Comparison of Biphasic Insulin Aspart 30 Individually Adjusted by the Subject and the Trial Physician, Respectively, Both Combined With Metformin in Subjects With Type 2 Diabetes (SimpleMix™)

• Change in fasting plasma glucose (FPG) (central laboratory values) [ Time Frame: Week 0, week 20 ] [ Designated as safety issue: No ]
• Number of hypoglycaemic episodes [ Time Frame: from week 0 to week 20 ] [ Designated as safety issue: No ]
• Patient Reported Outcomes evaluated: Treatment-Related Impact Measures for Diabetes (TRIM-D) [ Time Frame: Weeks 0, 4 and 20 ] [ Designated as safety issue: No ]

This trial is conducted in Asia, Europe and South America. The aim of this trial is to confirm efficacy of subject driven titration (individually adjusted) of biphasic insulin aspart 30 twice daily in terms of glycaemic control assessed by change in glucosylated haemoglobin (HbA1c).

• Diabetes
• Diabetes Mellitus, Type 2

• Experimental: Subject-driven group
  Intervention: Drug: biphasic insulin aspart 30
• Active Comparator: Investigator-driven group
  Intervention: Drug: biphasic insulin aspart 30

Inclusion Criteria:

• Diagnosed with type 2 diabetes for a minimum of 12 months prior to Visit 1 (screening)
• Currently treated with a basal insulin analogue for at least 3 months prior to Visit 1 (screening)
• Stable treatment (no change in dose or regimen) with a total daily dose of at least 1500 mg metformin or maximum tolerated dose (minimum 1000 mg) ± additional OAD treatment. The metformin treatment must have been stable for at least 2 months prior to Visit 1 (screening)
• HbA1c higher or equal to 7.0% and below or equal to 10.0% (one re-test within one week of screening visit is allowed. The last sample will be conclusive)
• Body Mass Index (BMI) below or equal to 40.0 kg/m^2
• Able and willing to eat at least 2 main meals each day during the trial
• Able and willing to adhere to the protocol including compliance with performance of self measured plasma glucose (SMPG), injection regimen and titrating themselves according to the protocol
• Experience in performing self measured plasma glucose (SMPG)

Exclusion Criteria:

• Treatment with any thiazolidinedione (TZD) and glucagon-like peptide-1 (GLP-1) receptor agonists or pramlintide within the last 3 months prior to Visit 1 (screening)
• Impaired hepatic function defined as alanine aminotransferase (ALAT) above or equal to 2.5 times upper referenced limit (one re-test within one week of screening visit is allowed. The last sample will be conclusive)
• Impaired kidney function with serum creatinine above or equal to 133 µmol/L (1.5 mg/dL) for males and above or equal to 124 µmol/L (1.4 mg/dL) for females (one re-test within one week of screening visit is allowed. The last sample will be conclusive)
• Cardiac problems or uncontrolled treated/untreated severe hypertension (defined as systolic blood pressure higher or equal to 180 mmHg and/or diastolic blood pressure higher or equal to 100 mmHg)
• Previous use of pre-mixed insulin products (pre-mixed insulin analogues or pre-mixed human preparations) or bolus insulin. Previous use of pre-mixed or bolus insulin products is allowed only in case of hospitalisation or a severe condition requiring intermittent use of pre-mixed or bolus insulin products for less than 14 consecutive days, but not during the last 3 months prior to screening visit (Visit 1)