A Research Study Comparing a New Medicine Oral Semaglutide to Sitagliptin in People With Type 2 Diabetes

This study compares 2 medicines for type 2 diabetes: oral semaglutide (a new medicine) and sitagliptin (a medicine doctors can already prescribe). Participants will either get oral semaglutide or sitagliptin ‐ which treatment is decided by chance. Participants will get 2 tablets a day to take first thing in the morning on an empty stomach. Only 1 tablet has study medicine in it. The other tablet is a dummy medicine (placebo). After taking the semaglutide tablet, participants may not eat or drink anything for at least 30 minutes. After the 30 minutes, participants must take the sitagliptin tablet. Then participants can have their first meal of the day and take any other medicines they may need, including their metformin. The study will last for about 7 months (33 weeks). Participants will have 8 clinic visits and 1 phone call with the study doctor. At all 8 of the clinic visits, participants will have blood samples taken.