Pioglitazone Hydrochloride and Glimepiride Tablets

Dosage Forms And Strengths

• 30 mg/2 mg tablet: White to off-white, round, convex tablets, debossed with “4833G” on one side and “30/2” on the other
• 30 mg/4 mg tablet: White to off-white, round, convex tablets, debossed with “4833G” on one side and “30/4” on the other

Storage And Handling

DUETACT is available in 30 mg pioglitazone plus 2 mg glimepiride or 30 mg pioglitazone plus 4 mg glimepiride tablets as follows:

30 mg/2 mg tablet: white to off-white, round, convex tablets, debossed with 4833G on one side and 30/2 on the other, available in:

NDC 64764-302-30 Bottles of 30
NDC 64764-302-90 Bottles of 90

30 mg/4 mg tablet: white to off-white, round, convex tablets, debossed with 4833G on one side and 30/4 on the other, available in:

NDC 64764-304-30 Bottles of 30
NDC 64764-304-90 Bottles of 90

Storage

Store at 25°C (77°F); excursions permitted to 15° to 30°C (59° to 86°F) [see USP Controlled Room Temperature]. Keep container tightly closed and protect from moisture and humidity.

Distributed by: Takeda Pharmaceuticals America, Inc., Deerfield, IL 60015. Revised: March 2015

Pioglitazone

During controlled clinical trials, one case of overdose with pioglitazone was reported. A male patient took 120 mg per day for four days, then 180 mg per day for seven days. The patient denied any clinical symptoms during this period.

In the event of overdosage, appropriate supportive treatment should be initiated according to the patient's clinical signs and symptoms.

Glimepiride

An overdosage of glimepiride, as with other sulfonylureas, can produce severe hypoglycemia. Mild episodes of hypoglycemia can be treated with oral glucose. Severe hypoglycemic reactions constitute medical emergencies requiring immediate treatment. Severe hypoglycemia with coma, seizure, or neurological impairment can be treated with glucagon or intravenous glucose. Continued observation and additional carbohydrate intake may be necessary because hypoglycemia may recur after apparent clinical recovery [see WARNINGS AND PRECAUTIONS].

Mechanism Of Action

DUETACT combines 2 antihyperglycemic agents with different mechanisms of action to improve glycemic control in patients with type 2 diabetes: pioglitazone, a member of the thiazolidinedione class, and glimepiride, a member of the sulfonylurea class. Thiazolidinediones are insulin-sensitizing agents that act primarily by enhancing peripheral glucose utilization, whereas sulfonylureas are insulin secretagogues that act primarily by stimulating release of insulin from functioning pancreatic beta cells.

Pioglitazone is a thiazolidinedione that depends on the presence of insulin for its mechanism of action. Pioglitazone decreases insulin resistance in the periphery and in the liver resulting in increased insulin-dependent glucose disposal and decreased hepatic glucose output. Pioglitazone is not an insulin secretagogue. Pioglitazone is an agonist for peroxisome proliferator-activated receptor-gamma (PPARγ). PPAR receptors are found in tissues important for insulin action such as adipose tissue, skeletal muscle, and liver. Activation of PPARγ nuclear receptors modulates the transcription of a number of insulin responsive genes involved in the control of glucose and lipid metabolism.

In animal models of diabetes, pioglitazone reduces the hyperglycemia, hyperinsulinemia, and hypertriglyceridemia characteristic of insulin-resistant states such as type 2 diabetes. The metabolic changes produced by pioglitazone result in increased responsiveness of insulin-dependent tissues and are observed in numerous animal models of insulin resistance.

Because pioglitazone enhances the effects of circulating insulin (by decreasing insulin resistance), it does not lower blood glucose in animal models that lack endogenous insulin.

Glimepiride primarily lowers blood glucose by stimulating the release of insulin from pancreatic beta cells. Sulfonylureas bind to the sulfonylurea receptor in the pancreatic beta cell plasma membrane, leading to closure of the ATP-sensitive potassium channel, thereby stimulating the release of insulin.

Pharmacodynamics

Clinical studies demonstrate that pioglitazone improves insulin sensitivity in insulinresistant patients. Pioglitazone enhances cellular responsiveness to insulin, increases insulin-dependent glucose disposal and improves hepatic sensitivity to insulin. In patients with type 2 diabetes, the decreased insulin resistance produced by pioglitazone results in lower plasma glucose concentrations, lower plasma insulin concentrations, and lower HbA1c values. In controlled clinical trials, pioglitazone had an additive effect on glycemic control when used in combination with a sulfonylurea, metformin, or insulin [see Clinical Studies].

Patients with lipid abnormalities were included in clinical trials with pioglitazone. Overall, patients treated with pioglitazone had mean decreases in serum triglycerides, mean increases in HDL cholesterol, and no consistent mean changes in LDL and total cholesterol. There is no conclusive evidence of macrovascular benefit with pioglitazone or any other antidiabetic medication [see WARNINGS AND PRECAUTIONS and ADVERSE REACTIONS].

