This study compares two treatments for patients with a condition called neurofibromatosis type 1 (NF1) and low-grade glioma (LGG), a type of brain tumor. The two treatments are **Selumetinib**, a drug that blocks enzymes to stop tumor growth, and **Carboplatin/Vincristine (CV)**, which are chemotherapy drugs that kill or stop the growth of tumor cells. The trial aims to see if Selumetinib is as effective as CV and if it helps improve vision in patients with tumors in the optic pathway (vision nerves).

• The study lasts several years, with follow-ups up to 10 years.
• Patients will be assigned to one of two groups to receive one of the treatments.
• Regular MRI scans and health check-ups will be part of the study.

To join, patients need to be 2 to 21 years old, have NF1, and meet certain health criteria. They should not have received other treatments for their tumor besides surgery. Females must not be pregnant, and both males and females must agree to use contraception. The study is to learn more about the effectiveness of these treatments and their impact on quality of life and vision.