This study is looking at a treatment called *codrituzumab* for kids and young adults who have solid tumors. *Solid tumors* are lumps of cancer cells, and *codrituzumab* is a medicine researchers want to test for safety and side effects. The study will also explore how the body handles this medicine. Participants need to be between 1 and 21 years old and have a tumor that didn’t respond to regular treatments or came back after treatment. It's important that their tumor makes a protein called *GPC3*. This protein will be checked before joining the full study.
- *Study Length*: You might be in this study for a while, including visits to the hospital or clinic.
- *Risks*: There could be side effects from the treatment, which the doctors will monitor closely.
- *Eligibility*: Participants must not be on other cancer treatments or have certain health issues.