This randomized phase II trial studies how well obinutuzumab works as maintenance treatment in patients with central nervous system lymphoma who have achieved the disappearance of all signs of cancer in response to treatment (complete response) or a decrease in the size of a tumor, or in the extent of cancer in the body, in response to treatment (partial response). Immunotherapy with obinutuzumab, may induce changes in body's immune system and may interfere with the ability of tumor cells to grow and spread.
CD20+ B-cell primary central nervous system lymphoma (PCNSL) confirmed at the time of diagnosis by histology, cytology, or immunocytochemistry from cerebrospinal fluid (CSF); diagnosis must be documented by pathology report.
Must have undergone first-line treatment with a high-dose methotrexate-based chemotherapy regimen with or without brain radiotherapy; high-dose methotrexate is defined as >= 3 grams/m²; methotrexate dose reduction for creatinine clearance < 100 ml/min is permitted
Must be within 75 days of completion of first-line treatment regimen at the time of randomization; must have achieved objective response (PR or CR/unconfirmed complete response [CRu]) to first-line treatment
Brain magnetic resonance imaging (MRI) documenting objective response must be obtained within 30 days before randomization
History of severe allergic or anaphylactic reactions to monoclonal antibody therapy
Clinical evidence of extra-central nervous system (CNS) (systemic) non-Hodgkin lymphoma
Known hypersensitivity to any of the study drugs
History of other malignancy that could affect compliance with the protocol or interpretation of results