Bruton's Tyrosine Kinase (BTK) Inhibitor, Ibrutinib, in Patients With Newly Diagnosed or Refractory/Recurrent Primary Central Nervous System Lymphoma (PCNSL) and Refractory/Recurrent Secondary Central Nervous System Lymphoma (SCNSL)

"Arm A: Ibrutinib will be given once daily. The starting dose cohort (level 1) will receive 560 mg/day (4 x 140 mg capsules). During the dose escalation period of the study, the 3+3 design will be applied (see Table 3). Participants will be assigned to cohorts of increasing oral daily doses of ibrutinib (560mg, 840mg) until disease progression, intolerable toxicity or death. Three patients with recurrent/refractory PCNSL or recurrent/refractory SCNSL will be treated with daily oral ibrutinib for a 28-day cycle starting at dose level 1 and observed for toxicities during cycle 1. Arm B: Ibrutinib will be given at the MTD defined in Arm A."

Arm C1: HD-MTX at 3.5g/m2 (standard hydration/leucovorin support) will be given on day 1 and 15 of each 28-day cycle for a total of 4 cycles totaling 8 HD-MTX administrations. Ibrutinib will be given between days 5 and 14 as well as days 19 and 28 of each cycle and continued daily after completion of HD-MTX treatments.The starting dose of ibrutinib is 560 mg/day (4x140mg capsules)

Arm C2: Intravenous rituximab (500mg/m2) will be given on day 0, 14, and 28 of cycle 1 and day 14 and 28 of all following cycles. HD-MTX at 3.5g/m2 (standard hydration/leucovorin support) will be given on day 1 and 15 of each 28-day cycle for a maximum of 4 cycles totaling 8 HD-MTX administrations. Ibrutinib will be given between days 5 and 14 as well as days 19 and 28 of each cycle and continued daily after completion of HD-MTX treatments. The starting dose of ibrutinib is 560 mg/day (4x140mg capsules; dose level 1) (see Table 4). Filgrastim will be given at days 7-11 and 22-26.

Arm D: THIS IS THE ONLY ARM RECRUITING: : Oral procarbazine (100mg/m2/day) will be given on Day 1 through 7 during each cycle. Patients will be maintained on a tyramine-free diet during procarbazine administration.