2.1 Important Dosage and Administration Information

• Obtain liver tests (serum alanine and aspartate aminotransferases, alkaline phosphatase, and total bilirubin) prior to initiating pioglitazone and metformin hydrochloride tablets [see Warnings and Precautions (5.5)].
• Pioglitazone and metformin hydrochloride tablet contains 15 mg of pioglitazone and 500 mg of metformin hydrochloride or 15 mg of pioglitazone and 850 mg of metformin hydrochloride in each tablet.
• Take pioglitazone and metformin hydrochloride tablets with meals to reduce gastrointestinal adverse reactions with metformin [see Adverse Reactions (6.1)].
• If a dose is missed, do not double the next dose.

2.2 Recommended Dosage and Administration

Recommended Starting Dosage Based on Current Regimen

Individualize the starting dosage of pioglitazone and metformin hydrochloride tablets based on the patient's current regimen and the available strength of pioglitazone and metformin hydrochloride tablets (see Table 1).

Dosage Titration for Additional Glycemic Control

Titrate the pioglitazone and metformin hydrochloride tablets dosage gradually, as needed, after assessing therapeutic response and tolerability.

Pioglitazone and metformin hydrochloride tablets may be increased to a maximum recommended total daily dosage of three tablets per day (45 mg of pioglitazone and 2,550 mg of metformin hydrochloride). Total daily dosages of 2,550 mg of metformin hydrochloride may be taken in divided doses three times a day to reduce gastrointestinal adverse reactions [see Adverse Reactions (6.1)].

2.3 Recommendations for Use in Patients with Renal Impairment

• Assess renal function prior to initiation of pioglitazone and metformin hydrochloride tablets and periodically thereafter [see Use in Specific Populations (8.6)].

• Pioglitazone and metformin hydrochloride tablets are contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/min.

• Initiation of pioglitazone and metformin hydrochloride tablets in patients with an eGFR between 30 to 45 mL/min is not recommended.

• In patients taking pioglitazone and metformin hydrochloride tablets whose eGFR later falls below 45 mL/min, assess the benefit and risk of continuing therapy.

• Discontinue pioglitazone and metformin hydrochloride tablets if the patient's eGFR later falls below 30 mL/min [see Contraindications (4), Warnings and Precautions (5.2)].

2.4 Recommendations for Congestive Heart Failure

Starting Dosage in Patients with NYHA Class I or II Congestive Heart Failure

For patients with preexisting NYHA Class I or II congestive heart failure, the recommended starting dosage of pioglitazone and metformin hydrochloride tablets are 15 mg of pioglitazone and 500 mg of metformin or 15 mg of pioglitazone and 850 mg of metformin [see Boxed Warning and Warnings and Precautions (5.1)].

Monitoring for Fluid Retention and Dosage Modifications for Congestive Heart Failure

After initiation of pioglitazone and metformin hydrochloride tablets or with dosage increase, monitor patients carefully for adverse reactions related to fluid retention as has been seen with pioglitazone (e.g., weight gain, edema and signs and symptoms of congestive heart failure).

If congestive heart failure develops while taking pioglitazone and metformin hydrochloride tablets, consider discontinuation of pioglitazone and metformin hydrochloride tablets or dosage reduction of pioglitazone in pioglitazone and metformin hydrochloride tablets [see Boxed Warning and Warnings and Precautions (5.1)].

2.5 Coadministration with Strong CYP2C8 Inhibitors

The maximum recommended dosage of pioglitazone and metformin hydrochloride tablets is one tablet (15 mg of pioglitazone and 850 mg of metformin hydrochloride) once daily when used in combination with gemfibrozil or other strong CYP2C8 inhibitors [see Drug Interactions (7.1), Clinical Pharmacology (12.3)].

2.6 Discontinuation for Iodinated Contrast Imaging Procedures

Discontinue pioglitazone and metformin hydrochloride tablets at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min; 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 pioglitazone and metformin hydrochloride tablets if renal function is stable [see Warnings and Precautions (5.2)].

5.1 Congestive Heart Failure

Pioglitazone, like other thiazolidinediones, can cause dose-related fluid retention when used alone or in combination with other antidiabetic medications and is most common when pioglitazone is used in combination with insulin. Fluid retention may lead to or exacerbate congestive heart failure. Observe patients for signs and symptoms of congestive heart failure. If congestive heart failure develops while taking pioglitazone and metformin hydrochloride, consider discontinuation of pioglitazone and metformin hydrochloride or dosage reduction of pioglitazone in pioglitazone and metformin hydrochloride [see Boxed Warning, Contraindications (4), Adverse Reactions (6.1)].

5.2 Lactic Acidosis

Lactic Acidosis

There have been postmarketing cases of metformin-associated lactic acidosis, including fatal cases. These cases had a subtle onset and were accompanied by nonspecific symptoms such as malaise, myalgias, abdominal pain, respiratory distress, or increased somnolence; however, hypothermia, hypotension and resistant bradyarrhythmias have occurred with severe acidosis. Metformin-associated lactic acidosis was characterized by elevated blood lactate concentrations (greater than 5 mmol/L), anion gap acidosis (without evidence of ketonuria or ketonemia), an increased lactate:pyruvate ratio, and metformin plasma levels generally greater than 5 mcg/mL. Metformin decreases liver uptake of lactate increasing lactate blood levels which may increase the risk of lactic acidosis, especially in patients at risk.

If metformin-associated lactic acidosis is suspected, general supportive measures should be instituted promptly in a hospital setting, along with immediate discontinuation of pioglitazone and metformin hydrochloride. In pioglitazone and metformin hydrochloride-treated patients with a diagnosis or strong suspicion of lactic acidosis, prompt hemodialysis is recommended to correct the acidosis and remove accumulated metformin (metformin hydrochloride is dialyzable, with a clearance of up to 170 mL/min under good hemodynamic conditions). Hemodialysis has often resulted in reversal of symptoms and recovery.

