Bortezomib Consolidation Trial

Inclusion Criteria: * MM patients who have received high dose Melphalan with ASCT 3-4 months prior to registration and have not progressed * Age 18 - 70 years * Life expectancy \> 6 months * Written informed consent * Creatinine \< 400µmol/L * Bilirubin \< 3x upper limit of normal * WHO performance status 0-2 * Contraceptive precautions where appropriate Exclusion Criteria: * Received bortezomib previously * On, or planned for, steroid therapy * Poor performance status (ECOG ≥ 3) * Disease progression at any stage * Past history of polio, cord compression or other neurological condition resulting in persisting neurological deficit ≥ grade 2 * Severe hepatic impairment, indicated by bilirubin ≥ 3x upper limit of normal, or AST \> 2.5x upper limit of normal * Pregnant or lactating women * Allergic reaction attributable to bortezomib or to compounds containing boron or mannitol * Severe cardiovascular disease * History of acute infiltrative pulmonary or pericardial disease * History of hypotension or has decreased blood pressure * Peripheral neuropathy ≥ grade 2, or neuropathic pain * Serious medical or psychiatric illness likely to interfere with participation in this clinical study * Received any drugs or agents that inhibit or induce CYP2C19 or CYP3A4 within 14 days before the first dose of bortezomib * Need for therapy with concomitant CYP 3A4 or CYP2C19 inhibitors * Have received an experimental drug or used an experimental medical device within 4 weeks before the planned start of treatment