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A lifetime modelled economic evaluation comparing pioglitazone and rosiglitazone for the treatment of type 2 diabetes mellitus in the UK.

INTRODUCTION: Adding pioglitazone or rosiglitazone to existing therapy are alternative treatment options for patients with type 2 diabetes mellitus who have insufficient glycaemic control while receiving the maximal tolerated dose of metformin monotherapy. Our objective was to develop a lifetime model of type 2 diabetes mellitus and its sequelae in order to compare the costs and benefits of pioglitazone versus rosiglitazone in combination with metformin. METHODS: A decision-analytic model employing a first order Monte Carlo simulation of a Markov process was constructed. The model incorporated surrogate outcome measures from a large randomised controlled trial (RCT) [n = 802] that compared the glycaemic and lipid control of pioglitazone and rosiglitazone monotherapy. These efficacy data were used with a recently validated and peer-reviewed UKPDS (UK Prospective Diabetes Study) algorithm to simulate the progression of these surrogate outcomes to final health outcomes, including quality of life (QOL) and mortality, and to calculate the risks of diabetic complications and death. The model perspective was of the UK NHS and included direct healthcare costs only (pounds, 2004/5 values). Patient outcomes measured in the model included life-expectancy (LE) and QALYs. The base-case analysis was run for 56-year-old male Caucasions with a haemoglobin A(1c) (HbA(1c)) of 7.57% and a body mass index of 33.14 kg/m(2). RESULTS: Patients treated with pioglitazone experienced a reduction in the total cholesterol to high-density lipoprotein-cholesterol (TC : HDL-C) ratio of 0.34, whereas the TC : HDL-C ratio increased by 0.65 in those receiving rosiglitazone (p < 0.001). The HbA(1c) profile was similar between the treatment groups (p = 0.13), as were other known risk factors for diabetes complications. The lifetime healthcare costs per patient estimated by the model were 9585 pounds for pioglitazone and 10,299 pounds for rosiglitazone. Patients treated with pioglitazone had a discounted LE of 8.83 years versus 8.79 years for those treated with rosiglitazone. Patients treated with pioglitazone also gained additional QALYs (6.8070 vs 6.7686). With improved health outcomes and lower costs, treatment with pioglitazone dominated rosiglitazone treatment. CONCLUSION: Evidence from the only large head-to-head RCT comparing rosiglitazone and pioglitazone suggests that more favourable changes in serum lipid profiles in patients treated with pioglitazone translate into improved health outcomes in terms of reduced morbidity and mortality and greater gains in QOL. In addition, this analysis indicates that treatment with pioglitazone is associated with lower costs than rosiglitazone. Therefore, in the UK, adjunctive pioglitazone may represent a cost-effective treatment choice for patients with type 2 diabetes who have insufficient glycaemic control while receiving the maximal tolerated dose of metformin monotherapy.

Blood Glucose↗

[The effect of pioglitazone on apoptotic cardiomyocytes for ischemia reperfusion].

OBJECTIVE: This study was to investigate the effect of pioglitazone on apoptotic cardiomyocytes with the model of ischemia-reperfusion at rat heart in vivo. METHODS: Sprague-Dawley rats were randomly divided into two groups. One was 30 min reperfusion group, which was subdivided into sham (n = 5), model (vehicle, n = 6) and pioglitazone 3 mg/kg (n = 7) with 30 min ischemia followed by 30 min reperfusion to detect the area of myocardial infarction (MI). Another was 2 h reperfusion group, which was further subdivided into sham (n = 5), model (vehicle, n = 6), and pioglitazone 0.3 mg/kg (n = 6), 1 mg/kg (n = 7) and 3 mg/kg (n = 6). Apart from the sham, pioglitazone and vehicle were administered intravenously 30 min before occlusion. Then hearts were excised, paraffined and cut into 4 microm thick. Immunohistochemistry, in situ hybridization, TUNEL and DNA agarose gel electrophoresis were performed to detect the expression of Bax, Bcl-2, Caspase-3 and PPARgamma protein and PPARgamma mRNA. RESULTS: (1) Compared with model, nec/aar of pioglitazone decreased by 28% (P < 0.01). The nec/lv ratio reduced by 32% (P < 0.01). (2) In a dose-dependent manner, the expressions of Bax and Caspase-3 were depressed, while the expression of Bcl-2, PPARgamma protein and PPARgamma mRNA were enhanced by pioglitazone. (3) The apoptotic index of subgroups injected pioglitazone reduced significantly by TUNEL compared with model (P < 0.05). Agarose gel electrophoresis demonstrated that DNA ladder existed in model, pioglitazone 0.3 mg/kg and pioglitazone 1 mg/kg, but not pioglitazone 3 mg/kg. CONCLUSIONS: Pioglitazone could protect the heart from I/R injury evidenced by the improvement in the expression of PPARgamma at the levels of protein and mRNA after pioglitazone administrated, and by the decrease in the apoptotic cardiomyocytes.

Animals↗

Long-term efficacy and tolerability of add-on pioglitazone therapy to failing monotherapy compared with addition of gliclazide or metformin in patients with type 2 diabetes.