In a 26-week, placebo-controlled, dose-ranging monotherapy study, mean serum triglycerides decreased in the 15 mg, 30 mg, and 45 mg pioglitazone dose groups compared to a mean increase in the placebo group. Mean HDL cholesterol increased to a greater extent in patients treated with pioglitazone than in the placebo-treated patients. There were no consistent differences for LDL and total cholesterol in patients treated with pioglitazone compared to placebo (Table 12).

Table 12: Lipids in a 26-Week Placebo-Controlled Monotherapy Dose-Ranging Study

In the two other monotherapy studies (16 weeks and 24 weeks) and in combination therapy studies with sulfonylurea (16 weeks and 24 weeks), metformin (16 weeks and 24 weeks) or insulin (16 weeks and 24 weeks), the results were generally consistent with the data above.

In healthy subjects, the time to reach maximal effect (minimum blood glucose concentrations) was approximately by two to three hours after single oral doses of glimepiride. The effects of HbA1C, fasting plasma glucose, and post-prandial glucose have been assessed in clinical trials.

Pharmacokinetics

DUETACT

Bioequivalence studies were conducted following a single dose of the DUETACT 30 mg/2 mg and 30 mg/4 mg tablets and concomitant administration of pioglitazone (30 mg) and glimepiride (2 mg or 4 mg) under fasting conditions in healthy subjects.

Based on the area under the curve (AUC) and maximum concentration (Cmax) of both pioglitazone and glimepiride, DUETACT 30 mg/2 mg and 30 mg/4 mg were bioequivalent to pioglitazone 30 mg concomitantly administered with glimepiride (2 mg or 4 mg, respectively).

Food did not change the systemic exposures of glimepiride or pioglitazone following administration of DUETACT. The presence of food did not significantly alter the time to peak serum concentration (Tmax) of glimepiride or pioglitazone and Cmax of pioglitazone. However, for glimepiride, there was a 22% increase in Cmax when DUETACT was administered with food.

Pioglitazone

Following once-daily administration of pioglitazone, steady-state serum concentrations of both pioglitazone and its major active metabolites, M-III (keto derivative of pioglitazone) and M-IV (hydroxyl derivative of pioglitazone), are achieved within seven days. At steady-state, M-III and M-IV reach serum concentrations equal to or greater than that of pioglitazone. At steady-state, in both healthy volunteers and patients with type 2 diabetes, pioglitazone comprises approximately 30% to 50% of the peak total pioglitazone serum concentrations (pioglitazone plus active metabolites) and 20% to 25% of the total AUC.

Cmax, AUC, and trough serum concentrations (Cmin) for pioglitazone and M-III and M-IV, increased proportionally with administered doses of 15 mg and 30 mg per day. Following oral administration of pioglitazone, Tmax of pioglitazone was within two hours. Food delays Tmax to three to four hours but does not alter the extent of absorption (AUC).

Glimepiride

Studies with single oral doses of glimepiride in healthy subjects and with multiple oral doses in patients with type 2 diabetes showed peak drug concentrations (Cmax) two to three hours post-dose. When glimepiride was given with meals, the mean Cmax and AUC were decreased by 8% and 9%, respectively.

Glimepiride does not accumulate in serum following multiple dosing. The pharmacokinetics of glimepiride does not differ between healthy subjects and patients with type 2 diabetes. Clearance (CL/F) of glimepiride after oral administration does not change over the 1 mg to 8 mg dose range, indicating linear pharmacokinetics.

In healthy subjects, the intra- and inter-individual variabilities of glimepiride pharmacokinetic parameters were 15% to 23% and 24% to 29%, respectively.

Pioglitazone

The mean apparent volume of distribution (Vd/F) of pioglitazone following single-dose administration is 0.63 ± 0.41 (mean ± SD) L/kg of body weight. Pioglitazone is extensively protein bound ( > 99%) in human serum, principally to serum albumin. Pioglitazone also binds to other serum proteins, but with lower affinity. M-III and M-IV are also extensively bound ( > 98%) to serum albumin.

Glimepiride

After intravenous (IV) dosing in healthy subjects, Vd/F was 8.8 L (113 mL/kg), and the total body clearance (CL) was 47.8 mL/min. Protein binding was greater than 99.5%.

Pioglitazone

Pioglitazone is extensively metabolized by hydroxylation and oxidation; the metabolites also partly convert to glucuronide or sulfate conjugates. Metabolites M-III and M-IV are the major circulating active metabolites in humans.

