**Ziftomenib Study for Childhood Leukemia** This study is testing a new combination of drugs for children with a type of blood cancer called leukemia. The main goal is to find the best dose of a drug called ziftomenib when used with chemotherapy. The study is for kids whose leukemia has come back (relapsed) or hasn't responded to other treatments (refractory). Children aged 0-21 years can join, but most will be under 18. Participants must have certain types of leukemia confirmed by genetic tests. They also need to meet health requirements, such as good organ function and recovery from past treatments. Girls who can have babies need a negative pregnancy test, and all participants must agree to use birth control during and after the study. **Key Points:** - **Participation Length:** The study involves multiple visits over several months. - **Eligibility:** Must meet health and genetic criteria; some past treatments are allowed. - **Risks:** Includes side effects from new drug combinations and chemotherapy. Kids with certain types of leukemia might benefit from new treatment options, but there are risks involved. Families should discuss with doctors before joining the study.