ARAVA (leflunomide) is a pyrimidine synthesis inhibitor. The chemical name for leflunomide is N-(4´-trifluoromethylphenyl)-5-methylisoxazole-4-carboxamide. It has an empirical formula C 12 H 9 F 3 N 2 O 2 , a molecular weight of 270.2 and the following structural formula: ARAVA is available for oral administration as tablets containing 10, 20, or 100 mg of active drug. Combined with leflunomide are the following inactive ingredients: colloidal silicon dioxide, crospovidone, hypromellose, lactose monohydrate, magnesium stearate, polyethylene glycol, povidone, starch, talc, titanium dioxide, and yellow ferric oxide (20 mg tablet only). Chemical Structure

ARAVA is indicated for the treatment of adults with active rheumatoid arthritis (RA). ARAVA is a pyrimidine synthesis inhibitor indicated for the treatment of adults with active rheumatoid arthritis.

ARAVA Tablets are available in three strengths: Tablets: 10 mg, supplied as white, round film-coated tablet embossed with "ZBN" on one side Tablets: 20 mg, supplied as light-yellow, triangular film-coated tablet embossed with "ZBO" on one side Tablets: 100 mg, supplied as white, round film-coated tablet embossed with "ZBP" on one side Tablets: 10 mg, 20 mg, 100 mg.

Loading dosage for patients at low risk for ARAVA-associated hepatotoxicity and ARAVA-associated myelosuppression: 100 mg daily for 3 days. Maintenance dosage: 20 mg daily. Maximum recommended daily dosage: 20 mg once daily. If 20 mg once daily is not tolerated, may decrease dosage to 10 mg once daily. Screen patients for active and latent tuberculosis, pregnancy test (females), blood pressure, and laboratory tests before starting ARAVA

Recommended Dosage The recommended dosage of ARAVA is 20 mg once daily. Treatment may be initiated with or without a loading dose, depending upon the patient's risk of ARAVA-associated hepatotoxicity and ARAVA-associated myelosuppression. The loading dose provides steady-state concentrations more rapidly. For patients who are at low risk for ARAVA-associated hepatotoxicity and ARAVA-associated myelosuppression, the recommended ARAVA loading dose is 100 mg once daily for 3 days. Subsequently administer 20 mg once daily. For patients at high risk for ARAVA-associated hepatotoxicity (e.g., those taking concomitant methotrexate) or ARAVA-associated myelosuppression (e.g., patients taking concomitant immunosuppressants), the recommended ARAVA dosage is 20 mg once daily without a loading dose . The maximum recommended daily dose is 20 mg once per day. Consider dosage reduction to 10 mg once daily for patients who are not able to tolerate 20 mg daily (i.e., for patients who experience any adverse events listed in Table 1). Monitor patients carefully after dosage reduction and after stopping therapy with ARAVA, since the active metabolite of leflunomide, teriflunomide, is slowly eliminated from the plasma . After stopping ARAVA treatment, an accelerated drug elimination procedure is recommended to reduce the plasma concentrations of the active metabolite, teriflunomide . Without use of an accelerated drug elimination procedure, it may take up to 2 years to reach undetectable plasma teriflunomide concentrations after stopping ARAVA

Evaluation and Testing Prior to Starting ARAVA Prior to starting ARAVA treatment, the following evaluations and tests are recommended: Evaluate patients for active tuberculosis and screen patients for latent tuberculosis infection Laboratory tests including serum alanine aminotransferase (ALT); and white blood cell, hemoglobin or hematocrit, and platelet counts For females of reproductive potential, pregnancy testing Check blood pressure

