Targretin® (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). Each soft gelatin capsule for oral administration contains 75 mg of bexarotene.

The chemical name is 4-[1-(5,6,7,8-tetrahydro-3,5,5,8,8-pentamethyl-2-naphthalenyl) ethenyl] benzoic acid, and the structural formula is as follows:

Bexarotene is an off-white to white powder with a molecular weight of 348.48 and a molecular formula of C₂₄H₂₈O₂. It is insoluble in water and slightly soluble in vegetable oils and ethanol, USP.

Each Targretin® (bexarotene) capsule also contains the following inactive ingredients: polyethylene glycol 400, NF, polysorbate 20, NF, povidone, USP, and butylated hydroxyanisole, NF. The capsule shell contains gelatin, NF, sorbitol special-glycerin blend, and titanium dioxide, USP.

Last updated on RxList: 9/19/2008

Targretin® (bexarotene) capsules are indicated for the treatment of cutaneous manifestations of cutaneous T-cell lymphoma in patients who are refractory to at least one prior systemic therapy.

The recommended initial dose of Targretin® capsules is 300 mg/m²/day. (See Table 4.) Targretin® capsules should be taken as a single oral daily dose with a meal. See CONTRAINDICATIONS: Pregnancy Category X section for precautions to prevent pregnancy and birth defects in women of child-bearing potential.

Table 4. Targretin® Capsule Initial Dose Calculation According to Body Surface Area

Dose Modification Guidelines: The 300 mg/m²/day dose level of Targretin® capsules may be adjusted to 200 mg/m²/day then to 100 mg/m²/day, or temporarily suspended, if necessitated by toxicity. When toxicity is controlled, doses may be carefully readjusted upward. If there is no tumor response after eight weeks of treatment and if the initial dose of 300 mg/m²/day is well tolerated, the dose may be escalated to 400 mg/m²/day with careful monitoring.

Duration of Therapy: In clinical trials in CTCL, Targretin® capsules were administered for up to 97 weeks.

Targretin® capsules should be continued as long as the patient is deriving benefit.

Targretin® capsules are supplied as 75-mg off-white, oblong soft gelatin capsules, imprinted with "Targretin®," in high density polyethylene bottles with child-resistant closures.

Bottles of 100 capsules................................................................NDC 64365-502-01

Store at 2°-25°C (36°-77°F). Avoid exposing to high temperatures and humidity after the bottle is opened. Protect from light.

Manufactured for: Ligand Pharmaceuticals Incorporated, San Diego, CA 92121 by: R.P. Scherer St. Petersburg, FL 33716. FDA rev date: 4/21/2003

Last updated on RxList: 9/19/2008

The safety of Targretin® capsules has been evaluated in clinical studies of 152 patients with CTCL who received Targretin® capsules for up to 97 weeks and in 352 patients in other studies. The mean duration of therapy for the 152 patients with CTCL was 166 days. The most common adverse events reported with an incidence of at least 10% in patients with CTCL treated at an initial dose of 300 mg/m²/day of Targretin® capsules are shown in Table 1. The events at least possibly related to treatment are lipid abnormalities (elevated triglycerides, elevated total and LDL cholesterol and decreased HDL cholesterol), hypothyroidism, headache, asthenia, rash, leukopenia, anemia, nausea, infection, peripheral edema, abdominal pain, and dry skin. Most adverse events occurred at a higher incidence in patients treated at starting doses of greater than 300 mg/m²/day (see Table 1).

Adverse events leading to dose reduction or study drug discontinuation in at least two patients were hyperlipemia, neutropenia/leukopenia, diarrhea, fatigue/lethargy, hypothyroidism, headache, liver function test abnormalities, rash, pancreatitis, nausea, anemia, allergic reaction, muscle spasm, pneumonia, and confusion.

The moderately severe (NCI Grade 3) and severe (NCI Grade 4) adverse events reported in two or more patients with CTCL treated at an initial dose of 300 mg/m²/day of Targretin® capsules (see Table 2) were hypertriglyceridemia, pruritus, headache, peripheral edema, leukopenia, rash, and hypercholesteremia. Most of these moderately severe or severe adverse events occurred at a higher rate in patients treated at starting doses of greater than 300 mg/m²/day than in patients treated at a starting dose of 300 mg/m²/day.

As shown in Table 3, in patients with CTCL receiving an initial dose of 300 mg/m²/day, the incidence of NCI Grade 3 or 4 elevations in triglycerides and total cholesterol was 28% and 25%, respectively. In contrast, in patients with CTCL receiving greater than 300 mg/m²/day, the incidence of NCI Grade 3 or 4 elevated triglycerides and total cholesterol was 45% and 45%, respectively. Other Grade 3 and 4 laboratory abnormalities are shown in Table 3.

In addition to the 152 patients enrolled in the two CTCL studies, 352 patients received Targretin® capsules as monotherapy for various advanced malignancies at doses from 5 mg/m²/day to 1000 mg/m²/day. The common adverse events (incidence greater than 10%) were similar to those seen in CTCL.

