New twists on proteasome inhibitors

In July, