Pioglitazone Hydrochloride and Metformin Hydrochloride Dailymed

1 Indications And Usage

Pioglitazone and metformin hydrochloride tablets are indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus when treatment with both pioglitazone and metformin is appropriate [see Clinical Studies (14)].

Important Limitations of Use

Pioglitazone exerts its antihyperglycemic effect only in the presence of endogenous insulin. Pioglitazone and metformin hydrochloride tablets should not be used to treat type 1 diabetes or diabetic ketoacidosis, as it would not be effective in these settings.

Use caution in patients with liver disease [see Warnings and Precautions (5.5)].


Pioglitazone and metformin hydrochloride tablets are a thiazolidinedione and biguanide combination product indicated as an adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus when treatment with both pioglitazone and metformin is appropriate. (1, 14)

Important Limitations of Use:

• •Not for treatment of type 1 diabetes or diabetic ketoacidosis. (1)

• •Congestive heart failure: Fluid retention may occur and can exacerbate or lead to congestive heart failure. Combination use with insulin and use in congestive heart failure NYHA Class I and II may increase risk. Monitor patients for signs and symptoms. (5.1)
• •Lactic acidosis: See boxed warning. (5.2)
• •Edema: Dose-related edema may occur. (5.3)
• •Hypoglycemia: When used with insulin or an insulin secretagogue, a lower dose of the insulin or insulin secretagogue may be needed to reduce the risk of hypoglycemia. (5.4)
• •Hepatic effects: Postmarketing reports of hepatic failure, sometimes fatal. Causality cannot be excluded. If liver injury is detected, promptly interrupt pioglitazone and metformin hydrochloride tablets and assess patient for probable cause, then treat cause if possible, to resolution or stabilization. Do not restart pioglitazone and metformin hydrochloride tablets if liver injury is confirmed and no alternate etiology can be found. (5.5)
• •Bladder cancer: May increase the risk of bladder cancer. Do not use in patients with active bladder cancer. Use caution when using in patients with a prior history of bladder cancer. (5.6)
• •Fractures: Increased incidence in female patients. Apply current standards of care for assessing and maintaining bone health. (5.7)
• •Macular edema: Postmarketing reports. Recommend regular eye exams in all patients with diabetes according to current standards of care with prompt evaluation for acute visual changes. (5.8)
• •Vitamin B₁₂ deficiency: Metformin may lower vitamin B₁₂ levels. Monitor hematologic parameters annually. (5.9)
• •Macrovascular outcomes: There have been no clinical studies establishing conclusive evidence of macrovascular risk reduction with pioglitazone and metformin hydrochloride tablets. (5.10)

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. Patients treated with pioglitazone and metformin hydrochloride tablets should be observed for signs and symptoms of congestive heart failure. If congestive heart failure develops, it should be managed according to current standards of care and discontinuation or dose reduction of pioglitazone and metformin hydrochloride tablets must be considered [see Boxed Warning, Contraindications (4), and Adverse Reactions (6.1)].

5.2 Lactic Acidosis

There have been post-marketing 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), and an increased lactate: pyruvate ratio; 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 tablets. In pioglitazone and metformin hydrochloride tablets-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 tablets 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:

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 (2.2), Clinical Pharmacology (12.3)].

• •Before initiating pioglitazone and metformin hydrochloride tablets, obtain an eGFR.
• •Pioglitazone and metformin hydrochloride tablets are contraindicated in patients with an eGFR less than 30 mL/min /1.73 m². Initiation of pioglitazone and metformin hydrochloride tablets are not recommended in patients with eGFR between 30 – 45 mL/min/1.73 m² [see Contraindications (4)].
• •Obtain an eGFR at least annually in all patients taking pioglitazone and metformin hydrochloride tablets. 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 tablets whose eGFR later falls below 45 mL/min/1.73 m², assess the benefit and risk of continuing therapy.

The concomitant use of pioglitazone and metformin hydrochloride tablets 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.

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)].

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 tablets at the time of, or prior to, an iodinated contrast imaging procedure in patients with an eGFR between 30 and 60 mL/min/1.73 m2; 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 tablets if renal function is stable.

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 tablets should be temporarily discontinued while patients have restricted food and fluid intake.

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 tablets.

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 tablets.