In the 504 patients (CTCL and non-CTCL) who received Targretin® capsules as monotherapy, drug-related serious adverse events that were fatal in one patient each, were acute pancreatitis, subdural hematoma, and liver failure.

In the patients with CTCL receiving an initial dose of 300 mg/m²/day of Targretin® capsules, adverse events reported at an incidence of less than 10%, and not included in Tables 1-3 or discussed in other parts of labeling and possibly related to treatment were as follows:

Body as a Whole: chills, cellulitis, chest pain, sepsis, and monilia.

Cardiovascular: hemorrhage, hypertension, angina pectoris, right heart failure, syncope, and tachycardia.

Digestive: constipation, dry mouth, flatulence, colitis, dyspepsia, cheilitis, gastroenteritis, gingivitis, liver failure, and melena.

Hematic and Lymphatic: eosinophilia, thrombocythemia, coagulation time increased, lymphocytosis, and thrombocytopenia.

Metabolic and Nutritional: LDH increased, creatinine increased, hypoproteinemia, hyperglycemia, weight decreased, weight increased, and amylase increased.

Musculoskeletal: arthralgia, myalgia, bone pain, myasthenia, and arthrosis.

Nervous: depression, agitation, ataxia, cerebrovascular accident, confusion, dizziness, hyperesthesia, hypesthesia, and neuropathy.

Respiratory: pharyngitis, rhinitis, dyspnea, pleural effusion, bronchitis, cough increased, lung edema, hemoptysis, and hypoxia.

Skin and Appendages: skin ulcer, acne, alopecia, skin nodule, macular papular rash, pustular rash, serous drainage, and vesicular bullous rash.

Special Senses: dry eyes, conjunctivitis, ear pain, blepharitis, corneal lesion, keratitis, otitis externa, and visual field defect.

Urogenital: albuminuria, hematuria, urinary incontinence, urinary tract infection, urinary urgency, dysuria, kidney function abnormal, and breast pain.

Table 1. Adverse Events with Incidence ≥ 10% in CTCL Trials

Table 2. Incidence of Moderately Severe and Severe Adverse Events Reported in at Least Two Patients (CTCL Trials)

Table 3. Treatment-Emergent Abnormal Laboratory Values in CTCL Trials

Drug-Food Interaction

In all clinical trials, patients were instructed to take Targretin® capsules with or immediately following a meal. In one clinical study, plasma bexarotene AUC and Cmax values were substantially higher following a fat-containing meal versus those following the administration of a glucose solution. Because safety and efficacy data are based upon administration with food, it is recommended that Targretin® capsules be administered with food (see CLINICAL PHARMACOLOGY: Food Effects and DOSAGE AND ADMINISTRATION).

Drug-Drug Interactions

No formal studies to evaluate drug interactions with bexarotene have been conducted. Bexarotene oxidative metabolites appear to be formed by cytochrome P450 3A4.

On the basis of the metabolism of bexarotene 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 Targretin® 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 Targretin® capsules is not recommended.

Based on interim data, concomitant administration of Targretin® 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 hormone contraceptives (see CLINICAL PHARMACOLOGY: Drug-Drug Interactions and CONTRAINDICATIONS: Pregnancy: Category X). Thus, if treatment with Targretin® capsules is intended in woman with child-bearing potential, it is strongly recommended that two reliable forms of contraception be used concurrently, one of which should be non-hormonal.

Renal Insufficiency

No formal studies have been conducted with Targretin® capsules in patients with renal insufficiency. Urinary elimination of bexarotene and its known metabolites is a minor excretory pathway for bexarotene (<1% of administered dose), but because renal insufficiency can result in significant protein binding changes, and bexarotene is >99% protein bound, pharmacokinetics may be altered in patients with renal insufficiency.

Protein Binding

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.

Drug/Laboratory Test Interactions

CA125 assay values in patients with ovarian cancer may be increased by Targretin® capsule therapy.

Last updated on RxList: 9/19/2008

Lipid abnormalities: Targretin® capsules induce major lipid abnormalities in most patients. These must be monitored and treated during long term therapy. About 70% of patients with CTCL who received an initial dose of ≥ 300 mg/m²/day of Targretin® capsules had fasting triglyceride levels greater than 2.5 times the upper limit of normal. About 55% had values over 800 mg/dL with a median of about 1200 mg/dL in those patients. Cholesterol elevations above 300 mg/dL occurred in approximately 60% and 75% of patients with CTCL who received an initial dose of 300 mg/m²/day or greater than 300 mg/m²/day, respectively. Decreases in high density lipoprotein (HDL) cholesterol to less than 25 mg/dL were seen in about 55% and 90% of patients receiving an initial dose of 300 mg/m²/day or greater than 300 mg/m²/day, respectively, of Targretin® capsules. The effects on triglycerides, HDL cholesterol, and total cholesterol were reversible with cessation of therapy, and could generally be mitigated by dose reduction or concomitant antilipemic therapy.

