Voglibose prevents diabetes in high-risk Asians

Medical Tribune July 2009 SFII
David Brill

Alpha-glucosidase inhibitors could play an important role in preventing, as well as treating, the growing epidemic of type 2 diabetes in Asia.

A recent trial found that adding voglibose to diet and exercise counseling almost halved the risk of developing diabetes in Japanese patients with impaired glucose tolerance (IGT).

The study extends similar findings from Western populations, where acarbose has been shown to reduce the progression from IGT to diabetes – notably in the Study to Prevent Non-Insulin-Dependent Diabetes Mellitus (STOP-NIDDM) trial. [Lancet 2002;359(9323):2072-7] Equivalent studies in Asian populations, however, were previously lacking.

The researchers, led by Professor Ryuzo Kawamori, Juntendo University School of Medicine, Tokyo, randomized subjects to placebo or voglibose (0.2 mg three times a day). The trial was terminated early, following an interim analysis. [Lancet 2009;373(9675):1607-14]

At a mean of 48 weeks of treatment, 50 of 897 patients taking voglibose had developed diabetes, compared to 106 of 881 who took placebo (hazard ratio 0.595, 95 percent CI 0.43 – 0.82; P=0.0014). More people achieved normoglycemia in the voglibose group: 559 of 897, versus 454 of 881 in the placebo group (P<0.0001).

Singapore diabetes expert Dr. Kevin Tan said that alpha-glucosidase inhibitors offer a good option in cases which need more aggressive intervention than lifestyle therapies alone.

“The results of this study mirror those of acarbose in STOP-NIDDM and demonstrate the efficacy of this group of alpha-glucosidase inhibitors in preventing type 2 diabetes – now in an Asian population as well,” said Tan, vice president of the Diabetic Society of Singapore and a private practitioner at Mount Elizabeth Medical Centre.

“Lifestyle interventions remain central as they are simple and available to all and, moreover, their effects are sustainable. However, lifestyle interventions are notoriously difficult to maintain at the same intensity over time and therefore safe and effective medications to complement them are needed as well. Alpha-glucosidase inhibitors are amongst the safest of compounds as there is minimal absorption into the body and no interference with the metabolism of other drugs,” he said.

The epidemic of type 2 of diabetes continues to boom in Asia, with total numbers predicted to increase from some 114 million patients in 2007 to 180 million in 2025. The prevalence of IGT is expected to rise from 157 million to 213. [JAMA 2009 May 27;301(20):2129-40]

The worst-affected countries appear to be those undergoing significant economic and dietary changes: the overall prevalence in China, for example, rose from 1 percent in 1980 to 5.5 percent in 2001. For affluent urban areas such as Hong Kong and Taiwan, the figure is as high as 10 percent. [Diabetes Res Clin Pract 2006 Aug;73(2):126-34]

Adverse events in the Japanese study were more common with voglibose than placebo (P<0.0001) – mostly comprising gastrointestinal symptoms such as flatulence, abdominal distention and diarrhea. There were also six serious advents in the voglibose group, consisting of colonic polyp, cholecystitis, inguinal hernia, liver dysfunction, rectal neoplasm and subarachnoid hemorrhage. Two placebo patients experienced serious events – one cerebral infarction and one case of cholecystitis.

Alpha-glucosidase inhibitors could feasibly be given in combination with metformin, which has also shown good results in diabetes prevention studies, wrote Dr. André Scheen of the University of Liège, Belgium, in an accompanying commentary. This dual approach, using acarbose, is currently being trialed in Canada. [Lancet 2009 May 9;373(9675):1579-80; Diabetes Obes Metab 2006;8(5):531-7]