Educate patients and their families about the symptoms of lactic acidosis and if these symptoms occur instruct them to discontinue pioglitazone and metformin hydrochloride and report these symptoms to their healthcare provider.

For each of the known and possible risk factors for metformin-associated lactic acidosis, recommendations to reduce the risk of and manage metformin-associated lactic acidosis are provided below:

Renal Impairment

The postmarketing metformin-associated lactic acidosis cases primarily occurred in patients with significant renal impairment. The risk of metformin accumulation and metformin-associated lactic acidosis increases with the severity of renal impairment because metformin is substantially excreted by the kidney. Clinical recommendations based upon the patient’s renal function include [see Dosage and Administration (2.3), Clinical Pharmacology (12.3)].

• Before initiating pioglitazone and metformin hydrochloride, obtain an eGFR.
• Pioglitazone and metformin hydrochloride is contraindicated in patients with an eGFR less than 30 mL/min. Initiation of pioglitazone and metformin hydrochloride is not recommended in patients with eGFR between 30 to 45 mL/min [see Contraindications (4)].
• Obtain an eGFR at least annually in all patients taking pioglitazone and metformin hydrochloride. In patients at increased risk for the development of renal impairment (e.g., the elderly), renal function should be assessed more frequently.
• In patients taking pioglitazone and metformin hydrochloride whose eGFR later falls below 45 mL/min, assess the benefit and risk of continuing therapy.

Drug Interactions

The concomitant use of pioglitazone and metformin hydrochloride with specific drugs may increase the risk of metformin-associated lactic acidosis: those that impair renal function, result in significant hemodynamic change, interfere with acid-base balance or increase metformin accumulation (e.g., cationic drugs) [see Drug Interactions (7)]. Therefore, consider more frequent monitoring of patients.

Age 65 or Greater

The risk of metformin-associated lactic acidosis increases with the patient's age because elderly patients have a greater likelihood of having hepatic, renal, or cardiac impairment than younger patients. Assess renal function more frequently in elderly patients [see Use in Specific Populations (8.5)].

Radiological Studies with Contrast

Administration of intravascular iodinated contrast agents in metformin-treated patients has led to an acute decrease in renal function and the occurrence of lactic acidosis. Stop pioglitazone and metformin hydrochloride at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min; in patients with a history of hepatic impairment, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast. Re-evaluate eGFR 48 hours after the imaging procedure, and restart pioglitazone and metformin hydrochloride if renal function is stable.

Surgery and Other Procedures

Withholding of food and fluids during surgical or other procedures may increase the risk for volume depletion, hypotension and renal impairment. Pioglitazone and metformin hydrochloride should be temporarily discontinued while patients have restricted food and fluid intake.

Hypoxic States

Several of the postmarketing cases of metformin-associated lactic acidosis occurred in the setting of acute congestive heart failure (particularly when accompanied by hypoperfusion and hypoxemia). Cardiovascular collapse (shock), acute myocardial infarction, sepsis, and other conditions associated with hypoxemia have been associated with lactic acidosis and may also cause prerenal azotemia. When such events occur, discontinue pioglitazone and metformin hydrochloride.

Excessive Alcohol Intake

Alcohol potentiates the effect of metformin on lactate metabolism and this may increase the risk of metformin-associated lactic acidosis. Warn patients against excessive alcohol intake while receiving pioglitazone and metformin hydrochloride.

Hepatic Impairment

Patients with hepatic impairment have developed with cases of metformin-associated lactic acidosis. This may be due to impaired lactate clearance resulting in higher lactate blood levels. Therefore, avoid use of pioglitazone and metformin hydrochloride in patients with clinical or laboratory evidence of hepatic disease.

5.3 Edema

In controlled clinical trials with pioglitazone, edema was reported more frequently in patients treated with pioglitazone than in placebo-treated patients and is dose related [see Adverse Reactions (6.1)]. In postmarketing experience, reports of new onset or worsening of edema have been received.

Pioglitazone and metformin hydrochloride should be used with caution in patients with edema. Because thiazolidinediones, including pioglitazone, can cause fluid retention, which can exacerbate or lead to congestive heart failure, pioglitazone and metformin hydrochloride should be used with caution in patients at risk for congestive heart failure. Patients treated with pioglitazone and metformin hydrochloride should be monitored for signs and symptoms of congestive heart failure [see Boxed Warning, Warnings and Precautions (5.1)].

5.4 Hypoglycemia with Concomitant Use with Insulin or Insulin Secretagogues

Insulin and insulin secretagogues, such as sulfonylureas, are known to cause hypoglycemia. Therefore, a lower dosage of insulin or insulin secretagogue may be required to minimize the risk of hypoglycemia when used in combination with pioglitazone and metformin hydrochloride[see Drug Interactions (7.6, 7.7)].

5.5 Hepatic Effects

There have been postmarketing reports of fatal and non-fatal hepatic failure in patients taking pioglitazone, although the reports contain insufficient information necessary to establish the probable cause. There has been no evidence of drug-induced hepatotoxicity in the pioglitazone controlled clinical trial database to date [see Adverse Reactions (6.1)].

Patients with type 2 diabetes mellitus may have fatty liver disease or cardiac disease with episodic congestive heart failure, both of which may cause liver test abnormalities, and they may also have other forms of liver disease, many of which can be treated or managed. Therefore, obtaining a liver test panel (serum alanine aminotransferase [ALT], aspartate aminotransferase [AST], alkaline phosphatase, and total bilirubin) and assessing the patient is recommended before initiating pioglitazone and metformin hydrochloride therapy. In patients with abnormal liver tests, pioglitazone and metformin hydrochloride should be initiated with caution.

