Febuxostat

Boxed Warning 2/2019 Indications and Usage 2/2019 Warnings and Precautions Cardiovascular Death ( 5.1 ) 2/2019

1 INDICATIONS AND USAGE Febuxostat tablets are xanthine oxidase (XO) inhibitor indicated for the chronic management of hyperuricemia in adult patients with gout who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable. Febuxostat tablets are not recommended for the treatment of asymptomatic hyperuricemia. Febuxostat tablets are xanthine oxidase (XO) inhibitor indicated for the chronic management of hyperuricemia in adult patients with gout who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable. For the safe and effective use of allopurinol, see allopurinol prescribing information. Limitations of Use: Febuxostat tablets are not recommended for the treatment of asymptomatic hyperuricemia. Febuxostat tablets are xanthine oxidase (XO) inhibitor indicated for the chronic management of hyperuricemia in patients with gout who have an inadequate response to a maximally titrated dose of allopurinol, who are intolerant to allopurinol, or for whom treatment with allopurinol is not advisable. ( 1 ) For the safe and effective use of allopurinol, see allopurinol prescribing information. Limitations of Use: Febuxostat tablets are not recommended for the treatment of asymptomatic hyperuricemia. ( 1 )

2 DOSAGE AND ADMINISTRATION Recommended dosage is 40 mg or 80 mg once daily. The recommended starting dosage is 40 mg once daily. For patients who do not achieve a serum uric acid (sUA) less than 6 mg/dL after 2 weeks, the recommended dosage is 80 mg once daily. ( 2.1 ) Patients with severe renal impairment: Limit the dosage to 40 mg once daily. ( 2.2 , 8.6 ) Flare prophylaxis is recommended upon initiation of febuxostat tablets. ( 2.4 ) Can be administered without regard to food or antacid use. ( 2.1 ) 2.1 Recommended Dosage The recommended febuxostat tablets dosage is 40 mg or 80 mg once daily. The recommended starting dosage of febuxostat tablets are 40 mg once daily. For patients who do not achieve a serum uric acid (sUA) less than 6 mg/dL after two weeks, the recommended febuxostat tablets dosage is 80 mg once daily. Febuxostat tablets can be taken without regard to food or antacid use [ see Clinical Pharmacology (12.3)]. Concurrent prophylactic treatment with a non-steroidal anti-inflammatory drug (NSAID) or colchicine is recommended [see Dosage and Administration (2.4) and Warnings and Precautions (5.2) ] . 2.2 Dosage Recommendations in Patients with Renal Impairment and Hepatic Impairment The recommended dosage of febuxostat tablets are limited to 40 mg once daily in patients with severe renal impairment. No dose modification is necessary when administering febuxostat tablets in patients with mild or moderate renal impairment [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ]. No dosage modification is necessary in patients with mild to moderate hepatic impairment [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3) ] . 2.3 Serum Uric Acid Level Monitoring Testing for the target serum uric acid level of less than 6 mg/dL may be performed as early as two weeks after initiating febuxostat tablets therapy. 2.4 Recommended Prophylaxis for Gout Flares Gout flares may occur after initiation of febuxostat tablets due to changing serum uric acid levels resulting in mobilization of urate from tissue deposits. Flare prophylaxis with a non-steroidal anti-inflammatory drug (NSAID) or colchicine is recommended upon initiation of febuxostat tablets. Prophylactic therapy may be beneficial for up to six months [see Clinical Studies ( 14.1 )] . If a gout flare occurs during febuxostat tablets treatment, febuxostat tablets need not be discontinued. The gout flare should be managed concurrently, as appropriate for the individual patient [see Warnings and Precautions ( 5.2)] .

3 DOSAGE FORMS AND STRENGTHS 40 mg tablets are green colored, round shaped, biconvex, film coated tablets debossed with “40” on one side and “F” on other side. 80 mg tablets are yellow colored, capsule shaped, biconvex film coated tablets debossed with “80” on one side and plain surface on other side. Tablet: 40 mg, 80 mg. ( 3 )

4 CONTRAINDICATIONS Febuxostat tablets are contraindicated in patients being treated with azathioprine or mercaptopurine [see Drug Interactions (7)] . Febuxostat tablets are contraindicated in patients being treated with azathioprine or mercaptopurine. (4)

