"Bexarotene Gel 1% Enhances Efficacy of Phototherapy for Psoriasis: Presented at AAD"
By Bruce Sylvester
SAN FRANCISCO, CA -- March 6, 2006 -- Treatment with bexarotene gel 1% appears to enhance the efficacy of narrowband ultraviolet B (UVB) phototherapy with minimal toxicity in patients with plaque psoriasis.
Researchers reported these results here during a discussion session of selected research on March 5[th at the 64th Annual Meeting of the American Academy of Dermatology (AAD).
"We did this study to see whether the bexarotene topical gel would act synergistically with the narrowband ultraviolet B phototherapy, "said lead investigator Melissa Magliocco, MD, Instructor of Medicine, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, New Jersey, United States. "Basically, we wanted to see if it enhances the efficacy of the phototherapy."
"The take-home point of this is that [bexarotene gel 1%] does act synergistically when compared to placebo-plus-narrow-band UVB," Dr. Magliocco added.
Ultraviolet B phototherapy is widely used to treat psoriasis, however, its effectiveness depends on the thickness of the plaques. Retinoid gels reduce the thickness of the plaques but do not treat the psoriasis, she explained.
Dr. Magliocco and her colleagues hypothesized that since limited UVB penetration through thick plaques inhibits efficacy of treatment, combining retinoid treatment with UVB would cause a synergistic improvement of efficacy in patients with psoriasis.
Bexarotene is a topical retinoid that is FDA-approved for the treatment of cutaneous T-cell lymphoma.
The investigators randomly assigned 23 subjects with moderate to severe psoriasis to apply either active bexarotene 1% or placebo gel to target lesions on the right and left sides of the body. For 10 weeks, subjects applied treatment in a blinded fashion to the assigned sides of the body. They also underwent phototherapy 3 times per week for 8 weeks, beginning 2 weeks after the start of topical treatment.
The researchers evaluated the psoriasis plaques at weekly for 8 weeks, beginning at the start of narrowband UVB treatments. They assessed for efficacy using target lesion score and photography.
In the 15 subjects who completed the trial, the investigators found that bexarotene plus narrowband UVB combination was significantly more effective than placebo/narrowband UVB.
Mean target lesion scores decrease from baseline for drug-treated lesions by 66.4% and it was 53.2% for placebo-treated lesions.
Due to the small size of the study population, the researchers used the Wilcoxon rank-sum test to analyze differences in score changes between active drug and placebo. "Score improvement with drug was significantly greater compared with placebo (P =.045)," they wrote in their abstract.
Changes in score components (scaling, erythema, induration) were measured separately and the researchers found that the percent reduction in induration was statistically significant (P =.024), while changes in scaling and erythema (P =.189 and P =.120, respectively) were not.
Adverse events were mild and included rash and skin irritation, Dr. Magliocco said.
"One of the implications of our findings is that one can use bexarotene with the phototherapy to reduce the amount of time that patients would spend in phototherapy," she said.
Patients usually consider phototherapy to be inconvenient because they have to go for treatments in a clinic about 2 or 3 times per week for at least 10 weeks, Dr. Magliocco explained. "So by using the gel with the phototherapy, you can possibly reduce the amount of treatments that your patients receive," she added.
The investigator-initiated trial was supported by a grant from Ligand Pharmaceuticals Inc.
[Presentation title: Bexarotene 1% Gel With Narrowband UVB Phototherapy for Moderate to Severe Psoriasis: a Randomized, Double-Blind, Bilateral, Vehicle-Controlled Trial. Abstract P31]
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