Inclusion Criteria
Confirmed diagnosis of CD20-positive DLBCL
Adequate organ function
Willing to use an approved contraceptive method (for example, intrauterine device [IUD], birth control pills, or barrier device) during and for 3 months after discontinuation of study treatment
Women of childbearing potential must have a negative serum pregnancy test within 7 days prior to start of treatment
Able to swallow tablets
Have adequate transportation to allow for required follow-up visits
Agree to have blood stored for possible future biomarker analysis
Exclusion Criteria
Received treatment with an investigational drug within the last 30 days
Receiving, or has received, any other radiation or systemic anticancer treatment for lymphoma
Pregnant or breastfeeding
Have known central nervous system (CNS) involvement
Have any significant concomitant disorder, including active bacterial, fungal, or viral infection, incompatible with participation in the study
Have a second primary malignancy (except adequately treated non-melanoma skin cancer)- Patients who have had another malignancy in the past, but have been disease-free for more than 5 years, are eligible
Unable to discontinue use of a concomitant medication that is a strong inducer or inhibitor of CYP3A4
Have a history of severe allergic or anaphylactic reaction to monoclonal antibody therapy
Confirmed diagnosis of progressive multifocal leukoencephalopathy
Have any of the following cardiac disorders: uncontrolled hypertension, unstable angina, myocardial infarction within 8 weeks of Day1, NYHA Grade 2 or higher congestive heart failure, ventricular arrhythmia requiring medication within 1 year of Day 1, NYHA Grade 2 or higher peripheral vascular disease
Received a live vaccine within 28 days of study Day 1
HIV positive
Have evidence of chronic hepatitis C infection as indicated by antibody to HCV with positive HCV-RNA
Have evidence of chronic hepatitis B infection as indicated by either: 1. HBsAg+ or 2. HBcAb+ with HBV-DNA+