Bexarotene preferentially binds and activates RXR isoforms with Kd=14±2 nM, 21±4 nM and 29±7 nM for RXRα, RXRβ and RXRγ isoforms [1]. Bexarotene efficiently reduces the proliferation of leukemia (HL-60) cells. Bexarotene inhibits HL-60 cell proliferation by 37% at 1 μM [1]. Bexarotene treated cells as a single agent displayed anti-proliferative effects at high doses, with IC50s of 40.62±0.45 μM (PC3) and 50.20±4.10 μM (DU145) [2]. Bexarotene (20 and 40 μM) and Docetaxel (5 and 10 μM) show synergistic effects on the suppression of PC3 and DU145 cell growth [2]. Bexarotene (20 and 40 μM) suppresses cyclin D1 and cyclin D3 expression in PC3 and DU145 cells [2].

In a rat model of Parkinson's disease (PD), bexarotene (1 mg/kg/day) effectively prevents the development of behavioral deficits and dopamine neuron degeneration, thereby significantly reducing changes in serum T4 and triglycerides [1]. One medication that works well at stopping the development and spread of lung tumors is bexarotene. In mice of all three genotypes (p53wt/wtK-raswt/wt, p53val135/wtK-raswt/wt, or p53wt/wtK-rasko/wt), bexarotene (100?mg/kg by gavage) inhibits tumor diversity and tumor volume. Bexarotene decreased the progression of adenoma to adenocarcinoma in p53wt/wtK-rasko/wt by about 50%. and mice that were p53wt/wtK-raswt/wt [3].

Cell Proliferation Assay[2]
Cell Types: The human PCa androgen-independent cell lines PC3 and DU145
Tested Concentrations: 5, 10, 20, 30, 40 μM for PC3 cells; 1, 5, 10, 20, 40 μM for DU145 cells.
Incubation Duration: 24 and 48 hrs (hours)
Experimental Results: demonstrated an antiproliferative effect with the IC50s were 40.62±0.45 µM (PC3) and 50.20±4.10 µM (DU145).

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Cell Viability Assay[2]
Cell Types: PC3 and DU145 cells
Tested Concentrations: 20 and 40 µM
Incubation Duration: 24 or 48 hrs (hours)
Experimental Results: diminished cyclin D1, and cyclin E2 after 24 hrs (hours) treatment. Not only diminished the expression of cyclin D1 and cyclin E2 but repressed cyclin B1 and CDK1 expression after 48 hrs (hours) treatment.

Animal/Disease Models: UL53-3 mice (p53wt/wtK-raswt/wt, p53val135/wtK-raswt/wt, or p53wt/wtK-rasko/wt)[3]
Doses: 100 mg/kg
Route of Administration: Gavage with 18 gage of gavage -needle, 0.1 mL per mouse per day, 5 times a week, continued for 12 weeks
Experimental Results: Inhibited both tumor multiplicity and tumor volume in mice of all three genotypes.

Absorption, Distribution and Excretion
Urinary elimination of bexarotene and its known metabolites is a minor excretory pathway (<1% of administered dose).
After oral administration, bexarotene is absorbed with a Tmax of about two hours. ...Studies in patients with advanced malignancies show approximate single dose linearity within the therapeutic range and low accumulation with multiple doses. Plasma bexarotene AUC and Cmax values resulting from a 75 to 300 mg dose were 35% and 48% higher, respectively, after a fat-containing meal than after a glucose solution. Bexarotene is highly bound (>99%) to plasma proteins. The plasma proteins to which bexarotene binds have not been elucidated, and the ability of bexarotene to displace drugs bound to plasma proteins and the ability of drugs to displace bexarotene binding have not been studied.
The renal elimination of bexarotene and its metabolites was examined in patients with Type 2 diabetes mellitus. Neither bexarotene nor its metabolites were excreted in urine in appreciable amounts. Bexarotene is thought to be eliminated primarily through the hepatobiliary system.

