WARNINGS
Included as part of the "PRECAUTIONS" Section
PRECAUTIONS
Differentiation Syndrome
Differentiation syndrome, which may be life-threatening or fatal, has been observed in patients with acute promyelocytic leukemia (APL) treated with TRISENOX. In clinical trials, 16-23% of patients treated with TRISENOX for APL developed differentiation syndrome. Symptoms include unexplained fever, dyspnea, hypoxia, pulmonary infiltrates, pleural or pericardial effusion, weight gain, peripheral edema, hypotension, renal insufficiency, hepatopathy and multi-organ dysfunction. Differentiation syndrome has been observed with and without concomitant hyperleukocytosis, and it has occurred as early as day 1 of induction to as late as the second month induction therapy. When TRISENOX is used in combination with tretinoin, prednisone prophylaxis is advised [see DOSAGE AND ADMINISTRATION].
At the first signs of differentiation syndrome, interrupt treatment with TRISENOX and administer dexamethasone 10 mg intravenously twice daily. Continue high-dose steroids until signs and symptoms have abated for at least 3 days [see DOSAGE AND ADMINISTRATION].
Cardiac Conduction Abnormalities
Patients treated with TRISENOX can develop QTc prolongation, torsade de pointes, and complete heart block. In the clinical trials of patients with newly-diagnosed low-risk APL treated with TRISENOX in combination with tretinoin, 11% experienced QTc prolongation > 450 msec for men and > 460 msec for women throughout the treatment cycles. In the clinical trial of patients with relapsed or refractory APL treated with TRISENOX monotherapy, 40% had at least one ECG tracing with a QTc interval greater than 500 msec. A prolonged QTc was observed between 1 and 5 weeks after start of TRISENOX infusion, and it usually resolved by 8 weeks after TRISENOX infusion. There are no data on the effect of TRISENOX on the QTc interval during the infusion of the drug.
The risk of torsade de pointes is related to the extent of QTc prolongation, concomitant administration of QTc prolonging drugs, a history of torsade de pointes, pre-existing QTc interval prolongation, congestive heart failure, administration of potassium-wasting diuretics, or other conditions that result in hypokalemia or hypomagnesemia. The risk may be increased when TRISENOX is coadministered with medications that can lead to electrolyte abnormalities (such as diuretics or amphotericin B) [see DRUG INTERACTIONS].
Prior to initiating therapy with TRISENOX, assess the QTc interval by electrocardiogram, correct pre-existing electrolyte abnormalities, and consider discontinuing drugs known to prolong QTc interval. Do not administer TRISENOX to patients with ventricular arrhythmia or prolonged QTc. If possible, discontinue drugs that are known to prolong the QTc interval. If it is not possible to discontinue the interacting drug, perform cardiac monitoring frequently [see DRUG INTERACTIONS]. During TRISENOX therapy, maintain potassium concentrations above 4 mEq/L and magnesium concentrations above 1.8 mg/dL. Monitor ECG weekly, and more frequently for clinically unstable patients.
For patients who develop a QTc greater than 500 msec, immediately withhold treatment with TRISENOX and any medication known to prolong the QTc interval. Correct electrolyte abnormalities. When the QTc normalizes, resume TRISENOX at a reduced dose [see DOSAGE AND ADMINISTRATION].
Encephalopathy
Serious encephalopathies were reported in patients receiving TRISENOX. Monitor patients for neurological symptoms such as confusion, decreased level of consciousness, seizures, cognitive deficits, ataxia, visual symptoms and ocular motor dysfunction. Advise patients and caregivers of the need for close observation.
Wernicke’s Encephalopathy
Wernicke’s encephalopathy occurred in patients receiving TRISENOX. Wernicke’s encephalopathy is a neurologic emergency that can be prevented and treated with thiamine. Consider testing thiamine levels in patients at risk for thiamine deficiency (e.g., chronic alcohol use, malabsorption, nutritional deficiency, concomitant use of furosemide). Administer parenteral thiamine in patients with or at risk for thiamine deficiency. Monitor patients for neurological symptoms and nutritional status while receiving TRISENOX. If Wernicke’s encephalopathy is suspected, immediately interrupt TRISENOX and initiate parenteral thiamine.
