The results of a new study indicate that pioglitazone is superior to gliclazide in sustaining glycemic control for up to two years in type 2 diabetics.

Pioglitazone is marketed under the name Actos in the U.S. by Takeda Pharmaceuticals America, Inc. and Eli Lilly and Company, which sponsored the study. Actos belongs to a class of drugs called thiazolidinediones, and gliclazide belongs to a class called sulfonylureas.

Several research groups have shown similar decreases in blood sugar levels after one year of Actos or sulfonylurea therapy, but the effects in the second year are less clear, researchers note in the medical journal Diabetes Care.

It’s possible that the long-term control of blood sugar resulting from treatment with the two classes of drugs may be different “because of the differences in their mechanisms of action,” Dr. Meng H. Tan, from Eli Lilly and Co., in Indianapolis and colleagues write.

To investigate, Tan’s group compared the time it took for blood sugar levels to increase, as measured by HbA1c blood levels greater than eight percent. Two hundred seventy type 2 diabetics received Actos and 297 received gliclazide in a randomized, multicenter two-year study.

The researchers found that more patients treated with Actos than with gliclazide maintained a level of HbA1c less than eight percent at any time during the second year of treatment. The difference between the two groups was apparent as early as week 32 and widened at each subsequent study visit, becoming significant from week 52 on.

At the end of two years, 48 percent of Actos-treated patients and 37 percent of gliclazide-treated patients had HbA1c below eight percent.

Actos, compared with gliclazide, produced a larger decrease in HbA1c, a larger increase in insulin sensitivity and a smaller increase in beta-cell function, the investigators report.

SOURCE: Diabetes Care, March 2005.