This study is testing medicines called JAK Inhibitors for people with new Type 1 Diabetes (T1D). JAK inhibitors are medicines that can help the body by stopping some actions of the immune system that are harmful. There are two medicines being tested: abrocitinib and ritlecitinib. Some people will get these medicines, and others will get a placebo, which is a pill that doesn't have any medicine in it. The study is "double-blind," meaning neither the doctors nor the participants will know who is getting the medicine or the placebo. This helps keep the results fair.

The study will last at least 12 months, with another 12 months of follow-up. Participants need to be between 12 and 35 years old and have been diagnosed with T1D within the last 100 days. They must also meet other health criteria to join.

• Participants will receive free diabetes care and health check-ups during the study.
• The study requires regular visits to the clinic for tests and monitoring.
• Participants must avoid certain medications and conditions to ensure safety.