This study tests a medicine called **poly-ICLC** (also known as Hiltonol®) for children with a type of brain tumor called **low-grade gliomas (LGG)**. The study focuses on kids who have a genetic condition called **Neurofibromatosis type 1 (NF1)**. To join, kids must be under 22 years old and meet specific health criteria. The study lasts for 48 weeks with treatments every 4 weeks, totaling 12 cycles. It will check if poly-ICLC helps shrink the tumor. Doctors will also look at how long it takes for the tumor to grow back, if there are any changes in vision for those with certain types of tumors, and if there are any side effects. The study requires children to have had at least one previous treatment for their tumor.

• **Length**: 48 weeks (12 cycles of treatment)
• **Eligibility**: Must be under 22, specific health conditions apply
• **Risks**: Possible side effects from the treatment