In vitro data demonstrate that multiple CYP isoforms are involved in the metabolism of pioglitazone which include CYP2C8 and, to a lesser degree, CYP3A4 with additional contributions from a variety of other isoforms including the mainly extrahepatic CYP1A1. In vivo study of pioglitazone in combination with gemfibrozil, a strong CYP2C8 inhibitor, showed that pioglitazone is a CYP2C8 substrate [see DOSAGE AND ADMINISTRATION and DRUG INTERACTIONS]. Urinary 6ß-hydroxycortisol/cortisol ratios measured in patients treated with pioglitazone showed that pioglitazone is not a strong CYP3A4 enzyme inducer.

Glimepiride

Glimepiride is completely metabolized by oxidative biotransformation after either an IV or oral dose. The major metabolites are the cyclohexyl hydroxy methyl derivative (M1) and the carboxyl derivative (M2). CYP2C9 is involved in the biotransformation of glimepiride to M1. M1 is further metabolized to M2 by one or several cytosolic enzymes. In animals, M1 possesses about one-third of the pharmacological activity of glimepiride, but it is unclear whether M1 results in clinically meaningful effects on blood glucose in humans. M2 is inactive.

Pioglitazone

Following oral administration, approximately 15% to 30% of the pioglitazone dose is recovered in the urine. Renal elimination of pioglitazone is negligible and the drug is excreted primarily as metabolites and their conjugates. It is presumed that most of the oral dose is excreted into the bile either unchanged or as metabolites and eliminated in the feces.

The mean serum half-life (t½) of pioglitazone and its metabolites (M-III and M-IV) range from three to seven hours and 16 to 24 hours, respectively. Pioglitazone has an apparent clearance, CL/F, calculated to be five to seven L/hr.

Glimepiride

When 14C-glimepiride was given orally to three healthy male subjects, approximately 60% of the total radioactivity was recovered in the urine in seven days. M1 and M2 accounted for 80% to 90% of the radioactivity recovered in the urine. The ratio of M1 to M2 in the urine was approximately 3:2 in two subjects and 4:1 in one subject. Approximately 40% of the total radioactivity was recovered in feces. M1 and M2 accounted for approximately 70% (ratio of M1 to M2 was 1:3) of the radioactivity recovered in feces. No parent drug was recovered from urine or feces. After IV dosing in patients, no significant biliary excretion of glimepiride or its M1 metabolite was observed.

Pioglitazone

The serum elimination half-life of pioglitazone, M-III, and M-IV remains unchanged in patients with moderate [creatinine clearance (CLcr) 30 to 50 mL/min] and severe (CLcr < 30 mL/min) renal impairment when compared to subjects with normal renal function. Therefore, no dose adjustment in patients with renal impairment is required.

Glimepiride

In a single-dose, open-label study glimepiride 3 mg was administered to patients with mild, moderate and severe renal impairment as estimated by CLcr: Group I consisted of five patients with mild renal impairment (CLcr > 50 mL/min), Group II consisted of 3 patients with moderate renal impairment (CLcr = 20 to 50 mL/min) and Group III consisted of seven patients with severe renal impairment (CLcr < 20 mL/min). Although, glimepiride serum concentrations decreased with decreasing renal function, Group III had a 2.3-fold higher mean AUC for M1 and an 8.6-fold higher mean AUC for M2 compared to corresponding mean AUCs in Group I. The t½ for glimepiride did not change, while the t½ for M1 and M2 increased as renal function decreased. Mean urinary excretion of M1 plus M2 as a percentage of dose decreased from 44.4% for Group I to 21.9% for Group II and 9.3% for Group III.

Pioglitazone

Compared with healthy controls, subjects with impaired hepatic function (Child-Turcotte- Pugh Grade B/C) have an approximate 45% reduction in pioglitazone and total pioglitazone (pioglitazone, M-III, and M-IV) mean Cmax but no change in the mean AUC values. Therefore, no dose adjustment in patients with hepatic impairment is required. There are postmarketing reports of liver failure with pioglitazone and clinical trials have generally excluded patients with serum ALT > 2.5 times the upper limit of the reference range. Use DUETACT with caution in patients with liver disease [see WARNINGS AND PRECAUTIONS].

Glimepiride

It is unknown whether there is an effect of hepatic impairment on glimepiride pharmacokinetics because the pharmacokinetics of glimepiride has not been adequately evaluated in patients with hepatic impairment.

Pioglitazone

In healthy elderly subjects, Cmax of pioglitazone was not significantly different, but AUC values were approximately 21% higher than those achieved in younger subjects. The mean t½ of pioglitazone was also prolonged in elderly subjects (about 10 hours) as compared to younger subjects (about seven hours). These changes were not of a magnitude that would be considered clinically relevant.

Glimepiride

A comparison of glimepiride pharmacokinetics in patients with type 2 diabetes ≤ 65 years and those > 65 years was evaluated in a multiple-dose study using 6 mg daily dose. There were no significant differences in glimepiride pharmacokinetics between the two age groups. The mean AUC at steady state for the older patients was approximately 13% lower than that for the younger patients; the mean weight-adjusted clearance for the older patients was approximately 11% higher than that for the younger patients.

