Ibrutinib and Rituximab in Treating Patients With Relapsed or Refractory Mantle Cell Lymphoma or Older Patients With Newly Diagnosed Mantle Cell Lymphoma

PRIMARY OBJECTIVES: I. To evaluate the response rate of ibrutinib plus rituximab in patients with relapsed and/or refractory mantle cell lymphoma (MCL). II. To evaluate the safety and response rate of ibrutinib plus rituximab in elderly patients (\> 65) with newly-diagnosed, untreated MCL. SECONDARY OBJECTIVES: I. To further evaluate the toxicity profile of the combination of ibrutinib and rituximab in patients with relapsed and/or refractory MCL. II. To estimate the overall response rate (ORR); (partial response \[PR\] or better), the response duration (DOR), progression-free survival (PFS), time to progression (TTP) and overall survival (OS) in patients with relapsed and/or refractory MCL; clinical benefit response (CBR) = (minimal response \[MR\] + ORR) will also be evaluated. III. To estimate the response duration, PFS, time to progression (TTP), and OS in elderly patients (\> 65) with newly-diagnosed, untreated MCL. EXPLORATORY OBJECTIVES: I. To correlate detected gene mutations and changes in gene and/or protein expression with response to treatment. OUTLINE: Patients receive ibrutinib orally (PO) daily on days 1-28 and rituximab intravenously (IV) over 4-8 hours on days 1, 8, 15, and 22 of course 1; on day 1 of courses 3-8; and on day 1 of every other course for all subsequent courses. Treatment with rituximab repeats every 28 days for up to 2 years in the absence of disease progression or unacceptable toxicity. Courses with ibrutinib repeat every 28 days in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 1 year and then every 6 months thereafter.