This clinical trial is focused on studying the safety of a medication called Rapamycin in children who have a condition known as Familial Adenomatous Polyposis. Familial Adenomatous Polyposis is a genetic disorder that causes the growth of numerous polyps in the colon and rectum, which can lead to cancer if not treated. The medication being tested, Rapamycin, is taken in the form of coated tablets and is intended to help manage this condition.

The purpose of the study is to evaluate how safe Rapamycin is for adolescents aged 12 to 17 who have been diagnosed with Familial Adenomatous Polyposis. Participants in the study will receive one of two doses of Rapamycin. Throughout the study, the safety of the medication will be closely monitored by checking for any adverse events, which are unwanted effects that might occur during or after taking the medication. The study will also involve regular colonoscopies, which are procedures that allow doctors to look inside the colon to see how the polyps are changing over time.

The study will last for several months, during which participants will take Rapamycin and undergo various assessments to ensure their safety and to observe any changes in the polyps. The results from these assessments will help researchers understand the safety profile of Rapamycin in treating Familial Adenomatous Polyposis in young patients. This information could be valuable in developing effective treatments for this condition in the future.