The purpose of this study is to find out if baricitinib can preserve beta-cell function in participants newly diagnosed with type 1 diabetes. Participation in the study will last about 60 weeks.

Inclusion Criteria:

• Have a new diagnosis of type 1 diabetes within 100 days prior to starting study intervention

• Have at least one diabetes-related autoantibody found at screening

• Show signs of remaining beta-cell function

  • stimulated (peak or 90 min) C-peptide ≥0.2 nmol/L (0.6 ng/mL) at screening

• Weigh at least 8 kilograms (kg) (18 pounds) at screening

Exclusion Criteria:

• Have any other type of diabetes including gestational
• Have uncontrolled high blood pressure
• Have had a heart attack, heart disease, stroke, or heart failure
• Have a history or high risk of venous thromboembolism, lymphoproliferative disease or malignancy
• Have a current or recent clinically serious medical condition or infection

Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.

Data are available 6 months after the primary publication or approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.

A research proposal must be approved by an independent review panel and researchers must sign a data sharing agreement.