Metformin

12.1 Mechanism of Action ZITUVIMET ZITUVIMET combines two antihyperglycemic agents with complementary mechanisms of action to improve glycemic control in patients with type 2 diabetes mellitus: sitagliptin, a DPP- 4 inhibitor, and metformin HCl, a member of the biguanide class. Sitagliptin Sitagliptin is a DPP-4 inhibitor, which is believed to exert its actions in patients with type 2 diabetes mellitus by slowing the inactivation of incretin hormones. Concentrations of the active intact hormones are increased by sitagliptin, thereby increasing and prolonging the action of these hormones. Incretin hormones, including glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are released by the intestine throughout the day, and levels are increased in response to a meal. These hormones are rapidly inactivated by the enzyme DPP-4. The incretins are part of an endogenous system involved in the physiologic regulation of glucose homeostasis. When blood glucose concentrations are normal or elevated, GLP-1 and GIP increase insulin synthesis and release from pancreatic beta cells by intracellular signaling pathways involving cyclic AMP. GLP-1 also lowers glucagon secretion from pancreatic alpha cells, leading to reduced hepatic glucose production. By increasing and prolonging active incretin levels, sitagliptin increases insulin release and decreases glucagon levels in the circulation in a glucose-dependent manner. Sitagliptin demonstrates selectivity for DPP-4 and does not inhibit DPP-8 or DPP-9 activity in vitro at concentrations approximating those from therapeutic doses. Metformin Metformin is an antihyperglycemic agent which improves glucose tolerance in patients with type 2 diabetes mellitus, lowering both basal and postprandial plasma glucose. Metformin decreases hepatic glucose production, decreases intestinal absorption of glucose, and improves insulin sensitivity by increasing peripheral glucose uptake and utilization. With metformin t

1 INDICATIONS AND USAGE ZITUVIMET is a combination of sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, and metformin hydrochloride (HCl), a biguanide, indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. ( 1 ) Limitations of Use: ZITUVIMET is not recommended in patients with type 1 diabetes mellitus. ( 1 ) ZITUVIMET has not been studied in patients with a history of pancreatitis. ( 1 ) ZITUVIMET is indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus. Limitations of Use ZITUVIMET is not recommended in patients with type 1 diabetes mellitus. ZITUVIMET has not been studied in patients with a history of pancreatitis. It is unknown whether patients with a history of pancreatitis are at increased risk for the development of pancreatitis while using ZITUVIMET. [see Warnings and Precautions ( 5.2 )].

2 DOSAGE AND ADMINISTRATION Take ZITUVIMET orally twice daily with meals. ( 2.1 ) Individualize the dosage of ZITUVIMET on the basis of the patient's current regimen, effectiveness, and tolerability. ( 2.1 ) The maximum recommended daily dose is 100 mg of sitagliptin and 2,000 mg of metformin HCl. ( 2.1 ) The recommended starting dose in patients not currently treated with metformin is 50 mg sitagliptin and 500 mg metformin HCl twice daily, with gradual dose escalation recommended to reduce gastrointestinal side effects associated with metformin. ( 2.1 ) The starting dose in patients already treated with metformin should provide sitagliptin dosed as 50 mg twice daily (100 mg total daily dose) and the dose of metformin already being taken. For patients taking metformin HCl 850 mg twice daily, the recommended starting dose of ZITUVIMET is 50 mg sitagliptin and 1,000 mg metformin HCl twice daily. ( 2.1 ) Prior to initiation, assess renal function with estimated glomerular filtration rate (eGFR) ( 2.2 ) ○ Do not use in patients with eGFR below 30 mL/min/1.73 m 2 ○ ZITUVIMET is not recommended in patients with eGFR between 30 and less than 45 mL/min/1.73 m 2 . ZITUVIMET may need to be discontinued at time of, or prior to, iodinated contrast imaging procedures. ( 2.3 ) 2.1 Recommended Dosage Take ZITUVIMET orally twice daily with meals. Individualize the dosage of ZITUVIMET on the basis of the patient's current regimen, effectiveness, and tolerability. The maximum recommended daily dose is 100 mg of sitagliptin and 2,000 mg of metformin hydrochloride (HCl). Do not split or divide ZITUVIMET tablets. The recommended starting dose in patients not currently treated with metformin is 50 mg sitagliptin and 500 mg metformin HCl twice daily, with gradual dose escalation recommended to reduce gastrointestinal side effects associated with metformin. The starting dose in patients already treated with metformin should provide sitagliptin dosed as 50 mg twice daily (100 mg total daily dose) and the dose of metformin already being taken. For patients taking metformin HCl 850 mg twice daily, the recommended starting dose of ZITUVIMET is 50 mg sitagliptin and 1,000 mg metformin HCl twice daily. 2.2 Recommendations for Use in Renal Impairment Assess renal function prior to initiation of ZITUVIMET and periodically thereafter. ZITUVIMET is contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/min/1.73 m 2 [see Contraindications ( 4 ) and Warnings and Precautions ( 5.1 )]. ZITUVIMET is not recommended in patients with an eGFR between 30 and less than 45 mL/min/1.73 m 2 because these patients require a lower dosage of sitagliptin than what is available in the fixed combination ZITUVIMET product. 2.3 Discontinuation for Iodinated Contrast Imaging Procedures Discontinue ZITUVIMET at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min/1.73 m 2 ; in patients with a history of liver disease, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate eGFR 48 hours after the imaging procedure; restart ZITUVIMET if renal function is stable [see Warnings and Precautions ( 5.1 )].