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Metabolism / Metabolites
Four bexarotene metabolites have been identified in plasma: 6- and 7-hydroxy-bexarotene and 6- and 7-oxo-bexarotene. In vitro studies suggest that cytochrome P450 3A4 is the major cytochrome P450 responsible for formation of the oxidative metabolites and that the oxidative metabolites may be glucuronidated. The oxidative metabolites are active in in vitro assays of retinoid receptor activation, but the relative contribution of the parent and any metabolites to the efficacy and safety of /bexarotene/ is unknown.
Bexarotene has known human metabolites that include 6-hydroxy-bexarotene, 7-hydroxy-bexarotene, and 7-oxo-bexarotene.

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Biological Half-Life
7 hours
Terminal half-life of bexarotene is about seven hours.

Hepatotoxicity
Serum aminotransferase elevations occur in 5% of patients treated with bexarotene, but the abnormalities are generally mild, transient and not associated with symptoms or jaundice. However, cases of clinically apparent liver injury with jaundice have been reported with bexarotene therapy, some of which were severe and even fatal. Hepatotoxicity appears to be more common with higher doses. The clinical features of the hepatic injury with bexarotene have not been described in any detail and case reports of hepatotoxicity have yet to be published. Nevertheless, the product label mentions hepatotoxicity and recommends prospective monitoring of routine liver tests.
Likelihood score: D (possible but uncommon cause of clinically apparent liver injury).

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Protein Binding
>99%

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Interactions
Because bexarotene is metabolized by cytochrome P450 3A4, ketoconazole, itraconazole, erythromycin, gemfibrozil, grapefruit juice, and other inhibitors of cytochrome P450 3A4 would be expected to lead to an increase in plasma bexarotene concentrations. Furthermore, rifampin, phenytoin, phenobarbital and other inducers of cytochrome P450 3A4 may cause a reduction in plasma bexarotene concentrations.
Concomitant administration of /bexarotene/ capsules and gemfibrozil resulted in substantial increases in plasma concentrations of bexarotene, probably at least partially related to cytochrome P450 3A4 inhibition by gemfibrozil. Under similar conditions, bexarotene concentrations were not affected by concomitant atorvastatin administration. Concomitant administration of gemfibrozil with /bexarotene/ capsules is not recommended.
Based on interim data, concomitant administration of /bexarotene/ capsules and tamoxifen resulted in approximately a 35% decrease in plasma concentrations of tamoxifen, possibly through an induction of cytochrome P450 3A4. Based on this known interaction, bexarotene may theoretically increase the rate of metabolism and reduce plasma concentrations of other substrates metabolized by cytochrome P450 3A4, including oral or other systemic hormonal contraceptives.
Leukopenic and/or thrombocytopenic effects of bexarotene may be increased with concurrent or recent therapy /with blood dycrasia-causing medications/ if these medications cause the same effects; dosage adjustment of the bone marrow depressant, if necessary, should be based on blood counts.
For more Interactions (Complete) data for BEXAROTENE (10 total), please visit the HSDB record page.

[1]. A review of the molecular design and biological activities of RXR agonists. Med Res Rev. 2019 Jul;39(4):1372-1397.

[2]. Synergistic effect of a retinoid X receptor-selective ligand bexarotene and docetaxel in prostate cancer. Onco Targets Ther. 2019 Sep 24;12:7877-7886.

[3]. Prevention of lung cancer progression by bexarotene in mouse models. Oncogene. 2006 Mar 2;25(9):1320-9.

Bexarotene is a retinoid, a member of benzoic acids and a member of naphthalenes. It has a role as an antineoplastic agent.
Bexarotene (Targretin) is an 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.
Bexarotene is a Retinoid.
Bexarotene is a retinoid analogue that is used to treat the skin manifestations of cutaneous T cell lymphoma (CTCL). Bexarotene therapy is associated with a high rate of serum enzyme elevations and rare instances of clinically apparent acute liver injury.
Bexarotene is a synthetic retinoic acid agent with potential antineoplastic, chemopreventive, teratogenic and embryotoxic properties. Bexarotene selectively binds to and activates retinoid X receptors (RXRs), thereby inducing changes in gene expression that lead to cell differentiation, decreased cell proliferation, apoptosis of some cancer cell types, and tumor regression. (NCI04)
A rexinoid (an RXR-binding ligand), tetrahydronaphthalene derivative and RETINOID X RECEPTOR antagonist that is used in the treatment of CUTANEOUS T-CELL LYMPHOMA.

