Study of the Effects of XOMA 052 on Insulin Production in Subjects With Well Controlled Type 1 Diabetes

Inclusion criteria: * Stable Type 1 diabetes of \> 2 year duration * No clinically significant change in treatment regimen for T1D * Age ≥ 18 years and ≤ 55 years * HbA1c \< 7.0% * Positive GAD65 and/or IA-2 auto-antibodies * Peak C-peptide \> 100 pM following IV injection of 1 mg glucagon * Body-mass index (BMI) \> 18 and \< 28 kg/m2 * Willingness to maintain current doses/regimens of vitamins and dietary supplements through the end of the study Exclusion criteria: * Current infection or history of infection * Positive for Hep B surface antigen (HBsAg), Hep C virus (HCV), or HIV * History of tuberculosis or positive PPD test * Presence of foot, leg, or decubitus ulcers * Current immunosuppressive treatment or documented immunodeficiency * History of severe allergic or anaphylactic reactions * History of asthma requiring systemic corticosteroid therapy * Coronary intervention (PCI, stent placement) or hospitalization for cardiovascular condition within the last 12 months * Uncontrolled hypertension * History of congestive heart failure (NYHA Class III or IV) * History of a coronary event within the last 12 months * Female subjects who are pregnant, planning to become pregnant, have recently delivered, or are breast-feeding * History of malignancy within the last 5 years * Receipt of a live (attenuated) vaccine within the last 3 months Other protocol-defined inclusion/exclusion criteria may apply