6 ADVERSE REACTIONS The following adverse reactions are also discussed elsewhere in the prescribing information: Lactic Acidosis [see Warnings and Precautions ( 5.1 )] Pancreatitis [see Warnings and Precautions ( 5.2 )] Heart Failure [see Warnings and Precautions ( 5.3 )] Acute Renal Failure [see Warnings and Precautions ( 5.4 )] Vitamin B12 Deficiency [see Warnings and Precautions ( 5.5 )] Hypoglycemia with Concomitant Use with Insulin or Insulin Secretagogues [see Warnings and Precautions ( 5.6 )] Hypersensitivity Reactions [see Warnings and Precautions ( 5.7 )] Severe and Disabling Arthralgia [see Warnings and Precautions ( 5.8 )] Bullous Pemphigoid [see Warnings and Precautions ( 5.9 )] Most common adverse reactions (incidence ≥5% of patients simultaneously started on sitagliptin and metformin and more commonly than in patients treated with placebo were diarrhea, upper respiratory tract infection, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Zydus Pharmaceuticals (USA) Inc. at 1-877-993-8779 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. Common Adverse Reactions Sitagliptin and Metformin Coadministration in Patients with Type 2 Diabetes Mellitus Inadequately Controlled on Diet and Exercise Table 1 summarizes the most common (≥5% of patients) adverse reactions reported in a 24-week placebo-controlled factorial trial in which sitagliptin and metformin were coadministered to patients with type 2 diabetes mellitus inadequately controlled on diet and exercise. Table 1: Sitagliptin and Metformin Coadministered to Patients with Type 2 Diabetes Mellitus Inadequately Controlled on Diet and Exercise: Adverse Reactions Reported in ≥5% of Patients Receiving Combination Therapy (and Greater than in Patients Receiving Placebo) Intent-to-treat population. Number of Patients (%) Placebo Sitagliptin 100 mg once daily Metformin HCl 500 mg/ Metformin HCl 1,000 mg twice daily Data pooled for the patients given the lower and higher doses of metformin. Sitagliptin 50 mg twice daily + Metformin HCl 500 mg/ Metformin HCl 1,000 mg twice daily N = 176 N = 179 N = 364 N = 372 Diarrhea 7 (4) 5 (2.8) 28 (7.7) 28 (7.5) Upper Respiratory Tract Infection 9 (5.1) 8 (4.5) 19 (5.2) 23 (6.2) Headache 5 (2.8) 2 (1.1) 14 (3.8) 22 (5.9) Sitagliptin Add-on Therapy in Patients with Type 2 Diabetes Mellitus Inadequately Controlled on Metformin Alone In a 24-week placebo-controlled trial of sitagliptin 100 mg administered once daily added to a twice daily metformin regimen, there were no adverse reactions in ≥5% of patients and more commonly than in patients given placebo. Discontinuation of therapy due to clinical adverse reactions was similar to the placebo treatment group (sitagliptin and metformin, 1.9%; placebo and metformin, 2.5%). Gastrointestinal Adverse Reactions The incidences of pre-selected gastrointestinal adverse experiences in patients treated with sitagliptin and metformin were similar to those reported for patients treated with metformin alone. See Table 2. Table 2: Pre-selected Gastrointestinal Adverse Reactions Reported in Patients with Type 2 Diabetes Mellitus Receiving Sitagliptin and Metformin Number of Patients (%) Trial of Sitagliptin and Metformin in Patients Inadequately Controlled on Diet and Exercise Trial of Sitagliptin Add-on in Patients Inadequately Controlled on Metformin Alone Placebo Sitagliptin 100 mg once daily Metformin HCl 500 mg/ Metformin HCl 1,000 mg twice daily Data pooled for the patients given the lower and higher doses of metformin. Sitagliptin 50 mg twice daily + Metformin HCl 500 mg/ Metformin HCl 1,000 mg twice daily Placebo and Metformin HCl ≥1,500 mg daily Sitagliptin 100 mg once daily and Metformin HCl ≥1,500 mg daily N = 176 N = 179 N = 364 N = 372 N = 237 N = 464 Diarrhea 7 (4) 5 (2.8) 28 (7.7) 28 (7.5) 6 (2.5) 11 (2.4) Nausea 2 (1.1) 2 (1.1) 20 (5.5) 18 (4.8) 2 (0.8) 6 (1.3) Vomiting 1 (0.6) 0 (0) 2 (0.5) 8 (2.2) 2 (0.8) 5 (1.1) Abdominal Pain Abdominal discomfort was included in the analysis of abdominal pain in the trial of initial therapy. 4 (2.3) 6 (3.4) 14 (3.8) 11 (3) 9 (3.8) 10 (2.2) Sitagliptin in Combination with Metformin and Glimepiride In a 24-week placebo-controlled trial of sitagliptin 100 mg as add-on therapy in patients with type 2 diabetes mellitus inadequately controlled on metformin and glimepiride (sitagliptin, N=116; placebo, N=113), the adverse reactions reported in ≥5% of patients treated with sitagliptin and more commonly than in patients treated with placebo were: hypoglycemia ( see Table 3) and headache (6.9%, 2.7%). Sitagliptin in Combination with Metformin and Rosiglitazone In a placebo-controlled trial of sitagliptin 100 mg as add-on therapy in pat

