Abemaciclib (LY2835219) in Patients With Recurrent Primary Brain Tumors

Inclusion Criteria: Cohort A specific inclusion: * Histologically confirmed IDHwt, RB intact, grade II or III glioma that has recurred after first line therapy (consisting of at least maximum feasible surgical resection and radiation therapy). There is no limit on the number of prior therapies or types of therapies patients can have received. * Measurable disease on imaging (1cm) or measurable non-enhancing tumor. * At least 12 weeks elapsed since prior radiotherapy Cohort B specific inclusion: * Patients with histologically confirmed glioma of any grade (II-IV) who are planned for a standard of care surgical debulking/resection and for whom participation in this study would not cause a medically unacceptable delay in surgery. * Patients must have relapsed/progressed following therapy (consisting of at least maximum feasible surgical resection and radiation therapy). Cohort C specific Inclusion: * Histologically confirmed IDH mutant glioma, meningioma, schwanomma, PCNSL, ependymoma, or other Primary Brain Tumors that have recurred despite previous standard of care therapy. Because this cohort is, in part, meant to allow patients access to therapy who might not otherwise be eligible for other clinical trials - deviations from standard of care treatment or histological confirmation can be presented to and approved by the Principal Investigator for inclusion in the study. * Histologically confirmed PCNSL that has recurred after prior methotrexate-based chemotherapy or for …