Measure liver tests promptly in patients who report symptoms that may indicate liver injury, including fatigue, anorexia, right upper abdominal discomfort, dark urine or jaundice. In this clinical context, if the patient is found to have clinically significant liver enzyme elevations (serum ALT greater than three times the ULN) and if abnormal liver tests persist or worsen, pioglitazone and metformin hydrochloride should be interrupted and investigation done to establish the probable cause. Pioglitazone and metformin hydrochloride should not be restarted in these patients without another explanation for the liver test abnormalities.

5.6 Urinary Bladder Tumors

Tumors were observed in the urinary bladder of male rats in the two year carcinogenicity study [see Nonclinical Toxicology (13.1)]. In addition, during the three year PROactive clinical trial, 14 patients out of 2,605 (0.54%) randomized to pioglitazone and 5 out of 2,633 (0.19%) randomized to placebo were diagnosed with bladder cancer. After excluding patients in whom exposure to study drug was less than one year at the time of diagnosis of bladder cancer, there were 6 (0.23%) cases on pioglitazone and 2 (0.08%) cases on placebo. After completion of the trial, a large subset of patients was observed for up to 10 additional years, with little additional exposure to pioglitazone. During the 13 years of both PROactive and observational follow-up, the occurrence of bladder cancer did not differ between patients randomized to pioglitazone or placebo [Hazard Ratio (HR) = 1.00; (95% Confidence Interval (CI) : 0.59,1.72)].

Findings regarding the risk of bladder cancer in patients exposed to pioglitazone vary among observational studies; some did not find an increased risk of bladder cancer associated with pioglitazone, while others did.

A large prospective10 year observational cohort study conducted in the United States (U.S) found no statistically significant increase in the risk of bladder cancer in diabetic patients ever exposed to pioglitazone, compared to those never exposed to pioglitazone [HR = 1.06; (95% CI: 0.89, 1.26)].

A retrospective cohort study conducted with data from the United Kingdom found a statistically significant association between ever exposure to pioglitazone and bladder cancer [HR = 1.63; (95% CI: 1.22, 2.19)].

Associations between cumulative dose or cumulative duration of exposure to pioglitazone and bladder cancer were not detected in some studies including the 10 year observational study in the U.S., but were in others. Inconsistent findings and limitations inherent in these and other studies preclude conclusive interpretations of the observational data.

Pioglitazone may be associated with an increase in the risk of urinary bladder tumors. There are insufficient data to determine whether pioglitazone is a tumor promoter for urinary bladder tumors.

Consequently, pioglitazone and metformin hydrochloride should not be used in patients with active bladder cancer and the benefits of glycemic control versus unknown risks for cancer recurrence with pioglitazone and metformin hydrochloride should be considered in patients with a prior history of bladder cancer.

5.7 Fractures

In PROactive (the Prospective Pioglitazone Clinical Trial in Macrovascular Events), 5,238 patients with type 2 diabetes mellitus and a history of macrovascular disease were randomized to pioglitazone (N=2,605), force-titrated up to 45 mg daily or placebo (N=2,633) in addition to standard of care. During a mean follow-up of 34.5 months, the incidence of bone fracture in females was 5.1% (44/870) for pioglitazone versus 2.5% (23/905) for placebo. This difference was noted after the first year of treatment and persisted during the course of the study. The majority of fractures observed in female patients were nonvertebral fractures including lower limb and distal upper limb. No increase in the incidence of fracture was observed in men treated with pioglitazone (1.7%) versus placebo (2.1%). The risk of fracture should be considered in the care of patients, especially female patients, treated with pioglitazone and metformin hydrochloride and attention should be given to assessing and maintaining bone health according to current standards of care.

5.8 Macular Edema

Macular edema has been reported in postmarketing experience in diabetic patients who were taking pioglitazone or another thiazolidinedione. Some patients presented with blurred vision or decreased visual acuity, but others were diagnosed on routine ophthalmologic examination.

Most patients had peripheral edema at the time macular edema was diagnosed. Some patients had improvement in their macular edema after discontinuation of the thiazolidinedione.

Patients with diabetes should have regular eye exams by an ophthalmologist according to current standards of care. Patients with diabetes who report any visual symptoms should be promptly referred to an ophthalmologist, regardless of the patient's underlying medications or other physical findings [see Adverse Reactions (6.1)].

5.9 Vitamin B12 Levels

In metformin clinical trials of 29-week duration, a decrease to subnormal levels of previously normal serum vitamin B12 levels was observed in approximately 7% of patients. Such decrease, possibly due to interference with B12 absorption from the B12-intrinsic factor complex, may be associated with anemia but appears to be rapidly reversible with discontinuation of metformin or vitamin B12 supplementation. Certain individuals (those with inadequate vitamin B12 or calcium intake or absorption) appear to be predisposed to developing subnormal vitamin B12 levels. Measure hematologic parameters on an annual basis and vitamin B12 at 2 to 3 year intervals in patients on pioglitazone and metformin hydrochloride and manage any abnormalities [see Adverse Reactions (6.1)].

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.

Pioglitazone

Over 8,500 patients with type 2 diabetes mellitus have been treated with pioglitazone in randomized, double-blind, controlled clinical trials, including 2,605 patients with type 2 diabetes mellitus and macrovascular disease treated with pioglitazone from the PROactive clinical trial. In these trials, over 6,000 patients have been treated with pioglitazone for six months or longer, over 4,500 patients have been treated with pioglitazone for one year or longer, and over 3,000 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 add-on 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%).

In the PROactive trial, the incidence of withdrawals due to adverse events was 9% 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.

Common Adverse Events: 16 to 26 Week Monotherapy Trials

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.