AIMS/HYPOTHESIS: The aim of this analysis was to examine the long-term effects of pioglitazone or gliclazide addition to failing metformin monotherapy and pioglitazone or metformin addition to failing sulphonylurea monotherapy in patients with type 2 diabetes. METHODS: Two 2-year, randomised, multicentre trials were performed in patients with inadequately controlled type 2 diabetes (HbA1c 7.5-11% inclusive), who were receiving either metformin or a sulphonylurea at > or = 50% of the maximum recommended dose or at the maximum tolerated dose. In the first study, patients on metformin received add-on therapy with pioglitazone (15-45 mg/day, n = 317) or gliclazide (80-320 mg/day, n = 313). In the second study, patients on sulphonylurea therapy were randomised to receive add-on therapy with either pioglitazone (15-45 mg/day, n = 319) or metformin (850-2,550 mg/day, n = 320). HbA(1)c, fasting plasma glucose, insulin and lipids were investigated. RESULTS: At week 104, the mean reduction from baseline in HbA(1)c was 0.89% for pioglitazone and 0.77% for gliclazide addition to metformin (p = 0.200). There was a statistically significant between-group difference for the change in mean fasting plasma glucose at week 104 (-1.8 mmol/l for pioglitazone vs -1.1 mmol/l for gliclazide, p < 0.001). There were no significant differences in changes from baseline in glycaemic parameters for pioglitazone compared with metformin addition to sulphonylurea therapy. Whether added to metformin or sulphonylurea, pioglitazone caused significantly greater decreases in triglycerides and significantly greater increases in HDL cholesterol than the comparator regimens (p < or = 0.001). There were decreases in LDL cholesterol in the comparator groups and these were significantly different from the small changes observed with pioglitazone (p < 0.001). All treatment regimens were well tolerated. There were weight increases of 2.5 kg and 3.7 kg in the pioglitazone and 1.2 kg in the gliclazide add-on groups, and there was a mean decrease of 1.7 kg in the metformin add-on group. CONCLUSIONS/INTERPRETATION: As add-on therapy to existing sulphonylurea or metformin therapy, pioglitazone improved glycaemic control and this improvement was sustained over 2 years. Furthermore, there were potential benefits in terms of improvements in specific lipid abnormalities. This could offer an advantage over the addition of other oral agents in the long-term treatment of diabetes.

Adult↗

Pioglitazone hydrochloride in combination with sulfonylurea therapy improves glycemic control in patients with type 2 diabetes mellitus: a randomized, placebo-controlled study.

PURPOSE: To evaluate the efficacy and tolerability of pioglitazone in combination with a sulfonylurea in the treatment of type 2 diabetes mellitus. SUBJECTS AND METHODS: This 16-week, double-blind study included patients on a stable regimen of a sulfonylurea for > or = 30 days and with a glycosylated hemoglobin (HbA1C) level > or = 8.0%. Patients were randomly assigned to receive once daily pioglitazone 15 mg (n = 184), pioglitazone 30 mg (n = 189), or placebo plus sulfonylurea (n = 187). RESULTS: Patients receiving pioglitazone + sulfonylurea had significant (P < 0.05) decreases from baseline in HbA1C and fasting plasma glucose levels compared with patients treated with placebo + sulfonylurea. As compared with placebo, HbA1C decreased by 0.9% (95% confidence interval [CI]: 0.06% to 1.2%) with pioglitazone 15 mg and 1.3% (CI: 1% to 1.6%) with 30 mg pioglitazone; fasting plasma glucose levels decreased by 39 mg/dL (95% CI: 27 to 52 mg/dL) with pioglitazone 15 mg and by 58 mg/dL (95% CI: 46-70 mg/dL) with 30 mg pioglitazone. Both pioglitazone + sulfonylurea groups had significant (P < 0.05) mean percent decreases in triglyceride levels (17%, 95% CI: 6% to 27% for 15 mg; 26%, 95% CI: 16% to 36% for 30 mg) and increases in high-density lipoprotein cholesterol levels (6%, 95% CI: 1% to 11% for 15 mg; 13%, CI: 8% to 18% for 30 mg) compared with placebo + sulfonylurea. There were small but statistically significant mean percent increases in low-density lipoprotein cholesterol levels in all groups. Pioglitazone was well tolerated, and the rates of adverse events were similar in all groups. CONCLUSION: In patients with type 2 diabetes, pioglitazone plus sulfonylurea significantly improves HbA1C and fasting plasma glucose levels with beneficial effects on serum triglyceride and HDL-cholesterol levels.

Adult↗

A systematic review of the clinical effectiveness of pioglitazone in the treatment of type 2 diabetes mellitus.

