The primary purpose of the protocol is to demonstrate that the new regimen (insulin glargine+regular insulin ) is no worse than the reference regimen (insulin glargine+lys-pro insulin ) in reducing the incidence of severe nocturnal hypoglycemia at the end point; the secondary purpose is to compare the two study regimens as far as the glycemic control (measured by HbA1c), the daily Mean Blood Glucose (MBG) and the mean amplitude of glycemic excursion (MAGE index), calculated on the basis of Self Monitoring Blood Glugose (SMBG) data, are concerned and to verify the safety of basal insulinization with Lantus.