indication

Used orally for the treatment of skin manifestations of cutaneous T-cell lymphoma (CTCL) in patients who are refractory to at least one prior systemic therapy. Also used topically for the treatment of skin lesions in early (stage IA and IB) CTCL in patients who experience refractory or persistent disease with the use of other therapies or are intolerant of other therapies.

pharmacology

Bexarotene is a member of a subclass of retinoids that selectively activate retinoid X receptors (RXRs). These retinoid receptors have biologic activity distinct from that of retinoic acid receptors (RARs). Bexarotene is indicated for the treatment of cutaneous manifestations of cutaneous T-cell lymphoma in patients who are refractory to at least one prior systemic therapy. Bexarotene selectively binds and activates retinoid X receptor subtypes (RXR_α, RXR_β, RXR_γ). RXRs can form heterodimers with various receptor partners such as retinoic acid receptors (RARs), vitamin D receptor, thyroid receptor, and peroxisome proliferator activator receptors (PPARs). Once activated, these receptors function as transcription factors that regulate the expression of genes that control cellular differentiation and proliferation. Bexarotene inhibits the growth in vitro of some tumor cell lines of hematopoietic and squamous cell origin. It also induces tumor regression in vivo in some animal models.

mechanism of action

Bexarotene selectively binds with and activates retinoid X receptor subtypes. There are three subtypes in total: RXR_α, RXR_β, RXR_γ. The exact mechanism of action of bexarotene in the treatment of CTCL is unknown but the drug has activity in all clinical stages of CTCL.

half life

7 hours

route of elimination

Urinary elimination of bexarotene and its known metabolites is a minor excretory pathway (<1% of administered dose).

drug interactions

Conivaptan: Conivaptan may increase the serum concentration of CYP3A4 substrates such as bexarotene. Upon completion/discontinuation of conivaptan, allow at least 7 days before initiating therapy with drugs that are CYP3A4 substrates. Consider therapy modification.

Demeclocycline: Tetracycline derivatives like demeclocycline may enhance the adverse/toxic effect of Retinoic Acid Derivatives. Due to the risk of developing pseudotumor cerebri (also known as intracranial hypertension), avoid this combination of drugs if possible. If used concomitantly, monitor for evidence of this interaction (eg, dizziness, diplopia, headache).

Desogestrel: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of desogestrel, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Doxycycline: Tetracycline derivatives like doxycycline may enhance the adverse/toxic effect of Retinoic Acid Derivatives. Due to the risk of developing pseudotumor cerebri (also known as intracranial hypertension), avoid this combination of drugs if possible. If used concomitantly, monitor for evidence of this interaction (eg, dizziness, diplopia, headache).

Drospirenone: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of drospirenone, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Ethynodiol Diacetate: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of ethynodiol diacetate it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Etonogestrel: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of etonogestrel, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Gemfibrozil: Gemfibrozil may increase the serum concentration of bexarotene. This combination should be avoided.

Levonorgestrel: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of levonorgestrel, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Medroxyprogesterone: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of medroxyprogesterone, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Minocycline: Tetracycline derivatives like minocycline may enhance the adverse/toxic effect of Retinoic Acid Derivatives. Due to the risk of developing pseudotumor cerebri (also known as intracranial hypertension), avoid this combination of drugs if possible. If used concomitantly, monitor for evidence of this interaction (eg, dizziness, diplopia, headache).

Norelgestromin: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of norelgestromin, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Norethindrone: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of norethindrone, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Norgestimate: Bexarotene may decrease the serum concentration of Contraceptives (Progestins). Since bexarotene is teratogenic and can lower serum concentrations of norgestimate, it is advised that women of childbearing potential use two forms of contraception (including at least one non-hormonal form).

Tetracycline: Tetracycline may enhance the adverse/toxic effect of Retinoic Acid Derivatives. Due to the risk of developing pseudotumor cerebri (also known as intracranial hypertension), avoid this combination of drugs if possible. If used concomitantly, monitor for evidence of this interaction (eg, dizziness, diplopia, headache).

Tigecycline: Tigecycline may enhance the adverse/toxic effect of Retinoic Acid Derivatives. The development of pseudotumor cerebri (intracranial hypertension) is of particular concern. Avoid this combination.

Vitamin A: Bexarotene increases the risk of vitamin A toxicity. Avoid vitamin A supplementation while taking bexarotene.