The purpose of this study is to provide patients who have relapsed or refractory Mantle Cell Lymphoma (MCL) with early access to an investigational medication called ibrutinib (PCI-32765) and to collect safety information about the drug.

Inclusion Criteria:

• Patients, 18 years of age and older, with Mantle Cell Lymphoma who have relapsed or refractory disease after prior therapy are eligible.

Exclusion Criteria:

• Patients eligible for enrollment in any other ongoing clinical study of ibrutinib are not eligible.
• Patients previously treated with ibrutinib are not eligible.
• Patients enrolled in another interventional clinical study with therapeutic intent are not eligible.