No pharmacokinetic studies of DUETACT were performed in pediatric patients.

Pioglitazone

Safety and efficacy of pioglitazone in pediatric patients have not been established. DUETACT is not recommended for use in pediatric patients [see Use in Specific Populations].

Pioglitazone

The mean Cmax and AUC values of pioglitazone were increased 20% to 60% in women compared to men. In controlled clinical trials, HbA1c decreases from baseline were generally greater for females than for males (average mean difference in HbA1c 0.5%). Because therapy should be individualized for each patient to achieve glycemic control, no dose adjustment is recommended based on gender alone.

Glimepiride

There were no differences between males and females in the pharmacokinetics of glimepiride when adjustment was made for differences in body weight.

Pioglitazone

Pharmacokinetic data among various ethnic groups are not available.

Glimepiride

No studies have been conducted to assess the effects of race on glimepiride pharmacokinetics but in placebo-controlled trials of glimepiride in patients with type 2 diabetes, the reduction in HbA1c was comparable in Caucasians (n=536), blacks (n=63), and Hispanics (n=63).

The pharmacokinetics of glimepiride and its metabolites were measured in a singledose study involving 28 patients with type 2 diabetes who either had normal body weight or were morbidly obese. While the Tmax, CL/F, and Vd/F of glimepiride in the morbidly obese patients were similar to those in the normal weight group, the morbidly obese had lower Cmax and AUC than those of normal body weight. The mean Cmax, AUC0-24, AUC0-∞ values of glimepiride in normal vs. morbidly obese patients were 547 ± 218 ng/mL vs. 410 ± 124 ng/mL, 3210 ± 1030 hours•ng/mL vs. 2820 ± 1110 hours•ng/mL and 4000 ± 1320 hours•ng/mL versus 3280 ± 1360 hours•ng/mL, respectively.

Drug-Drug Interactions

Coadministration of pioglitazone (45 mg) and a sulfonylurea (5 mg glipizide) administered orally once daily for seven days did not alter the steady-state pharmacokinetics of glipizide. Glimepiride and glipizide have similar metabolic pathways and are mediated by CYP2C9; therefore, drug-drug interaction between pioglitazone and glimepiride is considered unlikely. Specific pharmacokinetic drug interaction studies with DUETACT have not been performed, although such studies have been conducted with the individual pioglitazone and glimepiride components.

Table 13: Effect of Pioglitazone Coadministration on Systemic Exposure of Other Drugs

Table 14: Effect of Coadministered Drugs on Pioglitazone Systemic Exposure

Aspirin

In a randomized, double-blind, two-period, crossover study, healthy subjects were given either placebo or aspirin 1 gram three times daily for a total treatment period of 5 days. On Day 4 of each study period, a single 1 mg dose of glimepiride was administered. The glimepiride doses were separated by a 14-day washout period. Coadministration of aspirin and glimepiride resulted in a 34% decrease in the mean glimepiride AUC and a 4% decrease in the mean glimepiride Cmax.

Cimetidine and Ranitidine

In a randomized, open-label, 3-way crossover study, healthy subjects received either a single 4 mg dose of glimepiride alone, glimepiride with ranitidine (150 mg twice daily for 4 days; glimepiride was administered on Day 3), or glimepiride with cimetidine (800 mg daily for 4 days; glimepiride was administered on Day 3). Coadministration of cimetidine or ranitidine with a single 4 mg oral dose of glimepiride did not significantly alter the absorption and disposition of glimepiride.

Propranolol

In a randomized, double-blind, two-period, crossover study, healthy subjects were given either placebo or propranolol 40 mg three times daily for a total treatment period of five days. On Day 4 or each study period, a single 2 mg dose of glimepiride was administered. The glimepiride doses were separated by a 14-day washout period. Concomitant administration of propranolol and glimepiride significantly increased glimepiride Cmax, AUC, and t½ by 23%, 22%, and 15%, respectively, and decreased glimepiride CL/F by 18%. The recovery of M1 and M2 from urine was not changed.

Warfarin

In an open-label, two-way, crossover study, healthy subjects received 4 mg of glimepiride daily for 10 days. Single 25 mg doses of warfarin were administered six days before starting glimepiride and on Day 4 of glimepiride administration. The concomitant administration of glimepiride did not alter the pharmacokinetics of R- and S-warfarin enantiomers. No changes were observed in warfarin plasma protein binding. Glimepiride resulted in a statistically significant decrease in the pharmacodynamic response to warfarin. The reductions in mean area under the prothrombin time (PT) curve and maximum PT values during glimepiride treatment were 3.3% and 9.9%, respectively, and are unlikely to be clinically relevant.

