Warnings for Targretin
Included as part of the "PRECAUTIONS" Section
Precautions for Targretin
Hyperlipidemia
TARGRETIN induces substantial elevations in lipids in most patients. About 70% of patients with CTCL who received an initial dose of ≥300 mg/m2/day of TARGRETIN 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. Monitor lipid changes and treat abnormalities during therapy. The effects on triglycerides, HDL cholesterol, and total cholesterol were reversible with cessation of therapy, and could generally be mitigated by dose reduction and/or concomitant antilipemic therapy.
Perform fasting blood lipid determinations before TARGRETIN therapy is initiated and weekly until the lipid response to TARGRETIN is established, which usually occurs within 2 to 4 weeks, and monitor at 8-week intervals thereafter. Fasting triglycerides should be normal or normalized with appropriate intervention prior to initiating TARGRETIN therapy. Maintain triglyceride levels below 400 mg/dL to reduce the risk of clinical sequelae [see Pancreatitis]. If fasting triglycerides are elevated or become elevated during treatment, institute antilipemic therapy, and if necessary, reduce or interrupt the dose of TARGRETIN. 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, avoid gemfibrozil use with TARGRETIN [see DRUG INTERACTIONS].
Pancreatitis
Acute pancreatitis, including a fatal case, has been reported in four patients with CTCL and in six patients with non-CTCL cancers treated with TARGRETIN; 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. Interrupt TARGRETIN and evaluate if pancreatitis is suspected. 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) may be at greater risk for pancreatitis associated with TARGRETIN [see Hyperlipidemia].
Hepatotoxicity, Cholestasis, And Hepatic Failure
TARGRETIN caused elevations in liver chemistry tests (LFTs) in 5% (AST), 2% (ALT), and 0% (bilirubin) in patients with CTCL receiving an initial dose of 300 mg/m2/day. In contrast, with an initial dose greater than 300 mg/m2/day of TARGRETIN, 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, elevated LFTs resolved within 1 month in 80% of patients following a decrease in dose or discontinuation of therapy. Obtain baseline LFTs and monitor LFTs after 1, 2, and 4 weeks of treatment initiation, and if stable, at least every 8 weeks thereafter during treatment. Interrupt or discontinue TARGRETIN if test results exceed three times the upper limit of normal values for AST, ALT, or bilirubin.
Hypothyroidism
TARGRETIN induces hypothyroidism in about half of all patients treated by causing a reversible reduction in levels of thyroid hormone (total thyroxine [total T4]) and thyroid-stimulating hormone (TSH). The incidence of decreases in TSH and total T4 were 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. Consider treatment with thyroid hormone supplementation in patients with hypothyroidism. In the 300 mg/m2/day initial dose group, 37% of patients were treated with thyroid hormone replacement. Obtain baseline thyroid function tests and patients monitor during treatment.
Neutropenia
Leukopenia in the range of 1000 to <3000 WBC x 106/L occurred in 18% of patients with CTCL receiving an initial dose of 300 mg/m2/day of TARGRETIN. Patients receiving an initial dose greater than 300 mg/m2/day of TARGRETIN had an incidence of leukopenia of 43%. No patient with CTCL treated with TARGRETIN developed leukopenia of less than 1000 WBC x 106/L. The usual time to onset of leukopenia was 4 to 8 weeks after initiating TARGRETIN. The leukopenia observed in most patients was predominantly 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 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. Obtain complete blood counts (CBC) at baseline and periodically during treatment.
Cataracts
Posterior subcapsular cataracts occurred in preclinical toxicity studies in rats and dogs administered bexarotene daily for 6 months. New cataracts or worsening of previous cataracts occurred in 15 of 79 patients who were monitored with serial slit lamp examinations. Because of the high prevalence and rate of cataract formation in older patient populations, the relationship of TARGRETIN and cataracts cannot be determined in the absence of an appropriate control group. Patients treated with TARGRETIN who experience visual difficulties should have an appropriate ophthalmologic evaluation.
