- Subjects fulfilling at least one of the below criteria: a) Experienced at least one severe hypo episode within the last year (according to the ADA (American Diabetes Association) definition, April 2013) b) Moderate chronic renal failure, defined as glomerular filtration rate 30 - 59 mL/min/1.73 m^2 per CKD-Epi (chronic kidney disease epidemiology collaboration) c) Hypoglycaemic symptom unawareness d) Diabetes mellitus duration for more than 15 years e) Recent episode of hypoglycaemia (defined by symptoms of hypoglycaemia and/or episode with low glucose measurement (below or equal to 70 mg/dL [below or equal to 3.9 mmol/L])) within the last 12 weeks prior to Visit 1 (screening)