Retinoids

The therapeutic efficacy of some retinoids, such as isotretinoin, etretinate, and acitretin in CTCL, has been confirmed in several small, monotherapy studies.58-61 Response rates range from 44 to 67%, with CR rates from 21 to 35%. They seem to be equally effective, with median response duration around 8 months. Common effects consisted of skin and mucous membrane dryness. Oral bexarotene is a USFDA approved synthetic retinoid for refractory CTCL that selectively binds to RXR. In two multicenter phase II-III clinical trials it has been tested in early and advanced stages of CTCL patients.62 63 Reported response rates in early stages were between 45 and 54%. An overall response rate was observed in 94 patients with advanced disease, with only 4% complete responders, and with a median duration of 10 months. At the recommended dose of 300 mg/m2 daily, it is associated with significant side effects, such as hyperlipidemia, hypothy-roidism, and cytopenias. Retrospective comparison data suggest that there may be little difference in efficacy between bexarotene (RXR-specific retinoid) and agents such as all-trans retinoic acid (RAR-specific retinoid), but clear differences in toxicity exist.64

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