Common Adverse Events: 16 to 24 Week Add-on Combination Therapy Trials

A summary of the overall incidence and types of common adverse events reported in trials of pioglitazone add-on to metformin is provided in Table 3. Terms that are reported represent those that occurred at an incidence of >5% and more commonly with the highest tested dose of pioglitazone.

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema.”

Common Adverse Events: 24 Week Pioglitazone and Metformin Hydrochloride Clinical Trial

Table 4 summarizes the incidence and types of adverse reactions reported in a controlled, 24 week double-blind clinical trial of pioglitazone and metformin hydrochloride dosed twice daily in patients with inadequate glycemic control on diet and exercise (N=600).

In this 24 week trial, abdominal pain was reported in 2% of patients in the pioglitazone and metformin hydrochloride group, 1.6% in the pioglitazone monotherapy group and 3.3% in the metformin monotherapy group.

Common Adverse Events: PROactive Trial

A summary of the overall incidence and types of common adverse events reported in the PROactive trial is provided in Table 5. 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.

Mean duration of patient follow-up was 34.5 months.

Congestive Heart Failure

A summary of the incidence of adverse events related to congestive heart failure is provided in Table 6 for the 16 to 24 week add-on to metformin trials. None of the events were fatal.

Congestive heart failure events leading to hospitalization that occurred during the PROactive trial are summarized in Table 9.

Cardiovascular Safety

In the PROactive trial, 5,238 patients with type 2 diabetes mellitus and a history of macrovascular disease were randomized to pioglitazone (N=2,605), force-­titrated up to 45 mg daily or placebo (N=2,633) 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 (HR = 0.9; 95% CI: 0.8, 1.02; p=0.1).

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 10.

CABG = coronary artery bypass grafting; PCI = percutaneous intervention.

Weight Gain

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 11, 12, and 13 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, the PROactive trial, and the 24 week pioglitazone and metformin hydrochloride trial.

Note: Median exposure for both pioglitazone and placebo was 2.7 years.

Note: Trial duration of 24 weeks.

Edema

Edema induced from taking pioglitazone is reversible when pioglitazone is discontinued. The edema usually does not require hospitalization unless there is co-existing congestive heart failure.

In the 24 week pioglitazone and metformin hydrochloride trial, edema was reported in 3% of patients in the pioglitazone and metformin hydrochloride group, 4.2% in the pioglitazone monotherapy group, and 1.4% in the metformin monotherapy group.

A summary of the frequency and types of edema adverse events occurring in clinical investigations of pioglitazone is provided in Table 14.

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema.”

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema.”

Hepatic Effects

There has been no evidence of pioglitazone-induced hepatotoxicity in the pioglitazone controlled clinical trial database to date. One randomized, double-blind, three 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 3/1,051 (0.3%) patients treated with pioglitazone and 9/1,046 (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 drug-induced liver injury.

Hypoglycemia

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% vs 13.4%) and in the 24-week add-on to insulin trial (47.8% vs 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).

Urinary Bladder Tumors

Tumors were observed in the urinary bladder of male rats in the two year carcinogenicity study [see Nonclinical Toxicology (13.1)]. During the three-year PROactive clinical trial, 14 patients out of 2,605 (0.54%) randomized to pioglitazone and 5 out of 2,633 (0.19%) randomized to placebo were diagnosed with bladder cancer. After excluding patients in whom exposure to study drug was less than one year at the time of diagnosis of bladder cancer, there were 6 (0.23%) cases on pioglitazone and 2 (0.08%) cases on placebo. After completion of the trial, a large subset of patients was observed for up to 10 additional years, with little additional exposure to pioglitazone. During the 13 years of both PROactive and observational follow-up, the occurrence of bladder cancer did not differ between patients randomized to pioglitazone or placebo (HR =1; [95% CI: 0.59 1.72]) [see Warnings and Precautions (5.6)].

Metformin hydrochloride

In a double-blind clinical study of metformin in patients with type 2 diabetes mellitus, a total of 141 patients received metformin therapy (up to 2,550 mg per day) and 145 patients received placebo. Adverse reactions reported in greater than 5% of the metformin patients, and that were more common in metformin than placebo-treated patients, are listed in Table 16. In this trial, diarrhea led to discontinuation of study medication in 6% of patients treated with metformin.

Laboratory Abnormalities

Pioglitazone

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 four 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 2,150 to 11,400 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.

Metformin

Vitamin B12 Concentrations

In metformin clinical trials of 29-week duration, a decrease to subnormal levels of previously

normal serum vitamin B12 levels was observed in approximately 7% of patients.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of pioglitazone and/or metformin. 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.

Pioglitazone

Cardiac Disorders: Rapid increases in weight, edema, congestive heart failure with and without previously known heart disease or concomitant insulin administration

Eye Disorders: New onset or worsening diabetic macular edema with decreased visual acuity

Hepatobiliary Disorders: Fatal and nonfatal hepatic failure

Metformin

Hepatobiliary Disorders: Cholestatic, hepatocellular, and mixed hepatocellular liver injury.

7.1 Strong CYP2C8 Inhibitors

An inhibitor of CYP2C8 (e.g., gemfibrozil) significantly increases the exposure (area under the serum concentration-time curve or AUC) and half-life (t1/2) of pioglitazone. Therefore, the maximum recommended dosage of pioglitazone and metformin hydrochloride is 15 mg of pioglitazone and 850 mg of metformin hydrochloride once daily if used in combination with gemfibrozil or other strong CYP2C8 inhibitors [see Dosage and Administration (2.3), Clinical Pharmacology (12.3)].