BACKGROUND: Pioglitazone is a member of a recently developed class of glucose-lowering agents, the thiazolidinediones, used in the treatment of type 2 diabetes mellitus. In the United States, it is approved for use both as monotherapy and in combination with metformin, a sulfonylurea, or insulin; in Europe, it is approved for use in combination with metformin or a sulfonylurea but not insulin. OBJECTIVE: This article presents a systematic review of the published literature on the effectiveness of pioglitazone in the treatment of type 2 diabetes, both as monotherapy and in combination with other antidiabetic agents. METHODS: The peer-reviewed English- and foreign-language literature was searched using MEDLINE, PubMED, EMBASE, Science Citation Index, the Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register, the UK National Health Service Centre for Reviews and Dissemination databases, and the Office of Health Economics Health Economic Evaluations Database. Searches were not limited to specific publication types, study designs, dates, or languages. The latest search was performed in March 2001. For a trial to be included in the review, at least 1 outcome measure had to involve the effects of pioglitazone on glycemic control or cardiovascular risk factors, or its side effects. Because of the heterogeneity of studies, no formal meta-analysis was performed. RESULTS: Eleven studies met the inclusion criteria, 6 involving pioglitazone monotherapy and 5 involving combination therapy. Full reports were available for only 6 of the 11 studies. No studies directly compared pioglitazone with other antidiabetic drugs. Both as monotherapy and in combination therapy, pioglitazone produced decreases in blood glucose levels (up to 95 mg/dL) and glycosylated hemoglobin (up to 2.6%). At doses of > or = 30 mg/d, pioglitazone was associated with reductions in triglyceride levels (-30-70 mg/dL) and increases in high-density lipoprotein cholesterol (HDL-C) levels (-4-5 mg/dL). Pioglitazone treatment was associated with significant weight gain (up to 4 kg over 16 weeks). Adverse effects included mild edema (in up to 11.7% of patients) and a clinically nonsignificant decrease in hemoglobin concentrations. Abnormal results on liver function testing were no more common in treated patients than in control groups. CONCLUSIONS: Pioglitazone has been shown to reduce blood glucose levels in patients with type 2 diabetes. Although the observed decreases in triglyceride levels and increases in HDL-C levels could be expected to lead to a reduction in cardiovascular risk, the effects of weight gain may counteract this benefit. The evidence suggests that the preferred role for pioglitazone may be as an adjunct to metformin or a sulfonylurea in patients whose condition is not well controlled with monotherapy and for whom a metformin-sulfonylurea combination is contraindicated. There is a need for large-scale, long-term studies comparing the effectiveness of combination therapy that includes pioglitazone with that of other combinations of antidiabetic drugs.

Adult↗

A randomized, double-blind, placebo-controlled, clinical trial of the effects of pioglitazone on glycemic control and dyslipidemia in oral antihyperglycemic medication-naive patients with type 2 diabetes mellitus.

OBJECTIVE: The goal of this study was to compare the effects of 2 doses of pioglitazone hydrochloride (a thiazolidinedione insulin sensitizer) with placebo on glycated hemoglobin (HbA(1c)), insulin sensitivity, and lipid profiles in patients with type 2 diabetes mellitus who had suboptimal glycemic control and mild dyslipidemia. METHODS: Patients with type 2 diabetes mellitus (HbA(1c) >/=6.5% and </=9.8%) who had not previously received insulin or oral antihyperglycemic medications (OAMs) were randomized to treatment with placebo, pioglitazone 30 mg QD, or pioglitazone 45 mg QD in double-blind fashion for 16 weeks at 41 centers in Canada and Spain. RESULTS: A total of 297 patients were randomized (99 in each group). Overall, 286 (96.3%) were white. Mean (SD) age was 58.4 (10.9) years (range, 24-85 years), mean (SD) body mass index was 31.4 (4.8) kg/m(2), mean (SD) duration of type 2 diabetes mellitus was 20.0 (37.4) months, and 30.6% of patients were receiving medication for dyslipidemia. Treatment with pioglitazone 30 or 45 mg QD for 16 weeks reduced mean HbA(1c) by 0.8% and 0.9% from baseline, respectively (both P < 0.001 vs baseline and placebo). A reduction in HbA(1c) of 0.2% was observed in the placebo group (P = 0.025). In patients with medium (>/=7% to <8%) or high (>/=8% to </=9.8%) baseline HbA(1c), both doses of pioglitazone significantly reduced HbA(1c) (both P < 0.001 vs placebo). Pioglitazone 30 and 45 mg significantly reduced fasting serum insulin versus placebo (P = 0.008 and P = 0.006, respectively) and increased insulin sensitivity by Homeostasis Model Assessment versus placebo (P = 0.039 and P = 0.001, respectively). Relative to placebo, pioglitazone 30 and 45 mg significantly increased high-density lipoprotein cholesterol (HDL-C [P = 0.028 and P < 0.001, respectively]) and lowered the atherogenic index of plasma (P = 0.018 and P < 0.001, respectively). Pioglitazone 45 mg also significantly reduced serum triglycerides, apolipoprotein B, and total cholesterol:HDL-C ratio versus placebo (P = 0.007, P = 0.015, and P = 0.005, respectively). Pioglitazone 30 and 45 mg were associated with a significant reduction in serum alanine aminotransferase relative to placebo (P = 0.036 and P = 0.005, respectively). Pioglitazone appeared to be safe and was well tolerated. CONCLUSIONS: In the present study, pioglitazone 30 and 45 mg produced significant improvements in HbA(1c), insulin sensitivity, and lipid profile in OAM-naive patients with type 2 diabetes mellitus with suboptimal glycemic control and mild dyslipidemia.

Adult↗

The pharmacokinetics of pioglitazone in patients with impaired renal function.

