This is a 24-week randomized placebo-controlled study to investigate the effect of an oral IL-1beta inhibitor AC-201 in patients with type 2 diabetes mellitus already treated on different background diabetes therapies.

Inclusion Criteria:

• Understanding of the study procedures and agreement to participate in the study by giving written informed consent
• Males and females age 20 to 75 years, inclusive
• HbA1c ≥7.5% and ≤10%
• BMI ≤45 kg/m2
• FPG ≤270 mg/dL
• Diagnosis of type 2 diabetes mellitus for ≥6 months
• On a stable regimen of oral anti-diabetic medications for ≥3 months
• Willingness to maintain stable diet and exercise throughout the study
• Willingness to maintain current doses/regimens of vitamins and dietary supplements throughout the study
• Female patients of childbearing potential and female partners of male patients must be willing to use adequate contraception during the study. All females of childbearing potential must have a negative urine pregnancy test at screening.

Exclusion Criteria:

• History of type 1 diabetes and/or history of ketoacidosis
• History of diabetic neuropathy resulting in significant functional impairment and/or requiring active medical or surgical management, including chronic pain syndromes, gastroparesis, skin ulceration, or amputation
• History of long-term therapy with insulin (>30 days) within 1 year of screening;
• Pregnancy or lactation
• Current treatment with any of the following medications within 2 months of screening
• Anti inflammatory drugs, including chronic daily use of systemic corticosteroids (aspirin ≤325 mg per day is allowed)
• IL-1 modulators: anakinra and rilonacept
• Immunosuppressive drugs: TNF inhibitors and IL-6 monoclonal antibody
• History of severe hypoglycemic episodes within 6 months of screening
• Hypersensitivity to AC-201 or anthraquinone derivatives
• Surgery within 30 days prior to screening
• Serum creatinine >1.5 mg/dL for males or >1.4 mg/dL for females
• Presence of cancer or history of cancer within the past 5 years other than basal or squamous cell carcinoma of the skin and carcinoma in situ of the cervix
• Advanced stage heart failure: New York Heart Association Class III or IV cardiac status or hospitalization for congestive heart failure
• History of unstable angina, myocardial infarction, uncontrolled arrhythmias, cerebrovascular accident, transient ischemic attack, or any revascularization, including percutaneous transluminal coronary angioplasty, within 6 months of screening
• Uncontrolled hypertension (defined as systolic blood pressure >160 mmHg or diastolic blood pressure >100 mmHg on ≥3 assessments at screening)
• Known to be infected with human immunodeficiency virus (HIV)
• History of acquired immune deficiency syndrome
• History of TB, active TB (pulmonary, extra-pulmonary, or military), or a positive test for TB confirmed by a PA chest x-ray within 6 months prior to screening
• History of acute infection with Epstein-Barr Virus (EBV), cytomegalovirus (CMV), or hepatitis C virus (HCV) within 4 weeks prior to screening
• History of chronic active (not latent) hepatitis B virus, HCV, or CMV infection;
• History of drug or alcohol abuse
• Aspartate aminotransferase >3 × the upper limit of normal (ULN) or alanine aminotransferase >3 × ULN at screening
• Total bilirubin >1.5 × ULN at screening
• Triglycerides >500 mg/dL at screening
• Poor mental function or any other reason to expect patient difficulty in complying with the study requirements
• Acute infections that may affect blood glucose control within 4 weeks prior to screening
• Known bilateral renal artery stenosis, patient with a solitary kidney, or a post renal transplant
• History of autoimmune disease or collagen vascular disease
• History of hyperthyroidism or hypocorticism
• Participation in any AC-201 studies within 1 year prior to screening
• Participation in an investigational drug study within 30 days prior to screening
• Any other serious diseases which, in the opinion of the investigator, might pose a risk to the patient or make participation not in the patient's best interest.