Fasting blood lipid determinations should be performed before Targretin® capsules therapy is initiated and weekly until the lipid response to Targretin® capsules is established, which usually occurs within two to four weeks, and at eight week intervals thereafter. Fasting triglycerides should be normal or normalized with appropriate intervention prior to initiating Targretin® capsules therapy. Attempts should be made to maintain triglyceride levels below 400 mg/dL to reduce the risk of clinical sequelae (see WARNINGS: Pancreatitis). If fasting triglycerides are elevated or become elevated during treatment, antilipemic therapy should be instituted, and if necessary, the dose of Targretin® capsules reduced or suspended. In the 300 mg/m²/day initial dose group, 60% of patients were given lipid lowering drugs. Atorvastatin was used in 48% (73/152) of patients with CTCL. Because of a potential drug-drug interaction (see PRECAUTIONS: Drug-Drug Interactions), gemfibrozil is not recommended for use with Targretin® capsules.

Pancreatitis: Acute pancreatitis has been reported in four patients with CTCL and in six patients with non-CTCL cancers treated with Targretin® capsules; the cases were associated with marked elevations of fasting serum triglycerides, the lowest being 770 mg/dL in one patient. One patient with advanced non-CTCL cancer died of pancreatitis. Patients with CTCL who have risk factors for pancreatitis (e.g., prior pancreatitis, uncontrolled hyperlipidemia, excessive alcohol consumption, uncontrolled diabetes mellitus, biliary tract disease, and medications known to increase triglyceride levels or to be associated with pancreatic toxicity) should generally not be treated with Targretin® capsules (see WARNINGS: Lipids abnormalities and PRECAUTIONS: Laboratory Tests).

Liver function test abnormalities: For patients with CTCL receiving an initial dose level of 300 mg/m²/day of Targretin® capsules, elevations in liver function tests (LFTs) have been observed in 5% (SGOT/AST), 2% (SGPT/ALT), and 0% (bilirubin). In contrast, with an initial dose greater than 300 mg/m²/day of Targretin® capsules, the incidence of LFT elevations was higher at 7% (SGOT/AST), 9% (SGPT/ALT), and 6% (bilirubin). Two patients developed cholestasis, including one patient who died of liver failure. In clinical trials, elevation of LFTs resolved within one month in 80% of patients following a decrease in dose or discontinuation of therapy. Baseline LFTs should be obtained, and LFTs should be carefully monitored after one, two and four weeks of treatment initiation, and if stable, at least every eight weeks thereafter during treatment. Consideration should be given to a suspension or discontinuation of Targretin® capsules if test results reach greater than three times the upper limit of normal values for SGOT/AST, SGPT/ALT, or bilirubin.

Hepatic Insufficiency: No specific studies have been conducted with Targretin® capsules in patients with hepatic insufficiency. Because less than 1% of the dose is excreted in the urine unchanged and there is in vitro evidence of extensive hepatic contribution to bexarotene elimination, hepatic impairment would be expected to lead to greatly decreased clearance. Targretin® capsules should be used only with great caution in this population.

Thyroid axis alterations: Targretin® capsules induce biochemical evidence of or clinical hypothyroidism in about half of all patients treated, causing a reversible reduction in thyroid hormone (total thyroxine [total T4]) and thyroid-stimulating hormone (TSH) levels. The incidence of decreases in TSH and total T4 about 60% and 45%, respectively, in patients with CTCL receiving an initial dose of 300 mg/m²/day. Hypothyroidism was reported as an adverse event in 29% of patients. Treatment with thyroid hormone supplements should be considered in patients with laboratory evidence of hypothyroidism. In the 300 mg/m²/day initial dose group, 37% of patients were treated with thyroid hormone replacement. Baseline thyroid function tests should be obtained and patients monitored during treatment.

Leukopenia: A total of 18% of patients with CTCL receiving an initial dose of 300 mg/m²/day of Targretin® capsules had reversible leukopenia in the range of 1000 to <3000 WBC/mm³. Patients receiving an initial dose greater than 300 mg/m²/day of Targretin® capsules had an incidence of leukopenia of 43%. No patient with CTCL treated with Targretin® capsules developed leukopenia of less than 1000 WBC/mm³. The time to onset of leukopenia was generally four to eight weeks. The leukopenia observed in most patients was explained by neutropenia. In the 300 mg/m²/day initial dose group, the incidence of NCI Grade 3 and Grade 4 neutropenia, respectively, was 12% and 4%. The leukopenia and neutropenia experienced during Targretin® capsules therapy resolved after dose reduction or discontinuation of treatment, on average within 30 days in 93% of the patients with CTCL and 82% of patients with non-CTCL cancers. Leukopenia and neutropenia were rarely associated with severe sequelae or serious adverse events. Determination of WBC with differential should be obtained at baseline and periodically during treatment.