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 tablets 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 tablets 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 tablets should be used with caution in patients at risk for congestive heart failure. Patients treated with pioglitazone and metformin hydrochloride tablets should be monitored for signs and symptoms of congestive heart failure [see Boxed Warning, Warnings and Precautions (5.1), and Patient Counseling Information (17.1)].

5.4 Hypoglycemia

Patients receiving pioglitazone and metformin hydrochloride tablets in combination with insulin or other antidiabetic medications (particularly insulin secretagogues such as sulfonylureas) may be at risk for hypoglycemia. A reduction in the dose of the concomitant antidiabetic medication may be necessary to reduce the risk of hypoglycemia [see Drug Interactions (7.7)]. Hypoglycemia can also occur when caloric intake is deficient or when strenuous exercise is not compensated by caloric supplement. Elderly, debilitated, or malnourished patients, and those with adrenal or pituitary insufficiency or alcohol intoxication are particularly susceptible to hypoglycemic effects. Hypoglycemia may be difficult to recognize in the elderly, and in people who are taking beta-adrenergic blocking drugs.

5.5 Hepatic Effects

There have been postmarketing reports of fatal and nonfatal 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 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 tablets therapy.

In patients with abnormal liver tests, pioglitazone and metformin hydrochloride tablets 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 abnormal liver tests (ALT greater than three times the upper limit of the reference range), pioglitazone and metformin hydrochloride tablets treatment should be interrupted and investigation done to establish the probable cause. Pioglitazone and metformin hydrochloride tablets should not be restarted in these patients without another explanation for the liver test abnormalities.

Patients who have serum ALT greater than three times the reference range with serum total bilirubin greater than two times the reference range without alternative etiologies are at risk for severe drug-induced liver injury, and should not be restarted on pioglitazone and metformin hydrochloride tablets. For patients with lesser elevations of serum ALT or bilirubin and with an alternate probable cause, treatment with pioglitazone and metformin hydrochloride tablets can be used with caution.

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 2605 (0.54%) randomized to pioglitazone and 5 out of 2633 (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 two (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 = 1.00; [95% 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 prospective 10-year observational cohort study conducted in the United States 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 tablets 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 tablets 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), 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. 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 tablets 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 B Levels

In controlled clinical trials of metformin of 29 weeks’ duration, a decrease to subnormal levels of previously normal serum vitamin B₁₂ levels, without clinical manifestations, was observed in approximately 7% of patients. Such decrease, possibly due to interference with B₁₂ absorption from the B₁₂-intrinsic factor complex, is, however, very rarely associated with anemia and appears to be rapidly reversible with discontinuation of metformin or vitamin B₁₂ supplementation. Measurement of hematologic parameters on an annual basis is advised in patients on pioglitazone and metformin hydrochloride tablets and any apparent abnormalities should be appropriately investigated and managed. Certain individuals (those with inadequate vitamin B₁₂ or calcium intake or absorption) appear to be predisposed to developing subnormal vitamin B₁₂ levels. In these patients, routine serum vitamin B₁₂ measurements at two- to three- year intervals may be useful.

5.10 Macrovascular Outcomes

There have been no clinical studies establishing conclusive evidence of macrovascular risk reduction with pioglitazone and metformin hydrochloride tablets.

6 Adverse Reactions

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

• •Congestive heart failure [see Boxed Warning and Warnings and Precautions (5.1)]
• •Lactic acidosis [see Boxed Warning and Warnings and Precautions (5.2)]
• •Edema [see Warnings and Precautions (5.3)]
• •Fractures [see Warnings and Precautions (5.7)]

Most common adverse reactions (> 5%) are upper respiratory tract infection, edema, diarrhea, headache and weight gain. (6.1)

To report SUSPECTED ADVERSE REACTIONS, contact Mylan Pharmaceuticals Inc. at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

6.1 Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

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 from 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 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 (3.0%).

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 1. 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 1. 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

% of Patients
	Placebo N = 259	Pioglitazone N = 606
Upper Respiratory Tract Infection	8.5	13.2
Headache	6.9	9.1
Sinusitis	4.6	6.3
Myalgia	2.7	5.4
Pharyngitis	0.8	5.1

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 2. Terms that are reported represent those that occurred at an incidence of > 5% and more commonly with the highest tested dose of pioglitazone.

