Combined therapy with insulin lispro Mix 75/25 plus metformin or insulin glargine plus metformin: a 16-week, randomized, open-label, crossover study in patients with type 2 diabetes beginning insulin therapy.

Objective: This study aimed to assess glycemic response to a mixture of 75% insulin lispro protamine suspension and 25% insulin lispro (Mix 75/25) BID plus metformin versus insulin glargine QD plus metformin in patients with type 2 diabetes mellitus (DM).

Methods: Adults new to insulin therapy were enrolled in a multicenter, randomized, prospective, open-label, crossover study with 16 weeks on each treatment. Variables included glycosylated hemoglobin (HbA(1c)), hypoglycemia rate, fasting blood glucose (FBG), 2-hour postprandial blood glucose (ppBG), and rise in blood glucose after meals.

Results: One hundred five patients (mean age, 55 years) were randomized. There was no difference in baseline mean values for either treatment sequence group for body mass index, duration of DM, or HbA(1c). Ninety-five patients completed the study and 67 were included in the efficacy analysis. Mix 75/25 was associated with lower mean (SD) HbA(1c) at end point (7.4% [1.1%] vs 7.8% [1.1%]; P = 0.002). More patients using Mix 75/25 achieved target HbA(1c) < or =7.0% (42% [30/71] vs 18% [13/71]; P < 0.001). With Mix 75/25, the mean (SD) 2-hour ppBG was similar after lunch but lower after breakfast (156.4 [43.6] vs 171.1 [44.9] mg/dL; P = 0.012) and dinner (164.8 [42.5] mg/dL vs 193.8 [51.0] mg/dL; P < 0.001), although FBG was higher (139.3 [36.6] mg/dL vs 123.9 [34.9] mg/dL; P < 0.001). Rise in ppBG was lower with Mix 75/25 after breakfast (16.9 [47.0] mg/dL vs 47.4 [34.8] mg/dL; P < 0.001) and dinner (14.2 [44.1] mg/dL vs 45.9 [41.3] mg/dL; P < 0.001). Gain in mean (SD) body weight was greater with Mix 75/25 than insulin glargine (2.3 [4.0] kg vs 1.6 [4.0] kg; P = 0.006). For all randomized patients, mean (SD) hypoglycemia rates were lower with insulin glargine (0.68 [1.38] vs 0.39 [1.24] episodes/patient per 30 days; P = 0.041), although nocturnal hypoglycemia was similar.

Conclusion: In this study population, Mix 75/25 plus metformin was associated with lower HbA(1c) than insulin glargine plus metformin, smaller rise in ppBG after breakfast and dinner, and higher proportion of patients achieving HbA(1c) < or =7.0%, with a slight increase in overall (but not nocturnal) hypoglycemia.