SAN FRANCISCO — An SPF 40 sunscreen containing two UVA filters—ecamsule and avobenzone—protected patients from flares of polymorphous light eruption significantly better than formulations containing only one UVA filter, in a large outdoor randomized trial.
La Roche-Posay's novel sunscreen, marketed over the counter by L'Oréal as Anthelios 40, contains ecamsule 3%, avobenzone 2%, octocrylene 10% for UVB protection, and titanium dioxide 5% as a physical filter providing protection across the UV spectrum.
Ecamsule provides enhanced protection in the short-UVA range, where avobenzone is less effective. Ecamsule protects against UV in the 290- to 400-nm range, with peak protection at 345 nm. It is also more photostable than avobenzone, Dr. Vincent DeLeo explained at the annual meeting of the American Academy of Dermatology.
Dr. DeLeo of St. Luke's-Roosevelt Hospital in New York reported on 144 adult patients with polymorphous light eruption (PMLE) who participated in the randomized, double-blind clinical trial. They applied the dual-UVA-filter sunscreen daily on one side of the body and the same product minus either the ecamsule or avobenzone on the other side. Then they went outdoors for controlled doses of natural sunlight.
The primary study end point was a composite efficacy measure consisting of delayed time to onset of PMLE or lower global flare severity, based on a 10-point scale assessing itching, papules, vesicles, and erythema.
In paired comparisons, the success rate was 56% with the dual-UVA-filter sunscreen, vs. 11% for the ecamsule-deprived sunscreen, and 36% with the dual-UVA-filter sunscreen, compared with 16% for the avobenzone-deprived product. Both differences were statistically significant.
Flares of PMLE occurred later and with a higher cumulative UVA dose with the dual-UVA-filter sunscreen than with either of the single-filter products.
L'Oréal, which funded the study, has exclusive patent rights to ecamsule (Mexoryl SX), approved by the Food and Drug Administration in July 2006 as the first new UVA filter in nearly 2 decades.