Excimer laser combination boosts laser therapy in psoriasis treatment

Nov. 29, 2010
In early testing of two patients, an experimental protocol combining an excimer laser, clobetasol spray and topical calcitriol ointment achieved fast, impressive results in patients with severe generalized psoriasis.

In early testing of two patients, an experimental protocol combining an excimer laser, clobetasol spray (a topical steroid) and topical calcitriol ointment achieves fast, impressive results in patients with severe generalized psoriasis, as reported by Dermatology Times.

By combining the PhotoMedex XTRAC Velocity excimer laser with a topical steroid, says Tina Bhutani, M.D., a clinical research fellow under John Y.M. Koo, M.D., professor and vice chairman, department of dermatology, University of California, San Francisco, "We can be more aggressive with the laser therapy, because we're providing an anti-inflammatory agent at the same time." Specifically, Dr. Bhutani says, "We can treat 10 to 20% body surface area in an average of 10 minutes."

The excimer laser uses one UVB wavelength (308 nm), Dr. Bhutani says. "What makes it unique is that we're using a targeted headpiece to deliver the light. Unlike traditional narrowband UVB or psoralen plus UVA (PUVA), in which we are exposing not only the psoriatic skin but also normal skin, with the excimer laser we are only treating the psoriatic plaques. Therefore, we can treat more aggressively because the psoriatic skin can take much more light" than normal skin. Each application of the laser treats an area about one square centimeter, she says.

Dr. Koo adds, "By not exposing the normal skin, we can sometimes go up to 10 times the amount of light that is usually the limit for traditional phototherapy. That allows us to treat patients with far fewer sessions." Patients then apply their first dose of clobetasol spray immediately after laser treatment, while still in the office.

Altogether, the treatment protocol requires four weeks of twice-daily clobetasol spray plus excimer laser twice weekly. For the next four weeks, patients use calcitriol ointment twice daily and excimer laser twice weekly for weeks five and six, then as needed thereafter to maintain a Psoriasis Area and Severity Index (PASI) 75 response. For the last four weeks, patients use clobetasol spray twice daily, calcitriol ointment twice daily and excimer laser only if needed.

The two patients treated with the protocol had maintained PASI 90 at eight weeks. "Both of them look great," and neither has required laser treatment after the initial six weeks, Dr. Bhutani says.

Dr. Bhutani says the laser's most serious side effect risk involves transient minor burning. "With a topical steroid," she says, "there is a question of a risk of adrenal suppression. However, there have been no cases in the literature reporting serious steroid adrenal suppression. With Vectical, the only theoretical risk is hypercalcemia," which is very unlikely with the product's low concentration, she says.

Dr. Koo says that since the experimental protocol does not suppress the immune system, "This external approach is practical without the concern of full-body, lifelong immunosuppression."

In total, the researchers plan to treat 30 patients within a year. "We purposely went slowly with the first patients because this has never been attempted before—treating generalized psoriasis with entirely external means, but very aggressively. When we do this type of pioneering study, sometimes we don't know if we're going to encounter unexpected side effects," Dr. Koo says. However, he says, patients have tolerated the treatment well; only one experienced very minor burning.

"The reason we are excited is that these two patients had fantastic results, achieving PASI 90 within six weeks. That is impossible with any treatment we have other than something much more internally toxic, such as very high-dose cyclosporine," Dr. Koo says.

Source: Dermatology Times


Posted by Lee Mather

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