Hepatotoxicity
In the clinical trials, 44% of patients with newly-diagnosed low-risk APL treated with TRISENOX in combination with tretinoin experienced elevated aspartate aminotransferase (AST), alkaline phosphatase, and/or serum bilirubin. These abnormalities resolved with temporary discontinuation of TRISENOX and/or tretinoin. During treatment with TRISENOX, monitor liver chemistries at least 2-3 times per week through recovery from toxicities. Withhold treatment with TRISENOX and/or tretinoin if elevations in AST), alkaline phosphatase, and/or serum bilirubin occur to greater than 5 times the upper limit of normal [see DOSAGE AND ADMINISTRATION].
Long-term liver abnormalities can occur in APL patients treated with TRISENOX in combination with tretinoin. In a published series, mild liver dysfunction and hepatic steatosis were seen in 15% and 43%, respectively, of patients at a median of 7 years (range 0-14 years) after treatment with arsenic trioxide in combination with tretinoin.
Carcinogenesis
The active ingredient of TRISENOX, arsenic trioxide, is a human carcinogen. Monitor patients for the development of second primary malignancies.
Embryo-Fetal Toxicity
TRISENOX can cause fetal harm when administered to a pregnant woman. Arsenic trioxide was embryolethal and teratogenic in rats when administered on gestation day 9 at a dose approximately 10 times the recommended human daily dose on a mg/m2 basis. A related trivalent arsenic, sodium arsenite, produced teratogenicity when administered during gestation in mice at a dose approximately 5 times the projected human dose on a mg/m2 basis and in hamsters at an intravenous dose approximately equivalent to the projected human daily dose on a mg/m2 basis. Advise pregnant women of the potential risk to a fetus. Advise females and males of reproductive potential to use effective contraception during and after treatment with TRISENOX [see Use In Specific Populations].
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Carcinogenicity studies have not been conducted with TRISENOX by intravenous administration
[see WARNINGS AND PRECAUTIONS].
Arsenic trioxide and trivalent arsenite salts have not been demonstrated to be mutagenic to bacteria, yeast, or mammalian cells. Arsenite salts are clastogenic in vitro (human fibroblast, human lymphocytes, Chinese hamster ovary cells, Chinese hamster V79 lung cells). Trivalent arsenic was genotoxic in the chromosome aberrations assay and micronucleus bone marrow assay in mice.
The effect of arsenic on fertility has not been adequately studied in humans. Decreased testicular weight and impaired spermatogenesis have been reported in animal studies. Male Wistar rat pups were administered 1.5 mg/kg sodium arsenite solution via the intraperitoneal route from postnatal days 1 to 14 and testes were collected for evaluation on postnatal days 15, 21, and 50. Results of this study revealed an altered morphology of the seminiferous tubules along with degeneration of spermatogenic cells, increased number of sperm with abnormal morphology, and decreased sperm counts. In beagle dogs administered intravenous arsenic trioxide for 90 days, reduced inner cell layers within seminiferous tubules and significantly decreased numbers of spermatocytes, spermatozoa, and sperm cells were observed at doses of 1 mg/kg/day and higher. The 1 mg/kg/day dose is approximately 3 times the recommended human daily dose on a mg/m2 basis.
Use In Specific Populations
Pregnancy
Risk Summary
Based on the mechanism of action [see CLINICAL PHARMACOLOGY] and findings in animal studies, TRISENOX can cause fetal harm when administered to a pregnant woman. Arsenic trioxide was embryolethal and teratogenic in rats when administered on gestation day 9 at a dose approximately 10 times the recommended human daily dose on a mg/m2 basis (see Data). A related trivalent arsenic, sodium arsenite, produced teratogenicity when administered during gestation in mice at a dose approximately 5 times the projected human dose on a mg/m2 basis and in hamsters at an intravenous dose approximately equivalent to the projected human daily dose on a mg/m2 basis. There are no studies with the use of TRISENOX in pregnant women, and limited published data on arsenic trioxide use during pregnancy are insufficient to inform a drug-associated risk of major birth defects and miscarriage. Advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2-4% and 15-20%, respectively.
Data
Human Data
One patient was reported to deliver a live infant with no reported congenital anomalies after receiving arsenic trioxide during the first five months of pregnancy. A second patient became pregnant three months after discontinuing arsenic trioxide and was reported to have a normal pregnancy outcome. A third patient was a pregnant healthcare provider who experienced dermal contact with liquid arsenic trioxide and had a normal pregnancy outcome after treatment and monitoring. A fourth patient who became pregnant while receiving arsenic trioxide had a miscarriage.
