Patients receive bendamustine IV over 1 hour on days1-3 and mitoxantrone hydrochloride IV over 30 minutes on day 1. Treatment repeats every 28 days for at least 2 courses in the absence of disease progression or unacceptable toxicity. Patients with responding disease (i.e., complete response or partial response) after 2 courses receive 2 additional courses of treatment for a total of 4 courses.