Table 2. 16- to 24-Week Clinical Trials of Pioglitazone Add-on to Metformin

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema”.
	16-Week Placebo-Controlled Trial Adverse Events Reported in > 5% of Patients and More Commonly in Patients Treated with Pioglitazone + Metformin than in Patients Treated with Placebo + Metformin
	% of Patients
	Placebo + Metformin N = 160	Pioglitazone 30 mg + Metformin N = 168
Edema	2.5	6.0
Headache	1.9	6.0
	24-Week Non-Controlled Double-Blind Trial Adverse Events Reported in > 5% of Patients and More Commonly in Patients Treated with Pioglitazone 45 mg + Metformin than in Patients Treated with Pioglitazone 30 mg + Metformin
	% of Patients
	Pioglitazone 30 mg + Metformin N = 411	Pioglitazone 45 mg + Metformin N = 416
Upper Respiratory Tract Infection	12.4	13.5
Edema	5.8	13.9
Headache	5.4	5.8
Weight Increased	2.9	6.7

Table 3 summarizes the incidence and types of adverse reactions reported in a controlled, 24-week double-blind clinical trial of pioglitazone and metformin hydrochloride tablets dosed twice daily in patients with inadequate glycemic control on diet and exercise (N = 600).

Table 3. Adverse Events (≥ 5% for Pioglitazone and Metformin Hydrochloride Tablets) Reported by Patients with Inadequate Glycemic Control on Diet and Exercise in a 24-Week Double-Blind Clinical Trial of Pioglitazone and Metformin Hydrochloride Tablets Administered Twice Daily

% of Patients
	Pioglitazone and Metformin Hydrochloride Tablets 15/850 mg Twice Daily N = 201	Pioglitazone 15 mg Twice Daily N = 190	Metformin 850 mg Twice Daily N = 209
Diarrhea	9.0	2.6	15.3
Headache	5.5	2.6	4.8

In this 24-week trial, abdominal pain was reported in 2.0% of patients in the pioglitazone and metformin hydrochloride tablets group, 1.6% in the pioglitazone monotherapy group and 3.3% in the metformin monotherapy group.

A summary of the overall incidence and types of common adverse events reported in the PROactive trial is provided in Table 4. 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 4. PROactive Trial: Incidence and Types of Adverse Events Reported in > 5% of Patients Treated with Pioglitazone and More Commonly than Placebo

	% of Patients
	Placebo N = 2633	Pioglitazone N = 2605
Hypoglycemia	18.8	27.3
Edema	15.3	26.7
Cardiac Failure	6.1	8.1
Pain in Extremity	5.7	6.4
Back Pain	5.1	5.5
Chest Pain	5.0	5.1

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 5 for the 16- to 24-week add-on to metformin trials. None of the events were fatal.

Table 5. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) Patients Treated with Pioglitazone or Placebo Added on to Metformin

	Number (%) of Patients
	Placebo-Controlled Trial (16 weeks)		Non-Controlled Double-Blind Trial (24 weeks)
	Placebo + Metformin N = 160	Pioglitazone 30 mg + Metformin N = 168	Pioglitazone 30 mg + Metformin N = 411	Pioglitazone 45 mg + Metformin N = 416
At least one congestive heart failure event	0	1 (0.6%)	0	1 (0.2%)
Hospitalized	0	1 (0.6%)	0	1 (0.2%)

 

Table 6. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF)

Patients Treated with Pioglitazone or Placebo Added on to a Sulfonylurea
	Number (%) of Patients
	Placebo-Controlled Trial (16 weeks)			Non-Controlled Double-Blind Trial (24 weeks)
	Placebo + Sulfonylurea N = 187	Pioglitazone 15 mg + Sulfonylurea N = 184	Pioglitazone 30 mg + Sulfonylurea N = 189	Pioglitazone 30 mg + Sulfonylurea N = 351	Pioglitazone 45 mg + Sulfonylurea N = 351
At least one congestive heart failure event	2 (1.1%)	0	0	1 (0.3%)	6 (1.7%)
Hospitalized	2 (1.1%)	0	0	0	2 (0.6%)
Patients Treated with Pioglitazone or Placebo Added on to Insulin
	Number (%) of Patients
	Placebo-Controlled Trial (16 weeks)			Non-Controlled Double-Blind Trial (24 weeks)
	Placebo + Insulin N = 187	Pioglitazone 15 mg + Insulin N = 191	Pioglitazone 30 mg + Insulin N = 188	Pioglitazone 30 mg + Insulin N = 345	Pioglitazone 45 mg + Insulin N = 345
At least one congestive heart failure event	0	2 (1.0%)	2 (1.1%)	3 (0.9%)	5 (1.4%)
Hospitalized	0	2 (1.0%)	1 (0.5%)	1 (0.3%)	3 (0.9%)
Patients Treated with Pioglitazone or Placebo Added on to Metformin
	Number (%) of Patients
	Placebo-Controlled Trial (16 weeks)			Non-Controlled Double-Blind Trial (24 weeks)
	Placebo + Metformin N = 160	Pioglitazone 30 mg + Metformin N = 168		Pioglitazone 30 mg + Metformin N = 411	Pioglitazone 45 mg + Metformin N = 416
At least one congestive heart failure event	0	1 (0.6%)		0	1 (0.2%)
Hospitalized	0	1 (0.6%)		0	1 (0.2%)