Vitamin A Supplementation Hazard
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.
Hypoglycemia Risk In Patients With Diabetes Mellitus
In patients using insulin, agents enhancing insulin secretion (e.g., sulfonylureas), or insulin sensitizers (e.g., thiazolidinedione class), based on the mechanism of action, TARGRETIN could enhance the action of these agents, resulting in hypoglycemia. Hypoglycemia has not been associated with the use of TARGRETIN as monotherapy.
Photosensitivity
Retinoids as a class have been associated with photosensitivity. In vitro assays indicate that bexarotene is a potential photosensitizing agent. Phototoxicity manifested as sunburn and skin sensitivity to sunlight occurred in patients who were exposed to direct sunlight while receiving TARGRETIN. Advise patients to minimize exposure to sunlight and artificial ultraviolet light while receiving TARGRETIN.
Laboratory Tests
Before initiating TARGRETIN therapy, obtain a CBC, fasting lipid profile, liver function tests, and a thyroid profile. Fasting triglycerides should be normal or normalized with appropriate intervention prior to therapy. Monitor lab tests during TARGRETIN therapy as described above.
Hyperlipidemia usually occurs within the initial 2 to 4 weeks. Therefore, weekly lipid determinations are recommended during this interval. Subsequently, in patients not hyperlipidemic, determinations can be performed less frequently [see Hyperlipidemia].
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 1, 2, and 4 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 Hepatotoxicity, Cholestasis, And Hepatic Failure, Hypothyroidism, Neutropenia, Cataracts].
Drug/Laboratory Test Interactions
CA125 assay values in patients with ovarian cancer may be increased by TARGRETIN therapy.
Patient Counseling Information
Advise the patient to read the FDA-approved patient labeling (PATIENT INFORMATION).
Inform the patient or caregiver about the following:
Birth Defects
Advise patients that TARGRETIN is contraindicated in pregnancy [see CONTRAINDICATIONS]. TARGRETIN is a member of the retinoid class of drugs that is associated with birth defects in humans [see Use In Specific Populations].
- Advise females of reproductive potential that they must avoid pregnancy while taking TARGRETIN and for at least 1 month following discontinuation of therapy.
- Advise females of reproductive potential of the importance of monthly pregnancy testing while taking TARGRETIN.
- Advise females of reproductive potential to use effective contraception for 1 month prior to the initiation of therapy, during therapy, and for at least 1 month following discontinuation of therapy and that two reliable forms of contraception should be used simultaneously, one of which should be non-hormonal.
- Advise females of reproductive potential that TARGRETIN therapy should be initiated on the second or third day of a normal menstrual period.
- Instruct patient to immediately stop taking TARGRETIN if she becomes pregnant while taking this drug.
- Advise male patients with sexual partners who are pregnant, possibly pregnant, or who could become pregnant that they must use condoms during sexual intercourse while taking TARGRETIN and for at least 1 month after the last dose of the drug.
Pancreatitis
Advise patients of the risk of developing pancreatitis, which may be accompanied by nausea, vomiting, and abdominal or back pain and to immediately contact their healthcare provider if these symptoms occur [see WARNINGS AND PRECAUTIONS].
Hepatotoxicity
Inform patients of the possibility of developing liver function abnormalities and serious hepatic toxicity. Advise patients to immediately contact their healthcare provider if signs of liver failure occur, including jaundice, anorexia, bleeding, or bruising [see WARNINGS AND PRECAUTIONS].
Neutropenia
Advise patients of the possibility of developing neutropenia and to immediately contact their healthcare provider should they develop a fever, particularly in association with any suggestion of infection [see WARNINGS AND PRECAUTIONS].
Cataracts
Advise patients of the possibility of developing new or worsening cataracts and to inform their healthcare provider about any changes in their vision during treatment with TARGRETIN [see WARNINGS AND PRECAUTIONS].
Vitamin A Supplementation Hazard
Advise patients to limit vitamin A intake to ≤15,000 IU/day to avoid potential additive toxic effects.
