A Study to Evaluate the Effect of ASP1941 in Combination With Metformin in Adult Patients With Type 2 Diabetes Mellitus

Inclusion Criteria:

- Subject has been diagnosed with Diabetes Mellitus type 2 (T2DM) for at least 6 months

- Subject has inadequate glycemic control indicated by an HbA1c level between 7.0% and
9.5% at start of the run-in period at Visit 1 AND does not meet any of the FPG
discontinuation criteria

- Subject has been on a stable dose of at least 1500 mg/day metformin monotherapy for at
least 6 weeks prior to Visit 1

- Subject is on a stable diet and exercise program (for at least 6 weeks prior to Visit
1) and is willing to remain on this program for the duration of the study

- Subject has a body mass index (BMI) 20 - 45 kg/m2 at Visit 1

- Female subject of childbearing potential has a negative serum pregnancy test (human
chorionic gonadotropin [hCG]) at Visit 1 and agrees to use an acceptable form of
contraception throughout the duration of the study OR is at least 1 year
post-menopausal (defined as amenorrhea for at least 1 year) or surgically sterile.
Male study subjects should be advised to use a male condom in addition to having their
partner use another acceptable method during the study and for 3 months after the last
dose

Exclusion Criteria:

- Subject has any known complication of T2DM indicating a late disease state that in the
investigator's opinion should preclude the subject from participation

- Subject has type 1 diabetes mellitus

- Subject is in need of insulin therapy or has received insulin within 3 months prior to
Visit 1, with the exception of acute use of <7 days

- Subject has a serum creatinine higher than upper limit of normal range at Visit 1

- Subject has an alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST)
higher than 3 times upper limit of normal range or has a total bilirubin more than 2
times upper limit of normal at Visit 1

- Subject has a urinary microalbumin/creatinine ratio above or equal to 300 mg/g at
Visit 1

- Subject has a symptomatic urinary tract infection (UTI) or symptomatic genital
infection at Visit 1 or during the placebo run-in period, including just prior to
randomization at Visit 2

- Subject has persistent, uncontrolled severe hypertension as indicated by a systolic
blood pressure >180 mmHg or a diastolic blood pressure of >110 mmHg taken in a sitting
position after 5 minutes of rest on at least 2 measurements (within 30 minutes of each
other) at Visit 1

- Subject has a significant cardiovascular disease, such as myocardial infarction or a
vascular intervention (e.g. angioplasty or stent) within 3 months prior to Visit 1, or
history of heart failure (New York Heart Association [NYHA] Class III IV)

- Subject is known to have hepatitis or be a carrier of hepatitis B surface antigen
(HBsAg), hepatitis C virus (HCV) antibody (enzyme linked immunosorbent assay [ELISA]
plus confirmatory test), or is known positive for human immunodeficiency virus (HIV)
HIV-1 and/or HIV 2

- Subject is currently receiving an excluded medication (loop-diuretics or systemic
corticosteroids) or has received any other oral anti-diabetic drug except for
metformin within 3 months prior to Visit 1

- Subject has history of lactic acidosis

- Subject has a history of drug or alcohol abuse/dependency within 12 months prior to
Visit 1 as defined in the Diagnostic and Statistical Manual-IV (DSM-IV)

- Subject has had a malignancy in the last 5 years, except for adequately treated basal
or squamous cell carcinoma of the skin or carcinoma in situ of the cervix

- Female subject who is pregnant, lactating or pre-menopausal with positive serum
pregnancy test (hCG) at Visit 1 or has an intention of becoming pregnant

- Subject has an unstable medical or psychiatric illness

- Subject has known or suspected hypersensitivity to ASP1941 or any components of the
formulations used

- Subject has previously received ASP1941

- Subject is concurrently participating in another drug study or has received an
investigational drug within 30 days (or the limit set by national law, whichever is
longer) prior to Visit 1

- Subject has any concurrent illness which, in the opinion of the investigator, may
interfere with treatment or evaluation of safety or completion of this study

- In the investigator's judgment, the subject is unable to adhere to the treatment
regimen, protocol procedures or study requirements