7.2 CYP2C8 Inducers

An inducer of CYP2C8 (e.g., rifampin) may significantly decrease the exposure (AUC) of pioglitazone. Therefore, if an inducer of CYP2C8 is started or stopped during treatment with pioglitazone and metformin hydrochloride, changes in diabetes treatment may be needed based on clinical response without exceeding the maximum recommended daily dosage of pioglitazone and metformin hydrochloride (45 mg of pioglitazone and 2,550 mg of metformin hydrochloride) [see Clinical Pharmacology (12.3)].

7.3 Carbonic Anhydrase Inhibitors

Topiramate or other carbonic anhydrase inhibitors (e.g., zonisamide, acetazolamide or dichlorphenamide) frequently causes a decrease in serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis. Concomitant use of these drugs with pioglitazone and metformin hydrochloride may increase the risk for lactic acidosis. Consider more frequent monitoring of these patients.

7.4 Drugs that Reduce Metformin Clearance

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 [OCT2]/multidrug and toxin extrusion [MATE] inhibitors such as ranolazine, vandetanib, dolutegravir, and cimetidine) could increase systemic exposure to metformin and may increase the risk for lactic acidosis [see Clinical Pharmacology (12.3)]. Consider the benefits and risks of concomitant use.

7.5 Alcohol

Alcohol is known to potentiate the effect of metformin on lactate metabolism. Warn patients against excessive alcohol intake while receiving pioglitazone and metformin hydrochloride.

7.6 Insulin Secretagogues or Insulin

Coadministration of pioglitazone and metformin hydrochloride with an insulin secretagogue (e.g., sulfonylurea) or insulin may increase the risk of hypoglycemia. If hypoglycemia occurs in a patient coadministered pioglitazone and metformin hydrochloride and an insulin secretagogue (e.g., sulfonylurea), the dose of the insulin secretagogue should be reduced.

7.7 Drugs Affecting Glycemic Control

Certain drugs tend to produce hyperglycemia and may lead to loss of glycemic control. These drugs include the thiazides and other diuretics, corticosteroids, phenothiazines, thyroid products, estrogens, oral contraceptives, phenytoin, nicotinic acid, sympathomimetics, calcium channel blockers, and isoniazid. When such drugs are administered to a patient receiving pioglitazone and metformin hydrochloride, the patient should be closely observed for loss of blood glucose control. When such drugs are withdrawn from a patient receiving pioglitazone and metformin hydrochloride, the patient should be observed closely for hypoglycemia.

7.8 Topiramate

A decrease in the exposure of pioglitazone and its active metabolites were noted with concomitant administration of pioglitazone and topiramate [see Clinical Pharmacology (12.3)]. The clinical relevance of this decrease is unknown; however, when pioglitazone and metformin hydrochloride and topiramate are used concomitantly, monitor patients for adequate glycemic control.

8.1 Pregnancy

Risk Summary

Limited data with pioglitazone and metformin hydrochloride or pioglitazone in pregnant women are not sufficient to determine a drug-associated risk for major birth defects or miscarriage. Published studies with metformin use during pregnancy have not reported a clear association with metformin and major birth defect or miscarriage risk (see Data). There are risks to the mother and fetus associated with poorly controlled diabetes in pregnancy [see Clinical Considerations].

In animal reproduction studies, no adverse developmental effects were observed when pioglitazone was administered to pregnant rats and rabbits during organogenesis at exposures up to 5 and 35 times the 45 mg clinical dose, respectively, based on body surface area. No adverse developmental effects were observed when metformin was administered to pregnant Sprague Dawley rats and rabbits during the period of organogenesis at doses up to 2 to 6 times, respectively, a 2,000 mg clinical dose, based on body surface area (see Data).

The estimated background risk of major birth defects is 6 to 10% in women with pre-gestational diabetes with a HbA1c >7 and has been reported to be as high as 20 to 25% in women with a HbA1c >10. The estimated background risk of miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively.

Clinical Considerations

Disease-Associated Maternal and/or Embryo/Fetal Risk

Poorly controlled diabetes in pregnancy increases the maternal risk for diabetic ketoacidosis, pre-eclampsia, spontaneous abortions, preterm delivery, still birth and delivery complications. Poorly controlled diabetes increases the fetal risk for major birth defects, still birth, and macrosomia related morbidity.

Data

Human Data

Published data from postmarketing studies have not reported a clear association with metformin and major birth defects, miscarriage, or adverse maternal or fetal outcomes when metformin was used during pregnancy. However, these studies cannot definitely establish the absence of any metformin-associated risk because of methodological limitations, including small sample size and inconsistent comparator groups.

Animal Data

Pioglitazone and Metformin hydrochloride

Animal reproduction studies were not conducted with the combined products in pioglitazone and metformin hydrochloride. The following data are based on studies conducted with the individual components of pioglitazone and metformin hydrochloride.

Pioglitazone

Pioglitazone administered to pregnant rats during organogenesis did not cause adverse developmental effects at a dose of 20 mg/kg (~5 times the 45 mg clinical dose), but delayed parturition and reduced embryo-fetal viability at 40 and 80 mg/kg, or ≥9 times the 45 mg clinical dose, by body surface area. In pregnant rabbits administered pioglitazone during organogenesis, no adverse developmental effects were observed at 80 mg/kg (~35 times the 45 mg clinical dose), but reduced embryo-fetal viability at 160 mg/kg, or ~69 times the 45 mg clinical dose, by body surface area. When pregnant rats received pioglitazone during late gestation and lactation, delayed postnatal development, attributed to decreased body weight, occurred in offspring at maternal doses of 10 mg/kg and above or ≥2 times the 45 mg clinical dose, by body surface area.

Metformin hydrochloride

Metformin hydrochloride did not cause adverse developmental effects when administered to pregnant Sprague Dawley rats and rabbits up to 600 mg/kg/day during the period of organogenesis. This represents an exposure of about 2 to 6 times a 2,000 mg clinical dose based on body surface area (mg/m2) for rats and rabbits, respectively.