6 ADVERSE REACTIONS The following serious adverse reactions are described elsewhere in the prescribing information: Cardiovascular Death [see Warnings and Precautions (5.1)] Hepatic Effects [see Warnings and Precautions (5.3)] Serious Skin Reactions [see Warnings and Precautions (5.4)] Adverse reactions occurring in at least 1% of patients treated with febuxostat, and at least 0.5% greater than placebo, are liver function abnormalities, nausea, arthralgia, and rash. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Ascend Laboratories, LLC at 1-877-ASC-RX01 (877-272-7901) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. In Phase 2 and 3 clinical studies, a total of 2757 patients with hyperuricemia and gout were treated with febuxostat 40 mg or 80 mg daily. For febuxostat 40 mg, 559 patients were treated for ≥6 months. For febuxostat 80 mg, 1377 patients were treated for ≥6 months, 674 patients were treated for ≥1 year and 515 patients were treated for ≥2 years. In the CARES study, a total of 3098 patients were treated with febuxostat 40 mg or 80 mg daily; of these, 2155 patients were treated for ≥1 year and 1539 were treated for ≥2 years [see Clinical Studies (14.2)]. Most Common Adverse Reactions In three randomized, controlled clinical studies (Studies 1, 2 and 3), which were six to 12 months in duration, the following adverse reactions were reported by the treating physician as related to study drug. Table 1 summarizes adverse reactions reported at a rate of at least 1% in febuxostat treatment groups and at least 0.5% greater than placebo. Table 1: Adverse Reactions Occurring in ≥ 1 % of Patients Treated with Febuxostat and at Least 0.5% Greater than Seen in Patients Receiving Placebo in Controlled Studies Ad verse Reactions P lacebo Febuxostat allopurinol* (N=134) 40 mg daily (N=757) 80 mg daily (N=1279) (N=1277) Liver Function Abnormalities 0.7% 6.6% 4.6% 4.2% Nausea 0.7% 1.1% 1.3% 0.8% Arthralgia 0% 1.1% 0.7% 0.7% Rash 0.7% 0.5% 1.6% 1.6% *Of the patients who received allopurinol, 10 received 100 mg, 145 received 200 mg, and 1122 received 300 mg, based on level of renal impairment. The most common adverse reaction leading to discontinuation from therapy was liver function abnormalities in 1.8% of febuxostat 40 mg, 1.2% of febuxostat 80 mg, and in 0.9% of patients treated with allopurinol. In addition to the adverse reactions presented in Table 1, dizziness was reported in more than 1% of patients treated with febuxostat although not at a rate more than 0.5% greater than placebo. In the CARES study, liver function abnormalities and diarrhea were reported in more than 1% of patients treated with febuxostat, although not at a rate more than 0.5% greater than allopurinol. Less Common Adverse Reactions In clinical studies the following adverse reactions occurred in less than 1% of patients and in more than one subject treated with doses ranging from 40 mg to 240 mg of febuxostat. This list also includes adverse reactions (less than 1% of patients) associated with organ systems from Warnings and Precautions. Blood and Lymphatic System Disorders : anemia, idiopathic thrombocytopenic purpura, leukocytosis/leukopenia, neutropenia, pancytopenia, splenomegaly, thrombocytopenia. Cardiac Disorders : angina pectoris, atrial fibrillation/flutter, cardiac murmur, ECG abnormal, palpitations, sinus bradycardia, tachycardia. Ear and Labyrinth Disorders : deafness, tinnitus, vertigo. Eye Disorders : vision blurred. Gastrointestinal Disorders : abdominal distention, abdominal pain, constipation, dry mouth, dyspepsia, flatulence, frequent stools, gastritis, gastroesophageal reflux disease, gastrointestinal discomfort, gingival pain, haematemesis, …

7 DRUG INTERACTIONS Concomitant administration of febuxostat with XO substrate drugs, azathioprine or mercaptopurine could increase plasma concentrations of these drugs resulting in severe toxicity. ( 7 ) 7.1 Xanthine Oxidase Substrate Drugs Febuxostat is an XO inhibitor. Based on a drug interaction study in healthy patients, febuxostat altered the metabolism of theophylline (a substrate of XO) in humans [see Clinical Pharmacology ( 12.3 )] . Therefore, use with caution when coadministering febuxostat with theophylline. A drug interaction study of febuxostat and azathioprine, also metabolized by XO, showed an increase in exposure of 6-mercaptopurine which may lead to toxicity [see Clinical Pharmacology (12.3) ] . Drug interaction studies of febuxostat with other drugs that are metabolized by XO (e.g., mercaptopurine) have not been conducted. Febuxostat is contraindicated in patients being treated with azathioprine or mercaptopurine [see Contraindications (4) ] . 7.2 Cytotoxic Chemotherapy Drugs Drug interaction studies of febuxostat with cytotoxic chemotherapy have not been conducted. No data are available regarding the safety of febuxostat during cytotoxic chemotherapy. 7.3 In Vivo Drug Interaction Studies Based on drug interaction studies in healthy patients, febuxostat does not have clinically significant interactions with colchicine, naproxen, indomethacin, hydrochlorothiazide, warfarin or desipramine [see Clinical Pharmacology ( 12.3 )] . Therefore, febuxostat may be used concomitantly with these medications.

