Topical hematoporphyrin derivative (HPD) photodynamic therapy for psoriasis Available to Purchase

Topical 1% HPD in a vehicle containing 1-dodecylazacycloheptan-2-one (Azone) was tested in a double-blind clinical study in 16 patients with plaque psoriasis. HPD or the Azone vehicle was applied twice daily for 8 weeks. Treatment sites were irradiated twice weekly with long-wave ultraviolet light (UVA), with dose escalations of 1-2 Joules/cm², to a maximum dosage of 20 Joules/cm². Lesions were scored weekly for erythema, scale, and elevation. There was a 25% overall improvement in lesions treated with HPD and UVA compared to HPD-treated lesions without UVA irradiation. A similar degree of improvement was obtained in lesions treated with vehicle alone and UVA irradiated. The use of occlusion in an attempt to enhance HPD penetration did not effectively increase therapeutic response. Lack of response is attributed to ineffective penetration of HPD in the thick psoriatic plaque.