8.2 Lactation

Risk Summary

There is no information regarding the presence of pioglitazone and metformin hydrochloride or pioglitazone in human milk, the effects on the breastfed infant, or the effects on milk production. Pioglitazone is present in rat milk; however, due to species-specific differences in lactation physiology, animal data may not reliably predict drug levels in human milk. Limited published studies report that metformin is present in human milk (see Data). However, there is insufficient information on the effects of metformin on the breastfed infant and no available information on the effects of metformin on milk production. The developmental and health benefits of breastfeeding should be considered along with the mother's clinical need for pioglitazone and metformin hydrochloride and any potential adverse effects on the breastfed infant from pioglitazone and metformin hydrochloride or from the underlying maternal condition.

Data

Published clinical lactation studies report that metformin is present in human milk which resulted in infant doses approximately 0.11% to 1% of the maternal weight-adjusted dosage and a milk/plasma ratio ranging between 0.13 and 1. However, the studies were not designed to definitely establish the risk of use of metformin during lactation because of small sample size and limited adverse event data collected in infants.

8.3 Females and Males of Reproductive Potential

Discuss the potential for unintended pregnancy with premenopausal women as therapy with pioglitazone and metformin hydrochloride, may result in ovulation in some anovulatory women.

8.4 Pediatric Use

Safety and effectiveness of pioglitazone and metformin hydrochloride in pediatric patients have not been established.

Pioglitazone and metformin hydrochloride is not recommended for use in pediatric patients based on adverse effects observed in adults, including fluid retention and congestive heart failure, fractures, and urinary bladder tumors [see Warnings and Precautions (5.1, 5.3, 5.6, 5.7)].

8.5 Geriatric Use

Pioglitazone

A total of 92 patients (15.2%) treated with pioglitazone in the three pooled 16 to 26 week double-blind, placebo-controlled, monotherapy trials were ≥65 years old and two patients (0.3%) were ≥75 years old. In the two pooled 16 to 24 week add-on to sulfonylurea trials, 201 patients (18.7%) treated with pioglitazone were ≥65 years old and 19 (1.8%) were ≥75 years old. In the two pooled 16 to 24 week add-on to metformin trials, 155 patients (15.5%) treated with pioglitazone were ≥65 years old and 19 (1.9%) were ≥75 years old. In the two pooled 16 to 24 week add-on to insulin trials, 272 patients (25.4%) treated with pioglitazone were ≥65 years old and 22 (2.1%) were ≥75 years old.

In PROactive Trial, 1,068 patients (41%) treated with pioglitazone were ≥65 years old and 42 (1.6%) were ≥75 years old.

In pharmacokinetic studies with pioglitazone, no significant differences were observed in pharmacokinetic parameters between elderly and younger patients [see Clinical Pharmacology (12.3)].

Although clinical experiences have not identified differences in effectiveness and safety between the elderly (≥65 years) and younger patients, these conclusions are limited by small sample sizes for patients ≥75 years old.

Metformin hydrochloride

Controlled clinical studies of metformin did not include sufficient numbers of elderly patients to determine whether they respond differently from younger patients, although other reported clinical experience has not identified differences in responses between the elderly and young patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy and the higher risk of lactic acidosis. Assess renal function more frequently in elderly patients [see Warnings and Precautions (5.2), Dosage and Administration (2.2)].

8.6 Renal Impairment

Metformin is substantially excreted by the kidney, and the risk of metformin accumulation and lactic acidosis increases with the degree of renal impairment. Pioglitazone and metformin hydrochloride is contraindicated in severe renal impairment, which includes patients with an eGFR below 30 mL/min [see Dosage and Administration (2.2), Contraindications (4), Warnings and Precautions (5.2), Clinical Pharmacology (12.3)].

8.7 Hepatic Impairment

Use of metformin in patients with hepatic impairment has been associated with some cases of lactic acidosis. Pioglitazone and metformin hydrochloride is not recommended in patients with hepatic impairment [see Warnings and Precautions (5.2)].

12.1 Mechanism of Action

Pioglitazone and metformin hydrochloride combines two antihyperglycemic agents: pioglitazone and metformin.

Pioglitazone

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 mellitus. 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.

Metformin hydrochloride

Metformin hydrochloride 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. Metformin does not produce hypoglycemia in either patients with type 2 diabetes mellitus or healthy subjects [except in specific circumstances, see Warnings and Precautions (5.4)] and does not cause hyperinsulinemia. With metformin therapy, insulin secretion remains unchanged while fasting insulin levels and day-long plasma insulin response may actually decrease.

12.2 Pharmacodynamics

Pioglitazone

Clinical studies demonstrate that pioglitazone improves insulin sensitivity in insulin-resistant patients. Pioglitazone enhances cellular responsiveness to insulin, increases insulin-dependent glucose disposal and improves hepatic sensitivity to insulin. In patients with type 2 diabetes mellitus, 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 (14)].

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  [see Adverse Reactions (6.1)].

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 (see Table 17).

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

12.3 Pharmacokinetics

Absorption

Pioglitazone and Metformin Hydrochloride

In bioequivalence studies of pioglitazone and metformin hydrochloride 15 mg/500 mg and 15 mg/850 mg, the area under the curve (AUC) and maximum concentration (Cmax) of both the pioglitazone and the metformin component following a single dose of the combination tablet were bioequivalent to pioglitazone hydrochloride 15 mg concomitantly administered with metformin hydrochloride immediate release (500 mg or 850 mg, respectively) tablets under fasted conditions in healthy subjects.

Administration of pioglitazone and metformin hydrochloride 15 mg/850 mg with food resulted in no change in overall exposure of pioglitazone. With metformin there was no change in AUC; however, mean peak serum concentration of metformin was decreased by 28% when administered with food. A delayed time to peak serum concentration was observed for both components (1.9 hours for pioglitazone and 0.8 hours for metformin) under fed conditions. These changes are not likely to be clinically significant.

