Efficacy and Safety of Ertugliflozin (MK-8835/PF-04971729) With Sitagliptin in the Treatment of Participants With Type 2 Diabetes Mellitus (T2DM) With Inadequate Glycemic Control on Diet and Exercise (MK-8835-017)

Each participant will be in the study for approximately 39 weeks including: a 1-week screening period, an 8-week (or greater) antihyperglycemic agent (AHA) wash-off period, a 2-week single-blind placebo run-in period, a 26-week double-blind treatment period, and a post-treatment telephone contact 14 days after the last dose of study drug.

Inclusion criteria

• Type 2 diabetes mellitus as per American Diabetes Association guidelines
• Not on antihyperglycemic agent (AHA) >=8 weeks with a Visit 1/Screening HbA1C >=8.0% and <=10.5% (>=64 mmol/mol and <=91 mmol/mol) OR on single allowable AHA (allowable AHAs prior to screening are: metformin, α-glucosidase inhibitors, sulfonylureas and glinides) with a Visit 1/Screening HbA1C >=7.5% and <=10.0% (>=58 mmol/mol and <=86 mmol/mol) OR on low-dose dual combination therapy (≤50% of maximum labeled dose of an AHA) with allowable AHAs with a Visit 1/Screening HbA1C >=7.5% and <=10.0% (>=58 mmol/mol and <=86 mmol/mol)
• Body mass index (BMI) >=18.0 kg/m^2
• Male or female not of reproductive potential
• Female of reproductive potential who agrees to (or have their partner agree to) remain abstinent from heterosexual activity or to use 2 acceptable combinations of contraception.

Exclusion criteria

• History of type 1 diabetes mellitus or diabetic ketoacidosis
• History of other specific types of diabetes (e.g., genetic syndromes, secondary pancreatic diabetes, diabetes due to endocrinopathies, drug- or chemical-induced, and post-organ transplant
• A known hypersensitivity or intolerance to any sodium glucose co-transporter (SGLT2) inhibitor or sitagliptin
• Has been treated with any of the following agents within 12 weeks of study start or during the pre-randomization period: insulin of any type (except for short-term use [i.e., <=7 days] during concomitant illness or other stress), other injectable anti-hyperglycemic agents (e.g., pramlintide, exenatide, liraglutide), pioglitazone or rosiglitazone, other sodium glucose co-transporter 2 (SGLT2) inhibitors, dipeptidyl-peptidase 4 inhibitors (DPP-4 inhibitors), bromocriptine (Cycloset™), colesevelam (Welchol™), any other AHA with the exception of the protocol-approved agents
• Is on a weight-loss program or weight-loss medication or other medication associated with weight changes and is not weight stable prior to study start
• Has undergone bariatric surgery within the past 12 months or >12 months and is not weight stable prior to study start
• A history of myocardial infarction, unstable angina, arterial revascularization, stroke, transient ischemic attack, or New York Heart Association (NYHA) functional Class III-IV heart failure within 3 months of study start
• Active, obstructive uropathy or indwelling urinary catheter
• History of malignancy <=5 years prior to study start, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer
• A known history of human immunodeficiency virus (HIV)
• A blood dyscrasia or any disorder causing hemolysis or unstable red blood cells, or a clinically important hematological disorder (e.g. aplastic anemia, myeloproliferative or myelodysplastic syndromes, thrombocytopenia)
• A medical history of active liver disease (other than non-alcoholic hepatic steatosis), including chronic active hepatitis B or C, primary biliary cirrhosis, or symptomatic gallbladder disease
• Any clinically significant malabsorption condition
• Current treatment for hyperthyroidism
• On thyroid replacement therapy and not on a stable dose for at least 6 weeks prior study start
• On a previous clinical study with ertugliflozin
• Participated in other studies involving investigational drug(s) 30 days prior to study start
• Surgical procedure within 6 weeks prior to study start or major surgery planned during the trial
• Positive urine pregnancy test
• Pregnant or breast-feeding, or planning to conceive during the trial, including 14 days following the last dose of study medication
• Planning to undergo hormonal therapy in preparation for egg donation during the trial, including 14 days following the last dose of study medication
• Routinely consumes >2 alcoholic drinks per day or >14 alcoholic drinks per week or engages in binge drinking
• Donated blood or blood products within 6 weeks of study start.