AIMS: To evaluate the effect of renal impairment on the pharmacokinetics and safety of pioglitazone and its metabolites M-III and M-IV with impaired renal function and normal renal function. METHODS: In a phase-I, open-label, parallel-group study, six healthy subjects with normal renal function (creatinine clearance> 80 ml min-1), nine patients with moderate renal impairment (creatinine clearance 30-60 ml min-1) and 12 patients with severe renal impairment (creatinine clearance < 30 ml min-1) received single and multiple oral doses of pioglitazone 45 mg. The serum pharmacokinetic profiles of pioglitazone and its metabolites M-III and M-IV were assessed for the first and last dose administered (day 1 and day 12, respectively). RESULTS: Pharmacokinetic data revealed no significant accumulation of pioglitazone or its metabolites M-III and M-IV in patients with renal impairment. There was no significant difference in the pharmacokinetic profile of pioglitazone in subjects with normal and with moderately impaired renal function. After single oral doses, mean area under the concentration-time curve (AUC) values were decreased in patients with severe renal impairment compared with healthy subjects with normal renal function for pioglitazone (13 476 vs 17 387, P = 0.371; -23%; confidence interval (CI) -57, 38), M-III metabolite (13 394 vs 15 071, P = 0.841; -11%; CI -74, 194) and M-IV metabolite (27 991 vs 49 856, P = 0.006; -44%; CI -62, -17). After repeated oral doses of pioglitazone, mean AUC values (microg.h l-1) were decreased in patients with severe renal impairment compared with healthy subjects with normal renal function for pioglitazone (8744 vs 14,565, P = 0.004; -40%; CI -57, -16), M-III (3991 vs 7,289, P = 0.0009; -45%; CI -60, -25) and M-IV (21 080 vs 25 706, P = 0.181; -18%; CI 39, 10). The tolerability and safety profile of pioglitazone was comparable between groups. CONCLUSIONS: Pioglitazone was well tolerated in patients with varying degrees of renal impairment. Although mean serum concentrations of pioglitazone and its metabolites are increased in patients with severe renal impairment, adjustment of starting and maintenance doses in these patients is probably unwarranted.

Administration, Oral↗

Long-term safety of pioglitazone versus glyburide in patients with recently diagnosed type 2 diabetes mellitus.

STUDY OBJECTIVE: To evaluate the long-term safety and efficacy of glyburide versus pioglitazone in patients with a recent diagnosis of type 2 diabetes mellitus. DESIGN: Prospective, randomized, multicenter, double-blind trial with a 16-week titration period and a 40-week maintenance period. SETTING: Sixty-five investigative sites in the United States and Puerto Rico. PATIENTS: Five hundred two subjects with a recent diagnosis of type 2 diabetes that was unsuccessfully treated with diet and exercise were randomly assigned to study treatment. Of the 251 patients in each treatment group, 128 (51.0%) glyburide-treated patients and 134 (53.4%) pioglitazone-treated patients completed the study. INTERVENTIONS: Dosages of randomly assigned glyburide and pioglitazone were titrated every 4 weeks for 16 weeks in 5-mg/day and 15-mg/day increments, respectively, until a fasting plasma glucose level between 69 and 141 mg/dl was achieved. The optimized regimen was maintained during the subsequent 40-week double-blind phase. MEASUREMENTS AND MAIN RESULTS: At week 56, glyburide and pioglitazone improved glucose control comparably (change in hemoglobin A(1c) -2.02% and -2.07%, respectively, p=0.669). Withdrawal due to lack of efficacy or adverse events occurred more frequently with glyburide (20.8%) than pioglitazone (12.8%, p<0.032). Significantly higher percentages of glyburide- than pioglitazone-treated patients had a hypoglycemic (24.3% vs 4.4%, p=0.0001) or cardiac (8.8% vs 4.4%, p=0.0478) event. Edema (4.8% vs 7.9%, p=0.1443) and weight gain (4.4% vs 4.0%, p=0.8238) did not differ significantly between the glyburide and pioglitazone groups. Only a few patients discontinued study drug because of weight gain (one glyburide, one pioglitazone), edema (one pioglitazone), or a cardiac event (two glyburide). CONCLUSION: With long-term treatment, both glyburide and pioglitazone resulted in comparable glycemic control; however, pioglitazone was associated with less hypoglycemia and fewer withdrawals due to lack of efficacy or adverse events.

Adolescent↗

Improvement of glycemic control, triglycerides, and HDL cholesterol levels with muraglitazar, a dual (alpha/gamma) peroxisome proliferator-activated receptor activator, in patients with type 2 diabetes inadequately controlled with metformin monotherapy: A double-blind, randomized, pioglitazone-comparative study.

OBJECTIVE: We sought to evaluate the effects of muraglitazar, a dual (alpha/gamma) peroxisome proliferator-activated receptor (PPAR) activator within the new glitazar class, on hyperglycemia and lipid abnormalities. RESEARCH DESIGN AND METHODS: A double-blind, randomized, controlled trial was performed in 1,159 patients with type 2 diabetes inadequately controlled with metformin. Patients received once-daily doses of either 5 mg muraglitazar or 30 mg pioglitazone for a total of 24 weeks in addition to open-label metformin. Patients were continued in a double-blind fashion for an additional 26 weeks. RESULTS: Analyses were conducted at week 24 for HbA1c (A1C) and at week 12 for lipid parameters. Mean A1C at baseline was 8.12 and 8.13% in muraglitazar and pioglitazone groups, respectively. At week 24, muraglitazar reduced mean A1C to 6.98% (-1.14% from baseline), and pioglitazone reduced mean A1C to 7.28% (-0.85% from baseline; P < 0.0001, muraglitazar vs. pioglitazone). At week 12, muraglitazar and pioglitazone reduced mean plasma triglyceride (-28 vs. -14%), apolipoprotein B (-12 vs. -6%), and non-HDL cholesterol (-6 vs. -1%) and increased HDL cholesterol (19 vs. 14%), respectively (P < 0.0001 vs. pioglitazone for all comparisons). At week 24, weight gain (1.4 and 0.6 kg, respectively) and edema (9.2 and 7.2%, respectively) were observed in the muraglitazar and pioglitazone groups; at week 50, weight gain and edema were 2.5 and 1.5 kg, respectively, and 11.8 and 8.9%, respectively. At week 50, heart failure was reported in seven patients (five with muraglitazar and two with pioglitazone), and seven deaths occurred: three from sudden death, two from cerebrovascular accident, and one from pancreatic cancer in the muraglitazar group and one from perforated duodenal ulcer in the pioglitazone group. CONCLUSIONS: We found that 5 mg muraglitazar resulted in greater improvements in A1C and lipid parameters than a submaximal dose of 30 mg pioglitazone when added to metformin. Weight gain and edema were more common when muraglitazar was compared with a submaximal dose of pioglitazone.

