New Class of Drugs Effective in Treating Diabetes?

November 13, 2002

OTTAWA - Two drugs that are members of the newest class of oral anti-diabetic agents, the thiazolidinediones, have an innovative mechanism of action but their effect on blood sugar reduction in patients with type 2 diabetes appears to be similar to that of other oral anti-diabetic drugs, says a report released today by the Canadian Coordinating Office for Health Technology Assessment (CCOHTA). These drugs are more expensive than other anti-diabetic drugs and may therefore have a significant impact on publicly funded drug plans.

There are two thiazolidinediones currently available in Canada, rosiglitazone and pioglitazone. These drugs lower blood glucose levels through a new mechanism of action that may contribute to decreasing insulin resistance, a key problem in type 2 diabetes. This form of diabetes is the most common and affects 90% of persons with diabetes. Serious long-term complications can develop that affect the eyes, kidneys, nerves and blood vessels.

CCOHTA reviewed several studies that compared the efficacy and safety of rosiglitazone and pioglitazone with other anti-diabetic agents. When used alone, these drugs led to a similar reduction in blood sugar, compared to other oral anti-diabetic drugs. When rosiglitazone and pioglitazone were added to another anti-diabetic agent, blood sugar was significantly reduced, compared to continuing a single anti-diabetic agent. This is consistent with the work of others that show combining two anti-diabetic agents provide a greater effect on blood sugar than using a single drug. Although thiazolidinediones were generally well tolerated in the studies reviewed by CCOHTA, concerns exist regarding their use in patients with liver disease or heart problems. Further research is required to evaluate the effects of these drugs on the development of diabetic complications and their long-term safety.

Based on a CCOHTA budget impact analysis, it is estimated that by 2004, if thiazolidinediones are listed in all publicly-funded drug plans throughout Canada, it would result in a net expenditure increase between $11.8 and $88.5 million dollars per year. The exact amount would depend on their utilization, the number of patients treated, and the listing status.

This publication is available online.

For further information contact Kirk Fergusson: 613 226-2553 ext. 276