After stopping ARAVA, it is recommended that an accelerated drug elimination procedure be used to reduce the plasma concentrations of the active metabolite, teriflunomide. Severe infections (including sepsis), pancytopenia, agranulocytosis, and thrombocytopenia: Stop ARAVA and use accelerated elimination procedure. Do not start ARAVA in patients with active infection. Monitor CBCs during treatment with ARAVA. Stevens-Johnson syndrome and toxic epidermal necrolysis, drug reaction with eosinophilia and systemic symptoms (DRESS): Stop ARAVA and use accelerated elimination procedure. Skin ulcers: If skin ulcer is suspected, discontinue leflunomide treatment and consider an accelerated drug elimination procedure. Peripheral neuropathy: If patient develops symptoms consistent with peripheral neuropathy, evaluate patient and consider discontinuing ARAVA. Interstitial lung disease: May be fatal. New onset or worsening symptoms may necessitate discontinuation of ARAVA and initiation of accelerated elimination procedure. Increased blood pressure: Monitor and treat. 5.1 Embryo-Fetal Toxicity ARAVA may cause fetal harm when administered to a pregnant woman. Teratogenicity and embryo-lethality occurred in animal reproduction studies with leflunomide at doses lower than the human exposure level . ARAVA is contraindicated for use in pregnant women . Exclude pregnancy before starting treatment with ARAVA in females of reproductive potential . Advise females of reproductive potential to use effective contraception during ARAVA treatment and during an accelerated drug elimination procedure after ARAVA treatment . If a woman becomes pregnant while taking ARAVA, stop treatment with ARAVA, apprise the patient of the potential risk to a fetus, and perform an accelerated drug elimination procedure to achieve nondetectable plasma concentrations of teriflunomide, the active metabolite of leflunomide . Upon discontinuing ARAVA, it is recommended that all females of reproductive potential undergo an accelerated drug elimination procedure. Women receiving ARAVA treatment who wish to become pregnant must discontinue ARAVA and undergo an accelerated drug elimination procedure, which includes verification that plasma concentrations of the active metabolite of leflunomide, teriflunomide, are less than 0.02 mg/L (0.02 mcg/mL). Based on animal data, human plasma concentrations of teriflunomide of less than 0.02 mg/L (0.02 mcg/mL) are expected to have minimal embryo-fetal risk

Hepatotoxicity Severe liver injury, including fatal liver failure, has been reported in some patients treated with ARAVA. Patients with pre-existing acute or chronic liver disease, or those with serum alanine aminotransferase (ALT) of greater than twice the upper limits of normal (>2 × ULN) before initiating treatment, should not be treated with ARAVA. Use caution when ARAVA is given with other potentially hepatotoxic drugs. Monitoring of ALT levels is recommended at least monthly for six months after starting ARAVA, and thereafter every 6 to 8 weeks. If ALT elevation >3-fold ULN occurs, interrupt ARAVA therapy and investigate the cause. If likely ARAVA-induced, perform the accelerated drug elimination procedure and monitor liver tests weekly until normalized . If ARAVA-induced liver injury is unlikely because some other cause has been found, resumption of ARAVA therapy may be considered. If ARAVA and methotrexate are given concomitantly, follow the American College of Rheumatology (ACR) guidelines for monitoring methotrexate liver toxicity with ALT, AST, and serum albumin testing

Procedure for Accelerated Elimination of ARAVA and its Active Metabolite The active metabolite of leflunomide, teriflunomide, is eliminated slowly from the plasma . Use of an accelerated drug elimination procedure will rapidly reduce plasma concentrations of leflunomide and its active metabolite, teriflunomide. Therefore, an accelerated elimination procedure should be considered at any time after discontinuation of ARAVA, and in particular, when a patient has experienced a severe adverse reaction (e.g., hepatotoxicity, serious infection, bone marrow suppression, Stevens-Johnson Syndrome, toxic epidermal necrolysis, peripheral neuropathy, interstitial lung disease), suspected hypersensitivity, or has become pregnant. It is recommended that all women of childbearing potential undergo an accelerated elimination procedure after stopping ARAVA treatment. Without use of an accelerated drug elimination procedure, it may take up to 2 years to reach plasma teriflunomide concentrations of less than 0.02 mg/L, the plasma concentration not associated with embryo-fetal toxicity in animals. Elimination can be accelerated by the following procedures: Administer cholestyramine 8 grams orally 3 times daily for 11 days. Alternatively, administer 50 grams of activated charcoal powder (made into a suspension) orally every 12 hours for 11 days. Verify plasma teriflunomide concentrations of less than 0.02 mg/L (0.02 µg/mL) by two separate tests at least 14 days apart. If plasma teriflunomide concentrations are higher than 0.02 mg/L, repeat cholestyramine and/or activated charcoal treatment. The duration of accelerated drug elimination treatment may be modified based on the clinical status and tolerability of the elimination procedure. The procedure may be repeated as needed, based on teriflunomide concentrations and clinical status. Use of the accelerated drug elimination procedure may potentially result in return of disease activity if the patient had been responding to ARAVA treatment

