Pioglitazone (Actos) and bladder cancer: Legal system triumphs over the evidence

Thiazolidinedione as a Promising Medicinal Scaffold for the Treatment of Type 2 Diabetes

BACKGROUND

Thiazolidinediones, also known as glitazones, are considered as biologically active scaffold and a well-established class of anti-diabetic agents for the treatment of type 2 diabetes mellitus. Thiazolidinediones act by reducing insulin resistance through elevated peripheral glucose disposal and glucose production. These molecules activate peroxisome proliferated activated receptor (PPARγ), one of the sub-types of PPARs, and a diverse group of its hybrid have also shown numerous therapeutic activities along with antidiabetic activity.

OBJECTIVE

The objective of this review was to collect and summarize the research related to the medicinal potential, structure-activity relationship and safety aspects of thiazolidinedione analogues designed and investigated in type 2 diabetes during the last two decades.

METHODS

The mentioned objective was achieved by collecting and reviewing the research manuscripts, review articles, and patents from PubMed, Science Direct, Embase, google scholar and journals related to the topic from different publishers like Wiley, Springer, Elsevier, Taylor and Francis, Indian and International government patent sites etc. Results: The thiazolidinedione scaffold has been a focus of research in the design and synthesis of novel derivatives for the management of type 2 diabetes, specifically in the case of insulin resistance. The complications like fluid retention, idiosyncratic hepatotoxicity, weight gain and congestive heart failure in the case of trosiglitazone, and pioglitazone have restricted their use. The newer analogues have been synthesized by different research groups to attain better efficacy and less side effects.

CONCLUSION

Thus, the potential of thiazolidinediones in terms of their chemical evolution, action on nuclear receptors, aldose reductase and free fatty acid receptor 1 is well established. The newer TZD analogues with better safety profiles and tolerability will soon be available in the market for common use without further delay.

Pioglitazone, Bladder Cancer and the Presumption of Innocence

BACKGROUND

Thiazolidinediones are potent exogenous agonists of PPAR-γ, which augment the effects of insulin to its cellular targets and mainly at the level of adipose tissue. Pioglitazone, the main thiazolidinedione in clinical practice, has shown cardiovascular and renal benefits in patients with type 2 diabetes, durable reduction of glycated hemoglobulin levels, important improvements of several components of the metabolic syndrome and beneficial effects of non-alcoholic fatty liver disease.

OBJECTIVE

Despite all of its established advantages, the controversy for an increased risk of developing bladder cancer, combined with the advent of newer drug classes that achieved major cardiorenal effects have significantly limited its use spreading a persistent shadow of doubt for its future role.

METHODS

Pubmed, Google and Scope databases have been thoroughly searched and relevant studies were selected.

RESULTS

This paper explores thoroughly both in vitro and in vivo (animal models and humans) studies that investigated the possible association of pioglitazone with bladder cancer.

CONCLUSION

Currently the association of pioglitazone with bladder cancer cannot be based on solid evidence. This evidence cannot justify its low clinical administration, especially in the present era of individualised treatment strategies. Definite clarification of this issue is imperative and urgently anticipated from future high quality and rigorous pharmacoepidemiologic research, keeping in mind its unique mechanism of action and its significant pleiotropic effects.

What Are the Current Pharmacological Therapies for Nonalcoholic Fatty Liver Disease?

Of the currently available drugs tested to treat nonalcoholic fatty liver disease (NAFLD), the most efficacious drugs are pioglitazone (an insulin sensitizer) and vitamin E (an antioxidant). By targeting insulin resistance, the key pathogenic mechanism underlying metabolic syndrome and NAFLD, pioglitazone maybe the preferred drug to treat NAFLD. As we await the results of research trials into multiple new drugs to treat NAFLD, when should we use the currently available patients to treat NAFLD at the present time? To date, no drug has been approved by regulatory agency specifically to treat NAFLD. However, many drugs have been approved to treat other components of metabolic syndrome such as diabetes mellitus and dyslipidemia. Are we underutilizing the currently available drugs to treat NAFLD? Herein, we review the benefits and concerns of the use of these currently available drugs to treat NAFLD and suggest clinical scenarios, wherein the clinician should consider using these drugs.

