The purpose of this study is to find the right dose of ONC206 that can be given safely to patients and to check whether the medication reaches the tumor tissue in the brain. The study is divided into different groups based on the type of tumor and previous treatments. Some patients will receive ONC206 alone, while others will receive it together with radiation therapy, which is a treatment that uses high-energy rays to target cancer cells. Some participants will receive ONC206 with a second course of radiation therapy if their tumor has grown back. There is also a part of the study that will measure how much of the medication gets into the tumor tissue by comparing it to the levels found in the blood before surgery.

During the study, patients will take ONC206 regularly and will have blood tests to check how the body processes the medication and to monitor for any side effects. Patients will also have imaging scans to see how the tumor responds to treatment. Some participants will need to provide tumor tissue samples that were collected during their standard medical care so researchers can study how the medication works in the tumor. The study will continue to monitor patients over time to gather information about safety and how well the treatment works.

The purpose of the study is to determine if certain treatment combinations can improve the chances of removing the tumor completely and increase the time patients remain free from disease progression. The study will also compare different chemotherapy schedules to see which is more effective for patients with tumors that could not be completely removed by surgery. For some patients, the study will assess the benefits of adding sodium valproate to the treatment plan, especially for those who cannot receive radiation therapy.

Participants in the study will undergo a series of treatments over several weeks, which may include surgery, chemotherapy, and possibly radiation therapy. The study will monitor the patients’ progress through regular medical assessments, including MRI scans, to evaluate the effectiveness of the treatments. The trial is designed to gather information that could lead to better treatment options for ependymoma in the future.

The purpose of the study is to find out which combination of these treatments is safe and effective for young patients with these challenging types of cancer. In the first stage of the study, researchers will determine which of the three chemotherapy regimens is safe to use with Nivolumab. The regimens being tested are: Cyclophosphamide and Vinblastine; Capecitabine alone; and a combination of Cyclophosphamide, Vinblastine, and Capecitabine. In the second stage, the study will focus on the most promising regimen from the first stage, with or without Nivolumab, to see how well it works in preventing the cancer from getting worse.

Participants in the study will receive their treatments either through an intravenous method, which means the medication is given directly into a vein, or orally, which means taking the medication by mouth. The study will monitor the participants over time to assess the safety of the treatments and their effectiveness in controlling the cancer. The study aims to provide valuable information that could lead to better treatment options for children and teenagers facing these difficult cancers.