This study is a randomized, placebo-controlled, double-blind, multi-center study to evaluate efficacy and safety of different doses of CS-3150 compared to placebo in Japanese Type 2 Diabetes Mellitus and Microalbuminuria.

The Primary endpoint is the change from baseline in urinary albumin to creatine ratio (UACR).

Inclusion Criteria:

• Subjects with type 2 diabetes mellitus
• Male or female subjects aged 20 years or older at informed consent
• Subjects with urinary albumin to creatine ratio (UACR) ≥ 45 mg/g Cr and < 300 mg/g Cr
• Estimated glomerular filtration rate by creatinine (eGFRcreat) ≥ 30 mL/min/1.73 m^2
• Subjects treated with angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) for at least 3 months prior to treatment period

Exclusion Criteria:

• Type 1 diabetes
• HbA1c (NGSP) >=8.4%
• Secondary glucose intolerance
• Subjects diagnosed with non-diabetic nephropathy
• Nephrotic syndrome
• Secondary hypertension or malignant hypertension
• Serum potassium level in any of the following categories: For subjects with eGFRcreat of ≥ 45 mL/min/1.73 m^2, serum potassium level of < 3.5 mEq/L or ≥ 5.1 mEq/L; For subjects with eGFRcreat of ≥ 30 mL/min/1.73 m^2 and < 45 mL/min/1.73 m^2, serum potassium level of < 3.5 mEq/L or ≥ 4.8 mEq/L

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.