Phase 3 Alogliptin Pediatric Study

The drug being tested in this study is called alogliptin. Alogliptin is being tested to treat children 10 to 17 years of age who have T2DM and are experiencing inadequate glycemic control. This study will look at HbA1c fluctuations in children who take alogliptin in addition to their background antidiabetic therapy. The study will enroll approximately 150 participants. Participants will be randomly assigned (by chance, like flipping a coin) to one of the two treatment groups-which will remain undisclosed to the participant and study doctor during the study (unless there is an urgent medical need): * Alogliptin 25 mg * Placebo (dummy inactive pill) - this is a tablet that looks like the tablet containing alogliptin 25 mg but has no active ingredient (that is, has no alogliptin). All participants will be asked to take one tablet at the same time each day throughout the study in addition to their current background antidiabetic therapy (metformin and/or insulin) if applicable. This multi-center trial will be conducted worldwide. The overall time to participate in this study is approximately 56 weeks. Participants will make multiple visits to the clinic, and will be contacted by telephone 2 weeks after the last dose of study drug for a follow-up assessment.