Safety and Efficacy of Sitagliptin Compared With Glimepiride in Elderly Patients With Type 2 Diabetes Mellitus (0431-251)

The primary objectives of this study are to determine if sitagliptin treatment is not
inferior to that of glimepiride as measured by the change in baseline A1C (hemoglobin A1C)
after 30 weeks of treatment, and if sitagliptin treatment results in a lower incidence of
symptomatic hypoglycemia compared to that of glimepiride. The study will also evaluate if
sitagliptin treatment, compared to glimepiride results in improvements in fasting plasma
glucose (FPG) levels, and plasma lipid levels after 30 weeks of treatment. Participants will
be randomized to either sitagliptin or glimepiride treatment after eligibility for study
participation is determined during screening and washout study phases. Participants and
study staff will not know to which treatment group they have been randomized (double-blind
design). The duration of study participation will be up to 40 weeks (with 9 clinic visits).
This will include a screening phase (Visit 1 to Visit 2) of 2 weeks maximum; a 6-week
(Visits 2 to 3) oral antihyperglycemic agent (AHA) wash-out phase (for those who have been
taking a AHA prior to the study); a placebo run-in phase (Visits 3 to 4), followed by up to
30 weeks of treatment with study medication.