The Purpose of This Study is to Test Any Good and Bad Effects of a Study Drug Called Abemaciclib (LY2835219) in Patients With Recurrent 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 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 whom methotrexate-based chemotherapy is deemed medically not in
the patient's best interest.

Glioma patients:

- Standard of care next generation sequencing via a CLIA certified platform must be
available, or planned and at a minimum include IDH, and RB status.

All cohorts:

- Patients must provide written informed consent prior to any screening procedures.

- Age 18 years or older.

- KPS ≥ 60

- Willing and able to comply with scheduled visits, treatment plan and laboratory tests

- Patient is able to swallow and retain oral medication

- Required baseline laboratory status:

- Hemoglobin > 8 g/dL (SI Units: 80 g/L). Patients may receive erythrocyte
transfusions to achieve this hemoglobin level at the discretion of the
investigator. Initial treatment must not begin earlier than the day after the
erythrocyte transfusion.

- Platelet count ≥ 100 x 10^9/L

- Absolute neutrophil count (ANC) ≥ 1.5 x 10^9/L without growth factor support

- Total bilirubin ≤ 1.5 x upper limit of normal (ULN)

- AST/SGOT and/or ALT/SGPT ≤ 3 x ULN

- Serum Creatinine ≤ 1.5 x ULN

- Stable dose of corticosteroids for > 5 days prior to baseline MRI

- Before starting study treatment, patients must have recovered from toxic effects of
prior therapies (except for residual alopecia or Grade 2 peripheral neuropathy) and at
least 3 weeks must have elapsed since any prior signaling pathway modulators, (e.g.,
EGFR, FGFR, or other tyrosine kinase inhibitors), at least 3 weeks must have elapsed
since temozolomide, 4 weeks must have elapsed since carboplatin or cisplatin, and at
least 6 weeks from nitrosoureas (e.g., BCNU, CCNU). In general, at least 4 weeks must
have elapsed from any other anticancer drug therapy (e.g. bevacizumab).

- Patients must be able to undergo contrast enhanced MRI scans (or contrast enhanced CT
scans for patients unable to tolerate MRI).

- Patients must have shown unequivocal evidence for tumor progression by MRI (or CT for
patients who cannot tolerate MRI) in comparison to a prior scan. The same type of
scan, i.e., MRI (or CT for patients who cannot undergo MRI) must be used throughout
the period of protocol treatment for tumor measurement.

- Life expectancy of greater than 8 weeks

- If a female of childbearing potential, must have a negative serum pregnancy test
within 7 days of the first dose of abemaciclib and agree to use a medically approved
contraceptive method during the treatment period and for 3 months following the last
dose of abemaciclib. If a male, agree to use a reliable method of birth control and to
not donate sperm during the treatment period and for at least 3 months following the
last dose of abemaciclib. Contraceptive methods may include an intrauterine device
[IUD] or barrier method. If condoms are used as a barrier method, a spermicidal agent
should be added as a double barrier protection.

Note: Cases of pregnancy that occur during maternal exposures to abemaciclib should be
reported. If a patient or spouse/partner is determined to be pregnant following abemaciclib
initiation, she must discontinue treatment immediately. Data on fetal outcome and
breast-feeding are collected for regulatory reporting and drug safety evaluation.

- Women must agree not to breast feed while on abemaciclib treatment and for at least
three months following the last dose of study therapy.

Exclusion Criteria:

- No limit on number of prior therapies

- Evidence of significant intracranial hemorrhage

- No other investigational or standard anti-tumor therapy allowed

- Patients must not have a known history of allergic reactions attributed to compounds
of similar chemical or biologic composition.

- Patients must not have a serious preexisting medical condition(s) or uncontrolled
intercurrent illness that would preclude participation in this study (for example,
interstitial lung disease, severe dyspnea at rest or requiring oxygen therapy, history
of major surgical resection involving the stomach or small bowel, or preexisting
Crohn's disease or ulcerative colitis or a preexisting chronic condition resulting in
baseline Grade 2 or higher diarrhea) or psychiatric illness/social situations that
would limit compliance with study requirements.

- Patients who have a personal history of any of the following conditions: syncope of
cardiovascular etiology, ventricular arrhythmia of pathological original (including,
but not limited to, ventricular tachycardia and ventricular fibrillation), or sudden
cardiac arrest.

- HIV-positive patients on combination antiretroviral therapy are ineligible because of
the potential for pharmacokinetic interactions. This applies only to patients who have
a documented history of HIV; HIV testing is not otherwise required.

- Have an active systemic fungal and/or known viral infection (for example, human
immunodeficiency virus antibodies, hepatitis B surface antigen, or hepatitis C
antibodies)

- Patients must not be on EIAEDs

- Females who are pregnant or lactating

- Must abstain from grapefruit juice

- Patients must not have other active concurrent malignancy

- Concurrent treatment on another clinical trial. Supportive care trials or
non-therapeutic trials (i.e. Quality of life) are allowed.