Evaluating combination therapy versus metformin only for patients with Type 2 diabetes

This study evaluated whether adding vildagliptin (Galvus) to metformin (Glucophage) could improve the duration of blood glucose control for patients with newly diagnosed Type 2 Diabetes (T2D). The authors found that this treatment combination improved long-term blood glucose control for these patients.

Treatment for T2D aims to reduce blood glucose (sugar) levels. Patients newly diagnosed with T2D are usually prescribed one anti-diabetes drug to lower their blood glucose levels. However, as the disease progresses, initial treatment eventually loses its effectiveness. When HbA1c levels (average blood glucose over the past 3 months) remain high (above 7%) after treatment, this is called treatment failure.

Research suggests that giving two anti-diabetes drugs together to newly diagnosed patients may help delay treatment failure. Metformin reduces blood glucose levels by slowing the liver's production of glucose. Vildagliptin works by increasing insulin secretion. Whether adding vildagliptin to metformin is more effective than metformin alone in delaying treatment failure for patients with T2D is unclear.

2001 patients newly diagnosed with T2D were divided into two groups. 998 patients received a combination of metformin plus vildagliptin. 1003 patients received metformin and a placebo (a substance with no active effect). The treatment period lasted 5 years. Patients were followed for an average of 59.8 months.

Overall, 43.6% of patients in the combination group and 62.1% of patients in the metformin group experienced treatment failure. The average time to treatment failure was approximately 61.9 months in the combination group and 36.1 months in the metformin only group. Combination treatment significantly reduced the risk of early treatment failure by 49%.

During the study, combination treatment was then given to all patients. Patients who started the study in the combination group had a 26% lower risk of treatment failure compared to patients who started with metformin only.

83.5% of patients in the combination group and 83.2% in the metformin group had side effects. The most common were joint pain (10% vs. 9.4%), urinary tract infections (7.3% vs. 7.1%), and low blood glucose levels (1.3% vs. 0.9%). Combination treatment reduced the number of heart attacks from 3.3% (metformin group) to 2.4% (combination group).

The authors concluded that metformin plus vildagliptin slowed treatment failure and improved long-term blood glucose control for patients with T2D. 

The manufacturer of vildagliptin, Novartis, funded this study. This study only examined one treatment combination, so the effects of other combinations are not known. The long-term benefits of metformin plus vildagliptin on heart health also need further investigation.