Abstract
Photo(chemo)therapy and oral retinoid therapy for psoriasis or cutaneous T-cell lymphoma are frequently combined to obtain an enhanced therapeutic effect with lower safety risks. Bexarotene, a new RXR-selective retinoid (rexinoid), has been developed for the treatment of cutaneous T-cell lymphoma and has recently been investigated in the treatment of psoriasis. In the present study the UV-modulating properties of bexarotene were evaluated by assessment of the minimal erythema dose (MED) for UVB light. In 11 patients participating in a phase II study of oral bexarotene 0.5 mg/kg/day (7 patients) or 3.0 mg/kg/day (4 patients) for plaque-type psoriasis, MED tests were performed on uninvolved psoriatic skin on the lower back of the subjects before and after 12-week treatment. Clinical scores of erythema and determination of the MED 24 h after irradiation did not show statistically significant changes between the exposed areas before and after bexarotene treatment or between the two doses tested. No photosensitizing reactions were observed. This study demonstrates that a single exposure to UVB irradiation is well tolerated in patients treated with bexarotene 0.5-3.0 mg/kg/day and suggests that it is not necessary to take precautions with respect to short-term effects of sun exposure during bexarotene treatment. Further study of bexarotene photo(chemo)therapy in cutaneous T-cell lymphoma and psoriasis is warranted.
