Study to Evaluate the Safety and Efficacy of the Addition of MK-3102 Compared With the Addition of Sitagliptin in Subjects With Type 2 Diabetes Mellitus With Inadequate Glycemic Control on Metformin (MK-3102-026)

Inclusion Criteria:

- Type 2 diabetes mellitus

- Currently on a stable dose of metformin monotherapy (≥1500 mg per day) for at least
12 weeks prior to study participation

- Male, or female who is not of reproductive potential or if of reproductive potential
agrees to abstain from heterosexual activity or use (or have their partner use)
acceptable contraception to prevent pregnancy during the study and for 21 days after
the last dose of study drug

Exclusion Criteria:

- History of type 1 diabetes mellitus or a history of ketoacidosis

- Has been treated with any antihyperglycemic agent (AHA) other than the
protocol-required metformin within 12 weeks prior to study participation or with
MK-3102 at any time prior to signing informed consent

- History of hypersensitivity to a dipeptidyl peptidase IV (DPP-4) inhibitor

- Is currently participating in, or has participated in, a trial in which the
participant received an investigational compound or used an investigational device
within the prior 12 weeks of signing the informed consent or is not willing to
refrain from participating in any other trial

- History of intolerance, hypersensitivity, or any other contraindication to metformin
or glimepiride

- Is on a weight loss program and is not in the maintenance phase or has been on a
weight loss medication in the past 6 months or has undergone bariatric surgery within
12 months prior to study participation

- Has undergone a surgical procedure within 4 weeks of study participation or has
planned major surgery during the study

- Is on or likely to require treatment ≥14 consecutive days or repeated courses of
corticosteroids (inhaled, nasal and topical corticosteroids are permitted)

- Currently being treated for hyperthyroidism or is on thyroid hormone replacement
therapy and has not been on a stable dose for at least 6 weeks

- Is expecting to undergo hormonal therapy in preparation to donate eggs during the
period of the trial, including 21 days after the last dose of trial medication

- History of active liver disease (other than non-alcoholic steatosis) including
chronic active hepatitis B or C, primary biliary cirrhosis, or symptomatic gall
bladder disease

- Human immunodeficiency virus (HIV)

- New or worsening signs or symptoms of coronary heart disease or congestive heart
failure within the past 3 months, or myocardial infarction, unstable angina, coronary
artery bypass grafting, percutaneous transluminal coronary angioplasty, stroke, or
transient ischemic attacks in the past 3 months

- Poorly controlled hypertension

- History of malignancy ≤5 years prior to study participation, except for adequately
treated basal cell or squamous cell skin cancer or in situ cervical cancer

- Hematological disorder (such as aplastic anemia, myeloproliferative or
myelodysplastic syndromes, thrombocytopenia)

- Positive urine pregnancy test

- Pregnant or breastfeeding, or is expecting to conceive during the study including 21
days following the last dose of blinded study drug

- User of recreational or illicit drugs or has had a recent history of drug abuse

- Routinely consumes >2 alcoholic drinks per day or >14 alcoholic drinks per week, or
engages in binge drinking

- Has donated blood products or has had phlebotomy of >300 mL within 8 weeks of study
participation, or intends to donate blood products within the projected duration of
the trial or has received, or is anticipated to receive, blood products within 12
weeks of study participation or within the projected duration of the trial