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Acarbose noninferior to metformin in type 2 diabetes
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Patients with newly diagnosed type 2 diabetes treated with acarbose experienced similar improvements in HbA1c as those treated with metformin, according to data from a randomized trial conducted in China.
“Robust evidence for metformin has been generated mostly from white populations with extrapolations for other populations; few studies have assessed metformin in other populations, especially in eastern Asian patients with lower BMI and exaggerated postprandial glucose excursion,” researchers wrote in The Lancet Diabetes & Endocrinology, noting that alpha-glucosidase inhibitors such as acarbose are commonly used as monotherapy in Asian countries.
Acarbose vs. metformin
The researchers conducted a 48-week, randomized, open-label, noninferiority trial enrolling 788 patients with newly diagnosed type 2 diabetes from 11 sites in China. The study included a 4-week lifestyle modification run-in phase followed by 24 weeks of monotherapy with metformin or acarbose (Precose, Bayer Healthcare Pharmaceuticals) and another 24 weeks during which add-on therapy was initiated if prespecified glucose targets were not met.
At 24 weeks, results revealed a 1.17% reduction in HbA1c from baseline in the acarbose group (n=391) and a 1.19% reduction in the metformin group (n=393). At 48 weeks, reductions in HbA1c were 1.11% in the acarbose group and 1.12% in the metformin group. Mean treatment difference was 0.01% (95% CI, –0.12 to 0.14), suggesting noninferiority.
Six serious adverse events occurred in the acarbose group and seven occurred in the metformin group. The most common events were mild to moderate gastrointestinal symptoms, occurring in 27% of patients in the acarbose group and 29% in the metformin group. Two patients in the acarbose group and four in the metformin group experienced hypoglycemic episodes.
Data indicated that the decrease in fasting plasma glucose was greater among patients in the metformin group vs. the acarbose group, whereas the decrease in postprandial 2-hour glucose was greater with acarbose vs. metformin. Progressive reductions in body weight were also noted in both groups, with a slightly more pronounced but insignificant reduction in the acarbose group.
Additionally, although insignificant, the researchers noted a trend toward greater efficacy in lowering HbA1c among patients with dietary carbohydrate intake greater than 65.5% with acarbose. This may be a potentially important finding because Chinese patients with newly diagnosed type 2 diabetes tend to have a higher carbohydrate intake, they wrote.
Both drugs demonstrated similar patterns of changes in glucose, insulin, glucagon-like peptide-1 and glucagon levels, but results also revealed certain differences.
“Both metformin and acarbose showed a significant rise in GLP-1 concentrations from 24 weeks onwards, although the decreases in glucagon seen in both groups were apparent mainly from 24 weeks onwards and occurred earlier with acarbose than with metformin,” Ronald C.W. Ma, MD, FRCP, of the Prince of Wales Hospital; the Li Ka Shing Institute of Health Sciences; and the Hong Kong Institute of Diabetes and Obesity at the Chinese University of Hong Kong, wrote in an accompanying commentary.
“Further studies to investigate these changes would be of interest. The increase in GLP-1 concentrations after acarbose is a marker of delayed and more distal intestinal absorption of carbohydrate.”
Clinical implications
The results of this first head-to-head comparison of metformin and acarbose as initial therapy for type 2 diabetes suggest that both drugs are similar in efficacy and well tolerated among Chinese patients, the researchers concluded.
“Metformin should remain as first-line treatment for patients with newly diagnosed type 2 diabetes, while patients with exaggerated postprandial excursion can be treated with an alpha-glucosidase inhibitor as an alternative therapy before cardiovascular benefits of acarbose are validated and confirmed in ongoing studies,” they wrote.
In his comment, Ma said little medium-term data for other agents being compared with metformin as monotherapy currently exist, stating that data on the medium-term and long-term outcome of patients receiving newer agents compared with metformin are “eagerly awaited.”
“[This trial] has provided invaluable information about the efficacy and benefits of acarbose compared with metformin,” he wrote. “[This trial] represents an applaudable contribution and important step towards the development of evidence-based and population-specific treatment guidelines for type 2 diabetes.”
For more information:
Yang W. Lancet. 2013;doi:10.1016/S2213-8587(13)70021-4.
Disclosure: This trial was funded by Bayer Healthcare (China) and Double-Crane Pharma. The researchers report no relevant financial disclosures. Ma reports receiving speaker honoraria or consultancy fees from Bayer, Boehringer Ingelheim, Danone, Eli Lilly, Nestle, Pfizer and Takeda, and research support from AstraZeneca, and Merck Sharp and Dohme.