This study is designed as a prospective, multi-centre, parallel group, double-blind randomized, placebo-controlled, phase 3 clinical study to evaluate the efficacy and safety of MP-513 (Teneligliptin).

Inclusion Criteria:

• A signed and dated informed consent form has been obtained from the subject, in accordance with International Conference on Harmonisation guidelines on Good Clinical Practice (ICH GCP), before any screening or study related procedures take place.
• The subject is aged ≥18 years at signature of the informed consent form.
• Hospitalization status: outpatient.
• The subject has had a documented diagnosis of type 2 diabetes mellitus for at least 3 months at the screening visit (Day -28).
• The subject is undergoing diet and exercise therapy, and diet and exercise regimen has not been changed for at least 8 consecutive weeks at the screening visit (Day -28). Subjects who cannot do exercise due to complication are not limited to this criteria.
• The subject's glycosylated fraction of haemoglobin(HbA1c) is ≥ 7.0% and < 10.0% at the screening visit (Day -28) and on Day -14.

Exclusion Criteria:

• The subject has a history of type 1 diabetes mellitus or a secondary form of diabetes.
• The subject has received insulin within 1 year prior to the screening visit (Day -28), with the exception of insulin therapy during hospitalization or insulin therapy for medical conditions not requiring hospitalization (< 2 weeks' duration).
• The subject has received an anti-diabetic drug within 8 weeks prior to the screening visit (Day -28).

FAS: All subjects in the randomized set who have received at least one dose of study medication during the double-blind treatment period and have at least one post-baseline efficacy observation. Subjects who were not diagnosed with type 2 diabetes mellitus were excluded.

24 weeks