Limitations of Use:

Febuxostat tablets is not recommended for the treatment of asymptomatic hyperuricemia.

2.1 Recommended Dose

The recommended febuxostat tablets dosage is 40 mg or 80 mg once daily.

The recommended starting dosage of febuxostat tablets is 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)].

2.2 Dosage Recommendations in Patients with Renal Impairment and Hepatic Impairment

No dose adjustment is necessary when administering febuxostat tablets in patients with mild or moderate renal impairment.

The recommended dosage of febuxostat tablets is limited to 40 mg once daily in patients with severe renal impairment [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3)].

No dose adjustment is necessary in patients with mild to moderate hepatic impairment [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3)].

2.3 Uric Acid Level

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 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)].

5.1 Cardiovascular Death

In a cardiovascular (CV) outcome study (ClinicalTrials.gov identifier NCT01101035), gout patients with established CV disease treated with febuxostat tablets had a higher rate of CV death compared to those treated with allopurinol. The CV outcomes study in patients with gout (CARES) was a randomized, double-blinded, allopurinol-controlled, non-inferiority study conducted to evaluate the risk of major adverse cardiovascular events (MACE) in patients with gout who were treated with febuxostat tablets. The study enrolled patients who had a history of major CV disease, cerebrovascular disease or diabetes mellitus with micro- and/or macrovascular disease. The primary endpoint was the time to first occurrence of MACE defined as the composite of CV death, nonfatal MI, nonfatal stroke, or unstable angina with urgent coronary revascularization. The study was designed to exclude a prespecified risk margin of 1.3 for the hazard ratio of MACE. Results showed that febuxostat tablets was non-inferior to allopurinol for the primary endpoint of MACE [Hazard Ratio: 1.03, 95% Confidence Interval (CI): 0.89, 1.21]. However, there was a significant increase in CV deaths in patients treated with febuxostat tablets (134 [1.5 per 100 patient-years]) compared to patients treated with allopurinol (100 [1.1 per 100 patient-years]) [Hazard Ratio: 1.34, 95% CI: 1.03, 1.73]. Sudden cardiac death was the most common cause of adjudicated CV deaths in the febuxostat tablets group (83 of 3,098; 2.7%) as compared to the allopurinol group (56 of 3,092; 1.8%). Febuxostat tablets was similar to allopurinol for nonfatal MI, nonfatal stroke and unstable angina with urgent coronary revascularization [see Clinical Studies (14.2)].

Because of the increased risk of CV death, febuxostat tablets should only be used in patients 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 [see Indications and Usage(1)].

Consider the risks and benefits of febuxostat tablets when deciding to prescribe or continue patients on febuxostat tablets [see Indications and Usage (1)]. Consider use of prophylactic low-dose aspirin therapy in patients with a history of CV disease. Physicians and patients should remain alert for the development of adverse CV event signs and symptoms. Patients should be informed about the symptoms of serious CV events and the steps to take if they occur.

5.2 Gout Flares

After initiation of febuxostat tablets, an increase in gout flares is frequently observed. This increase is due to reduction in serum uric acid levels, resulting in mobilization of urate from tissue deposits.

In order to prevent gout flares when febuxostat tablets is initiated, concurrent prophylactic treatment with an NSAID or colchicine is recommended [see Dosage and Administration (2.4)].

5.3 Hepatic Effects

There have been postmarketing reports of fatal and nonfatal hepatic failure in patients taking febuxostat tablets, although the reports contain insufficient information necessary to establish the probable cause. During randomized controlled studies, transaminase elevations greater than three times the upper limit of normal (ULN) were observed (AST: 2%, 2%, and ALT: 3%, 2% in febuxostat tablets and allopurinol-treated patients, respectively). No dose-effect relationship for these transaminase elevations was noted [see Clinical Pharmacology (12.3)].

Obtain a liver test panel (serum alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase, and total bilirubin) as a baseline before initiating febuxostat tablets.

Measure liver tests promptly in patients who report symptoms that may indicate liver injury, including fatigue, anorexia, right upper abdominal discomfort, dark urine or jaundice. In this clinical context, if the patient is found to have abnormal liver tests (ALT greater than three times the upper limit of the reference range), febuxostat tablets treatment should be interrupted and investigation done to establish the probable cause. Febuxostat tablets should not be restarted in these patients without another explanation for the liver test abnormalities.

Patients who have serum ALT greater than three times the reference range with serum total bilirubin greater than two times the reference range without alternative etiologies are at risk for severe drug-induced liver injury and should not be restarted on febuxostat tablets. For patients with lesser elevations of serum ALT or bilirubin and with an alternate probable cause, treatment with febuxostat tablets can be used with caution.

