Effects of Exenatide and Insulin Glargine in Subjects With Type 2 Diabetes

Beta-cell Function 4 Weeks After Cessation of Therapy

Treatment effect on beta-cell function as measured by the ratio of Week 56 arginine-stimulated insulin secretion during a hyperglycemic clamp(specifically, the incremental AUC of insulin with respect to basal value over a 10 min period \[i.e., clamp time 290 min to 300 min\]) to that at baseline (i.e., the ratio is calculated as arginine-stimulated insulin secretion at week 56 divided by arginine-stimulated insulin secretion at baseline \[week -2\]).

Time frame: Baseline (week -2) and 56 weeks

Change in First Phase C-peptide Release

Ratio of first phase C-peptide response to glucose at 52 weeks (end of on-drug period) and 56 weeks (during off-drug period) compared to first phase C-peptide response to glucose at baseline (i.e., C-peptide response to glucose at week 52 or week 56 divided by C-peptide response to glucose at baseline \[week -2\]). C-peptide is measured as a surrogate marker of insulin secretion. First phase C-peptide/insulin release is measured during the first ten minutes of glucose infusion during a hyperglycemic clamp procedure.

Time frame: baseline (week -2), 52 weeks, and 56 weeks

Change in Second Phase C-peptide Release

Ratio of second phase C-peptide response to glucose at 52 weeks (end of on-drug period) and 56 weeks (during off-drug period) compared to second phase C-peptide response to glucose at baseline (i.e., C-peptide response to glucose at week 52 or week 56 divided by C-peptide response to glucose at baseline \[week -2\]). C-peptide is measured as a surrogate marker of insulin secretion. Second phase C-peptide/insulin release is measured from time=10 minutes to time=80 minutes of glucose infusion during a hyperglycemic clamp procedure.