Reflections on the sulphonylurea story: A drug class at risk of extinction or a drug class worth reviving?

KATP channels in focus: Progress toward a structural understanding of ligand regulation

KATP channels are hetero-octameric complexes of four inward rectifying potassium channels, Kir6.1 or Kir6.2, and four sulfonylurea receptors, SUR1, SUR2A, or SUR2B from the ABC transporter family. This unique combination enables KATP channels to couple intracellular ATP/ADP ratios, through gating, with membrane excitability, thus regulating a broad range of cellular activities. The prominence of KATP channels in human physiology, disease, and pharmacology has long attracted research interest. Since 2017, a steady flow of high-resolution KATP cryoEM structures has revealed complex and dynamic interactions between channel subunits and their ligands. Here, we highlight insights from recent structures that begin to provide mechanistic explanations for decades of experimental data and discuss the remaining knowledge gaps in our understanding of KATP channel regulation.

Dorothy Hodgkin Lecture 2021: Drugs, genes and diabetes

Glycaemic response to metformin and sulphonylureas is heritable - with ~34%-37% of variation explainable by common genetic variation. The premise of this review is that by understanding how genetic variation contributes to drug response we can gain insights into the mechanisms of action of diabetes drugs. Here, I focus on two old drugs, metformin and sulphonylureas, where I would suggest we still have a lot to learn about their mechanism of action or their optimal use in clinical care. The fact that reduced function variants of the key transporter that takes metformin into the liver (OCT1) do not alter glycaemic response to metformin suggests that metformin does not need to get into the liver to work. A subsequent GWAS of metformin response identifies a robust variant that alters GLUT2 expression - which may support increasing evidence that metformin works primarily in the gut. For sulphonylureas, observation from patients with neonatal diabetes due to activating K_ATP channel mutations treated with sulphonylureas identified a novel role for sulphonylureas to enable β-cell incretin response. This work led to recent studies of low-dose sulphonylurea (20 mg gliclazide) in T2DM, which identified that at this dose sulphonylureas augment the incretin effect and increase β-cell glucose sensitivity, without increasing hypoglycaemia risk. This work, prompted by studies in monogenic diabetes, suggests that we have historically been using sulphonylureas at too high a dose. With increasing availability of genetic data pharmacogenomic studies in patients with diabetes should reveal mechanistic insights into old and new diabetes drugs, with the potential for optimized use and novel therapies.

The role of sulfonylureas in the treatment of type 2 diabetes

INTRODUCTION

Type 2 diabetes (T2D) is increasingly prevalent and associated with increased risk for cardiovascular and renal disease. After lifestyle modification, metformin is usually the first-line pharmacotherapy and sulfonylureas are traditionally added after metformin failure. However, with newer glucose lowering drugs that may have less risk of hypoglycemia or that may reduce cardiovascular and renal events, the position of sulfonylureas is being reevaluated.

AREAS COVERED

In this article, the authors review relevant publications related to the use of sulfonylureas.

EXPERT OPINION

Sulfonylureas are potent glucose lowering drugs. The risk of hypoglycemia varies with different drugs within the class and can be minimized by using the safer drugs, possibly in lower doses. Cardiovascular events do not appear to be increased with some of the newer generation drugs. The durability of glycemic control also appears comparable to other newer agents. Sulfonylureas are the preferred treatment for some types of monogenic diabetes and selection of T2D patients who may have greater benefit from sulfonylureas based on certain phenotypes and genotypes is likely to be refined further by precision medicine. Sulfonylureas are inexpensive and readily available everywhere and they are still the most frequently used second-line treatment for T2D in many parts of the world.

Cost-Effectiveness of Gliclazide-Based Intensive Glucose Control vs. Standard Glucose Control in Type 2 Diabetes Mellitus. An Economic Analysis of the ADVANCE Trial in Vietnam

