Despite the common practice of combining dexamethasone (Dex) with bortezomib (Bz) in patients with multiple myeloma (MM), until now there has been few prospective trials undertaken. We undertook a trial that recapitulated the original APEX study except that dexamethasone was incorporated from cycle 1. We also incorporated an exploratory maintenance component to the study. Twenty sites enrolled 100 relapsed/or refractory MM patients utilizing eight 21 day cycles of IV Bz [1.3 mg/m2; Day (D) 1, 4, 8, 11] and three 35 day cycles; Bz (1.3 mg/m2; Day (D) 1, 8, 15, 22). Our study was registered at www.clinicaltrials.gov (NCT00335348). Patients with stable disease or better received maintenance Bz (1.3 mg/m2) every 14 days until progression. Dexamethasone (20 mg) was given for 2 days with each Bz dose. A prospectively defined matched-analysis of primary (overall response rate; ORR) and secondary endpoints [Complete Response (CR) and time to progression (TTP)] compared our cohort to those on the Bz arm of the APEX trial. The addition of Dex improved ORR by 20 (56 vs. 36 ) [odds ratio 0.44 (0.24-0.80)]. The median TTP was also significantly longer (10.1 vs. 5.1 months) (hazard ratio 0.50, 95 CI: 0.35-0.72, P=0.0002) and our landmark analysis demonstrated that this was largely due to the early use of dexamethasone, as we were unable to demonstrate any benefit of bortezomib/dexamethasone maintenance therapy.