5.4 Serious Skin Reactions

Postmarketing reports of serious skin and hypersensitivity reactions, including Stevens-Johnson Syndrome, drug reaction with eosinophilia and systemic symptoms (DRESS) and toxic epidermal necrolysis (TEN) have been reported in patients taking febuxostat tablets. Discontinue febuxostat tablets if serious skin reactions are suspected [see Patient Counseling Information (17)]. Many of these patients had reported previous similar skin reactions to allopurinol. Febuxostat tablets should be used with caution in these patients.

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 tablets 40 mg or 80 mg daily. For febuxostat tablets 40 mg, 559 patients were treated for ≥6 months. For febuxostat tablets 80 mg, 1377 subjects 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 tablets 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)].

6.2 Postmarketing Experience

The following adverse reactions have been identified during postapproval use of febuxostat tablets. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Blood and Lymphatic System Disorders: agranulocytosis, eosinophilia.

Hepatobiliary Disorders: hepatic failure (some fatal), jaundice, serious cases of abnormal liver function test results, liver disorder.

Immune System Disorders: anaphylaxis, anaphylactic reaction.

Musculoskeletal and Connective Tissue Disorders: rhabdomyolysis.

Psychiatric Disorders: psychotic behavior including aggressive thoughts.

Renal and Urinary Disorders: tubulointerstitial nephritis.

Skin and Subcutaneous Tissue Disorders: generalized rash, Stevens-Johnson Syndrome, hypersensitivity skin reactions, erythema multiforme, drug reaction with eosinophilia and systemic symptoms, toxic epidermal necrolysis.

7.1 Xanthine Oxidase Substrate Drugs

Febuxostat tablets are 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 tablets with theophylline.

Drug interaction studies of febuxostat tablets with other drugs that are metabolized by XO (e.g., mercaptopurine and azathioprine) have not been conducted. Inhibition of XO by febuxostat tablets may cause increased plasma concentrations of these drugs leading to toxicity [see Clinical Pharmacology (12.3)]. febuxostat tablets arecontraindicated in patients being treated with azathioprine or mercaptopurine [see Contraindications (4)].

7.2 Cytotoxic Chemotherapy Drugs

Drug interaction studies of febuxostat tablets with cytotoxic chemotherapy have not been conducted. No data are available regarding the safety of febuxostat tablets during cytotoxic chemotherapy.

7.3 In Vivo Drug Interaction Studies

Based on drug interaction studies in healthy patients, febuxostat tablets does not have clinically significant interactions with colchicine, naproxen, indomethacin, hydrochlorothiazide, warfarin or desipramine [see Clinical Pharmacology (12.3)]. Therefore, febuxostat tablets may be used concomitantly with these medications.

8.1 Pregnancy

8.2 Lactation

8.4 Pediatric Use

Safety and effectiveness of febuxostat tablets 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 tablets 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 Cmax and AUC24 of febuxostat following multiple oral doses of febuxostat tablets in geriatric patients (≥65 years) were similar to those in younger patients (18 to 40 years) [see Clinical Pharmacology (12.3)].

8.6 Renal Impairment

No dose adjustment is necessary in patients with mild to moderate renal impairment (Clcr 30 to 89 mL/min). For patients with severe renal impairment (Clcr 15 to 29 mL/min), the recommended dosage of febuxostat tablets is limited to 40 mg once daily [see Dosage and Administration (2.2) and Clinical Pharmacology (12.3)].

8.7 Hepatic Impairment

No dose adjustment is necessary in patients with mild to moderate hepatic impairment (Child-Pugh Class A or B). No studies have been conducted in patients with severe hepatic impairment (Child-Pugh Class C); therefore, caution should be exercised in these patients [see Clinical Pharmacology (12.3)].

8.8 Secondary Hyperuricemia

No studies have been conducted in patients with secondary hyperuricemia (including organ transplant recipients); febuxostat tablets are not recommended for use in patients whom the rate of urate formation is greatly increased (e.g., malignant disease and its treatment, Lesch-Nyhan syndrome). The concentration of xanthine in urine could, in rare cases, rise sufficiently to allow deposition in the urinary tract.

12.1 Mechanism of Action

Febuxostat tablets, a xanthine oxidase inhibitor, achieve its therapeutic effect by decreasing serum uric acid. Febuxostat tablets are not expected to inhibit other enzymes involved in purine and pyrimidine synthesis and metabolism at therapeutic concentrations.

