Varenicline

12.1 Mechanism of Action Varenicline binds with high affinity and selectivity at α4β2 neuronal nicotinic acetylcholine receptors. The efficacy of varenicline in smoking cessation is believed to be the result of varenicline’s activity at α4β2 sub-type of the nicotinic receptor where its binding produces agonist activity, while simultaneously preventing nicotine binding to these receptors. Electrophysiology studies in vitro and neurochemical studies in vivo have shown that varenicline binds to α4β2 neuronal nicotinic acetylcholine receptors and stimulates receptor-mediated activity, but at a significantly lower level than nicotine. Varenicline blocks the ability of nicotine to activate α4β2 receptors and thus to stimulate the central nervous mesolimbic dopamine system, believed to be the neuronal mechanism underlying reinforcement and reward experienced upon smoking. Varenicline is highly selective and binds more potently to α4β2 receptors than to other common nicotinic receptors (>500-fold α3β4, >3,500-fold α7, >20,000-fold α1βγδ), or to non-nicotinic receptors and transporters (>2,000-fold). Varenicline also binds with moderate affinity (Ki = 350 nM) to the 5-HT3 receptor.

1 INDICATIONS AND USAGE Varenicline tablets are indicated for use as an aid to smoking cessation treatment. Varenicline tablets are a nicotinic receptor partial agonist indicated for use as an aid to smoking cessation treatment. ( 1 and 2.1 )

2 DOSAGE AND ADMINISTRATION Begin varenicline tablets dosing one week before the date set by the patient to stop smoking. Alternatively, the patient can begin varenicline tablets dosing and then quit smoking between days 8 and 35 of treatment. ( 2.1 ) Starting Week: 0.5 mg once daily on days 1 to 3 and 0.5 mg twice daily on days 4 to 7. ( 2.1 ) Continuing Weeks: 1 mg twice daily for a total of 12 weeks. ( 2.1 ) An additional 12 weeks of treatment is recommended for successful quitters to increase likelihood of long-term abstinence. ( 2.1 ) Consider a gradual approach to quitting smoking with varenicline tablets for patients who are sure that they are not able or willing to quit abruptly. Patients should begin varenicline tablets dosing and reduce smoking by 50% from baseline within the first four weeks, by an additional 50% in the next four weeks, and continue reducing with the goal of reaching complete abstinence by 12 weeks. Continue treatment for an additional 12 weeks, for a total of 24 weeks. ( 2.1 ) Severe Renal Impairment (estimated creatinine clearance less than 30 mL/min): Begin with 0.5 mg once daily and titrate to 0.5 mg twice daily. For patients with end-stage renal disease undergoing hemodialysis, a maximum of 0.5 mg daily may be given if tolerated. ( 2.2 ) Consider dose reduction for patients who cannot tolerate adverse effects. ( 2.1 ) Another attempt at treatment is recommended for those who fail to stop smoking or relapse when factors contributing to the failed attempt have been addressed. ( 2.1 ) Provide patients with appropriate educational materials and counseling to support the quit attempt. ( 2.1 ) 2.1 Usual Dosage for Adults Smoking cessation therapies are more likely to succeed for patients who are motivated to stop smoking and who are provided additional advice and support. Provide patients with appropriate educational materials and counseling to support the quit attempt. The patient should set a date to stop smoking. Begin varenicline tablets dosing one week before this date. Alternatively, the patient can begin varenicline tablets dosing and then quit smoking between days 8 and 35 of treatment. Varenicline tablets should be taken orally after eating and with a full glass of water. The recommended dose of varenicline tablets are 1 mg twice daily following a 1-week titration as follows: Days 1 to 3: 0.5 mg once daily Days 4 to 7: 0.5 mg twice daily Day 8 to end of treatment: 1 mg twice daily Patients should be treated with varenicline tablets for 12 weeks. For patients who have successfully stopped smoking at the end of 12 weeks, an additional course of 12 weeks treatment with varenicline tablets are recommended to further increase the likelihood of long-term abstinence. For patients who are sure that they are not able or willing to quit abruptly, consider a gradual approach to quitting smoking with varenicline tablets. Patients should begin varenicline tablets dosing and reduce smoking by 50% from baseline within the first four weeks, by an additional 50% in the next four weeks, and continue reducing with the goal of reaching complete abstinence by 12 weeks. Continue varenicline tablets treatment for an additional 12 weeks, for a total of 24 weeks of treatment. Encourage patients to attempt quitting sooner if they feel ready [see Clinical Studies (14.5) ]. Patients who are motivated to quit, and who did not succeed in stopping smoking during prior varenicline tablets therapy for reasons other than intolerability due to adverse events or who relapsed after treatment, should be encouraged to make another attempt with varenicline tablets once factors contributing to the failed attempt have been identified and addressed. Consider a temporary or permanent dose reduction in patients who cannot tolerate the adverse effects of varenicline tablets. 2.2 Dosage in Special Populations Patients with Impaired Renal Function No dosage adjustment is necessary for patients with mild to moderate renal impairment. For patients with severe renal impairment (estimated creatinine clearance less than 30 mL per min), the recommended starting dose of varenicline tablets are 0.5 mg once daily. The dose may then be titrated as needed to a maximum dose of 0.5 mg twice daily. For patients with end-stage renal disease undergoing hemodialysis, a maximum dose of 0.5 mg once daily may be administered if tolerated [see Use in Specific Populations (8.6) , Clinical Pharmacology (12.3) ] . Elderly and Patients with Impaired Hepatic Function No dosage adjustment is necessary for patients with hepatic impairment. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function [see Use in Specific Populations (8.5) ] .

