This is a single centre, randomised, double-blind, double-dummy, 3-treatment, 3-period cross-over, euglycaemic clamp study in subjects with type 2 diabetes on stable insulin treatment. Each subject will be randomly allocated to a treatment sequence and will be administered single subcutaneous doses of 0.8 U/kg Biochaperone® Combo, 0.8 U/kg Humalog® Mix25 or simultaneous subcutaneous injections of 0.2 U/kg Humalog® and 0.6 U/kg Lantus® during three separate dosing visits.

Inclusion Criteria:

• Type 2 diabetes mellitus (as diagnosed clinically) for ≥ 12 months
• HbA1c levels ≤ 9.0%
• Total insulin dose of < 1.2 U/kg/day
• Body mass index between 20.0 and 35.0 kg/m2 (both inclusive)
• Body weight ≤ 125.0 kg
• Fasting serum C-peptide ≤ 1 nmol/L
• Treated with a stable insulin regimen for ≥ 3 months prior to screening

Exclusion Criteria:

• Type 1 diabetes mellitus
• Known or suspected allergy to the trial products or related products
• Previous participation in this trial. Participation is defined as randomised
• Participation in any clinical trial within 3 months prior to this trial
• Clinically significant abnormal haematology, biochemistry, lipids, or urinalysis screening tests, as judged by the Investigator considering the underlying disease
• Supine blood pressure at screening outside the range of 90-160 mmHg for systolic or 50-95 mmHg for diastolic and/or resting supine heart rate outside the range 50 -90 beats per minute. This exclusion criterion also pertains to subjects being on antihypertensives
• Use of GLP-1 receptor agonists or oral antidiabetic drugs (OADs) other than stable intake of metformin within 4 weeks prior to screening
• Women of child bearing potential, not willing to use contraceptive methods