Adult↗

Pioglitazone, a specific ligand of the peroxisome proliferator-activated receptor gamma reduces gastric mucosal injury induced by ischaemia/ reperfusion in rat.

BACKGROUND: The peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-dependent nuclear receptor that has been implicated in the control of metabolism and numerous cellular processes, including cell cycle control, carcinogenesis, and inflammation. The present study was designed to investigate the effect of the specific PPARgamma ligand, pioglitazone, on the mucosal lesions induced by ischaemia and reperfusion (I/R) in rats. METHODS: I/R lesions were induced in Wistar rats by applying a small clamp to the coeliac artery for 30 min (ischaemic phase), followed by the removal of the clamp for 3 h (reperfusion phase). Vehicle (saline) or increasing doses of pioglitazone (2.5, 10, and 30 mg/kg i.g.) were given 30 min before exposure to I/R. The animals were killed immediately after the end of the reperfusion phase (time 0) and at 12 and 24h after I/R. The area of gastric lesions was measured by planimetry, and the gastric blood flow was determined by the H2 gas clearance method. The gastric mucosal gene expressions of PPARgamma, interleukin-1beta (IL-1beta), tumour necrosis factor alpha (TNF-alpha), leptin, cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) were examined by RT-PCR. In addition, protein expression of COX-2 and leptin was assessed by Western blot. RESULTS: The pretreatment with pioglitazone reduced in a dose-dependent manner the mean lesion area induced by I/R, and this effect was accompanied by a significant increase in the gastric blood flow. The decrease in gastric ulcerations by pioglitazone was also observed 12 and 24 h after the I/R. The PPARgamma mRNA was weakly expressed in the intact gastric mucosa but significantly up-regulated after exposure to I/R at each time interval studied. The expression of IL-1beta was not changed significantly after pioglitazone applied i.g. at doses 2.5 and 10 mg/kg, but it was down-regulated at the dose 30mg/kg. TNFalpha mRNA was strongly increased after the exposure to I/R, but it was down-regulated after pioglitazone pretreatment. In contrast, both leptin and COX-2 mRNA and protein expression were increased in the gastric mucosa after exposure to I/R. The pretreatment with pioglitazone caused a significant up-regulation of mRNA and protein expression of leptin, reaching its peak at the dose 30 mg/kg i.g. In contrast, COX-2 expression did not change significantly after the 2.5 and 10 mg/kg of pioglitazone, but it significantly decreased after pioglitazone at dose 30 mg/kg given to rats before exposure to I/R. CONCLUSIONS: Pioglitazone reduces the acute erosions and deeper gastric lesions induced by I/R. The beneficial effect of this PPARgamma ligand on I/R-induced gastric damage may be due to its anti-inflammatory properties, especially to the reduction in TNF-alpha expression and to up-regulation of leptin mRNA in the gastric mucosa. The inhibition of COX-2 expression by pioglitazone may reflect the anti-inflammatory properties of this compound.

Amino Acid Sequence↗

Pioglitazone inhibits the growth of human leukemia cell lines and primary leukemia cells while sparing normal hematopoietic stem cells.

Peroxisome proliferator-activated receptors (PPARs) compose a subfamily of nuclear hormone receptors functioning as transcriptional regulators. Originally, the PPARgamma ligand known as thiazolidinedione (TZD) was used for the treatment of diabetic patients. However, recent studies have shown that TZD also has an antitumor effect that inhibits cell growth in several types of human malignant neoplasms, including leukemia cell lines. Since pioglitazone is the only TZD currently available in clinics in Japan and the role of TZD in normal human hematopoietic cells or primary leukemia cells has not been previously reported, we investigated the effect of pioglitazone on human normal hematopoietic progenitor cells, primary leukemia cells, and leukemia cell lines (HL60, K562, U937, HEL, CEM, Jurkat, and NALM1). Pioglitazone inhibited the proliferation of leukemia cells in a dose-dependent manner. The viable cell numbers of HL60, K562, and Jurkat leukemia cell lines were profoundly reduced when the cells were cocultured with pioglitazone. Colony formation in the leukemia cell lines as well as the primary leukemia cells was significantly inhibited to 20-71% and 1-25% of that in control cultures by the addition of 100 and 300 microM of pioglitazone, respectively. However, the CFU-E and CFU-GM colonies of cells obtained from healthy volunteers were not altered in the presence of 100 microM of pioglitazone. Pioglitazone (300 microM) induced slight decrease of CFU-E and CFU-GM. BFU-E was more sensitive to pioglitazone than CFU-E and CFU-GM. Pioglitazone-induced growth inhibition in HL60 cells was associated with cell cycle arrest at the G1 phase, as has been reported for another TZD, troglitazone. Similar levels of PPARgamma protein were observed in both leukemia and normal bone marrow cells by Western blotting, suggesting that the expression of PPARgamma protein was not associated with the inhibitory potency of pioglitazone. In conclusion, our results suggest that pioglitazone may offer a new therapeutic approach to aid in the treatment of leukemia.

