- Part A: Patients receive bortezomib IV over 3-5 seconds on days 1 and 8, dexamethasone IV and etoposide IV over 2 hours on days 8-10, and ifosfamide IV continuously over 24-hours and carboplatin IV over 2 hours on day 9. Treatment repeats every 28 days until the maximum tolerated dose (MTD) is determined. Patients who tolerate the MTD of bortezomib may move on to part B.