FEBUXOSTAT

Febuxostat is a xanthine oxidase inhibitor. The active ingredient in febuxostat is 2-[3-cyano-4-(2-methylpropoxy) phenyl]-4-methylthiazole-5-carboxylic acid hemihydrate, with a molecular weight of 325.39. The molecular formula is C 16 H 16 N 2 O 3 S 1 / 2 H 2 O. The chemical structure is: Febuxostat is a non-hygroscopic, white to yellowish crystalline powder that is soluble in dimethyl formamide, slightly soluble in methanol and insoluble in water. The melting range is 207 o C to 210°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 colloidal silicon dioxide, croscarmellose sodium, hydroxypropyl cellulose, lactose monohydrate, microcrystalline cellulose and magnesium stearate. Febuxostat tablets are coated with polyvinyl alcohol, macrogol, titanium dioxide, talc, D&C yellow #10 aluminum lake, FD&C blue #1/brilliant blue FCF aluminum lake, FD&C blue #2/indigo carmine AL 3%-5% (40 mg), additionally iron oxide yellow (80 mg). febu-str

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 )

Recommended febuxostat tablets dosage is 40 mg or 80 mg once daily. The recommended starting dose 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 ) Can be administered without regard to food or antacid use. ( 2.1 ) Limit the dosage of febuxostat tablets to 40 mg once daily in patients with severe renal impairment. ( 2.2 , 8.6 ) 2.1 Recommended Dose The recommended febuxostat 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)]. 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 are 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 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)] .

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

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 Novadoz Pharmaceuticals LLC at 1-855-668-2369 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 S een in P atients Receiving P lacebo in Controlled Studies A d verse Reactions Placebo Febuxostat allopurinol* (N=134) 40 mg daily (N=75 7) 80 mg daily (N=127 9) (N=127 7) Liver Function Abn ormalities 0.7% 6.6% 4.6% 4.2% N ausea 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, hyperchlorhydria, hematochezia, mouth ulceration, pancreatitis, peptic ulcer, vomiting. General Disorders and Administration Site Conditions: asthenia, chest pain/discomfort, edema, fatigue, feeling abnormal, gait disturbance, influenza-like symptoms, mass, pain, thirst. Hepatobiliary Disorders: cholelithiasis/cholecystitis, hepatic steatosis, hepatitis, hepatomegaly. Immune System Disorder: hypersensitivity. Infections and Infestations: herpes zoster. Procedural Complications: contusion. Metabolism and Nutrition Disorders: anorexia, appetite decreased/increased, dehydration, diabetes mellitus, hypercholesterolemia, hyperglycemia, hyperlipidemia, hypertriglyceridemia, hypokalemia, weight decreased/increased. Musculoskeletal and Connective Tissue Disorders: arthritis, joint stiffness, joint swelling, muscle spasms/twitching/tightness/weakness, musculoskeletal pain/stiffness, myalgia. Nervous System Disorders: altered taste, balance disorder, cerebrovascular accident, Guillain-Barré syndrome, headache, hemiparesis, hypoesthesia, hyposmia, lacunar infarction, lethargy, mental impairment, migraine, paresthesia, somnolence, transient ischemic attack, tremor. Psychiatric Disorders: agitation, anxiety, depression, insomnia, irritability, libido decreased, nervousness, panic attack, personality change. Renal and Urinary Disorders: hematuria, nephrolithiasis, pollakiuria, proteinuria, renal failure, renal insufficiency, urgency, incontinence. Reproductive System and Breast Changes: breast pain, erectile dysfunction, gynecomastia. Respiratory, Thoracic and Mediastinal Disorders: bronchitis, cough, dyspnea, epistaxis, nasal dryness, paranasal sinus hypersecretion, pharyngeal edema, respiratory tract congestion, sneezing, throat irritation, upper respiratory tract infection. Skin and Subcutaneous Tissue Disorders: alopecia, angio-edema, dermatitis, dermographism, ecchymosis, eczema, hair color changes, hair growth abnormal, hyperhidrosis, peeling skin, petechiae, photosensitivity, pruritus, purpura, skin discoloration/altered pigmentation, skin lesion, skin odor abnormal, urticaria. Vascular Disorders: flushing, hot flush, hypertension, hypotension. Laboratory Parameters: activated partial thromboplastin time prolonged, creatine increased, bicarbonate decreased, sodium increased, EEG abnormal, glucose increased, cholesterol increased, triglycerides increased, amylase increased, potassium increased, TSH increased, platelet count decreased, hematocrit decreased, hemoglobin decreased, MCV increased, RBC decreased, creatinine increased, blood urea increased, BUN/creatinine ratio increased, creatine phosphokinase (CPK) increased, alkaline phosphatase increased, LDH increased, PSA increased, urine output increased/decreased, lymphocyte count decreased, neutrophil count decreased, WBC increased/decreased, coagulation test abnormal, low density lipoprotein (LDL) increased, prothrombin time prolonged, urinary casts, urine positive for white blood cells and protein. 6.2 Postmarketing Experience The following Adverse reactions have been identified during postapproval use of Febuxostat. 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.

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