At least 30% of patients initially treated with sulphonylureas for NIDOM will have a poor response, and in the remaining 70% the subsequent failure rate is approximately 4% to 5% per year. BRL 49653C has a different mechanism of action to the sulphonylureas, and therefore the effects on fasting plasma glucose and Hb A1c are expected to be additive. Since circulatory insulin levels should decrease, and plasma glucose should be regulated, these combinations are also anticipated to slow both the progression of diabetic complications and delay the need for exogenous insulin.