Bexarotene

Bexarotene is a selective retinoid X receptor (RXR) agonist. It binds to, and activates RXRs which function as ligand-activated transcription factors that control gene expression. This leads to modulation of cell growth, apoptosis, and differentiation. In patients with refractory or persistent early stage cutaneous T cell lymphoma (CTCL), the overall response rate was 54% after oral bexarotene 300 mg/m2/day. The overall response rate in patients with refractory or persistent advanced stage CTCL was 45% at the same dosage. An overall response rate of 63% was reported after topical bexarotene 0.1 to 1% twice daily in patients with early stage CTCL. Another trial reported an overall response rate of 44% after topical bexarotene 1% once daily escalated up to 4 times daily. Plaque elevation was significantly reduced, and the severity of moderate to severe psoriasis was substantially improved in patients receiving oral bexarotene 0.5 to 2 mg/kg/day. At clinically relevant oral dosages, bexarotene significantly decreases levels of serum thyrotropin and free thyroxine. The most common adverse events associated with oral bexarotene are hypertriglyceridemia, hypercholesterolemia, central hypothyroidism and headache. Reversible acute pancreatitis has occurred during oral bexarotene therapy. Adverse events associated with the topical formulation are limited to rash, pruritus, and pain.