Buparlisib (BKM120) In Patients With Recurrent/Refractory Primary Central Nervous System Lymphoma (PCNSL) and Recurrent/Refractory Secondary Central Nervous System Lymphoma (SCNSL)

Inclusion Criteria

• Participants must be able to understand and be willing to sign a written informed consent document.
• Subjects must be at least 18 years of age on the day of consenting to the study.
• Histologically documented PCNSL or SCNSL. Patients with SCNSL need to have cytology or tissue biopsy documenting lymphomatous involvement of the CNS
• Patients must have relapsed/refractory PCNSL or relapsed/refractory SCNSL
• All patients need to have received at least one prior CNS directed therapy. There is no restriction on the number of recurrences.
• Patients with parenchymal lesions must have unequivocal evidence of disease progression on imaging (MRI of the brain or head CT) 21 days prior to study registration. For patients with leptomeningeal disease only, CSF cytology must document lymphoma cells and/or imaging findings consistent with CSF disease 21 days prior to study registration.
• Participants must have a Karnofsky performance status (KPS) of ≥ 50.
• Participants must have adequate bone marrow and organ function shown by:

Absolute neutrophil count (ANC) ≥ 1.5x 109/L

• Platelets ≥ 100 x 109/L and no platelet transfusion within the past 14 days prior to study registration
• Hemoglobin (Hgb) ≥ 9 g/dL and no red blood cell (RBC) transfusion within the past 14 days prior to study registration
• International Normalized Ratio (INR) ≤ 1.5
• Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 1.5 times the ULN.
• Serum bilirubin ≤ upper limit of normal; or total bilirubin ≤ 2.0x the ULN with direct bilirubin within the normal range in patients with well documented Gilbert Syndrome.
• Participants must be able to take oral medication.
• Patients must be able to tolerate MRI scans.
• Patients must be able to tolerate lumbar puncture and/or Ommaya taps.
• Participants must have recovered to grade 1 toxicity from prior therapy.
• Participates must be able to submit 20 unstained slides from the initial tissue diagnosis for confirmation of diagnosis and correlative studies
• Life expectancy of > 3 months (in the opinion of the investigator) Note: Prior autologous stem cell transplant as well as radiation to the CNS is NOT an exclusion criterion. Prior allogenic stem cell transplant IS an exclusion criterion.

Exclusion Criteria

• Patients with SCNSL actively receiving treatment for extra-CNS disease are excluded. Patient should have complete resolution of their systemic disease not requiring additional systemic therapy (e.g. maintenance rituximab or decadron).
• The patient has received prior treatment with a PI3K inhibitor, AKT inhibitor, or mTOR inhibitor (e.g. rapamycin, MK2206, perifosine, etc.).
• Patient is concurrently using other approved or investigational antineoplastic agents
• Patient has received chemotherapy or targeted anticancer therapy, monoclonal antibodies ≤ 4 weeks or 5 half-lives, whichever is shorter, or 6 weeks for nitrosourea or mitomycin-C prior to starting the study drug, or the patient has not recovered side the side effects of such therapy
• Patient who has received wide field radiotherapy ≤ 4 weeks or limited field radiation for palliation ≤ 2 weeks prior to starting study drug or who have not recovered to grade 1 or better from related side effects of such therapy (except alopecia)
• Patient requires more than 8 mg of dexamethasone daily or the equivalent
• Patient is taking an enzyme inducing anti-epileptic drug (EIAED), including phenobarbital, phenytoin, fosphenytoin, primidone, carbamazepine, oxcarbazepine, eslicarbazepine, rufinamide, and felbamate. Participates must be off of any EIAED for a least two weeks prior to starting the study drug
• Patient is taking a drug known to be a strong inhibitor or inducers of the isoenzyme CYP3A. Participants must be off a strong CYP3A inhibitors and inducers for at least two weeks prior to starting the study drug.
• Patient is taking a drug with known risk to promote QT prolongation and Torsade de Pointes Patient is currently u