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 mellitus, 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 the Tmax to three to four hours, but does not alter the extent of absorption (AUC).

Metformin hydrochloride

The absolute bioavailability of a 500 mg metformin tablet given under fasting conditions is approximately 50 to 60%. Studies using single oral doses of metformin tablets of 500 mg to 1500 mg, and 850 mg to 2,550 mg, indicate that there is a lack of dose proportionality with increasing doses, which is due to decreased absorption rather than an alteration in elimination. At usual clinical doses and dosing schedules of metformin, steady-state plasma concentrations of metformin are reached within 24 to 48 hours and are generally <1 mcg/mL. During controlled clinical trials, maximum metformin plasma levels did not exceed 5 mcg/mL, even at maximum doses.

Food decreases the rate and extent of metformin absorption, as shown by a 40% lower mean Cmax, a 25% lower AUC, and a 35 minute prolongation of Tmax following administration of a single 850 mg tablet of metformin with food, compared to the same tablet strength administered fasting. The clinical relevance of these decreases is unknown.

Distribution

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.

Metformin hydrochloride

The Vd/F of metformin following single oral doses of 850 mg immediate-release metformin averaged 654 ± 358 L. Metformin is negligibly bound to plasma proteins. Metformin partitions into erythrocytes, most likely as a function of time.

Elimination

Metabolism

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 (2.3), Drug Interactions (7.1)]. Urinary 6ß­-hydroxycortisol/cortisol ratios measured in patients treated with pioglitazone showed that pioglitazone is not a strong CYP3A4 enzyme inducer.

Metformin hydrochloride

Intravenous single-dose studies in healthy subjects demonstrate that metformin is excreted unchanged in the urine and does not undergo hepatic metabolism (no metabolites have been identified in humans) nor biliary excretion.

Excretion

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 (t1/2) 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.

Metformin hydrochloride

Renal clearance is approximately 3.5 times greater than creatinine clearance (CrCl), which indicates that tubular secretion is the major route of metformin elimination. Following oral administration, approximately 90% of the absorbed drug is eliminated via the renal route within the first 24 hours, with a plasma elimination t1/2 of approximately 6.2 hours. In blood, the elimination t1/2 is approximately 17.6 hours, suggesting that the erythrocyte mass may be a compartment of distribution.

Specific Populations

Geriatric Patients

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 t1/2 of pioglitazone was also prolonged in elderly subjects (about ten hours) as compared to younger subjects (about seven hours). These changes are not considered clinically relevant.

Metformin hydrochloride

Limited data from controlled pharmacokinetic studies of metformin in healthy elderly subjects suggest that total CL/F is decreased, the t1/2 is prolonged, and Cmax is increased, compared to healthy young subjects. From these data, it appears that the change in metformin pharmacokinetics with aging is primarily accounted for by a change in renal function.

Pediatric Patients

Pioglitazone

Safety and efficacy of pioglitazone in pediatric patients have not been established. Pioglitazone and metformin hydrochloride is not recommended for use in pediatric patients [see Use in Specific Populations (8.4)].

Metformin hydrochloride

After administration of a single oral metformin 500 mg tablet with food, geometric mean metformin Cmax and AUC differed less than 5% between pediatric type 2 diabetic patients (12 to 16 years of age) and gender- and weight-matched healthy adults (20 to 45 years of age), and all with normal renal function.

Male and Female Patients

Pioglitazone

The mean Cmax and AUC values of pioglitazone were increased 20 to 60% in females compared to males. 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 dosage adjustment is recommended based on gender alone.

Metformin hydrochloride

Metformin pharmacokinetic parameters did not differ significantly between normal subjects and patients with type 2 diabetes mellitus when analyzed according to gender (males=19, females=16). Similarly, in controlled clinical studies in patients with type 2 diabetes mellitus, the antihyperglycemic effect of metformin was comparable in males and females.

Racial or Ethnic Groups

Pioglitazone

Pharmacokinetic data among various ethnic groups are not available.

Metformin hydrochloride

No studies of metformin pharmacokinetic parameters according to race have been performed. In controlled clinical studies of metformin in patients with type 2 diabetes mellitus, the antihyperglycemic effect was comparable in Whites (n=249), Blacks or African Americans (n=51), and Hispanics or Latinos (n=24).

Patients with Renal Impairment

Pioglitazone

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

Metformin hydrochloride

In patients with decreased renal function, the plasma and blood t1/2 of metformin is prolonged and the renal clearance is decreased [see Dosage and Administration (2.3), Contraindications (4), Warnings and Precautions (5.2)].

Patients with Hepatic Impairment

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 dosage 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 pioglitazone and metformin hydrochloride with caution in patients with liver disease [see Warnings and Precautions (5.5)].

Metformin hydrochloride

No pharmacokinetic studies of metformin have been conducted in subjects with hepatic impairment [see Warnings and Precautions (5.5)].

Drug Interaction Studies

Specific pharmacokinetic drug interaction studies with pioglitazone and metformin hydrochloride have not been performed, although such studies have been conducted with the individual pioglitazone and metformin components.

Pioglitazone

* Daily for 7 days unless otherwise noted.

† % change (with/without coadministered drug and no change = 0%); symbols of ↑ and ↓ indicate the exposure    

   increase and decrease, respectively.

‡ Pioglitazone had no clinically significant effect on prothrombin time.

* Daily for 7 days unless otherwise noted.

† Mean ratio (with/without coadministered drug and no change = 1-fold) % change (with/without coadministered drug and no change = 0%); symbols of ↑ and ↓ indicate the exposure increase and decrease, respectively.