Immunosuppression, Bone Marrow Suppression, and Risk of Serious Infections ARAVA is not recommended for patients with severe immunodeficiency, bone marrow dysplasia, or severe, uncontrolled infections. If a serious infection occurs, consider interrupting ARAVA therapy and initiating the accelerated drug elimination procedure . Medications like ARAVA that have immunosuppression potential may cause patients to be more susceptible to infections, including opportunistic infections, especially Pneumocystis jirovecii pneumonia, tuberculosis (including extra-pulmonary tuberculosis), and aspergillosis. Severe infections including sepsis, which may be fatal, have been reported in patients receiving ARAVA, especially Pneumocystis jirovecii pneumonia and aspergillosis. Most of the reports were confounded by concomitant immunosuppressant therapy and/or comorbid illness which, in addition to rheumatoid arthritis, may predispose patients to infection. Cases of tuberculosis were observed in clinical studies with teriflunomide, the metabolite of ARAVA. Prior to initiating ARAVA, all patients should be screened for active and inactive ("latent") tuberculosis infection as per commonly used diagnostic tests. ARAVA has not been studied in patients with a positive tuberculosis screen, and the safety of ARAVA in individuals with latent tuberculosis infection is unknown. Patients testing positive in tuberculosis screening should be treated by standard medical practice prior to therapy with ARAVA and monitored carefully during ARAVA treatment for possible reactivation of the infection. Pancytopenia, agranulocytosis, and thrombocytopenia have been reported in patients receiving ARAVA alone. These events have been reported most frequently in patients who received concomitant treatment with methotrexate or other immunosuppressive agents, or who had recently discontinued these therapies; in some cases, patients had a prior history of a significant hematologic abnormality. Patients taking ARAVA should have platelet, white blood cell count and hemoglobin or hematocrit monitored at baseline and monthly for six months following initiation of therapy and every 6 to 8 weeks thereafter. If used with concomitant methotrexate and/or other potential immunosuppressive agents, chronic monitoring should be monthly. If evidence of bone marrow suppression occurs in a patient taking ARAVA, stop treatment with ARAVA and perform an accelerated drug elimination procedure to reduce the plasma concentration of the ARAVA active metabolite, teriflunomide . In any situation in which the decision is made to switch from ARAVA to another antirheumatic agent with a known potential for hematologic suppression, it would be prudent to monitor for hematologic toxicity, because there will be overlap of systemic exposure to both compounds

Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis, and Drug Reactions with Eosinophilia and Systemic Symptoms Rare cases of Stevens-Johnson syndrome and toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms (DRESS) have been reported in patients receiving ARAVA. If a patient taking ARAVA develops any of these conditions, stop ARAVA treatment and perform an accelerated drug elimination procedure

Skin Ulcers Skin ulcers may occur in patients during therapy with leflunomide. If leflunomide-associated skin ulcer is suspected or if skin ulcers persist despite appropriate therapy, leflunomide discontinuation and an accelerated drug elimination procedure should be considered . The decision to resume leflunomide following skin ulcers should be based on clinical judgment of adequate wound healing

Malignancy and Lymphoproliferative Disorders The risk of malignancy, particularly lymphoproliferative disorders, is increased with the use of some immunosuppression medications. There is a potential for immunosuppression with ARAVA. No apparent increase in the incidence of malignancies and lymphoproliferative disorders was reported in the clinical trials of ARAVA, but larger dosages and longer-term studies would be needed to determine whether there is an increased risk of malignancy or lymphoproliferative disorders with ARAVA

Peripheral Neuropathy Cases of peripheral neuropathy have been reported in patients receiving ARAVA and in clinical studies with teriflunomide, the active metabolite of leflunomide. Most patients recovered after discontinuation of treatment, but some patients had persistent symptoms. Age older than 60 years, concomitant neurotoxic medications, and diabetes may increase the risk for peripheral neuropathy. If a patient taking ARAVA develops a peripheral neuropathy, consider discontinuing ARAVA therapy and performing an accelerated drug elimination procedure

Interstitial Lung Disease Interstitial lung disease and worsening of pre-existing interstitial lung disease have been reported during treatment with ARAVA and has been associated with fatal outcomes . The risk of ARAVA-associated interstitial lung disease is increased in patients with a history of interstitial lung disease. Interstitial lung disease is a potentially fatal disorder that may occur acutely at any time during therapy and has a variable clinical presentation. New onset or worsening pulmonary symptoms, such as cough and dyspnea, with or without associated fever, may be a reason for discontinuation of ARAVA therapy and for further investigation as appropriate. If discontinuation of ARAVA is necessary, consider performing an accelerated drug elimination procedure

Vaccinations No clinical data are available on the efficacy and safety of vaccinations during ARAVA treatment. Vaccination with live vaccines is, however, not recommended. The long half-life of the active metabolite of ARAVA should be considered when contemplating administration of a live vaccine after stopping ARAVA

Blood Pressure Monitoring In placebo-controlled studies with the active metabolite of ARAVA, teriflunomide, elevations in blood pressure were observed in some subjects. Blood pressure should be checked before starting treatment with ARAVA and monitored periodically thereafter .