Cataracts:Posterior subcapsular cataracts were observed in preclinical toxicity studies in rats and dogs administered bexarotene daily for 6 months. In 15 of 79 patients who had serial slit lamp examinations, new cataracts or worsening of previous cataracts were found. Because of the high prevalence and rate of cataract formation in older patient populations, the relationship of Targretin® capsules and cataracts cannot be determined in the absence of an appropriate control group. Patients treated with Targretin® capsules who experience visual difficulties should have an appropriate ophthalmologic evaluation.

Pregnancy: Category X. See CONTRAINDICATIONS.

General: Targretin® capsules should be used with caution in patients with a known hypersensitivity to retinoids. Clinical instances of cross reactivity have not been noted.

Vitamin A Supplementation: In clinical studies, patients were advised to limit vitamin A intake to ≤ 15,000 IU/day. Because of the relationship of bexarotene to vitamin A, patients should be advised to limit vitamin A supplements to avoid potential additive toxic effects.

Patients with Diabetes Mellitus: Caution should be used when administering Targretin® capsules in patients using insulin, agents enhancing insulin secretion (e.g., sulfonylureas), or insulin-sensitizers (e.g., troglitazone). Based on the mechanism of action, Targretin® capsules could enhance the action of these agents, resulting in hypoglycemia. Hypoglycemia has not been associated with the use of Targretin® capsules as monotherapy.

Photosensitivity: Retinoids as a class have been associated with photosensitivity.In vitro assays indicate that bexarotene is a potential photosensitizing agent. Mild phototoxicity manifested as sunburn and skin sensitivity to sunlight was observed in patients who were exposed to direct sunlight while receiving Targretin® capsules. Patients should be advised to minimize exposure to sunlight and artificial ultraviolet light while receiving Targretin® capsules.

Laboratory Tests

Blood lipid determinations should be performed before Targretin® capsules are given. Fasting triglycerides should be normal or normalized with appropriate intervention prior to therapy. Hyperlipidemia usually occurs within the initial two to four weeks. Therefore, weekly lipid determinations are recommended during this interval. Subsequently, in patients not hyperlipidemic, determinations can be performed less frequently (see WARNINGS: Lipid abnormalities).

A white blood cell count with differential should be obtained at baseline and periodically during treatment. Baseline liver function tests should be obtained and should be carefully monitored after one, two and four weeks of treatment initiation, and if stable, periodically thereafter during treatment. Baseline thyroid function tests should be obtained and then monitored during treatment as indicated (see WARNINGS: Leukopenia, Liver function test abnormalities, and Thyroid axis alterations).

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term studies in animals to assess the carcinogenic potential of bexarotene have not been conducted. Bexarotene is not mutagenic to bacteria (Ames assay) or mammalian cells (mouse lymphoma assay). Bexarotene was not clastogenic in vivo (micronucleus test in mice). No formal fertility studies were conducted with bexarotene. Bexarotene caused testicular degeneration when oral doses of 1.5 mg/kg/day were given to dogs for 91 days (producing an AUC of approximately one fifth the AUC at the recommended human daily dose).

Use in Nursing Mothers

It is not known whether bexarotene is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from bexarotene, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Use

Safety and effectiveness in pediatric patients have not been established.

Geriatric Use

Of the total patients with CTCL in clinical studies of Targretin® capsules, 64% were 60 years or older, while 33% were 70 years or older. No overall differences in safety were observed between patients 70 years or older and younger patients, but greater sensitivity of some older individuals to Targretin® capsules cannot be ruled out. Responses to Targretin® capsules were observed across all age group decades, without preference for any individual age group decade.

Last updated on RxList: 9/19/2008

Doses up to 1000 mg/m²/day of Targretin® capsules have been administered in short-term studies in patients with advanced cancer without acute toxic effects. Single doses of 1500 mg/kg and 720 mg/kg were tolerated without significant toxicity in rats and dogs, respectively. These doses are approximately 30 and 50 times, respectively, the recommended human dose on a mg/m² basis.

No clinical experience with an overdose of Targretin® capsules has been reported. Any overdose with Targretin® capsules should be treated with supportive care for the signs and symptoms exhibited by the patient.

Targretin® capsules are contraindicated in patients with a known hypersensitivity to bexarotene or other components of the product.

Pregnancy: Category X

Targretin® (bexarotene) capsules may cause fetal harm when administered to a pregnant woman. Targretin® capsules must not be given to a pregnant woman or a woman who intends to become pregnant. If a woman becomes pregnant while taking Targretin® capsules, Targretin® capsules must be stopped immediately and the woman given appropriate counseling.