Colesevelam

Concomitant administration of colesevelam and glimepiride resulted in reductions in glimepiride AUC0-∞ and Cmax of 18% and 8%, respectively. When glimepiride was administered 4 hours prior to colesevelam, there was not significant change in glimepiride AUC0-∞ and Cmax, -6% and 3%, respectively [see DOSAGE AND ADMINISTRATION and DRUG INTERACTIONS].

Animal Toxicology And/Or Pharmacology

Heart enlargement has been observed in mice (100 mg/kg), rats (4 mg/kg and above), and dogs (3 mg/kg) treated orally with the pioglitazone hydrochloride component of DUETACT (approximately 11, one, and two times the maximum recommended human oral dose for mice, rats, and dogs, respectively, based on mg/m²). In a one-year rat study, drug-related early death due to apparent heart dysfunction occurred at an oral dose of 160 mg/kg/day (approximately 35 times the maximum recommended human oral dose based on mg/m²). Heart enlargement was seen in a 13-week study in monkeys at oral doses of 8.9 mg/kg and above (approximately four times the maximum recommended human oral dose based on mg/m²), but not in a 52-week study at oral doses up to 32 mg/kg (approximately 13 times the maximum recommended human oral dose based on mg/m²).

Clinical Studies

There have been no clinical efficacy studies conducted with DUETACT. However, the efficacy and safety of the separate components have been previously established. The coadministration of pioglitazone and a sulfonylurea, including glimepiride, has been evaluated for efficacy and safety in two clinical studies. These clinical studies established an added benefit of pioglitazone in glycemic control of patients with inadequately controlled type 2 diabetes while on sulfonylurea therapy. Bioequivalence of DUETACT with coadministered pioglitazone and glimepiride tablets was demonstrated at the 30 mg/2 mg and 30 mg/4 mg dosage strengths [see CLINICAL PHARMACOLOGY].

Two clinical trials were conducted with pioglitazone in combination with a sulfonylurea. Both studies included patients with type 2 diabetes on any dose of a sulfonylurea, either alone or in combination with another antidiabetic agent. All other antidiabetic agents were withdrawn at least three weeks prior to starting study treatment.

In the first study, 560 patients were randomized to receive 15 mg or 30 mg of pioglitazone or placebo once daily for 16 weeks in addition to their current sulfonylurea regimen. Treatment with pioglitazone as add-on to sulfonylurea produced statistically significant improvements in HbA1c and FGP at endpoint compared to placebo add-on to sulfonylurea (Table 15).

Table 15: Glycemic Parameters in a 16-Week Placebo-Controlled, Add-on to Sulfonylurea Trial

In the second trial, 702 patients were randomized to receive 30 mg or 45 mg of pioglitazone once daily for 24 weeks in addition to their current sulfonylurea regimen. The mean reduction from baseline at Week 24 in HbA1c was 1.6% for the 30 mg dose and 1.7% for the 45 mg dose (see Table 16). The mean reduction from baseline at Week 24 in FPG was 52 mg/dL for the 30 mg dose and 56 mg/dL for the 45 mg dose.

The therapeutic effect of pioglitazone in combination with sulfonylurea was observed in patients regardless of the sulfonylurea dose.

Table 16: Glycemic Parameters in a 24-Week Add-on to Sulfonylurea Trial

Do not take glimepiride and pioglitazone for longer than recommended. Taking this medication for longer than 1 year (12 months) may increase your risk of developing bladder cancer. Talk with your doctor about your specific risk.

Before taking glimepiride and pioglitazone, tell your doctor if you have congestive heart failure or heart disease, a history of bladder cancer, a history of heart attack or stroke, liver disease, or kidney disease.

Take care not to let your blood sugar get too low. Low blood sugar (hypoglycemia) can occur if you skip a meal, exercise too long, drink alcohol, or are under stress. Symptoms include headache, hunger, weakness, sweating, tremor, irritability, or trouble concentrating. Carry hard candy or glucose tablets with you in case you have low blood sugar. Other sugar sources include orange juice and milk. Be sure your family and close friends know how to help you in an emergency.

Certain oral diabetes medications may increase your risk of serious heart problems. However, not treating your diabetes can damage your heart and other organs. Talk to your doctor about the risks and benefits of treating your diabetes with glimepiride and pioglitazone.

The following serious adverse reactions are discussed elsewhere in the labeling:

• Congestive Heart Failure [see BOXED WARNING and WARNINGS AND PRECAUTIONS]
• Hypoglycemia [see WARNINGS AND PRECAUTIONS]
• Edema [see WARNINGS AND PRECAUTIONS]
• Fractures [see WARNINGS AND PRECAUTIONS]
• Hemolytic Anemia [see WARNINGS AND PRECAUTIONS]

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.

The adverse events reported in at least 5% of patients in the controlled 16-week clinical studies between placebo plus a sulfonylurea and pioglitazone (15 mg and 30 mg combined) plus sulfonylurea treatment arms were upper respiratory tract infection (15.5% and 16.6%), accidental injury (8.6% and 3.5%), and combined edema/peripheral edema (2.1% and 7.2%), respectively.

