Study Comparing Abemaciclib and Temozolomide to Temozolomide Alone in Children and Young Adults with High-Grade Glioma After Radiation Therapy

Inclusion Criteria

• Diagnosed with high-grade glioma (HGG) based on specific medical criteria, including types like anaplastic astrocytoma and glioblastoma.
• Recent radiation therapy started within 6 weeks of diagnosis and completed 4 to 8 weeks before starting the study treatment.
• Good overall health with a life expectancy of at least 8 weeks and likely to complete at least one treatment cycle.
• Able to swallow or use a feeding tube.
• Stable or decreasing dose of any current steroid use at least 7 days before starting treatment.
• Willing to follow study procedures, including regular blood tests and MRI scans.
• At least 28 days since any major surgery or significant injury.
• Body surface area of at least 0.2 m².

Exclusion Criteria

• Have a type of brain tumor called Diffuse Intrinsic Pontine Glioma (DIPG) or similar tumors in the pons area of the brain.
• Tumor has returned or not responded to previous treatments, including radiation.
• Previously treated low-grade glioma that has now become high-grade.
• Have specific genetic mutations that can be treated with other available therapies.
• Have had other treatments for high-grade glioma, except surgery and radiation.
• Currently in another clinical trial that conflicts with this study.
• Have taken an investigational drug recently.
• Have had another cancer in the past 3 years that could affect study results.
• Have a serious medical condition that would prevent participation.
• Have an active infection requiring IV treatment, including certain viral infections.
• Allergic to temozolomide, abemaciclib, or similar drugs.
• Have received a live vaccine recently.
• Pregnant, breastfeeding, or planning to become pregnant during the study.