Bexarotene caused malformations when administered orally to pregnant rats during days 7-17 of gestation. Developmental abnormalities included incomplete ossification at 4 mg/kg/day and cleft palate, depressed eye bulge/microphthalmia, and small ears at 16 mg/kg/day. The plasma AUC of bexarotene in rats at 4 mg/kg/day is approximately one third the AUC in humans at the recommended daily dose. At doses greater than 10 mg/kg/day, bexarotene caused developmental mortality. The no effect dose for fetal effects in rats was 1 mg/kg/day (producing an AUC approximately one sixth of the AUC at the recommended human daily dose).

Women of child-bearing potential should be advised to avoid becoming pregnant when Targretin® capsules are used. The possibility that a woman of child-bearing potential is pregnant at the time therapy is instituted should be considered. A negative pregnancy test (e.g., serum beta-human chorionic gonadotropin, beta-HCG) with a sensitivity of at least 50 mlU/L should be obtained within one week prior to Targretin® capsules therapy, and the pregnancy test must be repeated at monthly intervals while the patient remains on Targretin® capsules. 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 (see CLINICAL PHARMACOLOGY: Drug-Drug Interactions and PRECAUTIONS: Drug-Drug Interactions). Thus, if treatment with Targretin® capsules is intended in a woman with child-bearing potential, it is strongly recommended that one of the two reliable forms of contraception should be non-hormonal. Male patients with sexual partners who are pregnant, possibly pregnant, or who could become pregnant must use condoms during sexual intercourse while taking Targretin® capsules and for at least one month after the last dose of drug. Targretin® capsules therapy should be initiated on the second or third day of a normal menstrual period. No more than a one month supply of Targretin® capsules should be given to the patient so that the results of pregnancy testing can be assessed and counseling regarding avoidance of pregnancy and birth defects can be reinforced.

Last updated on RxList: 9/19/2008

Mechanism of Action

Bexarotene selectively binds and activates retinoid X receptor subtypes (RXRα, RXRβ, RXRγ). 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.

Pharmacokinetics

General

After oral administration of Targretin® capsules, bexarotene is absorbed with a Tmax of

about two hours. Terminal half-life of bexarotene is about seven 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 300 mg dose were 35% and 48% higher, respectively, after a fat-containing meal than after a glucose solution (see PRECAUTIONS: Drug-Food Interaction and DOSAGE AND ADMINISTRATION). 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 (see PRECAUTIONS: Protein Binding). The uptake of bexarotene by organs or tissues has not been evaluated.

Metabolism

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 Targretin® capsules is unknown.

Elimination

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.

Special Populations

Elderly: Bexarotene Cmax and AUC were similar in advanced cancer patients <60 years old and in patients >60 years old, including a subset of patients >70 years old.

Pediatric: Studies to evaluate bexarotene pharmacokinetics in the pediatric population have not been conducted (see PRECAUTIONS: Pediatric Use).

Gender: The pharmacokinetics of bexarotene were similar in male and female patients with advanced cancer.

Ethnic Origin: The effect of ethnic origin on bexarotene pharmacokinetics is unknown.

Renal Insufficiency: No formal studies have been conducted with Targretin® capsules in patients with renal insufficiency. Urinary elimination of bexarotene and its known metabolites is a minor excretory pathway (<1% of administered dose), but because renal insufficiency can result in significant protein binding changes, pharmacokinetics may be altered in patients with renal insufficiency (see PRECAUTIONS: Renal Insufficiency).

Hepatic Insufficiency: No specific studies have been conducted with Targretin® capsules in patients with hepatic insufficiency. Because less than 1% of the dose is excreted in the urine unchanged and there is in vitro evidence of extensive hepatic contribution to bexarotene elimination, hepatic impairment would be expected to lead to greatly decreased clearance (see WARNINGS: Hepatic Insufficiency).

Drug-Drug Interactions

No specific studies to evaluate drug interactions with bexarotene have been conducted. Bexarotene oxidative metabolites appear to be formed by cytochrome P450 3A4.

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 Targretin® 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 Targretin® capsules is not recommended (see PRECAUTIONS: Drug-Drug Interactions).

Based on interim data, concomitant administration of Targretin® 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, including oral or other systemic hormonal contraceptives (see CONTRAINDICATIONS: Pregnancy: Category X and PRECAUTIONS: Drug-Drug Interactions).

Clinical Studies

Targretin® capsules were evaluated in 152 patients with advanced and early stage cutaneous T-cell lymphoma (CTCL) in two multicenter, open-label, historically-controlled clinical studies conducted in the U.S., Canada, Europe, and Australia.

The advanced disease patients had disease refractory to at least one prior systemic therapy (median of two, range one to six prior systemic therapies) and had been treated with a median of five (range 1 to 11) prior systemic, irradiation, and/or topical therapies. Early disease patients were intolerant to, had disease that was refractory to, or had reached a response plateau of six months on, at least two prior therapies. The patients entered had been treated with a median of 3.5 (range 2 to 12) therapies (systemic, radiation, and/or topical).

The two clinical studies enrolled a total of 152 patients, 102 of whom had disease refractory to at least one prior systemic therapy, 90 with advanced disease and 12 with early disease. This is the patient population for whom Targretin® capsules are indicated.

