Bioavailability, Biopotency and Food Effect Study of SCD0503 Compared to Subcutaneous Regular Human Insulin

Inclusion Criteria: * Male person with type 1 diabetes mellitus * Age between 18 and 64 years, both inclusive * Body Mass Index (BMI) between 18.5 and 29.9 kg/m2, both inclusive * HbA1c ≤ 8.5% * Fasting C-peptide \<= 0.20 nmol/L * Total insulin dose of \<1.2 (I)U/kg/day * Diabetes duration of at least 12 months at the time of screening * Stable insulin regimen for at least 2 months prior to inclusion into the trial Exclusion Criteria: * Systolic blood pressure \< 90 mmHg or \>139 mmHg and/or diastolic blood pressure \< 50 mmHg or \> 89 mmHg * Heart rate at rest outside the range of 50- 90 beats per minute * Clinically significant abnormal standard 12-lead electrocardiogram (ECG) after 5 minutes resting in supine position at screening * Proliferative retinopathy or maculopathy as judged by the investigator based on a recent (\<1 year) ophthalmologic examination * Peripheral neuropathy * More than one episode of severe hypoglycaemia with seizure, coma or requiring assistance of another person during the past 6 months pior to screening * Hospitalisation for diabetic ketoacidosis during the previous 6 months prior to screening * Significant history of alcoholism or drug abuse * Smoking more than 5 cigarettes or the equivalent per day * Tested positive for hepatitis Bs antigen * Tested positive for hepatitis C antibodies * Positive result to the test for HIV-1/2 antibodies or HIV-1 antigen * Estimated glomerular filtration rate (eGFR) \< 60.0 mL/min/1.73m2