Effect of type 2 diabetes and antihyperglycemic drug therapy on signs of tumor invasion in papillary thyroid cancer

PURPOSE

This retrospective study investigated the association between worrisome pathological features of papillary thyroid cancer indicative of invasion and type 2 diabetes, as well as antihyperglycemic drug therapy for diabetes.

METHODS

The records of 14,167 patients who had undergone primary surgery for thyroid cancer were retrospectively reviewed and screened for concomitant diabetes. The diabetic and nondiabetic groups were age and gender matched, and further stratified by treatment, including five single antihyperglycemic drugs.

RESULTS

The study population comprised 942 patients, including 471 patients each with and without diabetes. The rate of worrisome pathological features was higher in diabetic patients than in nondiabetic patients (49.26% cf. 30.57%, P < 0.001), mainly reflected by extrathyroidal extension (34.82% cf. 5.94%, P < 0.001) and lymph node metastasis (42.68% cf. 33.55%, P < 0.001). The number of lymph node metastases in those treated with acarbose (0.32) was significantly lower compared with groups given any of the other four antihyperglycemic drugs (ranging from 1.51 to 2.15; P = 0.001 to 0.05).

CONCLUSIONS

Papillary thyroid cancer complicated with type 2 diabetes has a higher risk of invasive tumor growth. Compared with other antihyperglycemic drugs, patients with acarbose had the lowest risk of aggressive tumor growth. These results may evoke pathophysiological hypotheses to be explored in preclinical and clinical studies.

Reducing the Burden of Diabetes Treatment: A Review of Low-cost Oral Hypoglycemic Medications

BACKGROUND

The vast majority of individuals diagnosed with diabetes are low/middle income and may have access to only three of the 11 oral hypoglycemic medications (OHMs) due to cost: metformin intermediate release (IR) or extended release (ER), sulfonylureas (glimepiride, glipizide, glyburide), and pioglitazone. Sulfonylureas and pioglitazone have had significant controversy related to potential adverse events, but it remains unclear whether these negative outcomes are class, drug, or dose-related.

OBJECTIVE

We conducted a narrative review of low-cost OHMs.

METHODS

We evaluated the maximum recommended (MAX) compared to the most effective (EFF) daily dose, time-to-peak change in HbA1c levels, and adverse events of low-cost oral hypoglycemic medications.

RESULTS

We found that the MAX was often greater than the EFF: metformin IR/ER (MAX: 2,550/2,000 mg, EFF: 1,500-2,000/1,500-2,000 mg), glipizide IR/ER (MAX: 40/20 mg, EFF: 20/5 mg), glyburide (MAX: 20 mg, EFF: 2.5-5.0 mg), pioglitazone (MAX: 45 mg, EFF: 45 mg). Time-to-peak change in HbA1c levels occurred at weeks 12-20 (sulfonylureas), 25-39 (metformin), and 25 (pioglitazone). Glimepiride was not associated with weight gain, hypoglycemia, or negative cardiovascular events relative to other sulfonylureas. Cardiovascular event rates did not increase with lower glyburide doses (p<0.05). Glimepiride and pioglitazone have been successfully used in renal impairment.

CONCLUSION

Metformin, glimepiride, and pioglitazone are safe and efficacious OHMs. Prescribing at the EFF rather than the MAX may avoid negative dose-related outcomes. OHMs should be evaluated as individual drugs, not generalized as a class, due to different dosing and adverse-event profiles; Glimepiride is the preferred sulfonylurea since it is not associated with the adverse events as others in its class.

