods can be used.