Cell Line, Tumor↗

Rosiglitazone and pioglitazone: new preparations. Two new oral antidiabetics both poorly assessed.

(1) Treatment of type 2 (non insulin-dependent) diabetes is based on lifestyle measures and management of cardiovascular risk. (2) The reference first-line drug therapy for type 2 diabetes, when drug therapy is needed, is single-agent treatment with metformin (a biguanide) for overweight patients, or with glibenclamide (a glucose-lowering sulphonylurea) for other patients. (3) If monotherapy fails to control blood glucose levels adequately, most clinical guidelines then recommend a combination of metformin with a glucose-lowering sulphonylurea, although the few available comparative clinical data raise the possibility of excess mortality with this treatment. (4) Rosiglitazone and pioglitazone (glitazones that reduce insulin resistance) have been authorized in the European Union for combination with a glucose-lowering sulphonylurea (for patients in whom metformin is ineffective or poorly tolerated) or with metformin (for obese patients). (5) None of the available trials of rosiglitazone and pioglitazone include data on mortality or morbidity. (6) There are fewer data on pioglitazone than on rosiglitazone. (7) According to short-term comparative trials, rosiglitazone and pioglitazone are more effective than placebo on blood glucose levels. Combinations of rosiglitazone or pioglitazone with metformin or with glucose-lowering sulphonylureas have not been compared with the metformin + glucose-lowering sulphonylurea combination or with insulin. (8) Rosiglitazone and pioglitazone frequently cause weight gain. (9) Pioglitazone has a slightly favourable effect on lipid profiles, unlike rosiglitazone, which increases LDL-cholesterol levels. (10) The main side effect of rosiglitazone and pioglitazone is sodium and water retention, which can provoke oedema, anaemia (by haemodilution), and even heart failure. Rosiglitazone and pioglitazone are also hepatotoxic. (11) Combining rosiglitazone with insulin is contraindicated, owing to the increased risk of heart failure. The same applies to pioglitazone. (12) In practice, neither rosiglitazone nor pioglitazone has a place in the management of type 2 diabetes, except in the context of strictly controlled long-term comparative clinical trials.

Administration, Oral↗

Pioglitazone treatment activates AMP-activated protein kinase in rat liver and adipose tissue in vivo.

Thiazolidinediones have been shown to activate AMP-activated protein kinase activity in cultured cells. Whether they have a similar effect in vivo and if so whether it is physiologically relevant is not known. To assess these questions, we examined the effects of pioglitazone, administered orally to intact rats, on AMPK phosphorylation (AMPK-P) (a measure of its activation) and acetyl CoA carboxylase (ACC) activity and malonyl CoA concentration in rat liver and adipose tissue. In the first study, measurements were made in the Dahl-salt-sensitive rat (Dahl-S), a strain of Sprague-Dawley rat with endogenous hypertriglyceridemia and high levels of malonyl CoA that are restored to control values by pioglitazone. Treatment with pioglitazone (20mg/kg bw/day for 3 weeks) did not significantly increase either P-AMPK or P-ACC (which varies inversely with ACC activity) in control rats. However, in the Dahl-S rats values for AMPK-P and ACC-P were 50% lower than in control rats and were doubled by pioglitazone treatment. In a second study, the effects of two weeks treatment with pioglitazone (3mg/kg bw/day administered orally) were evaluated in Wistar rats. Under basal conditions (no manipulation of the animals), pioglitazone increased AMPK phosphorylation by twofold and decreased ACC activity and the concentration of malonyl CoA by 50% in liver. Following a euglycemic-hyperinsulinemic clamp (6h), 50% decreases in AMPK and ACC phosphorylation (indicating an increase in its activity) and comparable increases in malonyl CoA concentration were observed in liver and adipose tissue. In both tissues, pre-treatment with pioglitazone prevented these changes. Where studied (in Wistar rats under basal conditions) treatment with pioglitazone decreased the concentration of ATP by 1/3 and increased the concentration of ADP and AMP in liver. The results indicate that treatment with pioglitazone can increase AMPK activity in rat liver and adipose tissue in a variety of circumstances. They also suggest that this activation of AMPK may be mediated by a change in cellular energy state. Whether these effects of pioglitazone contribute to its insulin-sensitizing and other actions in vivo remains to be determined.

AMP-Activated Protein Kinases↗

Association between congestive heart failure and hospitalization in patients with type 2 diabetes mellitus receiving treatment with insulin or pioglitazone: a retrospective data analysis.

