Recent-Onset Type 1 Diabetes Trial Evaluating Efficacy and Safety of Teplizumab

1. Is 8 to 17 years of age, inclusive, at the time of randomization/initiation of study drug administration.

2. Has received a diagnosis of type 1 diabetes (T1D) according to the criteria from the American Diabetes Association.

3. Is able to be randomized and initiate study drug within 6 weeks (42 days) of the formal T1D diagnosis.

4. Has a peak stimulated C-peptide of ≥0.2 pmol/mL from a mixed meal tolerance test (MMTT) at screening.

5. Has a positive result on testing for T1D-related autoantibodies.

1. Has any autoimmune disease other than T1D with the exception of stable thyroid or celiac disease.

2. Has an active infection and/or fever.

3. Has a history of or serologic evidence at screening of current or past infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV), or hepatitis C virus (HCV).

4. An individual who has a medical, psychological or social condition that, in the opinion of the Principal Investigator, would interfere with safe and proper completion of the trial.