The incidence and type of adverse events reported in at least 5% of patients in any combined treatment group from the 24-week study comparing pioglitazone 30 mg plus a sulfonylurea and pioglitazone 45 mg plus a sulfonylurea are shown in Table 1; the rate of adverse events resulting in study discontinuation between the two treatment groups was 6% and 9.7%, respectively.

Table 1: Adverse Events that Occurred in ≥ 5% of Patients in Any Treatment Group During the 24-Week Study

In US double-blind studies, anemia was reported in ≤ 2% of patients treated with pioglitazone plus a sulfonylurea [see WARNINGS AND PRECAUTIONS].

Over 8500 patients with type 2 diabetes have been treated with pioglitazone in randomized, double-blind, controlled clinical trials, including 2605 patients with type 2 diabetes and macrovascular disease treated with pioglitazone in the PROactive clinical trial. In these trials, over 6000 patients have been treated with pioglitazone for six months or longer, over 4500 patients have been treated with pioglitazone for one year or longer, and over 3000 patients have been treated with pioglitazone for at least two years.

In six pooled 16- to 26-week placebo-controlled monotherapy and 16- to 24-week addon combination therapy trials, the incidence of withdrawals due to adverse events was 4.5% for patients treated with pioglitazone and 5.8% for comparator-treated patients. The most common adverse events leading to withdrawal were related to inadequate glycemic control, although the incidence of these events was lower (1.5%) with pioglitazone than with placebo (3.0%).

In the PROactive trial, the incidence of withdrawals due to adverse events was 9.0% for patients treated with pioglitazone and 7.7% for placebo-treated patients. Congestive heart failure was the most common serious adverse event leading to withdrawal occurring in 1.3% of patients treated with pioglitazone and 0.6% of patients treated with placebo.

A summary of the incidence and type of common adverse events reported in three pooled 16- to 26-week placebo-controlled monotherapy trials of pioglitazone is provided in Table 2. Terms that are reported represent those that occurred at an incidence of > 5% and more commonly in patients treated with pioglitazone than in patients who received placebo. None of these adverse events were related to the pioglitazone dose.

Table 2: �Three Pooled 16- to 26-Week Placebo-Controlled Clinical Trials of Pioglitazone Monotherapy: Adverse Events Reported at an Incidence > 5% and More Commonly in Patients Treated with Pioglitazone than in Patients Treated with Placebo

A summary of the overall incidence and types of common adverse events reported in the PROactive trial is provided in Table 3. Terms that are reported represent those that occurred at an incidence of > 5% and more commonly in patients treated with pioglitazone than in patients who received placebo.

Table 3: PROactive Trial: Incidence and Types of Adverse Events Reported in > 5% of Patients Treated with Pioglitazone and More Commonly than Placebo

Mean duration of patient follow-up was 34.5 months.

A summary of the incidence of adverse events related to congestive heart failure is provided in Table 4 for the 16- to 24-week add-on to sulfonylurea trials, for the 16- to 24-week add-on to insulin trials, and for the 16- to 24-week add-on to metformin trials. None of the events were fatal.

Table 4: Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF)

Patients with type 2 diabetes and NYHA class II or early class III congestive heart failure were randomized to receive 24 weeks of double-blind treatment with either pioglitazone at daily doses of 30 mg to 45 mg (n=262) or glyburide at daily doses of 10 mg to 15 mg (n=256). A summary of the incidence of adverse events related to congestive heart failure reported in this study is provided in Table 5.

Table 5: Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) in Patients with NYHA Class II or III Congestive Heart Failure Treated with Pioglitazone or Glyburide

Congestive heart failure events leading to hospitalization that occurred during the PROactive trial are summarized in Table 6.

Table 6: Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) in PROactiveTrial

In the PROactive trial, 5238 patients with type 2 diabetes and a history of macrovascular disease were randomized to pioglitazone (N=2605), force-titrated up to 45 mg daily or placebo (N=2633) in addition to standard of care. Almost all patients (95%) were receiving cardiovascular medications (beta blockers, ACE inhibitors, angiotensin II receptor blockers, calcium channel blockers, nitrates, diuretics, aspirin, statins, and fibrates). At baseline, patients had a mean age of 62 years, mean duration of diabetes of 9.5 years, and mean HbA1c of 8.1%. Mean duration of follow-up was 34.5 months.

The primary objective of this trial was to examine the effect of pioglitazone on mortality and macrovascular morbidity in patients with type 2 diabetes mellitus who were at high risk for macrovascular events. The primary efficacy variable was the time to the first occurrence of any event in a cardiovascular composite endpoint that included all-cause mortality, nonfatal myocardial infarction (MI) including silent MI, stroke, acute coronary syndrome, cardiac intervention including coronary artery bypass grafting or percutaneous intervention, major leg amputation above the ankle, and bypass surgery or revascularization in the leg. A total of 514 (19.7%) patients treated with pioglitazone and 572 (21.7%) placebo-treated patients experienced at least one event from the primary composite endpoint (hazard ratio 0.90; 95% Confidence Interval: 0.80, 1.02; p=0.10).