7 DRUG INTERACTIONS Table 4 presents clinically significant drug interactions with ZITUVIMET: Table 4: Clinically Significant Drug Interactions with ZITUVIMET Carbonic Anhydrase Inhibitors Clinical Impact: Carbonic anhydrase inhibitors frequently cause a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with ZITUVIMET may increase the risk for lactic acidosis. Intervention: Consider more frequent monitoring of these patients. Examples: Topiramate, zonisamide, acetazolamide or dichlorphenamide. Drugs that Reduce Metformin Clearance Clinical Impact: Concomitant use of drugs that interfere with common renal tubular transport systems involved in the renal elimination of metformin (e.g., organic cationic transporter-2 [OCT 2 ] / multidrug and toxin extrusion [MATE] inhibitors) could increase systemic exposure to metformin and may increase the risk for lactic acidosis [see Clinical Pharmacology ( 12.3 )]. Intervention: Consider the benefits and risks of concomitant use with ZITUVIMET. Examples: Ranolazine, vandetanib, dolutegravir, and cimetidine. Alcohol Clinical Impact: Alcohol is known to potentiate the effect of metformin on lactate metabolism. Intervention: Warn patients against alcohol intake while receiving ZITUVIMET. Insulin Secretagogues or Insulin Clinical Impact: Coadministration of ZITUVIMET with an insulin secretagogue (e.g., sulfonylurea) or insulin may increase the risk of hypoglycemia. Intervention: Patients receiving an insulin secretagogue or insulin may require lower doses of the insulin secretagogue or insulin. Drugs Affecting Glycemic Control Clinical Impact: Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. Intervention: When such drugs are administered to a patient receiving ZITUVIMET, observe the patient closely for loss of blood glucose control. When such drugs are withdrawn from a patient receiving ZITUVIMET, observe the patient closely for hypoglycemia. Examples: Thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid. Carbonic anhydrase inhibitors may increase risk of lactic acidosis. Consider more frequent monitoring. ( 7 ) Drugs that reduce metformin clearance (such as ranolazine, vandetanib, dolutegravir, and cimetidine) may increase the accumulation of metformin. Consider the benefits and risks of concomitant use. ( 7 ) Alcohol can potentiate the effect of metformin on lactate metabolism. Warn patients against excessive alcohol intake. ( 7 )