‡ The half-life of pioglitazone increased from 8.3 hours to 22.7 hours in the presence of gemfibrozil [see Dosage and Administration (2.3), Drug Interactions (7.1)].

§ Indicates duration of concomitant administration with highest twice-daily dose of topiramate from Day 14 onwards over the 22 days of study.

 ¶ Additional decrease in active metabolites; 60% for M-III and 16% for M-IV.

Metformin hydrochloride

* All metformin and coadministered drugs were given as single doses.

† AUC = AUC0–∞.

‡ Ratio of arithmetic means.

§ Metformin hydrochloride extended-release tablets, 500 mg.

¶ At steady state with topiramate 100 mg every 12 hours and metformin 500 mg every 12 hours; AUC = AUC0-12h

* All metformin and coadministered drugs were given as single doses.

† AUC = AUC0–∞.

‡ Ratio of arithmetic means, p-value of difference <0.05.

§ AUC0-24hr reported.

¶ Ratio of arithmetic means.

13.1 Carcinogenesis, Mutagenesis, Impairment of Fertility

Pioglitazone and Metformin Hydrochloride

No animal studies have been conducted with pioglitazone and metformin hydrochloride. The following data are based on findings in studies performed with pioglitazone or metformin individually.

Pioglitazone

A two year carcinogenicity study was conducted in male and female rats at oral doses up to 63 mg/kg (approximately 14 times the maximum recommended human oral dose of 45 mg based on mg/m2). Drug-induced tumors were not observed in any organ except for the urinary bladder of male rats. Benign and/or malignant transitional cell neoplasms were observed in male rats at 4 mg/kg/day and above (approximately equal to the maximum recommended human oral dose based on mg/m2). Urinary calculi with subsequent irritation and hyperplasia were postulated as the mechanism for bladder tumors observed in male rats. A two year mechanistic study in male rats utilizing dietary acidification to reduce calculi formation was completed in 2009. Dietary acidification decreased but did not abolish the hyperplastic changes in the bladder. The presence of calculi exacerbated the hyperplastic response to pioglitazone but was not considered the primary cause of the hyperplastic changes. 

The relevance to humans of the bladder findings in the male rat cannot be excluded.

A two year carcinogenicity study was also conducted in male and female mice at oral doses up to 100 mg/kg/day (approximately 11 times the maximum recommended human oral dose based on mg/m2).  No drug-induced tumors were observed in any organ.

Pioglitazone hydrochloride was not mutagenic in a battery of genetic toxicology studies, including the Ames bacterial assay, a mammalian cell forward gene mutation assay (CHO/HPRT and AS52/XPRT), an in vitro cytogenetics assay using CHL cells, an unscheduled DNA synthesis assay, and an in vivo micronucleus assay.

No adverse effects upon fertility were observed in male and female rats at oral doses up to 40 mg/kg pioglitazone hydrochloride daily prior to and throughout mating and gestation (approximately nine times the maximum recommended human oral dose based on mg/m2).

Metformin hydrochloride

Long-term carcinogenicity studies have been performed in rats (dosing duration of 104 weeks) and mice (dosing duration of 91 weeks) at doses up to and including 900 mg/kg/day and 1500 mg/kg/day, respectively. These doses are both approximately four times a human daily dose of 2000 mg of the metformin component of pioglitazone and metformin hydrochloride based on body surface area comparisons. No evidence of carcinogenicity with metformin was found in either male or female mice. Similarly, there was no tumorigenic potential observed with metformin in male rats. There was, however, an increased incidence of benign stromal uterine polyps in female rats treated with 900 mg/kg/day. 

There was no evidence of mutagenic potential of metformin in the following in vitro tests: Ames test (S. typhimurium), gene mutation test (mouse lymphoma cells), or chromosomal aberrations test (human lymphocytes). Results in the in vivo mouse micronucleus test were also negative. 

Fertility of male or female rats was unaffected by metformin when administered at doses as high as 600 mg/kg/day, which is approximately three times the maximum recommended human daily dose of the metformin component of pioglitazone and metformin hydrochloride based on body surface area comparisons.

13.2 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 pioglitazone hydrochloride (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).

14.1 Patients Who Have Inadequate Glycemic Control with Diet and Exercise Alone

In a 24 week, randomized, double-blind clinical trial, 600 patients with type 2 diabetes mellitus inadequately controlled with diet and exercise alone (mean baseline HbA1c 8.7%) were randomized to pioglitazone and metformin hydrochloride 15/850 mg, pioglitazone 15 mg, or metformin 850 mg twice daily. Statistically significant improvements in HbA1c and fasting plasma glucose (FPG) were observed in patients treated with pioglitazone and metformin hydrochloride compared to either pioglitazone or metformin alone (see Table 22).

14.2 Patients Previously Treated with Metformin

The efficacy and safety of pioglitazone as add-on to metformin therapy have been established in two clinical studies [see Clinical Pharmacology (12.3)].

The two clinical trials testing pioglitazone as add-on to metformin therapy included patients with type 2 diabetes mellitus on any dose of metformin, 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 trial, 328 patients were randomized to receive either 30 mg of pioglitazone or placebo once daily for 16 weeks in addition to their current metformin regimen. Treatment with pioglitazone as add-on to metformin produced statistically significant improvements in HbA1c and FPG at endpoint compared to placebo add-on to metformin (see Table 23).

In the second trial, 827 patients were randomized to receive either 30 mg or 45 mg of pioglitazone once daily for 24 weeks in addition to their current metformin regimen. The mean reduction from baseline at Week 24 in HbA1c was 0.8% for the 30 mg dose and 1% for the 45 mg dose (see Table 24). The mean reduction from baseline at Week 24 in FPG was 38 mg/dL for the 30 mg dose and 51 mg/dL for the 45 mg dose.

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