8 USE IN SPECIFIC POPULATIONS Patients with severe hepatic impairment: No studies have been conducted in this patient population. Caution should be exercised in these patients. ( 8.7 ) Patients with secondary hyperuricemia (including patients being treated for Lesch-Nyhan syndrome or malignant disease, or in organ transplant recipients): febuxostat is not recommended for use as no studies have been conducted in this patient population. ( 8.8 ) 8.1 Pregnancy Risk Summary Limited available data with febuxostat use in pregnant women are insufficient to inform a drug associated risk of adverse developmental outcomes. No adverse developmental effects were observed in embryo-fetal development studies with oral administration of febuxostat to pregnant rats and rabbits during organogenesis at doses that produced maternal exposures up to 40 and 51 times, respectively, the exposure at the maximum recommended human dose (MRHD). No adverse developmental effects were observed in a pre-and postnatal development study with administration of febuxostat to pregnant rats from organogenesis through lactation at an exposure approximately 11 times the MRHD ( see Data ). 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 US general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Data Animal Data In an embryo-fetal development study in pregnant rats dosed during the period of organogenesis from gestation Days 7 – 17, febuxostat was not teratogenic and did not affect fetal development or survival at exposures up to approximately 40 times the MRHD (on an AUC basis at maternal oral doses up to 48 mg/kg/day). In an embryo-fetal development study in pregnant rabbits dosed during the period of organogenesis from gestation Days 6 – 18, febuxostat was not teratogenic and did not affect fetal development at exposures up to approximately 51 times the MRHD (on an AUC basis at maternal oral doses up to 48 mg/kg/day). In a pre-and postnatal development study in pregnant female rats dosed orally from gestation Day 7 through lactation Day 20, febuxostat had no effects on delivery or growth and development of offspring at a dose approximately 11 times the MRHD (on an AUC basis at a maternal oral dose of 12 mg/kg/day). However, increased neonatal mortality and a reduction in neonatal body weight gain were observed in the presence of maternal toxicity at a dose approximately 40 times the MRHD (on an AUC basis at a maternal oral dose of 48 mg/kg/day). Febuxostat crossed the placental barrier following oral administration to pregnant rats and was detected in fetal tissues. 8.2 Lactation Risk Summary There are no data on the presence of febuxostat in human milk, the effects on the breastfed infant, or the effects on milk production. Febuxostat is present in rat milk. The developmental and health benefits of breastfeeding should be considered along with the mother’s clinical need for febuxostat and any potential adverse effects on the breastfed child from febuxostat or from the underlying maternal condition. Data Animal Data Orally administered febuxostat was detected in the milk of lactating rats at up to approximately 7 times the plasma concentration. 8.4 Pediatric Use Safety and effectiveness of febuxostat in pediatric patients have not been established. 8.5 Geriatric Use No dose adjustment is necessary in elderly patients. Of the total number of patients in Studies 1, 2, and 3 (clinical studies of febuxostat in the treatment of gout) [ see Clinical Studies (14.1)], 16% were 65 and over, while 4% were 75 and over. Comparing patients in different age groups, no clinically significant differences in safety or effectiveness were observed but greater sensitivity of some older individuals cannot be ruled out. The …

12.1 Mechanism of Action Febuxostat, a xanthine oxidase inhibitor, achieves its therapeutic effect by decreasing serum uric acid. Febuxostat is not expected to inhibit other enzymes involved in purine and pyrimidine synthesis and metabolism at therapeutic concentrations.

11 DESCRIPTION Febuxostat is a xanthine oxidase inhibitor. The active ingredient in febuxostat tablets is 2-[3-cyano-4-(2-methylpropoxy) phenyl]-4-methylthiazole-5-carboxylic acid, with a molecular weight of 316.38. The molecular formula is C 16 H 16 N 2 O 3 S. The chemical structure is: Febuxostat is a non-hygroscopic, white to off white crystalline powder that is freely soluble in dimethylformamide; soluble in dimethylsulphoxide; sparingly soluble in ethanol; slightly soluble in methanol and acetonitrile; and practically insoluble in water. The melting range is 200°C to 202°C. Febuxostat tablets for oral use contain the active ingredient, febuxostat, and are available in two dosage strengths, 40 mg and 80 mg. Inactive ingredients include microcrystalline cellulose, lactose monohydrate, colloidal silicon dioxide, sodium lauryl sulfate, hydroxypropyl cellulose, croscarmellose sodium and magnesium stearate. Febuxostat tablets are coated with polyvinyl alcohol, polyethylene glycol, talc, titanium dioxide, D&C yellow #10 aluminum lake, FD&C blue #1 aluminum lake and iron oxide yellow. structure

10 OVERDOSAGE Febuxostat was studied in healthy patients in doses up to 300 mg daily for seven days without evidence of dose-limiting toxicities. No overdose of febuxostat was reported in clinical studies. Patients should be managed by symptomatic and supportive care should there be an overdose.

16 HOW SUPPLIED/STORAGE AND HANDLING Febuxostat 40 mg tablets are green colored, round shaped, biconvex, film coated tablets, debossed with "40" on one side and "F" on other side and supplied as: Bottles of 30 tablets.............................. (NDC 72205-028-30) Bottles of 90 tablets............................. (NDC 72205-028-90) Bottles of 500 tablets............................ (NDC 72205-028-05) Febuxostat 80 mg tablets yellow colored, capsule shaped, biconvex, film coated tablets, debossed with "80" on one side and plain on other side and supplied as: Bottles of 30 tablets.............................. (NDC 72205-029-30) Bottles of 90 tablets.............................. (NDC 72205-029-90) Bottles of 100 tablets............................ (NDC 72205-029-91) Bottles of 1000 tablets........................... (NDC 72205-029-99) Protect from light. Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [See USP Controlled Room Temperature].