Bortezomib Plus CHOP Every 2 Weeks for Advanced Stage DLBCL

Intended number of patients: 63 patients in total * Phase I: 9 patients for 3 levels * Phase II: 50 patients plus 3 patient from Phase I at MTD level * Plus 4 patients: considering 5% follow-up loss rate Study design and methodology: For phase I, 9 patients; 3 levels of bortezomib (1.0, 1.3 and 1.6 mg/m2), 3 patients at each dose level. If escalation of bortezomib beyond 1.0 mg/m2 is not possible, the trial will be stopped. For phase II, 53 patients (3 from phase I at MTD level); Reject when complete response rate equal or less than 12/19 or 37/53 by Simon two-stage optimal phase II design. Treatments: * Bortezomib: For phase I, 3 dose levels (1.0, 1.3 or 1.6 mg/m2), days 1 and 4, every 2 weeks. For phase II, suggested dose of Bortezomib through phase I, days 1 and 4, every 2 weeks. * CHOP2: cyclophosphamide 750mg/ m2 day 1, vincristine 1.4 mg/ m2 (max. 2 mg) day 1, doxorubicin 50 mg/ m2 day 1, prednisolone 100 mg days 1-5, every 2 weeks. * G-CSF: Lenograstim 5 microgram/kg subcutaneously days 4-13 every 2 weeks.