Tresiba has been studied in three main studies involving 1,578 adults with type 1 diabetes, where Tresiba (in combination with rapid acting mealtime insulin) was compared with insulin glargine or insulin detemir (other long acting insulins).

Six other main studies involving 4,076 adults with type 2 diabetes compared Tresiba with insulin glargine, insulin detemir or sitagliptin (a medicine taken by mouth for type 2 diabetes). Patients in these studies could also be given other diabetes medicines or rapid-acting insulin at mealtimes if needed. Another main study involving 177 adults with type 2 diabetes investigated the effectiveness of combining Tresiba and liraglutide (a GLP-1 receptor agonist).

In addition Tresiba was compared with insulin detemir in one main study involving 350 children aged 1 to 18 years of age with type 1 diabetes. Patients were also given rapid-acting insulin at mealtimes. After 26 weeks of treatment, patients had the option to either stop treatment or continue with it for up to a year.

All of the studies measured the level of a substance in the blood called glycosylated haemoglobin (HbA1c), which is the percentage of haemoglobin in the blood attached to glucose. HbA1c gives an indication of how well the blood glucose is controlled. Studies lasted for six months or one year.