Gastric Modulator (TANTALUS® System) Versus Insulin Treatment in Obese Type 2 Diabetic Patients - a Randomized Control Trial

Inclusion Criteria: * Able to provide written informed consent * Adult patients aged between 18 and 60 years (inclusive) * Male or female of Chinese ethnicity * Type 2 diabetes mellitus with disease duration of greater than 2 and less than 10 years * severe obesity, includes BMI 25 to 27.5 kg/m and central obesity defined by waist circumference greater than 90 cm in women and greater than 95 in men, or BMI greater than 27.5 to less than 35 kg/m * HbA1c greater than or equals to 7.5% but less than 10% despite treated with maximum dose or maximally tolerated dose of 2 anti-diabetic drugs (OAD) with good drug compliance Exclusion Criteria: * On anti-obesity drugs * On insulin treatment at the time of the recruitment * On glitazone or incretins (dipeptidyl peptidase-4 inhibitor or glucagons-like peptide-1) treatment * On any implantable device including cardiac pacing * Anticipated to have MRI examinations * Fasting C-peptide level less than 0.5g/L * Renal impairment (defined as serum creatinine greater than 150mol/L and/or estimated glomerular filtration rate less than 60 mL/min/1.73m) * Significant liver impairment (ALT more than 3 times upper limit of normal range) * Active malignant disease. Patients with malignant disease who have been disease-free for at least 5 years are eligible * Active infection * Active and uncontrolled thyroid diseases * Childbearing age female patients without reliable contraceptive methods * Life expectancy less than 12 months * Administration of another investigational drugs or procedures within 4 weeks before screening * Any medical illness or condition as judged by the investigators as ineligible to participate the study * Special population, e.g. prisoner, mentally disabled, investigators' student or employees