BACKGROUND: Thiazolidinediones (TZDs) are widely used oral antihyperglycemic drugs that facilitate insulin action and increase insulin-stimulated glucose metabolism, thereby decreasing insulin resistance. However, concerns have been raised regarding the association between TZD use and a heightened risk for congestive heart failure (CHF). OBJECTIVE: This study used claims data to conduct a retrospective examination of the CHF risk in patients with type 2 diabetes mellitus and to compare the association with CHF in those receiving the TZD pioglitazone and those receiving insulin. METHODS: Patients with type 2 diabetes aged > or =18 years who had begun treatment with pioglitazone or insulin between January 1999 and December 2001 were identified using the PharMetrics Patient-Centric database. The sample was restricted to patients for whom there were > or =12 months of data before the index date (date of the first prescription for pioglitazone or insulin) and > or =3 months of follow-up data. Patients receiving a diagnosis of CHF before the index date were excluded. The propensity score for receiving pioglitazone was estimated using logistic regression based on available observed patient characteristics. Patients receiving insulin were matched in a 1:1 ratio with patients receiving pioglitazone based on a difference of no more than +/-0.01 in the estimated propensity score for receiving pioglitazone therapy. CHF risk was examined using the Cox proportional-hazards model. RESULTS: After exclusion of ineligible patients, 1668 matched pairs of patients receiving pioglitazone or insulin were identified (50.9% men, 49.1% women; mean [SE] age, 51.2 [0.2] years). The 2-year crude incidence rate of CHF was significantly lower in the pioglitazone group compared with the insulin group (primary/secondary diagnosis of CHF, 2.0% vs 4.0%, respectively; P < 0.001; inpatient hospitalization for CHF, 0.7% vs 2.5%; P < 0.001). The hazard ratio for pioglitazone versus insulin was 0.501 (95% CI, 0.331-0.758; P = 0.001) for a primary or secondary diagnosis of CHF in any setting and 0.263 (95% CI, 0.135-0.511; P < 0.001) for any occurrence of an inpatient hospitalization for CHF. CONCLUSIONS: In this retrospective analysis of data from patients with type 2 diabetes, pioglitazone therapy was associated with significantly lower incidence rates of CHF and inpatient hospitalization compared with insulin therapy.

Cohort Studies↗

Effect of pioglitazone on body composition and energy expenditure: a randomized controlled trial.

BACKGROUND: Several clinical studies have demonstrated that body weight increases after treatment with thiazolidinediones (TZDs). Prior studies have demonstrated an increase in insulin-stimulated lipid storage in adipose tissue. Some, but not all, studies demonstrate reductions in visceral adipose tissue. Changes in body weight are the result of changes in energy intake, energy expenditure, or both. OBJECTIVES: Based on these findings, the primary aim of this study was to evaluate the effect of TZDs on visceral, subcutaneous, and total body fat. Secondary aims were to determine the effects of pioglitazone on (a) energy expenditure, (b) hunger and satiety, (c) blood lipids, and (d) the role of insulinemia/sulfonylurea usage on weight gain in patients with type 2 diabetes. SUBJECTS AND METHODS: We performed a randomized, double-blind, placebo-controlled trial in 48 men and women with type 2 diabetes who had not previously received treatment with TZDs. Patients were treated for 24 weeks with 45 mg/d of pioglitazone or a matching placebo. Body composition was measured by dual-energy x-ray absorptiometry. Visceral and subcutaneous fat were measured by computed tomography. Resting metabolic rate and thermogenic response to a test meal were measured by indirect calorimetry before and after a standardized meal. Hunger and satiety were measured with visual analog scales before and after the same test meal. Blood was collected for the measurement of fasting glucose and insulin levels, hemoglobin A 1c levels, and lipid content. RESULTS: Pioglitazone treatment resulted in a decrease in hemoglobin A(1c) level by 0.96 +/- 1.1% vs 0.11 +/- 0.8% in the placebo group (P < .005). Body weight and fat increased steadily in the patients treated with pioglitazone during the 6 months of the study (+3.9 +/- 3.1 kg at 6 months in pioglitazone-treated patients vs -0.8 +/- 3.4 kg in the placebo-treated patients). Subcutaneous fat in the trunk, arms, and legs were all increased in the pioglitazone-treated group. Visceral fat did not change significantly in either group. Neither resting metabolic rate nor the thermogenic responses to a meal were altered by pioglitazone. Subjective measures of hunger (visual analog scale) did not change with pioglitazone treatment. Triglycerides fell in the pioglitazone-treated group (-58.5 +/- 124 mg/dL, P < .003). Neither the prior use of sulfonylureas nor the level of insulinemia before treatment was a predictor of weight or fat change. CONCLUSION: Pioglitazone increased subcutaneous body fat, but not visceral fat. There was no measurable effect on energy expenditure or hunger/satiety. In contrast to the placebo-treated patient with diabetes, weight gain occurs in the face of falling hemoglobin A(1c) and triglyceride levels.

Adult↗

An increase in insulin sensitivity and basal beta-cell function in diabetic subjects treated with pioglitazone in a placebo-controlled randomized study.