6 ADVERSE REACTIONS The following serious adverse reactions were reported in postmarketing experience and are discussed in greater detail in other sections of the labeling: Neuropsychiatric Adverse Events including Suicidality [see Warnings and Precautions (5.1) ] Seizures [see Warnings and Precautions (5.2) ] Interaction with Alcohol [see Warnings and Precautions (5.3) ] Accidental Injury [see Warnings and Precautions (5.4) ] Cardiovascular Events [see Warnings and Precautions (5.5) ] Somnambulism [see Warnings and Precautions (5.6) ] Angioedema and Hypersensitivity Reactions [see Warnings and Precautions (5.7) ] Serious Skin Reactions [see Warnings and Precautions (5.8) ] In the placebo-controlled premarketing studies, the most common adverse events associated with varenicline (>5% and twice the rate seen in placebo-treated patients) were nausea, abnormal (vivid, unusual, or strange) dreams, constipation, flatulence, and vomiting. The treatment discontinuation rate due to adverse events in patients dosed with 1 mg twice daily was 12% for varenicline, compared to 10% for placebo in studies of three months’ treatment. In this group, the discontinuation rates that are higher than placebo for the most common adverse events in varenicline-treated patients were as follows: nausea (3% vs. 0.5% for placebo), insomnia (1.2% vs. 1.1% for placebo), and abnormal dreams (0.3% vs. 0.2% for placebo). Smoking cessation, with or without treatment, is associated with nicotine withdrawal symptoms and has also been associated with the exacerbation of underlying psychiatric illness. Most common adverse reactions (>5% and twice the rate seen in placebo-treated patients) were nausea, abnormal (e.g., vivid, unusual, or strange) dreams, constipation, flatulence, and vomiting. ( 6 ) To report SUSPECTED ADVERSE REACTIONS, contact Aurobindo Pharma USA, Inc. at 1-866-850-2876 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, the adverse reactions rates observed in the clinical studies of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. During the premarketing development of varenicline, over 4500 subjects were exposed to varenicline, with over 450 treated for at least 24 weeks and approximately 100 for a year. Most study participants were treated for 12 weeks or less. The most common adverse event associated with varenicline treatment is nausea, occurring in 30% of patients treated at the recommended dose, compared with 10% in patients taking a comparable placebo regimen [see Warnings and Precautions (5.9) ] . Table 1 shows the adverse events for varenicline and placebo in the 12- week fixed dose premarketing studies with titration in the first week [Studies 2 (titrated arm only), 4, and 5]. Adverse events were categorized using the Medical Dictionary for Regulatory Activities (MedDRA, Version 7.1). MedDRA High Level Group Terms (HLGT) reported in ≥5% of patients in the varenicline 1 mg twice daily dose group, and more commonly than in the placebo group, are listed, along with subordinate Preferred Terms (PT) reported in ≥1% of varenicline patients (and at least 0.5% more frequent than placebo). Closely related Preferred Terms such as ‘Insomnia’, ‘Initial insomnia’, ‘Middle insomnia’, ‘Early morning awakening’ were grouped, but individual patients reporting two or more grouped events are only counted once. Table 1. Common Treatment Emergent AEs (%) in the Fixed-Dose, Placebo-Controlled Studies (HLGTs >5% of Patients in the 1 mg BID varenicline Group and More Commonly than Placebo and PT ≥1% in the 1 mg BID varenicline Group, and 1 mg BID varenicline at Least 0.5% More than Placebo) SYSTEM ORGAN CLASS High Level Group Term Preferred Term Varenicline 0.5 mg BID N=129 Varenicline 1 mg BID N=821 Placebo N=805 * Includes PTs Abdominal (pain, pain upper, pain lower, discomfort, tenderness, distension) and Stomach discomfort ** Includes PTs Insomnia/Initial insomnia/Middle insomnia/Early morning awakening GASTROINTESTINAL (GI) GI Signs and Symptoms Nausea 16 30 10 Abdominal Pain * 5 7 5 Flatulence 9 6 3 Dyspepsia 5 5 3 Vomiting 1 5 2 GI Motility/Defecation Conditions Constipation 5 8 3 Gastroesophageal reflux disease 1 1 0 Salivary Gland Conditions Dry mouth 4 6 4 PSYCHIATRIC DISORDERS Sleep Disorder/Disturbances Insomnia ** 19 18 13 Abnormal dreams 9 13 5 Sleep disorder 2 5 3 Nightmare 2 1 0 NERVOUS SYSTEM Headaches Headache 19 15 13 Neurological Disorders NEC Dysgeusia 8 5 4 Somnolence 3 3 2 Lethargy 2 1 0 GENERAL DISORDERS General Disorders NEC Fatigue/Malaise/Asthenia 4 7 6 RESPIR/THORACIC/MEDIAST Respiratory Disorders NEC Rhinorrhea 0 1 0 Dyspnea 2 1 1 Upper Respiratory Tract Disorder 7 5 4 SKIN/SUBCUTANEOUS TISSUE Epidermal and Dermal Conditions Rash 1 3 2 Pruritis 0 1 1 METABOLISM and NUTRITION Appetite/General Nutrition Disorders Increase