Although there was no statistically significant difference between pioglitazone and placebo for the three-year incidence of a first event within this composite, there was no increase in mortality or in total macrovascular events with pioglitazone. The number of first occurrences and total individual events contributing to the primary composite endpoint is shown in Table 7.

Table 7: PROactive: Number of First and Total Events for Each Component within the Cardiovascular Composite Endpoint

Dose-related weight gain occurs when pioglitazone is used alone or in combination with other antidiabetic medications. The mechanism of weight gain is unclear but probably involves a combination of fluid retention and fat accumulation.

Tables 8 and 9 summarize the changes in body weight with pioglitazone and placebo in the 16- to 26-week randomized, double-blind monotherapy and 16- to 24-week combination add-on therapy trials and in the PROactive trial.

Table 8: Weight Changes (kg) from Baseline during Randomized, Double-Blind Clinical Trials

Table 9: Median Change in Body Weight in Patients Treated with Pioglitazone vs Patients Treated with Placebo During the Double-Blind Treatment Period in the PROactive Trial

Edema induced from taking pioglitazone is reversible when pioglitazone is discontinued. The edema usually does not require hospitalization unless there is coexisting congestive heart failure. A summary of the frequency and types of edema adverse events occurring in clinical investigations of pioglitazone is provided in Table 10.

Table 10: Adverse Events of Edema in Patients Treated with Pioglitazone

Table 11: Adverse Events of Edema in Patients in the PROactive Trial

There has been no evidence of pioglitazone-induced hepatotoxicity in the pioglitazonecontrolled clinical trial database to date. One randomized, double-blind, 3-year trial comparing pioglitazone to glyburide as add-on to metformin and insulin therapy was specifically designed to evaluate the incidence of serum ALT elevation to greater than three times the upper limit of the reference range, measured every eight weeks for the first 48 weeks of the trial then every 12 weeks thereafter. A total of 3/1051 (0.3%) patients treated with pioglitazone and 9/1046 (0.9%) patients treated with glyburide developed ALT values greater than three times the upper limit of the reference range. None of the patients treated with pioglitazone in the pioglitazone-controlled clinical trial database to date have had a serum ALT greater than three times the upper limit of the reference range and a corresponding total bilirubin greater than two times the upper limit of the reference range, a combination predictive of the potential for severe druginduced liver injury.

In the pioglitazone clinical trials, adverse events of hypoglycemia were reported based on clinical judgment of the investigators and did not require confirmation with fingerstick glucose testing.

In the 16-week add-on to sulfonylurea trial, the incidence of reported hypoglycemia was 3.7% with pioglitazone 30 mg and 0.5% with placebo. In the 16-week add-on to insulin trial, the incidence of reported hypoglycemia was 7.9% with pioglitazone 15 mg, 15.4% with pioglitazone 30 mg, and 4.8% with placebo.

The incidence of reported hypoglycemia was higher with pioglitazone 45 mg compared to pioglitazone 30 mg in both the 24-week add-on to sulfonylurea trial (15.7% versus 13.4%) and in the 24-week add-on to insulin trial (47.8% versus 43.5%).

Three patients in these four trials were hospitalized due to hypoglycemia. All three patients were receiving pioglitazone 30 mg (0.9%) in the 24-week add-on to insulin trial. An additional 14 patients reported severe hypoglycemia (defined as causing considerable interference with patient's usual activities) that did not require hospitalization. These patients were receiving pioglitazone 45 mg in combination with sulfonylurea (N=2) or pioglitazone 30 mg or 45 mg in combination with insulin (N=12).

Tumors were observed in the urinary bladder of male rats in the two-year carcinogenicity study [see Nonclinical Toxicology]. In two 3-year trials in which pioglitazone was compared to placebo or glyburide, there were 16/3656 (0.44%) reports of bladder cancer in patients taking pioglitazone compared to 5/3679 (0.14%) in patients not taking pioglitazone. After excluding patients in whom exposure to study drug was less than one year at the time of diagnosis of bladder cancer, there were six (0.16%) cases on pioglitazone and two (0.05%) cases on placebo. There are too few events of bladder cancer to establish causality.

Adverse events that occurred in controlled clinical trials with placebo and glimepiride monotherapy, other than hypoglycemia, included: headache (7.8% and 8.2%), accidental injury (3.4% and 5.8%), flu syndrome (4.4% and 5.4%), nausea (3.4% and 5.0%) and dizziness (2.4% and 5.0%), respectively.

