Evaluating the antidiabetic effects of R-verapamil in type 1 and type 2 diabetes mellitus mouse models

Effect of Verapamil on Blood Glucose in Type 1 and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

PURPOSE

Verapamil, an L-type calcium channel blocker treating hypertension, arrhythmia, and other cardiovascular diseases, has emerged as a potential drug for lowering blood glucose by regulating cellular calcium homeostasis and affecting expression of apoptosis-related proteins in pancreatic β-cells. However, this promising effect must be weighed against potential risks, including cardiovascular adverse effects of this drug.

METHODS

We conducted a systematic review and meta-analysis and included randomized controlled trials (RCTs) assessing verapamil in individuals with type 1 or type 2 diabetes. The primary outcomes were glycated hemoglobin (HbA1c) and serum glucose concentration. The secondary outcomes were area under the curve (AUC) values for C-peptide level, body weight, changes in HbA1c and blood glucose concentration pre- and post-intervention, and adverse drug reactions.

RESULTS

A total of eight RCTs involving 1100 patients were included in the analysis. Meta-analysis showed that verapamil effectively lowered blood glucose levels (weighted mean difference [WMD] -6.38, 95% CI -12.52, -0.25 mg/dL, P = 0.04; 6 trials), decreased HbA1c (WMD -0.45, 95% CI -0.66, -0.23%, P < 0.001; 7 trials), and increased C-peptide AUC (WMD 0.27, 95% CI 0.21, 0.32 pmol/mL, P < 0.0001; 2 trials) in patients with both type 1 and type 2 diabetes, without significant trial-related adverse events (OR 1.33, 95% CI 0.85, 2.09, P = 0.21).

CONCLUSION

The adjunctive use of verapamil to standard hypoglycemic therapy is a safe and effective means of improving glycemic control in diabetic patients. However, the limited scale of RCTs and heterogeneity of basic glucose-lowering regimens across studies might constrain generalizability of these findings. Future high-quality research is warranted to further elucidate the role of verapamil in diabetes management.

Emerging Anti-Diabetic Drugs for Beta-Cell Protection in Type 1 Diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disorder that damages beta cells in the pancreatic islets of Langerhans and results in hyperglycemia due to the loss of insulin. Exogenous insulin therapy can save lives but does not halt disease progression. Thus, an effective therapy may require beta-cell restoration and suppression of the autoimmune response. However, currently, there are no treatment options available that can halt T1D. Within the National Clinical Trial (NCT) database, a vast majority of over 3000 trials to treat T1D are devoted to insulin therapy. This review focuses on non-insulin pharmacological therapies. Many investigational new drugs fall under the category of immunomodulators, such as the recently FDA-approved CD-3 monoclonal antibody teplizumab. Four intriguing candidate drugs fall outside the category of immunomodulators, which are the focus of this review. Specifically, we discuss several non-immunomodulators that may have more direct action on beta cells, such as verapamil (a voltage-dependent calcium channel blocker), gamma aminobutyric acid (GABA, a major neurotransmitter with effects on beta cells), tauroursodeoxycholic acid (TUDCA, an endoplasmic reticulum chaperone), and volagidemab (a glucagon receptor antagonist). These emerging anti-diabetic drugs are expected to provide promising results in both beta-cell restoration and in suppressing cytokine-derived inflammation.

A Randomized Controlled Trial of R-Form Verapamil Added to Ongoing Metformin Therapy in Patients with Type 2 Diabetes

CONTEXT

There is a medical need for effective insulin-independent antidiabetic drugs that can promote pancreatic β-cell function and have a low risk of hypoglycemia in type 2 diabetes mellitus (T2DM) patients. R-form verapamil (R-Vera), which is able to enhance the survival of β-cells and has higher cardiovascular safety margin compared with racemic verapamil, was developed as a novel approach for T2DM treatment.

OBJECTIVE

This randomized, double-blind, placebo-controlled clinical trial was designed to evaluate the efficacy and safety of 3 dosages of R-Vera added to ongoing metformin therapy in T2DM patients who had inadequate glycemic control on metformin alone.

METHODS

Participants were randomly assigned in an equal ratio to receive R-Vera 450, 300, or 150 mg per day, or matching placebo, in combination with metformin. The primary endpoint was change in hemoglobin A1c (HbA1c) after 12 weeks of treatment.

RESULTS

A total of 184 eligible participants were randomized to receive either R-Vera or placebo plus metformin. At week 12, significant reductions in HbA1c were observed for R-Vera 300 mg/day (-0.36, P = 0.0373) and 450 mg/day (-0.45, P = 0.0098) compared with placebo. The reduction in HbA1c correlated with decreasing fasting plasma glucose levels and improved HOMA2-β score. Treatment with R-Vera was well tolerated with no hypoglycemic episodes occurring during the trial.

CONCLUSION

Addition of R-Vera twice daily to ongoing metformin therapy significantly improved glycemic control in T2DM patients. The favorable efficacy and safety profile of R-Vera 300 mg/day can be considered as the appropriate dose for clinical practice.