This trial is conducted in Europe. The aim of the trial is to investigate the safety, tolerability, pharmacokinetics (the exposure of the trial drug in the body) and pharmacodynamics (the effect of the investigated drug on the body) of insulin 287 in subjects with type 2 diabetes.

Inclusion Criteria:

• Male or female, age between 18 and 64 years (both inclusive) at the time of signing informed consent.
• Subject who is considered to be generally healthy (with the exception of conditions associated with diabetes mellitus), based on the medical history, physical examination, and the results of vital signs, ECG and laboratory safety tests, as judged by the investigator.
• Body mass index between 20.0 and 34.9 kg/m^2 (both inclusive).
• Type 2 diabetes mellitus (as diagnosed clinically) for ≥12 months (365 days).
• No change in insulin treatment regimen during the last 90 days prior to screening.
• Current total daily insulin treatment between 0.3 and 1.0 (I) U/kg/day (both inclusive).

Exclusion Criteria:

• Known or suspected hypersensitivity to trial products or related products.
• Female who is pregnant, breast-feeding, or intending to become pregnant or is of child-bearing potential and not using adequate contraceptive methods (adequate contraceptive measures as required by regulation or practice)(highly effective contraceptive methods are considered those with a failure rate less than 1% undesired pregnancies per year including surgical sterilisation,hormonal intrauterine devices (coil), oral hormonal contraceptives, sexual abstinence or a surgically sterilised partner). Females who are not postmenopausal can participate in the study if they use adequate contraceptive methods. Postmenopausal is defined as women aged <52 years and being amenorrheic for more than one year with serum follicle stimulating hormone (FSH level >40 IU/L or aged ≥ 52 years and being amenorrheic for less than one year and with serum FSH level > 40 IU/L or aged ≥ 52 years being amenorrheic for more than one year.
• Receipt of any investigational medicinal product within 3 months before the screening visit of this trial.
• History of deep leg vein thrombosis or repeated episodes of deep leg vein thrombosis in 1st degree relatives (parents, siblings or children) as judged by the investigator.
• Recurrent severe hypoglycaemia (more than 1 severe hypoglycaemic event within the past 180 days) or hypoglycaemic unawareness as judged by the investigator or hospitalisation for diabetic ketoacidosis within the past 180 days.
• Use of oral antidiabetic drugs (OADs) or GLP-1 receptor agonists (e.g. exenatide, liraglutide) within 3 months prior to screening.