This trial is conducted in Asia. The aim of this trial is to assess the safety, pharmacokinetics (the exposure of the trial drug in the body) and pharmacodynamics (the effect of the investigated drug on the body) of two insulin degludec/insulin aspart (IDegAsp) preparations and two insulin degludec (insulin 454) preparations in healthy Japanese male subjects. IDegAsp 45 (B) and insulin degludec (B) are explorative formulations, not similar to the proposed commercial formulations.

Inclusion Criteria:

• Healthy Japanese male subjects
• Body mass index (BMI) between 18.0 and 27.0 kg/m^2 (both inclusive)
• Body weight above or equal to 50 kg

Exclusion Criteria:

• The receipt of any investigational drug within 16 weeks prior to this trial (the planned first dosing)
• Any clinical laboratory values deviated from the reference range at the laboratory (except for cases within physiological change) or any abnormal electrocardiogram (ECG) findings at the screening, as judged by the investigator or sub-investigator
• Known or suspected allergy to trial product(s) or related products