Trial of Otelixizumab for Adolescents and Adults With Newly Diagnosed Type 1 Diabetes Mellitus (Autoimmune): DEFEND-2

Inclusion Criteria: * Ages 12-17 * Diagnosis of diabetes mellitus, consistent with ADA criteria * No more than 90 days between diagnosis and administration of study compounds * Requires insulin for type 1 diabetes mellitus, or has required insulin at some time between diagnosis and administration of study compounds. In Canada, has to be using insulin at the time of dosing. * Stimulated C-peptide level greater than 0.20 nmol/L and less than or equal to 3.50 nmol/L * Positive for one or more of the autoantibodies typically associated with T1DM: antibody to glutamic acid decarboxylase (anti-GAD); antibody to protein tyrosine phosphatase-like protein (anti-IA-2); zinc transporter autoantibodies (ZNT8); insulin autoantibodies (IAA). A subject who is positive for insulin autoantibodies (IAA) and negative for the other autoantibodies will only be eligible if the subject has used insulin for less than 7 days total. Exclusion Criteria: •Other, significant medical conditions based on the study doctor's evaluation