 

Table 7. 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

	Number (%) of Subjects
	Pioglitazone N = 262	Glyburide N = 256
Death due to cardiovascular causes (adjudicated)	5 (1.9%)	6 (2.3%)
Overnight hospitalization for worsening CHF (adjudicated)	26 (9.9%)	12 (4.7%)
Emergency room visit for CHF (adjudicated)	4 (1.5%)	3 (1.2%)
Patients experiencing CHF progression during study	35 (13.4%)	21 (8.2%)

Congestive heart failure events leading to hospitalization that occurred during the PROactive trial are summarized in Table 8.

Table 8. Treatment-Emergent Adverse Events of Congestive Heart Failure (CHF) in PROactive Trial

	Number (%) of Patients
	Placebo N = 2633	Pioglitazone N = 2605
At least one hospitalized congestive heart failure event	108 (4.1%)	149 (5.7%)
Fatal	22 (0.8%)	25 (1.0%)
Hospitalized, nonfatal	86 (3.3%)	124 (4.7%)

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 (HR 0.90; 95% CI: 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 9.

Table 9. PROactive Trial: Number of First and Total Events for Each Component Within the Cardiovascular Composite Endpoint

CABG = coronary artery bypass grafting; PCI = percutaneous intervention
Cardiovascular Events	Placebo N = 2633		Pioglitazone N = 2605
	First Events n (%)	Total Events n	First Events n (%)	Total Events n
Any event	572 (21.7)	900	514 (19.7)	803
All-cause mortality	122 (4.6)	186	110 (4.2)	177
Nonfatal myocardial infarction (MI)	118 (4.5)	157	105 (4.0)	131
Stroke	96 (3.6)	119	76 (2.9)	92
Acute coronary syndrome	63 (2.4)	78	42 (1.6)	65
Cardiac intervention (CABG/PCI)	101 (3.8)	240	101 (3.9)	195
Major leg amputation	15 (0.6)	28	9 (0.3)	28
Leg revascularization	57 (2.2)	92	71 (2.7)	115

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 10, 11, and 12 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 tablets trial.

Table 10. Weight Changes (kg) from Baseline During Randomized, Double-Blind Clinical Trials

		Control Group (Placebo)	Pioglitazone 15 mg	Pioglitazone 30 mg	Pioglitazone 45 mg
		Median (25th, 75th percentile)	Median (25th, 75th percentile)	Median (25th, 75th percentile)	Median (25th, 75th percentile)
Monotherapy (16 to 26 weeks)		-1.4 (-2.7, 0.0) N = 256	0.9 (-0.5, 3.4) N = 79	1.0 (-0.9, 3.4) N = 188	2.6 (0.2, 5.4) N = 79
Combination Therapy (16 to 24 weeks)	Sulfonylurea	-0.5 (-1.8, 0.7) N = 187	2.0 (0.2, 3.2) N = 183	3.1 (1.1, 5.4) N = 528	4.1 (1.8, 7.3) N = 333
	Metformin	-1.4 (-3.2, 0.3) N = 160	N/A	0.9 (-1.3, 3.2) N = 567	1.8 (-0.9, 5) N = 407
	Insulin	0.2 (-1.4, 1.4) N = 182	2.3 (0.5, 4.3) N = 190	3.3 (0.9, 6.3) N = 522	4.1 (1.4, 6.8) N = 338

 

Table 11. Median Change in Body Weight in Patients Treated with Pioglitazone Versus Patients Treated with Placebo During the Double-Blind Treatment Period in the PROactive Trial