Following oral administration, leflunomide is metabolized to an active metabolite, teriflunomide, which is responsible for essentially all of leflunomide's in vivo activity. Drug interaction studies have been conducted with both ARAVA (leflunomide) and with its active metabolite, teriflunomide, where the metabolite was directly administered to the test subjects. Drugs metabolized by CYP2C8 and OAT3 transporters: Monitor patients because teriflunomide may increase exposure of these drugs. Teriflunomide may increase exposure of ethinylestradiol and levonorgestrel. Choose an appropriate oral contraceptive. Drugs metabolized by CYP1A2: Monitor patients because teriflunomide may decrease exposure of these drugs. Warfarin: Monitor INR as teriflunomide may decrease INR. Drugs metabolized by BCRP and OATP1B1/B3 transporters: Monitor patients because teriflunomide may increase exposure of these drugs. Rosuvastatin: The dose of rosuvastatin should not exceed 10 mg once daily in patients taking ARAVA. Effect of Potent CYP and Transporter Inducers Leflunomide is metabolized by CYP450 metabolizing enzymes. Concomitant use of ARAVA and rifampin, a potent inducer of CYP and transporters, increased the plasma concentration of teriflunomide by 40%. However, when coadministered with the metabolite, teriflunomide, rifampin did not affect its pharmacokinetics. No dosage adjustment is recommended for ARAVA when coadministered with rifampin. Because of the potential for ARAVA concentrations to continue to increase with multiple dosing, caution should be used if patients are to be receiving both ARAVA and rifampin . Effect on CYP2C8 Substrates Teriflunomide is an inhibitor of CYP2C8 in vivo . In patients taking ARAVA, exposure of drugs metabolized by CYP2C8 (e.g., paclitaxel, pioglitazone, repaglinide, rosiglitazone) may be increased. Monitor these patients and adjust the dose of the concomitant drug(s) metabolized by CYP2C8 as required . Effect on Warfarin Coadministration of ARAVA with warfarin requires close monitoring of the international normalized ratio (INR) because teriflunomide, the active metabolite of ARAVA, may decrease peak INR by approximately 25%. Effect on Oral Contraceptives Teriflunomide may increase the systemic exposures of ethinylestradiol and levonorgestrel. Consideration should be given to the type or dose of contraceptives used in combination with ARAVA . Effect on CYP1A2 Substrates Teriflunomide, the active metabolite of ARAVA, may be a weak inducer of CYP1A2 in vivo . In patients taking ARAVA, exposure of drugs metabolized by CYP1A2 (e.g., alosetron, duloxetine, theophylline, tizanidine) may be reduced. Monitor these patients and adjust the dose of the concomitant drug(s) metabolized by CYP1A2 as required . Effect on Organic Anion Transporter 3 (OAT3) Substrates Teriflunomide inhibits the activity of OAT3 in vivo . In patients taking ARAVA, exposure of drugs which are OAT3 substrates (e.g., cefaclor, cimetidine, ciprofloxacin, penicillin G, ketoprofen, furosemide, methotrexate, zidovudine) may be increased. Monitor these patients and adjust the dose of the concomitant drug(s) which are OAT3 substrates as required . Effect on BCRP and Organic Anion Transporting Polypeptide B1 and B3 (OATP1B1/1B3) Substrates Teriflunomide inhibits the activity of BCRP and OATP1B1/1B3 in vivo . For a patient taking ARAVA, the dose of rosuvastatin should not exceed 10 mg once daily. For other substrates of BCRP (e.g., mitoxantrone) and drugs in the OATP family (e.g., methotrexate, rifampin), especially HMG-Co reductase inhibitors (e.g., atorvastatin, nateglinide, pravastatin, repaglinide, and simvastatin), consider reducing the dose of these drugs and monitor patients closely for signs and symptoms of increased exposures to the drugs while patients are taking ARAVA .