The purpose of this study is to evaluate any preliminary evidence of anticancer activity of pembrolizumab combined with either pemetrexed or abemaciclib when used following surgery and before standard therapy with radiation and temozolomide in patients with newly diagnosed high grade glioma.
Additional aims of the study are to:
- Find out the side effects (good and bad) of pembrolizumab combined with pemetrexed or abemaciclib;
- Evaluate tumor characteristics by collecting brain tumor tissue samples.
- Measure the amount of pembrolizumab, pemetrexed, and/or abemaciclib that gets in the body by collecting blood and cerebrospinal fluid.
- Look at biomarkers (biochemical features that can be used to measure the progress of disease or the effects of a drug) in blood and cerebrospinal fluid if available.