This clinical trial is focused on studying treatments for children and adolescents with solid tumors, which are abnormal masses of tissue that can occur in various parts of the body. The study involves two medications: niraparib and dostarlimab. Niraparib is taken orally in the form of tablets, while dostarlimab is given through an intravenous infusion, which means it is delivered directly into the bloodstream through a vein.
The purpose of the study is to find the best dose of these medications when used together in young patients. The study is divided into different parts. Initially, participants will receive increasing doses of the medications to determine the safest and most effective dose. After establishing the right dose, more participants will receive this dose to further understand how well the treatment works and how the body responds to it.
Throughout the study, participants will be closely monitored by healthcare professionals to ensure their safety and to observe any effects of the treatment. The study aims to provide valuable information that could help improve treatment options for children and adolescents with solid tumors in the future.



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