Introduction: ADVANCE was a large, multinational clinical study conducted over 5 years in type 2 diabetes mellitus (T2DM). In all, 11,140 patients were randomly assigned to receive gliclazide-based intensive glucose control (IGC) or standard glucose control (SGC). IGC was shown to significantly reduce the incidence of major macrovascular and microvascular events (composite endpoint) or major microvascular events compared with SGC, primarily by enhancing renal protection. We assessed the cost-effectiveness of IGC vs. SGC, based on the ADVANCE results, from a Vietnamese healthcare payer perspective. Materials and Methods: A partitioned survival times model across five health states (no complications, myocardial infarction, stroke, end-stage renal disease [ESRD], and diabetes-related eye-disease) was designed. Time-to-event curves were informed by the cumulative incidence of events and corresponding hazard ratios from the ADVANCE study. Health outcomes were expressed in terms of ESRD avoided and quality-adjusted life years (QALYs). Costs (in US $) comprised treatment costs and health state costs. Utility weights and costs were documented from literature reporting Vietnamese estimates. For sensitivity analyses, all parameters were individually varied within their 95% confidence interval bounds (when available) or within a ±30% range. Results: Over a 5-year horizon, IGC avoided 6.5 additional ESRD events per 1,000 patients treated compared with SGC (IGC, 3.5 events vs. SGC, 10.0 events) and provided 0.016 additional QALYs (IGC, 3.570 QALYs vs. SGC, 3.555 QALYs). Total costs were similar for the two strategies (IGC, $3,786 vs. SGC, $3,757). Although the total drug costs were markedly higher for IGC compared with SGC ($1,703 vs. $873), this was largely offset by the savings from better renal protection with IGC (IGC, $577 vs. SGC, $1,508). The incremental cost-effectiveness ratio (ICER) of IGC vs. SGC was $1,878/QALY gained, far below the threshold recommended by the World Health Organization (i.e., 1-3 × gross domestic product per inhabitant ≈$7,500 in Vietnam). The ICER of IGC vs. SGC per ESRD event avoided was $4,559/event. The findings were robust to sensitivity analysis. Conclusion: In Vietnam, gliclazide-based IGC was shown to be cost-effective compared with SGC from a healthcare payer perspective, as defined in the ADVANCE study.

Prescription of Sulphonylureas among Patients with Type 2 Diabetes Mellitus in Italy: Results from the Retrospective, Observational Multicentre Cross-Sectional SUSCIPE (Sulphonyl_UreaS_Correct_Internal_Prescription_Evaluation) Study

INTRODUCTION

Recent guidelines for the treatment of type 2 diabetes mellitus (T2DM) provide evidence supporting limited use of sulphonylureas (SUs), especially in specific risk patient categories, yet data from national registries still suggest their widespread use. The aim of this study was to investigate characteristics of patients with diabetes treated with SUs and quantify the proportion of patients that met the recommendations for use of SUs by recent guidelines and of those presenting characteristics representing an inappropriate prescription risk (IPR).

METHODS

A multicenter, retrospective, cross-sectional, observational study in patients with T2DM receiving treatment with SUs (as monotherapy or in combination with another diabetes therapy) was conducted between 2017 and 2018 in 22 outpatient diabetes clinics across Italy. Exclusion criteria were type 1 diabetes, diabetes mellitus secondary to other conditions, and presence of severe/life-threatening diseases.

RESULTS

A total of 510 patients with T2DM (306 men, 204 women; mean age ± standard deviation 69.8 ± 9.3 years) who were receiving treatment with a SU (as monotherapy or in combination therapy) were assessed in the study. Overall, 70.6% [n = 360; 95% confidence interval (CI) 66.4%, 74.5%] were assessed to have an IPR. Of these, approximately half presented one factor for risk of inappropriate prescription, and 27 and 10.6% presented two and three factors, respectively. In terms of factors contributing to the total burden of risk of inappropriate treatment with SUs, 37.5% (95% CI 33.2%, 41.8%) of all patients were obese; 33.3% (95% CI 29.3%, 37.6%)] were aged ≥ 75 years; 18.6% (95% CI 15.3%, 22.3%) had a history of cardiovascular disease; 14.1% (95% CI 11.2%, 17.4%) had chronic renal insufficiency; 1.8% (95% CI 0.8%, 3.3%) had a history of severe hypoglycemia; 1.8% (95% CI 0.8%; 3.3%) had cognitive impairment; and 2.4% (95% CI 1.2%, 4.1%) had a risky occupation.

CONCLUSIONS

The results of this study provide evidence of a high rate of inappropriate SU prescription risk among patients with T2DM, especially among those with overweight/obesity, older age, history of cardiovascular disease, and hypoglycemia.