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Drug 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.
FDA Label
Targretin capsules are indicated for the treatment of skin manifestations of advanced stage cutaneous T-cell lymphoma (CTCL) patients refractory to at least one systemic treatment.

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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.
Bexarotene selectively binds and activates retinoid X receptor subtypes (RXR(alpha), RXR(beta), RXR(gamma)). 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. The exact mechanism of action of bexarotene in the treatment of cutaneous T-cell lymphoma (CTCL) is unknown.

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Therapeutic Uses
THERAP CAT: Antineoplastic
Bexarotene is indicated for the treatment of cutaneous manifestations of cutaneous T-cell lyphoma in patients who are refractory to at least one other prior systemic therapy. /Included in US product label/

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Drug Warnings
May cause fetal harm; teratogenicity and embryolethality demonstrated in animals. No adequate and well-controlled studies to date in humans. Pregnancy should be avoided during therapy. If used during pregnancy, apprise of potential fetal hazard. ... Male patients receiving the drug should use condoms during sexual intercourse with women who are or may become pregnant.
Effective contraception must be used for one month prior to the initiation of therapy, during therapy and for at least one month following discontinuation of therapy; it is recommended that two reliable forms of contraception be used simultaneously unless abstinence is the chosen method. Bexarotene can potentially induce metabolic enzymes and thereby theoretically reduce the plasma concentrations of oral or other systemic hormonal contraceptives.
Hyperlipidemia occurred in 79% of patients receiving oral bexarotene in phase II-III clinical studies. Elevations in fasting triglycerides and cholesterol and decreases in HDL-cholesterol were observed in more than half of patients receiving 300 mg/sq m or more. Lipid abnormalities usually developed within 2-4 weeks and were reversible with cessation of therapy. If fasting triglycerides are elevated or become elevated during treatment, antilipemic therapy should be instituted, and the dosage of bexarotene reduced or suspended.
Acute pancreatitis has been reported in several patients treated with bexarotene and has been fatal in at least one patient. The manufacturer states that patients with cutaneous T-cell lymphoma (CTCL) who have risk factors for pancreatitis (eg, prior pancreatitis, uncontrolled hyperlipidemia, excessive alcohol consumption, uncontrolled diabetes mellitus, biliary tract disease, or drugs associated with pancreatic toxicity or known to increase triglyceride concentrations) generally should not be treated with bexarotene.
For more Drug Warnings (Complete) data for BEXAROTENE (15 total), please visit the HSDB record page.

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Pharmacodynamics
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.

C24H28O2

348

348.208

153559-49-0

Bexarotene-d4;2182068-00-2

82146

White to off-white solid powder

1.0±0.1 g/cm3

489.7±44.0 °C at 760 mmHg

230-231ºC

229.5±23.1 °C

0.0±1.3 mmHg at 25°C

1.556

8.55

1

2

3

26

551

0

NAVMQTYZDKMPEU-UHFFFAOYSA-N

InChI=1S/C24H28O2/c1-15-13-20-21(24(5,6)12-11-23(20,3)4)14-19(15)16(2)17-7-9-18(10-8-17)22(25)26/h7-10,13-14H,2,11-12H2,1,3-6H3,(H,25,26)

4-[1-(3,5,5,8,8-pentamethyl-6,7-dihydronaphthalen-2-yl)ethenyl]benzoic acid

LGD1069; LGD 1069; LG 100069; Ro26-445; LGD-1069; SR-11247; Ro 26 445; Targretin Ro 26-445; SR 11247; SR11247; 3-methyl TTNEB. Bexarotene; US trade name: Targretin.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: 2.62 mg/mL (7.52 mM) in 5% DMSO + 40% PEG300 + 5% Tween80 + 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with sonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: 2.62 mg/mL (7.52 mM) in 5% DMSO + 95% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (5.97 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 4: ≥ 2.08 mg/mL (5.97 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 5: ≥ 2.08 mg/mL (5.97 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)