In a randomized, double-blind, placebo-controlled monotherapy trial of 14 weeks duration, patients already on sulfonylurea therapy underwent a 3-week washout period then were randomized to glimepiride 1 mg, 4 mg, 8 mg or placebo. Patients randomized to glimepiride 4 mg or 8 mg underwent forced-titration from an initial dose of 1 mg to these final doses, as tolerated. The overall incidence of possible hypoglycemia (defined by the presence of at least one symptom that the investigator believed might be related to hypoglycemia; a concurrent glucose measurement was not required) was 4% for glimepiride 1 mg, 17% for glimepiride 4 mg, 16% for glimepiride 8 mg and 0% for placebo. All of these events were self-treated.

In a randomized, double-blind, placebo-controlled monotherapy trial of 22 weeks duration, patients received a starting dose of either 1 mg glimepiride or placebo daily. The dose of glimepiride was titrated to a target fasting plasma glucose of 90 -150 mg/dL. Final daily doses of glimepiride were 1, 2, 3, 4, 6 or 8 mg. The overall incidence of possible hypoglycemia (as defined above for the 14-week trial) for glimepiride versus placebo was 19.7% vs. 3.2%. All of these events were self-treated.

Glimepiride, like all sulfonylureas, can cause weight gain.

In clinical trials, allergic reactions, such as pruritus, erythema, urticaria, and morbilliform or maculopapular eruptions, occurred in less than 1% of glimepiridetreated patients. These may resolve despite continued treatment with glimepiride. There are postmarketing reports of more serious allergic reactions (e.g., dyspnea, hypotension, shock) [see WARNINGS AND PRECAUTIONS].

Elevated Serum Alanine Aminotransferase (ALT)

In 11 pooled placebo-controlled trials of glimepiride, 1.9% of glimepiride-treated patients and 0.8% of placebo-treated patients developed serum ALT greater than two times the upper limit of the reference range.

Laboratory Abnormalities

Hematologic Effects

Pioglitazone may cause decreases in hemoglobin and hematocrit. In placebo-controlled monotherapy trials, mean hemoglobin values declined by 2% to 4% in patients treated with pioglitazone compared with a mean change in hemoglobin of -1% to +1% in placebo-treated patients. These changes primarily occurred within the first 4 to 12 weeks of therapy and remained relatively constant thereafter. These changes may be related to increased plasma volume associated with pioglitazone therapy and are not likely to be associated with any clinically significant hematologic effects.

Creatine Phosphokinase

During protocol-specified measurement of serum creatine phosphokinase (CPK) in pioglitazone clinical trials, an isolated elevation in CPK to greater than 10 times the upper limit of the reference range was noted in nine (0.2%) patients treated with pioglitazone (values of 2150 to 11400 IU/L) and in no comparator-treated patients. Six of these nine patients continued to receive pioglitazone, two patients were noted to have the CPK elevation on the last day of dosing and one patient discontinued pioglitazone due to the elevation. These elevations resolved without any apparent clinical sequelae. The relationship of these events to pioglitazone therapy is unknown.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of pioglitazone and glimepiride. Because these reactions are reported voluntarily from a population of uncertain size, it is generally not possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

• New onset or worsening diabetic macular edema with decreased visual acuity [see WARNINGS AND PRECAUTIONS].
• Fatal and nonfatal hepatic failure [see WARNINGS AND PRECAUTIONS].

Postmarketing reports of congestive heart failure have been reported in patients treated with pioglitazone, both with and without previously known heart disease and both with and without concomitant insulin administration.

In postmarketing experience, there have been reports of unusually rapid increases in weight and increases in excess of that generally observed in clinical trials. Patients who experience such increases should be assessed for fluid accumulation and volumerelated events such as excessive edema and congestive heart failure [see BOXED WARNING and WARNINGS AND PRECAUTIONS].

• Serious hypersensitivity reactions, including anaphylaxis, angioedema, and Stevens-Johnson Syndrome [see WARNINGS AND PRECAUTIONS]
• Hemolytic anemia in patients with and without G6PD deficiency [see WARNINGS AND PRECAUTIONS]
• Impairment of liver function (e.g. with cholestasis and jaundice), as well as hepatitis, which may progress to liver failure.
• Porphyria cutanea tarda, photosensitivity reactions and allergic vasculitis
• Leukopenia, agranulocytosis, aplastic anemia, and pancytopenia
• Thrombocytopenia (including severe cases with platelet count less than 10,000/mcL) and thrombocytopenic purpura
• Hepatic porphyria reactions and disulfiram-like reactions
• Hyponatremia and syndrome of inappropriate antidiuretic hormone secretion (SIADH), most often in patients who are on other medications or who have medical conditions known to cause hyponatremia or increase release of antidiuretic hormone

Read the entire FDA prescribing information for Duetact (Pioglitazone Hydrochloride and Glimepiride Tablets)

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