 - Part 3: Bortezomib alone: After completing EPOCH-R-B therapy, patients are randomly assigned to receive or not to receive bortezomib alone. The drug is given in 2 doses over 5 days, with a break of 16 days before the next dose. These 3-week cycles continue for up to 18 months or until the disease comes back or worsens. Patients who are assigned to the group that does not receive bortezomib will be offered the drug if their disease relapses. 