The objective of the study is to evaluate change in insulin secretory capacity in patients with type 2 diabetes mellitus as determined by hyperglycemic clamp after a 28-day oral administration of DS-8500a at 75 mg in a placebo-controlled, 2 × 2 crossover study. In addition, safety of this regimen will be examined in this study.

Inclusion Criteria:

• Patients aged ≥ 20 years at the time of informed consent
• Japanese patients with type 2 diabetes
• Patients who have HbA1c ≥ 7.0% and < 9.0%

Exclusion Criteria:

• Patients with type 1 diabetes mellitus or with a history of diabetic coma, precoma, or ketoacidosis
• Patients receiving or requiring treatment with insulin
• Patients with a body mass index (BMI) of < 18.5 kg/m2 or ≥ 35.0 kg/m2
• Patients with clinically evident renal impairment (estimated glomerular filtration rate [eGFR] of < 45 mL/min per 1.73 m2) or clinically significant renal disease
• Patients with fasting plasma glucose ≥ 240 mg/dL

De-identified individual participant data (IPD) and applicable supporting clinical trial documents may be available upon request at https://vivli.org/. In cases where clinical trial data and supporting documents are provided pursuant to our company policies and procedures, Daiichi Sankyo will continue to protect the privacy of our clinical trial participants. Details on data sharing criteria and the procedure for requesting access can be found at this web address: https://vivli.org/ourmember/daiichi-sankyo/

Studies for which the medicine and indication have received European Union (EU) and United States (US), and/or Japan (JP) marketing approval on or after 01 January 2014 or by the US or EU or JP Health Authorities when regulatory submissions in all regions are not planned and after the primary study results have been accepted for publication.

Formal request from qualified scientific and medical researchers on IPD and clinical study documents from clinical trials supporting products submitted and licensed in the United States, the European Union and/or Japan from 01 January 2014 and beyond for the purpose of conducting legitimate research. This must be consistent with the principle of safeguarding study participants' privacy and consistent with provision of informed consent.