 An initial cohort of 6 patients at Mayo Clinic receives rituximab IV over 4-8 hours on day 1 and cladribine IV over 2 hours on days 4-8. If 2 or more patients experience unacceptable toxicity during the first course, the study is discontinued; otherwise, the study is opened for enrollment at all NCCTG sites. The phase II study is open for enrollment as of 51404. 