Bexarotene

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Bexarotene
Systematic (IUPAC) name
4-[1-(3,5,5,8,8-pentamethyltetralin-2-yl)ethenyl]
benzoic acid
Identifiers
CAS number 153559-49-0
ATC code L01XX25
PubChem 82146
DrugBank APRD00114
Chemical data
Formula C24H28O2 
Mol. mass 348.478 g/mol
Pharmacokinetic data
Bioavailability  ?
Protein binding >99%
Metabolism Bexarotene undergoes oxidative metabolism via CYP450 3A4 and its metabolites are then glucuronidated. Four bexrotene metabolites have been identified in the plasma: 6- and 7- hydroxy-bexarotene and 6-and 7-oxo-bexarotene. All of the metabolites are active in vitro, but their clinical significance is not known.
Half life 7 hours
Excretion Parent drug and metabolites are eliminated primarily through the hepatobiliary system. Less than 1% is excreted in the urine unchanged.
Therapeutic considerations
Pregnancy cat.

?

Legal status
Routes Oral and Topical

Bexarotene (Targretin) is an oral antineoplastic agent indicated by the FDA for Cutaneous T cell lymphoma. It has been used off-label for lung cancer, breast cancer, and Kaposi's sarcoma.

In Europe oral bexarotene is licensed for use in patients with skin manifestations of cutaneous T cell lymphoma who have had at least one systemic therapy. It is effective in reducing the patches plaques and tumours caused by the disease in half of the patients treated, and three quarters of patients report feeling better while on therapy (Duvic et al). The usual dose taken is 300mg/m2 a day. Side effects of therapy include hypothyroidism and raised triglycerides which occur in nearly all patients. The response is seen in about 3 months and will last for about a year.

Bexarotene is a retinoid specifically selective for retinoid X receptors, as opposed to the retinoic acid receptors.

RXRs are located primarily in visceral organs such as the liver and kidney. Activated RXRs form homodimers or heterodimers with RAR (retinoic acid receptors), vitamin D receptors, thyroid receptors or peroxisome proliferator activator receptors. Once activated, these retinoid receptor dimers bind to DNA at retinoic acid response elements and act as transcription factors that regulate the expression of genes which control cellular differentiation and proliferation. Retinoid agonists can activate the expression of retinoid regulated genes by removing negative transcription control or by facilitating positive transcriptional activity. They exert anticancer action by interfering with the growth of cells of the tumor.