Approximately 400 treatment-naïve LGG participants will be randomized 1:1 to either tovorafenib (Arm 1) or an Investigator's choice of SoC chemotherapy (Arm 2).
Arm 1 (tovorafenib): Treatment cycles will repeat every 28 days in the absence of disease progression. Participants will continue tovorafenib until any of the following occurs: disease progression, unacceptable toxicity, withdrawal of consent to treatment, or end of study.
Arm 2 (Investigator's Choice of SoC Chemotherapy): Participants will receive one of 4 SoC chemotherapy options selected by the treating Investigator: Children's Oncology Group - Vincristine/Carboplatin (COG-V/C) regimen, International Society for Paediatric Oncology - Low-Grade Glioma Vincristine/Carboplatin (SIOPe-LGG-V/C) regimen, vinblastine (VBL) regimen, or monthly carboplatin. The choice of SoC chemotherapy regimen will be selected prior to participant randomization. Treatment will continue until completion of therapy or until any of the following occurs: disease progression, unacceptable toxicity, withdrawal of consent to treatment, or end of study.
Participants who discontinue treatment due to disease progression will have (1) radiographic evidence of disease progression, as determined by the Investigator, or (2) clinical progression, as determined by the Investigator. Investigators are encouraged to discuss cases of clinical progression and early radiographic progression without clinical symptoms with the Sponsor Medical Monitor prior to treatment discontinuation or initiation of a different form of treatment for the malignancy. Participants may continue therapy beyond progressive disease (PD).
Inclusion Criteria:
* Less than 25 years of age with LGG with known activating RAF alteration.
* Histopathologic diagnosis of glioma or glioneuronal tumor.
* At least one measurable lesion as defined by RANO criteria.
* Meet indication for first-line systemic therapy.
Exclusion Criteria:
* Participant has any of the following tumor-histological findings:
1. Schwannoma
2. Subependymal giant cell astrocytoma (Tuberous Sclerosis)
3. Diffuse intrinsic pontine glioma, even if histologically diagnosed as World Health Organization (WHO) Grade I-II
* Participant's tumor has additional pathogenic molecular alterations, including but not limited to a) isocitrate dehydrogenase (IDH) 1/2 mutation, b) Histone H3 mutation, and c) neurofibromatosis Type 1 (NF-1) loss of function alteration.
* Known or suspected diagnosis of NF-1/ neurofibromatosis Type 2 (NF-2).
* Prior or ongoing nonsurgical anticancer therapy for this indication (eg, chemotherapy, oral/IV targeted therapy) including radiation.
