Abstract

OBJECTIVE—To assess the postprandial glucose-lowering effect of the human amylin analog pramlintide when given with either regular insulin or insulin lispro in subjects with type 1 diabetes, with an emphasis on the optimal dose timing relative to meals.

RESEARCH DESIGN AND METHODS—In this randomized, single-blind, placebo-controlled, five-way crossover study, 19 subjects with type 1 diabetes using regular insulin and 21 subjects with type 1 diabetes using insulin lispro underwent five consecutive mixed meal tests. In randomized order, subjects received subcutaneous injections of placebo at −15 min or 60 μg pramlintide at −15, 0, +15, or +30 min relative to the meal after an overnight fast. Regular insulin or insulin lispro was injected at −30 and 0 min, respectively, at doses that were adjusted appropriately for both the content of the standardized meal and the anticipated effects of pramlintide. Plasma glucose concentrations were measured before and during the 4-h postmeal period.

RESULTS—In both the regular insulin and insulin lispro groups, pramlintide injections at all four time points lowered the postprandial glucose excursion (36 to >100% reduction in incremental area under the concentration time curve from 0 to 4 h (AUC_{0–4 h}) compared with placebo. However, only preprandial injections of pramlintide (−15 and 0 min) were able to prevent the initial postprandial surge in glucose. The optimal time for pramlintide injection was 0 min, which reduced the postprandial glucose excursion by >100% compared with regular insulin plus placebo (incremental AUC_{0–4 h}: −0.6 ± 2.5 vs. 11.0 ± 2.9 mmol · h⁻¹ · l⁻¹, P < 0.0007) and by 75% compared with insulin lispro plus placebo (incremental AUC_{0–4 h}: 2.5 ± 2.1 vs. 10.0 ± 2.5 mmol · h⁻¹ · l⁻¹, P < 0.0098). No serious adverse events were reported.

CONCLUSIONS—Pramlintide, given at or just before a meal, reduces the postprandial glucose excursion in subjects with type 1 diabetes, regardless of whether added to regular insulin or a rapid-acting insulin analog.