AIMS: To investigate the effect of treatment with pioglitazone on beta-cell function and insulin sensitivity in Type 2 diabetes. METHODS: Thirty subjects with diet-controlled Type 2 diabetes were randomized to 3 months treatment with pioglitazone (n = 19) or placebo (n = 11). All subjects underwent basal sampling for homeostatic model assessment (HOMA), followed by an intravenous glucose tolerance test and hyperglycaemic clamp, followed by an euglycaemic hyperinsulinaemic clamp; at baseline and after treatment. RESULTS: All results are expressed as mean (sem). Pioglitazone increased basal insulin sensitivity by 24.7% (7.8) HOMA-%S vs. 2.1% (5.9) in the placebo group (P = 0.02). Stimulated insulin sensitivity, M/I, increased in the pioglitazone group compared with placebo: +15.1 (2.8) l kg(-1) min(-1) vs. +3.2 (2.9) l kg(-1) min(-1), respectively (P = 0.009). Pioglitazone increased adiponectin by 39.3 (6.3), ng/ml compared with a decrease of 0.8 (1.3) ng/ml with placebo (P = 0.00004). HOMA-%B increased with pioglitazone, +11.5% (4.8) vs. -2.0% (4.8) with placebo (P = 0.049), but there was no change in stimulated beta-cell function as determined by hyperglycaemic clamps. There was a significant reduction in the proinsulin/insulin ratio in the pioglitazone group, -0.057 (0.02) compared with placebo, +0.004 (0.02) (P = 0.03). There was a significant reduction in HbA(1c) of 0.6% (0.1) in the pioglitazone group compared with placebo (P = 0.003). There was no significant weight gain associated with pioglitazone therapy: +0.7 (sem 0.6) kg vs. +1.1 (sem 0.5) kg in placebo group (P = NS). CONCLUSIONS: Basal beta-cell function and insulin sensitivity improved following pioglitazone therapy. The improvement in proinsulin to insulin ratio suggests that beta-cells are under less stress.

Aged↗

Pioglitazone is metabolised by CYP2C8 and CYP3A4 in vitro: potential for interactions with CYP2C8 inhibitors.

Our objective was to identify the cytochrome P450 (CYP) enzymes that metabolise pioglitazone and to examine the effects of the CYP2C8 inhibitors montelukast, zafirlukast, trimethoprim and gemfibrozil on pioglitazone metabolism in vitro. The effect of different CYP isoform inhibitors on the elimination of a clinically relevant concentration of pioglitazone (1 microM) and the formation of the main primary metabolite M-IV were studied using pooled human liver microsomes. The metabolism of pioglitazone by CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP2E1, CYP3A4 and CYP3A5 was investigated using human recombinant CYP isoforms. In particular, the inhibitors of CYP2C8, but also those of CYP3A4, markedly inhibited the elimination of pioglitazone and the formation of M-IV by HLM. Inhibitors selective to other CYP isoforms had a minor effect only. Of the recombinant isoforms, CYP2C8 (20 pmol/ml) metabolised pioglitazone markedly (56% in 60 min.), and also CYP3A4 had a significant effect (37% in 60 min.). Montelukast, zafirlukast, trimethoprim and gemfibrozil inhibited pioglitazone elimination in HLM with IC50 values of 0.51 microM, 1.0 microM, 99 microM and 98 microM, respectively, and the formation of the metabolite M-IV with IC50 values of 0.18 microM, 0.78 microM, 71 microM and 59 microM, respectively. In conclusion, pioglitazone is metabolised mainly by CYP2C8 and to a lesser extent by CYP3A4 in vitro. CYP2C9 is not significantly involved in the elimination of pioglitazone. The effect of different CYP2C8 inhibitors on pioglitazone pharmacokinetics needs to be evaluated also in vivo because, irrespective of their in vitro CYP2C8 inhibitory potency, their pharmacokinetic properties may affect the extent of interaction.

Aryl Hydrocarbon Hydroxylases↗

Pioglitazone inhibits androgen production in NCI-H295R cells by regulating gene expression of CYP17 and HSD3B2.

Thiazolidinediones (TZDs) such as pioglitazone and rosiglitazone are widely used as insulin sensitizers in the treatment of type 2 diabetes. In diabetic women with polycystic ovary syndrome, treatment with pioglitazone or rosiglitazone improves insulin resistance and hyperandrogenism, but the mechanism by which TZDs down-regulate androgen production is unknown. Androgens are synthesized in the human gonads as well as the adrenals. We studied the regulation of androgen production by analyzing the effect of pioglitazone and rosiglitazone on steroidogenesis in human adrenal NCI-H295R cells, an established in vitro model of steroidogenesis of the human adrenal cortex. Both TZDs changed the steroid profile of the NCI-H295R cells and inhibited the activities of P450c17 and 3betaHSDII, key enzymes of androgen biosynthesis. Pioglitazone but not rosiglitazone inhibited the expression of the CYP17 and HSD3B2 genes. Likewise, pioglitazone repressed basal and 8-bromo-cAMP-stimulated activities of CYP17 and HSD3B2 promoter reporters in NCI-H295R cells. However, pioglitazone did not change the activity of a cAMP-responsive luciferase reporter, indicating that it does not influence cAMP/protein kinase A/cAMP response element-binding protein pathway signaling. Although peroxisome proliferator-activated receptor gamma (PPARgamma) is the nuclear receptor for TZDs, suppression of PPARgamma by small interfering RNA technique did not alter the inhibitory effect of pioglitazone on CYP17 and HSD3B2 expression, suggesting that the action of pioglitazone is independent of PPARgamma. On the other hand, treatment of NCI-H295R cells with mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) inhibitor 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one (PD98059) enhanced promoter activity and expression of CYP17. This effect was reversed by pioglitazone treatment, indicating that the MEK/ERK signaling pathway plays a role in regulating androgen biosynthesis by pioglitazone.

3-Hydroxysteroid Dehydrogenases↗