Treatment of type 2 diabetes mellitus with orally administered agents: advances in combination therapy

Role of Pharmacogenetics in Adverse Drug Reactions: An Update towards Personalized Medicine

Adverse drug reactions (ADRs) are an important and frequent cause of morbidity and mortality. ADR can be related to a variety of drugs, including anticonvulsants, anaesthetics, antibiotics, antiretroviral, anticancer, and antiarrhythmics, and can involve every organ or apparatus. The causes of ADRs are still poorly understood due to their clinical heterogeneity and complexity. In this scenario, genetic predisposition toward ADRs is an emerging issue, not only in anticancer chemotherapy, but also in many other fields of medicine, including hemolytic anemia due to glucose-6-phosphate dehydrogenase (G6PD) deficiency, aplastic anemia, porphyria, malignant hyperthermia, epidermal tissue necrosis (Lyell's Syndrome and Stevens-Johnson Syndrome), epilepsy, thyroid diseases, diabetes, Long QT and Brugada Syndromes. The role of genetic mutations in the ADRs pathogenesis has been shown either for dose-dependent or for dose-independent reactions. In this review, we present an update of the genetic background of ADRs, with phenotypic manifestations involving blood, muscles, heart, thyroid, liver, and skin disorders. This review aims to illustrate the growing usefulness of genetics both to prevent ADRs and to optimize the safe therapeutic use of many common drugs. In this prospective, ADRs could become an untoward "stress test," leading to new diagnosis of genetic-determined diseases. Thus, the wider use of pharmacogenetic testing in the work-up of ADRs will lead to new clinical diagnosis of previously unsuspected diseases and to improved safety and efficacy of therapies. Improving the genotype-phenotype correlation through new lab techniques and implementation of artificial intelligence in the future may lead to personalized medicine, able to predict ADR and consequently to choose the appropriate compound and dosage for each patient.

Efficacy and safety of sitagliptin/metformin fixed-dose combination compared with glimepiride in patients with type 2 diabetes: A multicenter randomized double-blind study

BACKGROUND

Early initiation of combination therapy using antihyperglycemic agents is recommended for treating type 2 diabetes (T2D). The present multicenter double-blind randomized parallel-group study examined the efficacy and safety of a sitagliptin and metformin fixed-dose combination (Sita/Met) compared with glimepiride in T2D patients as initial treatment.

METHODS

Type 2 diabetes patients (aged ≥18 years) were randomized to Sita/Met or glimepiride for 30 weeks after a wash-off run-in period. The primary endpoint was change from baseline (CFB) in HbA1c. Secondary endpoints included the proportion of patients achieving target goal (HbA1c < 7.0 % [53 mmol/mol]) and CFB in fasting plasma glucose (FPG). Safety assessments comprised weight gain from baseline and the incidence of adverse events (AEs).

RESULTS

In total, 292 patients were randomized to Sita/Met (n = 147) or glimepiride (n = 145). After 30 weeks, Sita/Met demonstrated superiority over glimepiride in reducing HbA1c (-1.49 % vs -0.71 %, respectively; between-group difference - 0.78 %; P < 0.001). A significantly higher proportion of patients achieved the target goal with Sita/Met (81.2 %) than with glimepiride (40.1 %; P < 0.001). Greater reduction in FPG occurred with Sita/Met than with glimepiride (least-squares mean difference - 23.5 mg/dL; P < 0.001). Both drugs were generally well tolerated. Hypoglycemia events and weight gain were significantly lower in patients with Sita/Met than with glimepiride (5.5 % vs 20.1 % and -0.83 vs +0.90 kg, respectively; both P < 0.001). No serious drug-related AEs or deaths were reported.

CONCLUSIONS

Compared with glimepiride, Sita/Met as an initial treatment led to significantly greater improvements in glycemic control and body weight changes, with a lower incidence of hypoglycemia, over 30 weeks.

A multicenter, phase III evaluation of the efficacy and safety of a new fixed-dose pioglitazone/glimepiride combination tablet in Japanese patients with type 2 diabetes

BACKGROUND

This study aimed to determine the efficacy and safety of pioglitazone/glimepiride as a fixed-dose combination (FDC) in Japanese patients with type 2 diabetes.

SUBJECTS AND METHODS

In this multicenter, phase III, open-label evaluation, eligible patients had to have a glycosylated hemoglobin (HbA(1c)) level of ≥7.4% and <10.4% halfway through a 4-week run-in period while being treated with glimepiride 1 or 3 mg once daily plus diet and exercise. At baseline, patients were assigned to 8 weeks of treatment with pioglitazone/glimepiride (15 mg/1 mg) FDC once daily (group A; n=31) or pioglitazone/glimepiride (30 mg/3 mg) FDC once daily (group B; n=31) according to their glimepiride dose during run-in.

RESULTS

Pioglitazone/glimepiride significantly reduced the mean HbA(1c) level from baseline (primary end point) by 0.59±0.556% in group A (P<0.0001) and by 0.55±0.637% in group B (P<0.0001). Corresponding reductions in the mean fasting blood glucose level were 12.5±21.67 mg/dL (P=0.0032) and 29.1±35.38 mg/dL (P<0.0001). Significant alterations from baseline to week 8 in either one or both treatment groups were also noted for the following parameters: 1,5-anhydroglucitol, glycoalbumin, triglycerides, high-density lipoprotein cholesterol, and free fatty acid levels. Five patients in group A (16.1%) had five treatment-related adverse events, and 10 patients in group B (32.3%) had 13 such events; all events were mild.

CONCLUSIONS

Pioglitazone/glimepiride as a FDC (30 mg/3 mg and 15 mg/1 mg once daily) significantly improved glycemic control and lipid profiles and was well tolerated in Japanese patients with type 2 diabetes.

Differential effects of 3 classes of antidiabetic drugs on olanzapine-induced glucose dysregulation and insulin resistance in female rats

BACKGROUND

The second-generation antipsychotic drug olanzapine is an effective pharmacological treatment for psychosis. However, use of the drug is commonly associated with a range of metabolic side effects, including glucose intolerance and insulin resistance. These symptoms have been accurately modelled in rodents.

METHODS

We compared the effects of 3 distinct classes of antidiabetic drugs, metformin (100 and 500 mg/kg, oral), rosiglitazone (6 and 30 mg/kg, oral) and glyburide (2 and 10 mg/kg, oral), on olanzapineinduced metabolic dysregulation. After acutely treating female rats with lower (7.5 mg/kg) or higher (15 mg/kg) doses of olanzapine, we assessed glucose intolerance using the glucose tolerance test and measured insulin resistance using the homeostatic model assessment of insulin resistance equation.

RESULTS

Both doses of olanzapine caused pronounced glucose dysregulation and insulin resistance, which were significantly reduced by treatment with metformin and rosiglitazone; however, glucose tolerance did not fully return to control levels. In contrast, glyburide failed to reverse the glucose intolerance caused by olanzapine despite increasing insulin levels.

LIMITATIONS

We evaluated a single antipsychotic drug, and it is unknown whether other antipsychotic drugs are similarly affected by antidiabetic treatments.

CONCLUSION

The present study indicates that oral hypoglycemic drugs that influence hepatic glucose metabolism, such as metformin and rosiglitazone, are more effective in regulating olanzapine-induced glucose dysregulation than drugs primarily affecting insulin release, such as glyburide. The current model may be used to better understand the biological basis of glucose dysregulation caused by olanzapine and how it can be reversed.