• Patients must be \>= 2 years and =\< 21 years at the time of enrollment

• Patients must have a body surface area (BSA) of \>= 0.5 m\^2 at enrollment

• Patients must have non-neurofibromatosis type 1 (non-NF1) low-grade glioma (LGG) without a BRAFV600E mutation as confirmed by Rapid Central Pathology and Molecular Screening Reviews performed on APEC14B1 (NCT02402244) Childhood Cancer Data Initiative (CCDI)-MCI, or accepted Clinical Laboratory Improvement Amendments (CLIA)-certified test and that has not been treated with any modality besides surgery. Note: Patients may be newly-diagnosed OR previously diagnosed, and there is no required time frame between biopsy/surgery and treatment initiation.

‣ Patients with residual tumor after resection or progressive tumor after initial diagnosis (with or without surgery) who have not received treatment (chemotherapy and/or radiation) are eligible

⁃ Patients must have two-dimensional measurable tumor \>= 1 cm\^2 to be eligible

⁃ Patients with ependymoma are not eligible

• Eligible histologies will include all tumors considered low-grade glioma or low-grade astrocytoma (World Health Organization \[WHO\] grade I and II) by 5th edition WHO classification of central nervous system (CNS) tumors with the exception of subependymal giant cell astrocytoma

• Patients with metastatic disease or multiple independent primary LGG are eligible

• Creatinine clearance or radioisotope glomerular filtration rate (GFR) \>= 70 mL/min/1.73 m\^2 OR a serum creatinine based on age/sex as follows (performed within 7 days prior to enrollment):

‣ Age: Maximum Serum Creatinine (mg/dL)

⁃ 2 to \< 6 years: 0.8 mg/dL (male); 0.8 mg/dL (female)

⁃ \>= 16 years: 1.7 mg/dL (male); 1.4 mg/dL (female)

• Total bilirubin =\< 1.5 x upper limit of normal (ULN) for age (performed within 7 days prior to enrollment) (children with a diagnosis of Gilbert's syndrome will be allowed on study regardless of their total and indirect \[unconjugated\] bilirubin levels as long as their direct \[conjugated\] bilirubin is \< 3.1 mg/dL)

• Serum glutamic pyruvic transaminase (SGPT) (alanine aminotransferase \[ALT\]) =\< 135 U/L (performed within 7 days prior to enrollment). For the purpose of this study, the ULN for SGPT is 45 U/L

• Albumin \>= 2 g/dL (performed within 7 days prior to enrollment)

• Left ventricular ejection fraction (LVEF) \>= 53% (or institutional normal; if the LVEF result is given as a range of values, then the upper value of the range will be used) by echocardiogram (performed within 4 weeks prior to enrollment)

• Corrected QT (QTc) interval =\< 450 msec by electrocardiography (EKG) (performed within 4 weeks prior to enrollment)

• Absolute neutrophil count \>= 1,000/uL (unsupported) (performed within 7 days prior to enrollment)

• Platelets \>= 100,000/uL (unsupported) (performed within 7 days prior to enrollment)

• Hemoglobin \>= 8 g/dL (may be supported) (performed within 7 days prior to enrollment)

• Patients with a known seizure disorder must be stable and must not have experienced a significant increase in seizure frequency within 2 weeks prior to enrollment

• Patients 2-17 years of age must have a blood pressure that is =\< 95th percentile for age, height, and sex at the time of enrollment (with or without the use of anti-hypertensive medications)

• Patients \>= 18 years of age must have a blood pressure =\< 130/80 mmHg at the time of enrollment (with or without the use of anti-hypertensive medications)

• Note for patients of all ages: Adequate blood pressure can be achieved using medication for the treatment of hypertension

• All patients must have ophthalmology toxicity assessments performed within 8 weeks prior to enrollment

• For all patients, a magnetic resonance imaging (MRI) of the brain (with orbital cuts for optic pathway tumors) and/or spine (depending on the site(s) of primary disease) with and without contrast must be performed within 8 weeks prior to enrollment

• Patients must have a performance status corresponding to Eastern Cooperative Oncology Group (ECOG) scores of 0, 1, or 2. Use Karnofsky for patients \> 16 years of age and Lansky for patients =\< 16 years of age

• Patients must have the ability to swallow whole capsules

• All patients have signed an appropriate consent form and Health Insurance Portability and Accountability Act (HIPAA) authorization form (if applicable)

• All patients and/or their parents or legal guardians must sign a written informed consent

• All patients have been consented and enrolled on APEC14B1 (NCT02402244) followed by enrollment on the ACNS1833 Pre-Enrollment Eligibility Screening (Step 0) on the same day to complete the Rapid Central Review

• All institutional, Food and Drug Administration (FDA), and National Cancer Institute (NCI) requirements for human studies must be met