12.2 Pharmacodynamics

12.3 Pharmacokinetics

In healthy patients, maximum plasma concentrations (Cmax) and AUC of febuxostat increased in a dose proportional manner following single and multiple doses of 10 mg (0.25 times the lowest recommended dosage) to 120 mg (1.5 times the maximum recommended dosage). There is no accumulation when therapeutic doses are administered every 24 hours. Febuxostat has an apparent mean terminal elimination half-life (t1/2) of approximately 5 to 8 hours. Febuxostat pharmacokinetic parameters for patients with hyperuricemia and gout estimated by population pharmacokinetic analyses were similar to those estimated in healthy patients.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Two year carcinogenicity studies were conducted in F344 rats and B6C3F1 mice. Increased transitional cell papilloma and carcinoma of the urinary bladder was observed at 24 mg/kg (25 times the MHRD on an AUC basis and 18.75 mg/kg (12.5 times the MHRD on an AUC basis) in male rats and female mice, respectively. The urinary bladder neoplasms were secondary to calculus formation in the kidney and urinary bladder.

Febuxostat showed a positive clastogenic response in a chromosomal aberration assay in a Chinese hamster lung fibroblast cell line with and without metabolic activation in vitro. Febuxostat was negative in the following genotoxicity assays: the in vitro Ames assay, in vitro chromosomal aberration assay in human peripheral lymphocytes, the L5178Y mouse lymphoma cell line assay, the in vivo mouse micronucleus assay, and the rat unscheduled DNA synthesis assay.

Fertility and reproductive performance were unaffected in male or female rats that received febuxostat at oral doses up to 48 mg/kg/day (approximately 31 and 40 times the MRHD on an AUC basis in males and females respectively).

13.2 Animal Toxicology

A 12 month toxicity study in beagle dogs showed deposition of xanthine crystals and calculi in kidneys at 15 mg/kg (approximately 4 times the MRHD on an AUC basis). A similar effect of calculus formation was noted in rats in a six month study due to deposition of xanthine crystals at 48 mg/kg (approximately 31 and 40 times the MRHD on an AUC basis in males and females respectively).

14.1 Management of Hyperuricemia in Gout

The efficacy of febuxostat tablets was demonstrated in three randomized, double-blind, controlled trials in patients with hyperuricemia and gout. Hyperuricemia was defined as a baseline serum uric acid level ≥8 mg/dL.

Study 1 (ClinicalTrials.gov identifier NCT00430248) randomized patients to: febuxostat tablets 40 mg daily, febuxostat tablets 80 mg daily, or allopurinol (300 mg daily for patients with estimated creatinine clearance (Clcr) ≥60 mL/min or 200 mg daily for patients with estimated Clcr ≥30 mL/min and ≤59 mL/min). The duration of Study 1 was six months.

Study 2 (ClinicalTrials.gov identifier NCT00174915) randomized patients to: placebo, febuxostat tablets 80 mg daily, febuxostat tablets 120 mg daily, febuxostat tablets 240 mg daily or allopurinol (300 mg daily for patients with a baseline serum creatinine ≤1.5 mg/dL or 100 mg daily for patients with a baseline serum creatinine greater than 1.5 mg/dL and ≤2 mg/dL). The duration of Study 2 was six months.

Study 3 (ClinicalTrials.gov identifier NCT00102440), a one year study, randomized patients to: febuxostat tablets 80 mg daily, febuxostat tablets 120 mg daily, or allopurinol 300 mg daily. Patients who completed Study 2 and Study 3 were eligible to enroll in a Phase 3 long-term extension studies in which patients received treatment with febuxostat tablets for over three years.

In all three studies, patients received naproxen 250 mg twice daily or colchicine 0.6 mg once or twice daily for gout flare prophylaxis. In Study 1 the duration of prophylaxis was six months; in Study 2 and Study 3 the duration of prophylaxis was eight weeks.

The efficacy of febuxostat tablets was also evaluated in a four week dose ranging study which randomized patients to: placebo, febuxostat tablets 40 mg daily, febuxostat tablets 80 mg daily, or febuxostat tablets 120 mg daily. Patients who completed this study were eligible to enroll in a long-term extension study in which patients received treatment with febuxostat tablets for up to five years.

Patients in these studies were representative of the patient population for which febuxostat tablets use is intended. Table 2 summarizes the demographics and baseline characteristics for the patients enrolled in the studies.