Animal Data
Studies in pregnant mice, rats, hamsters, and primates have shown that inorganic arsenicals cross the placental barrier when given orally or by injection. An increase in resorptions, neural-tube defects, anophthalmia and microphthalmia were observed in rats administered 10 mg/kg of arsenic trioxide on gestation day 9 (approximately 10 times the recommended human daily dose on a mg/m2 basis). Similar findings occurred in mice administered a 10 mg/kg dose of a related trivalent arsenic, sodium arsenite (approximately 5 times the projected human dose on a mg/m2 basis), on gestation days 6, 7, 8, or 9. Intravenous injection of 2 mg/kg sodium arsenite (approximately equivalent to the projected human daily dose on a mg/m2 basis) on gestation day 7 (the lowest dose tested) resulted in neural-tube defects in hamsters.
Lactation
Risk Summary
Arsenic trioxide is excreted in human milk. There is no information on the effects of arsenic trioxide on the breastfed child or on milk production. Because of the potential for serious adverse reactions in a breastfed child from TRISENOX, discontinue breastfeeding during treatment with TRISENOX and for two weeks after the final dose.
Females And Males Of Reproductive Potential
Pregnancy Testing
TRISENOX can cause fetal harm when administered to a pregnant woman. Conduct pregnancy testing in females of reproductive potential prior to initiation of treatment with TRISENOX [see Pregnancy].
Contraception
Females
Advise females of reproductive potential to use effective contraception during and after treatment with TRISENOX and for six months after the final dose.
Males
Advise males with female sexual partners of reproductive potential to use effective contraception during and after treatment with TRISENOX and for three months after the final dose.
Infertility
Males
Based on testicular toxicities including decreased testicular weight and impaired spermatogenesis observed in animal studies, TRISENOX may impair fertility in males of reproductive potential [see Nonclinical Toxicology].
Pediatric Use
The safety and efficacy of TRISENOX in combination with tretinoin in pediatric patients has not been established.
The safety and efficacy of TRISENOX as a single agent for treatment of pediatric patients with relapsed or refractory APL is supported by the pivotal phase 2 study in 40 patients with relapsed or refractory APL. Five patients below the age of 18 years (age range: 5 to 16 years) were treated with TRISENOX at the recommended dose of 0.15 mg/kg/day. A literature review included an additional 17 patients treated with arsenic trioxide for relapsed or refractory APL, with ages ranging from 4 to 21 years. No differences in efficacy and safety were observed by age.
Geriatric Use
Use of TRISENOX in combination with tretinoin in newly-diagnosed adult patients with low-risk APL is supported by a randomized, controlled trial that included 16 patients between the ages of 60 and 70 years. No differences in efficacy and safety were observed by age. A literature review included an additional 77 patients treated with arsenic trioxide in combination with tretinoin as part of induction and consolidation therapy for low and high risk APL, with ages ranging from 60 to 84 years. These studies showed lower survival rates in older patients. Monitor elderly patients frequently during treatment with TRISENOX.
The safety and efficacy of TRISENOX as a single agent in older patients with relapsed or refractory APL is supported by the pivotal phase 2 study in 40 patients with relapsed or refractory APL. Six patients age 65 and above (age range: 65 to 73 years) were treated with TRISENOX at the recommended dose. A literature review included an additional 4 patients treated with arsenic trioxide for relapsed or refractory APL with ages ranging from 69 to 72 years. No differences in efficacy and safety were observed by age.
Patients With Renal Impairment
Exposure of arsenic trioxide may be higher in patients with severe renal impairment [see CLINICAL PHARMACOLOGY]. Patients with severe renal impairment (creatinine clearance less than 30 mL/min) should be monitored for toxicity when these patients are treated with TRISENOX, and a dose reduction may be warranted.
The use of TRISENOX in patients on dialysis has not been studied.
Patients With Hepatic Impairment
Since limited data are available across all hepatic impairment groups, caution is advised in the use of TRISENOX in patients with hepatic impairment [see CLINICAL PHARMACOLOGY]. Monitor patients with severe hepatic impairment (Child-Pugh Class C) who are treated with TRISENOX for toxicity.