Does the treatment of type 2 diabetes mellitus with the DPP-4 inhibitor vildagliptin reduce HbA1c to a greater extent in Japanese patients than in Caucasian patients?

Abstract

Background

Previous work suggests that Japanese patients with type 2 diabetes mellitus (T2DM) may respond more favorably to a DPP-4 (dipeptidyl peptidase-4) inhibitor than Caucasians. We aimed to compare the efficacy of the DPP-4 inhibitor vildagliptin (50 mg twice daily [bid]) between Japanese and Caucasian populations.

Methods

This analysis pooled data from 19 studies of drug-naïve patients with T2DM who were treated for 12 weeks with vildagliptin 50 mg bid as monotherapy. The pool comprised Japanese patients (n=338) who had been treated in Japan and Caucasian patients (n=1,275) who were treated elsewhere. Change from baseline (Δ) in glycated hemoglobin (HbA1c) at 12 weeks (in millimoles per mole) versus baseline HbA1c (both in percentage National Glycohemoglobin Standardization Program units [NGSP%] and millimoles per mole) for each population was reported. Universal HbA1c in millimoles per mole was calculated from either the Japanese Diabetes Society or the NGSP% HbA1c standards.

Results

At baseline, mean values for Japanese and Caucasian patients, respectively, were as follows: age, 59 years and 56 years; % male, 69% and 57%. The average HbA1c was reduced from 7.90% to 6.96% (Japanese Diabetes Society) and from 8.57% to 7.50% (United States National Glycohemoglobin Standardization Program), while HbA1c was reduced from 63 mmol/mol to 53 mmol/mol and from 70 mmol/mol to 58 mmol/mol in Japanese and Caucasians, respectively. ΔHbA1c increased with increasing baseline in both populations. The slopes were the same (0.41, r²=0.36; and 0.41, r²=0.15), and the intercepts were 15.4 mmol/mol and 17.2 mmol/mol, respectively. In Japanese patients, mean ΔHbA1c was greater by 1.7 mmol/mol (0.2% NGSP HbA1c) at any given baseline HbA1c than in Caucasians (P=0.01).

Conclusion

The present pooled analysis suggests that Japanese patients respond better to vildagliptin treatment compared with Caucasians. However, when glycemic control was corrected by using the same glycemic standard, the difference in HbA1c reduction between these populations was not clinically meaningful.

Keywords:

• baseline HbA1c
• Caucasians
• Japanese
• vildagliptin
• type 2 diabetes

Acknowledgments

The authors gratefully acknowledge the investigators and patients participating in all the studies included in this analysis. The authors thank Anil Dandu (Novartis Healthcare Private Limited, India) for technical help and editorial assistance with submission of the manuscript.

Author contributions

All authors had full access to all data and take responsibility for the integrity of the data and accuracy of analyses. All authors provided input to the analytical approach, interpretation of data, and preparation, revision, and final approval of the manuscript.

Disclosure

JEF is an employee of Novartis Pharmaceuticals Corporation and also owns company shares. VB is an employee of Novartis Healthcare Pvt Ltd. RK consulted for and received honorarium from Novartis Pharma AG. The authors report no other conflicts of interest in this work.