PPARγ Agonists in Combination Cancer Therapies

Peroxisome proliferator-activated receptor-gamma (PPARγ) is a nuclear receptor acting as a transcription factor involved in the regulation of energy metabolism, cell cycle, cell differentiation, and apoptosis. These unique properties constitute a strong therapeutic potential that place PPARγ agonists as one of the most interesting and widely studied anticancer molecules. Although PPARγ agonists exert significant, antiproliferative and tumoricidal activity in vitro, their anticancer efficacy in animal models is ambiguous, and their effectiveness in clinical trials in monotherapy is unsatisfactory. However, due to pleiotropic effects of PPARγ activation in normal and tumor cells, PPARγ ligands interact with many antitumor treatment modalities and synergistically potentiate their effectiveness. The most spectacular example is a combination of PPARγ ligands with tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML). In this setting, PPARγ activation sensitizes leukemic stem cells, resistant to any previous form of treatment, to targeted therapy. Thus, this combination is believed to be the first pharmacological therapy able to cure CML patients. Within the last decade, a significant body of data confirming the benefits of the addition of PPARγ ligands to various antitumor therapies, including chemotherapy, hormonotherapy, targeted therapy, and immunotherapy, has been published. Although the majority of these studies have been carried out in vitro or animal tumor models, a few successful attempts to introduce PPARγ ligands into anticancer therapy in humans have been recently made. In this review, we aim to summarize shines and shadows of targeting PPARγ in antitumor therapies.

Thiazolidinediones: the Forgotten Diabetes Medications

PURPOSE OF REVIEW

Thiazolidinediones (TZDs) are the only pharmacologic agents that specifically treat insulin resistance. The beneficial effects of TZDs on the cardiovascular risk factors associated with insulin resistance have been well documented. TZD use has been limited because of concern about safety issues and side effects.

RECENT FINDINGS

Recent studies indicate that cardiovascular toxicity with rosiglitazone and increase in bladder cancer with pioglitazone are no longer significant issues. There are new data which show that pioglitazone treatment reduces myocardial infarctions and ischemic strokes. New data concerning TZD-mediated edema, congestive heart failure, and bone fractures improves the clinician's ability to select patients that will have minimal significant side effects. Thiazolidinediones are now generic and less costly than pharmaceutical company-promoted therapies. Better understanding of the side effects coupled with clear benefits on the components of the insulin resistance syndrome should promote TZD use in treating patients with type 2 diabetes.

Pioglitazone is superior to quetiapine, clozapine and tamoxifen at alleviating experimental autoimmune encephalomyelitis in mice

Recent evidence suggests that clozapine and quetiapine (atypical antipsychotics), tamoxifen (selective-estrogen receptor modulator) and pioglitazone (PPARγ agonist) may improve functional recovery in multiple sclerosis (MS). We have compared the effectiveness of oral administration of these drugs, beginning at peak disease, at reducing ascending paralysis, motor deficits and demyelination in mice subjected to experimental autoimmune encephalomyelitis (EAE). Mice were immunized with an immunogenic peptide corresponding to amino acids 35-55 of the myelin oligodendrocyte glycoprotein (MOG_35-55) in complete Freund's adjuvant and injected with pertussis toxin to induce EAE. Unlike clozapine, quetiapine and tamoxifen, administration of pioglitazone beginning at peak disease decreased both clinical scores and lumbar white matter loss in EAE mice. Using kinematic gait analysis, we found that pioglitazone also maintained normal movement of the hip, knee and ankle joints for at least 44 days after MOG_35-55 immunization. This long-lasting preservation of hindleg joint movements was accompanied by reduced white matter loss, microglial and macrophage activation and the expression of pro-inflammatory genes in the lumbar spinal cords of EAE mice. These results support clinical findings that suggest pioglitazone may reduce the progressive loss of motor function in MS by decreasing inflammation and myelin damage.

An updated meta-analysis of pioglitazone exposure and bladder cancer and comparison to the drug's effect on cardiovascular disease and non-alcoholic steatohepatitis

AIM

We performed a meta-analysis of epidemiological studies evaluating exposure to pioglitazone and the risk for bladder cancer and compared these results to the drug's effects on cardiovascular disease (CVD) and non-alcoholic steatohepatitis (NASH).

METHODS

Pubmed and Embase were searched for cohort and case control studies for all years through 2016.

RESULTS

Data from 17 papers were analyzed. In cohort studies, 822 of 357,888 pioglitazone-exposed patients (0.23%) developed bladder cancer while 7691 of 2,898,682 unexposed (0.26%) did. In case control studies, 3219 of 1,146,916 patients (0.28%) developed bladder cancer. A random effects model showed no significant association between ever vs never use or with cumulative doses of pioglitazone. However, there was a significant association with 1-2 years (HR = 1.28 [1.08-1.55]) and >2 years (HR = 1.42 [1.14-1.77]) of exposure. The numbers needed to treat for one additional case of bladder cancer ranged from 899 to 6380 while to benefit CVD and NASH, 4-256 and 2-12, respectively.

