Study Overview: This clinical trial is testing a new treatment called NEO100 (perillyl alcohol) for patients with certain types of brain tumors, specifically Grade III or IV gliomas with IDH1 mutations. The trial is divided into two phases, Phase 1 and Phase 2a, to evaluate the treatment's safety, how the body processes it, and its effectiveness.

Important Terms: "Glioma" is a type of brain tumor. "IDH1 mutation" is a change in a specific gene that can affect how the tumor behaves. "Pharmacokinetics" refers to how a drug is absorbed, distributed, and removed from the body.

• Participants will self-administer NEO100 through the nose four times a day for 28-day cycles, until the disease worsens or they choose to leave the study.
• This study includes frequent monitoring and requires participants to follow specific guidelines about previous cancer treatments and overall health.
• Potential risks include possible side effects from NEO100, interaction with other medications, and the study requirements may be demanding.

This trial aims to provide a new treatment option for brain cancer, focusing on patients whose tumors have a specific genetic mutation that might respond better to this therapy. Participants should discuss with their doctor if this is right for them based on their health and treatment history.