Hypoglycemia And Diabetes Mellitus
Advise females of reproductive potential that they must avoid pregnancy while taking TARGRETIN and for at least 1 month following discontinuation of therapy.
Advise patients of the possibility of developing hypoglycemia when using insulin, agents enhancing insulin secretion, or insulin sensitizers while on TARGRETIN therapy. Instruct patients on these medications to check their blood sugar frequently and to notify their physicians of any changes in blood sugar level [see WARNINGS AND PRECAUTIONS].
Photosensitivity
Advise patients of potential increased skin sensitivity to sunlight while taking TARGRETIN and to minimize exposure to sunlight and artificial ultraviolet light [see WARNINGS AND PRECAUTIONS].
Laboratory Tests
Advise patients of laboratory testing which will occur during therapy to monitor lipids, liver function, thyroid function, and white blood cell counts [see WARNINGS AND PRECAUTIONS]. If applicable, advise patients of monthly pregnancy testing [see Use In Specific Populations].
Administration Instructions
Advise patients to take TARGRETIN with a meal [see DOSAGE AND ADMINISTRATION].
Nonclinical Toxicology
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 Specific Populations
Pregnancy
Risk Summary
TARGRETIN, a retinoid, can cause fetal harm based on findings from animal studies when administered to a pregnant female and is contraindicated during pregnancy. Bexarotene was teratogenic and caused developmental mortality in rats following oral administration during organogenesis [see Data]. TARGRETIN must not be given to a pregnant female or a female who intends to become pregnant. If pregnancy does occur during treatment with TARGRETIN, immediately discontinue the drug and advise the pregnant female of the potential risk to a fetus.
The background risk of major birth defects and miscarriage for the indicated populations is unknown. However, the background risk in the U.S. general population of major birth defects is 2-4% and of miscarriage is 15-20% of clinically recognized pregnancies.
Data
Animal Data
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).
Lactation
Risk Summary
There is no information regarding the presence of TARGRETIN in human milk, the effects on the breast fed infant, or the effects on milk production. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from TARGRETIN, discontinue breastfeeding during treatment with TARGRETIN.
Females And Males Of Reproductive Potential
Pregnancy Testing
Obtain a negative serum pregnancy test (e.g., serum beta-human chorionic gonadotropin [beta-HCG]) with a sensitivity of at least 50 mIU/L within 1 week prior to TARGRETIN therapy. Obtain another pregnancy test at monthly intervals while the patient remains on TARGRETIN.
Contraception
Females
TARGRETIN can cause fetal harm when administered to a pregnant female [see Pregnancy]. Females of reproductive potential should be advised to avoid becoming pregnant when TARGRETIN is used. Effective contraception must be used for 1 month prior to the initiation of therapy, during therapy and for at least 1 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 DRUG INTERACTIONS]. Thus, if treatment with TARGRETIN is intended in a female with reproductive potential, it is strongly recommended that one of the two reliable forms of contraception should be non-hormonal. TARGRETIN therapy should be initiated on the second or third day of a normal menstrual period. No more than a 1-month supply of TARGRETIN 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.
Males
Male patients with sexual partners who are pregnant, possibly pregnant, or who could become pregnant must use condoms during sexual intercourse while taking TARGRETIN and for at least 1 month after the last dose of drug.
Pediatric Use
Safety and effectiveness of TARGRETIN in pediatric patients have not been established.
Geriatric Use
Of the total patients with CTCL in clinical trials of TARGRETIN, 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 cannot be ruled out. Responses to TARGRETIN were observed across all age group decades, without preference for any individual age group decade.
Hepatic Impairment
No specific studies have been conducted with TARGRETIN in subjects with hepatic impairment. Hepatic impairment is expected to lead to decreased clearance [see CLINICAL PHARMACOLOGY]. If TARGRETIN is used in patients with hepatic impairment, monitor for signs of toxicity that may be due to increased exposure.