Patients were initially treated with a starting dose of 650 mg/m²/day with a subsequent reduction of starting dose to 500 mg/m²/day. Neither of these starting doses was tolerated, and the starting dose was then reduced to 300 mg/m²/day. If, however, a patient on 300 mg/m²/day of Targretin® capsules showed no response after eight or more weeks of therapy, the dose could be increased to 400 mg/m²/day.

Tumor response was assessed in both studies by observation of up to five baseline-defined index lesions using a Composite Assessment of Index Lesion Disease Severity (CA). This endpoint was based on a summation of the grades, for all index lesions, of erythema, scaling, plaque elevation, hypopigmentation or hyperpigmentation, and area of involvement. Also considered in response assessment was the presence or absence of cutaneous tumors and extracutaneous disease manifestations.

All tumor responses required confirmation over at least two assessments separated by at least four weeks. A partial response was defined as an improvement of at least 50% in the index lesions without worsening, or development of new cutaneous tumors or non-cutaneous manifestations. A complete clinical response required complete disappearance of all manifestations of disease, but did not require confirmation by biopsy.

At the initial dose of 300 mg/m²/day, 1/62 (1.6%) of patients had a complete clinical tumor response and 19/62 (30%) of patients had a partial tumor response. The rate of relapse (25% increase in CA or worsening of other aspects of disease) in the 20 patients who had a tumor response was 6/20 (30%) over a median duration of observation of 21 weeks, and the median duration of tumor response had not been reached. Responses were seen as early as 4 weeks and new responses continued to be seen at later visits.

Last updated on RxList: 9/19/2008

Targretin®
(bexarotene) capsules, 75 mg

Patient's Instructions for Use

To help you get the full benefits from this medicine, you should read this leaflet carefully and ask your doctor to explain anything you do not understand.

What are the most important things I should know about Targretin® capsules?

• Targretin® capsules can cause major damage to a fetus. Pregnancy must be avoided in patients receiving Targretin® capsules.
• Targretin® capsules can greatly increase blood levels of lipids (triglycerides and cholesterol) and these levels must be monitored and, if elevated, treated.
• Targretin® capsules can cause an underactive thyroid and periodic blood tests will be needed to detect this. Medication to control the condition may be necessary.

What are Targretin® capsules?

Targretin® (tar-GRET-in) capsules contain bexarotene (beks-AIR-oh-teen). Targretin® capsules belong to a class of medicines known as retinoids. Each off-white, oblong soft gelatin Targretin® capsule contains 75 mg of bexarotene. Each capsule is imprinted with the name "Targretin®" in blue.

What are the uses for Targretin® capsules?

This medicine is used to treat the skin problems arising from a disease called cutaneous T-cell lymphoma, or CTCL. Your doctor must supervise the use of Targretin® capsules.

Do not take Targretin® capsules if you are allergic to this medicine.

If you have any of the following conditions, make sure you have discussed them with your doctor before you start to take this medicine.

• You are pregnant or think you may be pregnant.
• You have or previously had an inflamed pancreas (pancreatitis).
• You are breastfeeding.
• You are taking gemfibrozil (Lopid )*, a medication to reduce high triglyceride and cholesterol (fats) levels in the blood.
• You are taking tamoxifen (Nolvadex )^†.

Medical conditions you should tell your doctor about.

• If you are allergic to retinoid medications (for example: Accutane [isotretinoin], Soriatane [acitretin], Tegison [etretinate], Vesinoid [tretinoin]) t.
• If you have or ever had high triglyceride (a fatty substance) levels in your blood.
• If you have diabetes mellitus (sugar diabetes).
• If you have a history of or currently have gall bladder disease.
• If you have or have had any liver disease.
• If you regularly drink more than a small amount of alcohol.
• If you are currently taking any prescription medication especially for fungal infections, bacterial infections, or seizures.
• If you eat a lot of grapefruit or drink a lot of grapefruit juice.

When should you be extra careful while taking Targretin® capsules?

• Because vitamin A in large doses may cause some side effects which are similar to those seen in patients taking Targretin® capsules, do not take more than the recommended daily dietary allowance of vitamin A (4000 to 5000 International Units). If you take vitamins, check the label to see how much vitamin A they contain. If you are not sure, ask your doctor or pharmacist.
• Your skin may become more sensitive to sunlight while taking this medicine. Minimize exposure to sunlight and do not use a sunlamp.

How should Targretin® capsules be taken?