Note: Median exposure for both pioglitazone and placebo was 2.7 years.
	Placebo	Pioglitazone
	Median (25th, 75th percentile)	Median (25th, 75th percentile)
Change from baseline to final visit (kg)	-0.5 (-3.3, 2.0) N = 2581	+3.6 (0.0, 7.5) N = 2560

Table 12. Weight Changes (kg) from Baseline During Double-Blind Clinical Trial with Pioglitazone and Metformin Hydrochloride Tablets in Patients with Inadequate Glycemic Control on Diet and Exercise

Note: Trial duration of 24 weeks.
	Pioglitazone and Metformin Hydrochloride Tablets 15/850 mg Twice Daily	Pioglitazone 15 mg Twice Daily	Metformin 850 mg Twice Daily
	Median (25th , 75th percentile)	Median (25th , 75th percentile)	Median (25th , 75th percentile)
Change from baseline to final visit (kg)	1.00 (-1.0, 3.0) N = 198	1.35 (-0.7, 4.1) N = 178	-1.00 (-2.6, 0.4)N = 203

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.

In the 24-week pioglitazone and metformin hydrochloride tablets trial, edema was reported in 3.0% of patients in the pioglitazone and metformin hydrochloride tablets 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 13.

Table 13. Adverse Events of Edema in Patients Treated with Pioglitazone

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema”.
		Number (%) of Patients
		Placebo	Pioglitazone 15 mg	Pioglitazone 30 mg	Pioglitazone 45 mg
Monotherapy (16 to 26 weeks)		3 (1.2%) N = 259	2 (2.5%) N = 81	13 (4.7%) N = 275	11 (6.5%) N = 169
Combined Therapy (16 to 24 weeks)	Sulfonylurea	4 (2.1%) N = 187	3 (1.6%) N = 184	61 (11.3%) N = 540	81 (23.1%) N = 351
	Metformin	4 (2.5%) N = 160	N/A	34 (5.9%) N = 579	58 (13.9%) N = 416
	Insulin	13 (7.0%) N = 187	24 (12.6%) N = 191	109 (20.5%) N = 533	90 (26.1%) N = 345

Table 14. Adverse Events of Edema in Patients in the PROactive Trial

Note: The preferred terms of edema peripheral, generalized edema, pitting edema, and fluid retention were combined to form the aggregate term of “edema”.
Number (%) of Patients
Placebo N = 2633	Pioglitazone N = 2605
419 (15.9%)	712 (27.3%)

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 3/1051 (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 drug-induced 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 (13.1)]. During the three year PROactive clinical trial, 14 patients out of 2605 (0.54%) randomized to pioglitazone and 5 out of 2633 (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 two (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 = 1.00; 95% CI: 0.59 – 1.72) [see Warnings and Precautions (5.6)].

In a double-blind clinical study of metformin in patients with type 2 diabetes, a total of 141 patients received metformin therapy (up to 2550 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 uled in Table 15. In this trial, diarrhea led to discontinuation of study medication in 6% of patients treated with metformin.

Table 15. Most Common Adverse Reactions (> 5.0%) in a Placebo-Controlled Clinical Study of Metformin MonotherapyReactions that were more common in metformin than placebo-treated patients.

Adverse Reaction	Metformin Monotherapy (n = 141)	Placebo (n = 145)
	% of Patients
Diarrhea	53.2	11.7
Nausea/Vomiting	25.5	8.3
Flatulence	12.1	5.5
Asthenia	9.2	5.5
Indigestion	7.1	4.1
Abdominal Discomfort	6.4	4.8
Headache	5.7	4.8

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 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.

Vitamin B₁₂ Concentrations: Metformin may lower serum vitamin B₁₂ concentrations. Measurement of hematologic parameters on an annual basis is advised in patients on pioglitazone and metformin hydrochloride tablets and any apparent abnormalities should be appropriately investigated and managed [see Warnings and Precautions (5.9)].

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.

6.2 Postmarketing Experience

The following adverse reactions have been identified during post-approval use of pioglitazone. 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 (5.8)].
• •Fatal and nonfatal hepatic failure [see Warnings and Precautions (5.5)].

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 volume-related events such as excessive edema and congestive heart failure [see Boxed Warning and Warnings and Precautions (5.1)].

Cholestatic, hepatocellular, and mixed hepatocellular liver injury.