CONCLUSIONS

Given the very small prevalence of bladder cancer in diabetic patients exposed (or not) to pioglitazone (<0.3%) and the much greater beneficial effects of the drug on CVD and NASH, the use of pioglitazone should be resurrected.

Pharmacological management of type 2 diabetes: what's new in 2017?

INTRODUCTION

Novelties in the management of type 2 diabetes are dominated by the commercialisation of new glucose-lowering agents, which offer alternatives to older antidiabetic medications, and by the publication of several prospective placebo-controlled outcome trials, which demonstrated not only cardiovascular safety but also cardiovascular and renal protection with some new medications. Areas covered: Updates regarding the use of glucose-lowering agents are discussed from a clinical point of view. Some new viewpoints concern older antidiabetic agents such as metformin, sulfonylureas and glitazones whose benefit-risk balance has been revisited, especially in high risk patients. The recent data regarding DPP-4 inhibitors (gliptins) focused on the safety profile of this pharmacological class, including in patients with impaired renal function. The highlight concerns the cardiovascular (and renal) protection by some GLP-1 receptor agonists (liraglutide, semaglutide) and SGLT2 inhibitors (empagliflozin, canagliflozin) in patients with high cardiovascular risk. Finally, efficacy and safety of new combinations and advances in insulin therapy will be briefly discussed. Expert commentary: The recent data from randomized controlled trials, meta-analyses and observational real-life studies should trigger a revision of the algorithm for the treatment of hyperglycemia in type 2 diabetes, especially in patients with high cardiovascular and/or renal risk.

NASH Therapy: omega 3 supplementation, vitamin E, insulin sensitizers and statin drugs

Non-alcoholic steatohepatitis (NASH) is the more aggressive form of non-alcoholic fatty liver disease (NAFLD). NASH can progress to hepatic fibrosis, cirrhosis, portal hypertension and primary liver cancer. Therapy is evolving with a substantial number of trials of promising new agents now in progress. In this article however, we will examine data for several older forms of therapy which have been fairly extensively studied over the years: Polyunsaturated Fatty Acid (PUFA) supplements, vitamin E, insulin sensitizing agents with a focus on pioglitazone and statin agents. Early interest in PUFA derived from their potential benefit in cardio-metabolic disease and the close association of NAFLD/NASH with Metabolic Syndrome. Results have been variable although most studies show reduction of liver fat without other major effects and their effects are influenced by concomitant weight loss and underlying genetic factors. Vitamin E has had some efficacy in pediatric NASH but questionable efficacy in even mild NASH among adults. Pioglitazone has shown significant histological benefit in a number of trials but concern over side-effects (especially weight gain) have dampened enthusiasm. A newer insulin sensitizer, liraglutide, has also shown promise in a small randomized, controlled trial. Very limited data exists regarding the histological effects of the statins in NASH and these agents appear to be fairly neutral with neither clear cut benefit nor detriment. Their use is best guided by cardiovascular risks rather than liver histology.

Alpha-glucosidase inhibitors and risk of cancer in patients with diabetes mellitus: a systematic review and meta-analysis

Several studies have shown that anti-diabetic medications may modify the risk of cancer. We performed a systematic review and meta-analysis to evaluate the effect of alpha-glucosidase inhibitors (AGIs) on the risk of cancer in patients with diabetes mellitus. We conducted a systematic search of Medline, EMBASE, and Web of Science databases, up to September 30, 2016. Random-effects model was used to estimate the summary odds ratios (ORs) with 95% CI. Twenty-five studies (14 cohort, 7 case-control, and 4 randomized controlled trials) involving 1,285,433 patients with diabetes were included. Meta-analysis of observational studies showed that the use of AGIs was associated with a lower risk of developing cancer (OR = 0.86, 95% CI 0.78-0.96), especially gastrointestinal cancer (OR = 0.83, 95% CI 0.71-0.97). There was considerable heterogeneity across the studies introduced partly by the quality of included studies and adjustment for potential confounders. Meta-analysis of randomized controlled trials did not reveal any significant association between AGIs and cancer risk. Meta-analysis of observational studies indicated that AGIs may decrease the risk of cancer in individuals with diabetes.