• Always take Targretin® capsules the way your doctor tells you.
• Your doctor will tell you how many Targretin® capsules to take each day. You should take your daily dose of Targretin® capsules all at once. It is best to take them once each day with or immediately following a meal. For example, you might always take your daily amount of Targretin® capsules with your evening meal.
• Always swallow each capsule whole: do not chew them or dissolve them in liquid or in your mouth. Depending on your health and condition, your doctor may change your daily dose (the number of capsules you are taking) during your treatment.
• If you miss a dose, take it as soon as possible, with food. However, if it is nearly time for your next dose, skip the missed dose and continue your dose schedule as before. Do not take a double dose.
• If you take too many Targretin® capsules or someone else accidentally takes your medicine, contact your doctor, emergency room or the nearest hospital immediately.

How long before you can expect your CTCL to improve on Targretin® capsule treatment?

• Although some patients saw improvement within the first several weeks of Targretin® capsule treatment, most patients required several months or more of treatment to improve.
• Your doctor should determine how long you should be taking Targretin® capsules, and when treatment may be stopped.

What side effects do Targretin® capsules have?

The most common side effect is an increase in blood lipids (fats in the blood). Periodic blood tests will be needed to determine blood levels of lipids, including triglycerides and cholesterol. Medication may be needed to control high fat levels in the blood.

Another common side effect is underactive thyroid. The symptoms of underactive thyroid may be difficult to detect because they may develop very gradually and may be very mild. For example, you may begin to feel always tired, low on energy, or feeling unusually cold all the time. A thyroid hormone medication is readily available to fully control these temporary symptoms, so contact your doctor early if you feel you are beginning to experience any of these symptoms. Periodic blood tests will be needed to detect this.

When should you call your doctor about possible complications of Targretin® capsule treatment?

As an infrequent side effect of Targretin® capsule treatment, pancreatitis (inflamed pancreas) may occur. Symptoms of pancreatitis include persistent nausea, vomiting, and abdominal or back pain. If you develop any of these symptoms while taking Targretin® capsules, contact your doctor immediately.

All medications have side effects. You should call your physician regarding any questions or concerns you may have when taking Targretin® capsules.

How should Targretin® capsules be stored?

• The capsules should be stored in a dry place in a closed container, away from light and heat, at room temperature.
• The capsules should not be used after the expiration date printed on the bottle.
• Keep this medicine out of the reach and sight of children.

If Targretin® capsules are broken or leaking, do not touch the capsules or the contents and notify your pharmacist immediately. Should the contents of a broken capsule get on your skin, immediately wash the area with soap and water and notify your physician.

Further Information

• You can get more information on Targretin® capsules from your doctor or pharmacist.

* Lopsid (gemfibrozil tablets, USP) is a registered trademark of Parke-Davis, Division of Warner-Lambert Co.
^†Nolvadex (tamoxifen citrate) is a registered trademark of AstraZeneca LP.
‡ Accutane (isotretinoin) is a registered trademark of Roche Pharmaceuticals, Roche Laboratories Inc.
‡ Soriatane (acitretin) is a registered trademark of Roche Pharmaceuticals, Roche Laboratories Inc.
‡ Tegison (etretinate) is a registered trademark of Roche Pharmaceuticals, Roche Laboratories Inc.
‡ Vesanoid (tretinoin) is a registered trademark of Roche Pharmaceuticals, Roche Laboratories Inc.

Last updated on RxList: 9/19/2008

IMPORTANT NOTE: This is a summary and does not contain all possible information about this product. For complete information about this product or your specific health needs, ask your health care professional. Always seek the advice of your health care professional if you have any questions about this product or your medical condition. This information is not intended as individual medical advice and does not substitute for the knowledge and judgment of your health care professional. This information does not contain any assurances that this product is safe, effective, or appropriate for you.

BEXAROTENE - ORAL

(bex-ER-oh-teen)

COMMON BRAND NAME(S): Targretin

WARNING: This medication can cause severe birth defects if used during pregnancy. Women who are pregnant must not use bexarotene. If pregnancy occurs, notify your doctor immediately. You should have a pregnancy test and birth control counseling from your doctor before you start treatment with bexarotene and every month while you are taking the medication. Use 2 effective forms of birth control together (or completely avoid sexual intercourse) starting 1 month before treatment starts, during treatment, and for 1 month after you stop. One of your forms of birth control should be non-hormonal (e.g., barrier method such as condoms/cervical cap/diaphragm, copper coil IUD, or spermicide).

Males taking this medication should use a condom during sexual activity with a woman who is pregnant or may become pregnant, continuing until 1 month after their last dose.

USES: Bexarotene is used to treat skin problems from a certain type of cancer (cutaneous T-cell lymphoma-CTCL). It belongs to a class of drugs called retinoids (vitamin A derivatives). Bexarotene works by slowing or stopping the growth of cells.

HOW TO USE: Read the Patient Information Leaflet provided by your pharmacist before you start using bexarotene and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth with or immediately after a meal, usually once daily or as directed by your doctor. The dosage is based on your body size, medical condition, and response to therapy. Swallow the medication whole. Do not crush or chew the medication. Do not use the capsule if it is broken or leaking. If the contents of the capsule touch your skin, immediately wash the area with soap and water and tell your doctor.