14.2 Cardiovascular Safety Study

A randomized, double-blind, allopurinol-controlled CV outcomes study (CARES) was conducted to evaluate the CV risk of febuxostat tablets. The study compared the risk of MACE between patients treated with febuxostat tablets (N=3098) and allopurinol-treated patients (N=3092). The primary endpoint was the time to first occurrence of a MACE defined as the composite of CV death, nonfatal MI, nonfatal stroke, or unstable angina with urgent coronary revascularization. The study was designed to exclude a prespecified risk margin of 1.3 for the hazard ratio of MACE. An independent committee conducted a blinded evaluation of serious CV adverse events according to predefined criteria (adjudication) for determination of MACE. The study was event driven and patients were followed until a sufficient number of primary outcome events accrued. The median on-study follow-up time was 2.6 years.

Patients randomized to febuxostat tablets initially received 40 mg once daily which was increased to 80 mg once daily, if their sUA was ≥6mg/dL at Week 2. For patients randomized to allopurinol, those who had normal renal function or mild renal impairment (estimated creatinine clearance (eClcr) ≥60 to ˂90 mL/minute) initially received 300 mg once daily with 100 mg/day dose increments monthly until either sUA ˂6mg/dL or an allopurinol dosage of 600 mg once daily was achieved; those who had moderate renal impairment (eClcr ≥30 to ˂60 mL/minute) initially received 200 mg once daily with 100 mg/day dose increments monthly until either a sUA ˂6 mg/dL or an allopurinol dosage of 400 mg once daily was achieved.

The mean age of the population was 65 years (range: 44 to 93 years). Most patients were male (84%) and Caucasian (69%). Patients had a diagnosis of gout for approximately 12 years, a mean baseline sUA of 8.7 mg/dL, and 90% had experienced at least one gout flare in the past year. CV history included MI (39%), hospitalization for unstable angina (28%), cardiac revascularization (37%), and stroke (14%). The most prevalent comorbid conditions were hypertension (92%), hyperlipidemia (87%), diabetes mellitus (55%), diabetes mellitus with micro- or macrovascular disease (39%), and renal impairment [92% with an eClcr 30 to 89 mL/minute]. The use of CV disease medication was balanced across treatment groups. Baseline CV disease medications included: ACE inhibitors or ARBs (70%), lipid modifying agents (74%), aspirin (62%), beta-blockers (59%), calcium channel blockers (26%), and nonaspirin antiplatelet medications (31%).

Table 5 shows the study results for the primary MACE composite endpoint and its individual components. For the composite primary endpoint, the febuxostat tablets group was non-inferior compared with the allopurinol group. The rates of nonfatal MI, stroke, and unstable angina with urgent coronary revascularization were similar. There was a higher rate of CV deaths in patients treated with febuxostat tablets (134 CV deaths; 1.5 per 100 PY) than in allopurinol-treated patients (100 CV deaths; 1.1 per 100 PY). Sudden cardiac death was the most common cause of adjudicated CV deaths in the febuxostat tablets group (83 of 3,098; 2.7%) as compared to the allopurinol group (56 of 3,092; 1.8%). The biological plausibility of CV death associated with febuxostat tablets is unclear.

All-cause mortality was higher in the febuxostat tablets group (243 deaths [7.8%]; 2.6 per 100 PY) than the allopurinol group (199 deaths [6.4%]; 2.2 per 100 PY) [Hazard Ratio: 1.22, 95% CI: 1.01, 1.47], due to a higher rate of CV deaths.

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].

CV Death

Inform patients that gout patients with established CV disease treated with febuxostat tablets had a higher rate of CV death compared to those treated with allopurinol in a CV outcomes study. Inform all patients of the higher rate of CV death with febuxostat tablets compared to allopurinol. Instruct all patients (those with and without CV disease) to be alert for the development of signs and symptoms of CV events [see Warnings and Precautions (5.1)].

Gout Flares

Inform patients that after initiation of febuxostat tablets there was an increased frequency of gout flares. Instruct patients that it is recommended to initiate and continue gout prophylaxis therapy for six months while taking febuxostat tablets [see Warnings and Precautions (5.2)].

Hepatic Effects

Inform patients that hepatic effects have occurred in patients treated with febuxostat tablets and instruct them to inform their healthcare provider if they experience liver injury symptoms [see Warnings and Precautions (5.3)].

Serious Skin Reactions

Inform patients that serious skin and hypersensitivity reactions have occurred in patients treated with febuxostat tablets. Instruct patients to discontinue febuxostat tablets if they develop symptoms of these reactions [see Warnings and Precautions (5.4)].