Ibrutinib Combination Therapy in Transplant Ineligible Individuals With Newly Diagnosed Primary CNS Lymphoma

This study is being done to answer the following question: Can the addition of a new drug to the usual treatment lower the chance of primary central nervous system lymphoma growing or spreading? This study is being done to find out if this approach is better or worse than the usual approach for this type of cancer. The usual approach is defined as the care most people get for Primary Central Nervous System Lymphoma (PCNSL).