Avoid eating grapefruit or drinking grapefruit juice while being treated with this medication unless your doctor instructs you otherwise. Grapefruit can increase the amount of certain medications in your bloodstream. Consult your doctor or pharmacist for more details.

Do not increase your dose or take this medication more often than prescribed. Your condition will not improve any faster, and the risk of serious side effects may be increased.

It may take up to several months of continued use to see a response to treatment. Your dosage may need to be adjusted by your doctor during this time.

Since this drug can be absorbed through the skin, women who are pregnant or who may become pregnant should not handle this medication. Learn proper technique for safe handling and disposal of this medicine and its container. Consult your pharmacist.

SIDE EFFECTS: Headache, tiredness, nausea, vomiting, dry skin, diarrhea, or trouble sleeping may occur. If any of these effects persist or worsen, notify your doctor.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

This medication can frequently increase the level of "bad" fats (cholesterol/triglyceride) in your blood. Your doctor will order blood tests to measure these fats. If your blood fat levels get too high, your bexarotene dose may need to be lowered or stopped, or you may need to start cholesterol medication.

This medication can cause an underactive thyroid (hypothyroidism). Tell your doctor immediately if any of these symptoms of low thyroid occur: unusual weight gain, feeling cold, constipation, slow heartbeat, low on energy. Your doctor will order a blood test and may start you on thyroid medication.

Tell your doctor immediately if any of these unlikely but serious side effects occur: stomach pain, swelling of the hands/feet, muscle pain/stiffness/cramps, fast/pounding heartbeat.

Tell your doctor immediately if any of these rare but very serious side effects occur: severe abdominal/back/stomach pain, persistent nausea/vomiting, dark urine, vision changes, yellowing eyes and skin.

This medication can lower the body's ability to fight an infection. Notify your doctor promptly if you develop any signs of an infection such as fever, chills, or persistent sore throat.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice the following symptoms of an allergic reaction: rash, itching, swelling, dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Contact your doctor for medical advice about side effects. The following numbers do not provide medical advice, but in the US you may report side effects to the Food and Drug Administration (FDA) at 1-800-FDA-1088. In Canada, you may call Health Canada at 1-866-234-2345.

PRECAUTIONS: Before taking bexarotene, tell your doctor or pharmacist if you are allergic to it; or to other retinoids such as isotretinoin, acitretin, etretinate, tretinoin; or if you have any other allergies.

This medication should not be used if you have certain medical conditions. Before taking this medicine, consult your doctor or pharmacist if you have: pancreatitis.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: frequent alcohol use, cataracts, high blood fats (high cholesterol/triglyceride), diabetes, gallbladder disease, liver problems, thyroid problems (e.g., hypothyroidism).

This medication may make you more sensitive to the sun. Avoid prolonged sun exposure, tanning booths, and sunlamps. Use a sunscreen and wear protective clothing when outdoors.

Because this medication can lower your body's ability to fight an infection, wash your hands frequently to prevent the spread of infection.

This medication must not be used during pregnancy. If you become pregnant or think you may be pregnant, inform your doctor immediately. (See also Warning section.)

It is not known if this drug passes into breast milk. Due to the possible harm to the nursing infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: Your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with them first.

This drug should not be used with the following medication because a very serious interaction may occur: gemfibrozil.

If you are currently using the medication listed above, tell your doctor or pharmacist before starting bexarotene.

Before using this medication, tell your doctor or pharmacist of all prescription and nonprescription/herbal products you may use, especially of: drugs to treat diabetes (e.g., insulin, sulfonylureas such as glipizide), tamoxifen, vitamins/supplements that contain vitamin A, drugs affecting liver enzymes that remove bexarotene from your body (e.g., azole antifungals such as itraconazole/ketoconazole, macrolide antibiotics such as clarithromycin/erythromycin, cimetidine, rifamycins including rifabutin, St. John's wort, certain anti-seizure medicines such as phenytoin/phenobarbital).

This medication may decrease the effectiveness of hormonal-type birth control pills. This can result in pregnancy. You may need to use an additional form of reliable birth control while using this medication. (See also Warning section.) Consult your doctor or pharmacist for details.

This medication may interfere with certain laboratory tests (including CA-125 levels), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug. Consult your doctor for more details.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

OVERDOSE: If overdose is suspected, contact your local poison control center or emergency room immediately. US residents should call the US National Poison Hotline at 1-800-222-1222. Canada residents should call a provincial poison control center.

NOTES: Do not share this medication with others.

Laboratory and/or medical tests (e.g., pregnancy tests, liver/thyroid tests, cholesterol/triglyceride levels, white blood count) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

MISSED DOSE: If you miss a dose, take it with a meal as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

STORAGE: Store in a tightly closed container at room temperature between 36-77 degrees F (2-25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-800-854-1166 (USA) or 1-800-668-1507 (Canada).

Information last revised July 2008 Copyright(c) 2008 First DataBank, Inc.