7 DRUG INTERACTIONS Based on varenicline characteristics and clinical experience to date, varenicline has no clinically meaningful pharmacokinetic drug interactions [see Clinical Pharmacology (12.3) ]. Other Smoking Cessation Therapies: Safety and efficacy in combination with other smoking cessation therapies has not been established. Coadministration of varenicline and transdermal nicotine resulted in a high rate of discontinuation due to adverse events. ( 7.1 ) Effect of Smoking Cessation on Other Drugs: Pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) may be altered, necessitating dose adjustment. ( 7.2 ) 7.1 Use with Other Drugs for Smoking Cessation Safety and efficacy of varenicline in combination with other smoking cessation therapies have not been studied. Bupropion Varenicline (1 mg twice daily) did not alter the steady-state pharmacokinetics of bupropion (150 mg twice daily) in 46 smokers. The safety of the combination of bupropion and varenicline has not been established. Nicotine replacement therapy (NRT) Although co-administration of varenicline (1 mg twice daily) and transdermal nicotine (21 mg/day) for up to 12 days did not affect nicotine pharmacokinetics, the incidence of nausea, headache, vomiting, dizziness, dyspepsia, and fatigue was greater for the combination than for NRT alone. In this study, eight of twenty-two (36%) patients treated with the combination of varenicline and NRT prematurely discontinued treatment due to adverse events, compared to 1 of 17 (6%) of patients treated with NRT and placebo. 7.2 Effect of Smoking Cessation on Other Drugs Physiological changes resulting from smoking cessation, with or without treatment with varenicline, may alter the pharmacokinetics or pharmacodynamics of certain drugs (e.g., theophylline, warfarin, insulin) for which dosage adjustment may be necessary.