Although the discovery of the ubiquitin-proteasome pathway was an important biochemical advance, few people believed that its inhibition would represent a therapeutic strategy for cancer. However, encouraging results were reported from phase 1 (SUMMIT) and 2 (CREST) trials of bortezomib—the first proteasome inhibitor to be used in clinical practice—in patients with relapsed or refractory multiple myeloma. These findings prompted a large randomised trial (APEX) that compared bortezomib with high-dose...