Premixed insulin analogues for the treatment of diabetes mellitus

Premixed insulin analogues, consisting of rapid-acting and intermediate-acting insulin analogues, were developed to more closely mimic physiological endogenous insulin secretion and meet the needs of patients who require both basal and prandial insulin but wish to limit the number of daily injections. There is considerable variability in onset and duration of action, as well as peak insulin levels, obtained with human insulin formulations such as premixed human insulin 70/30. To overcome these limitations, premixed insulin analogues were developed. Peak insulin levels are twice as high and reached in half the time with the rapid-acting insulin component of a premixed insulin analogue. In the US, two premixed insulin analogue formulations are currently available: insulin lispro 75/25 (75% insulin lispro protamine suspension and 25% insulin lispro) and biphasic insulin aspart 70/30 (BIAsp 70/30; 70% insulin aspart protamine suspension and 30% insulin aspart). They are generally administered twice daily, just before breakfast and dinner. Data from various randomised trials show that both insulin lispro 75/25 and BIAsp 70/30 provide more effective postprandial control of blood glucose than premixed human insulin 70/30 or human insulin isophane suspension (NPH insulin). Longer-term glycaemic control, evaluated as changes in glycosylated haemoglobin, is comparable for premixed insulin analogues and premixed human insulin 70/30 in most studies. Three comparative, randomised trials have shown that patients with type 2 diabetes mellitus using premixed insulin analogues twice daily are more likely to reach glycaemic goals than those using only insulin glargine once daily. Some patients can also reach glycaemic goals with once-daily administration of a premixed insulin analogue. Although the incidence of hypoglycaemia is low, direct comparison across trials of premixed insulin analogues is difficult because of inconsistencies in reporting. Within trials, the incidence of both major (rare) and minor hypoglycaemic episodes during treatment with premixed insulin analogues is low and comparable with rates found with human insulin 70/30. Premixed insulin analogues can be safely used, and are effective and convenient for achieving overall glycaemic control in patients with diabetes. In addition, given the convenience of mealtime dose administration, compliance with insulin therapy may increase with premixed insulin analogues.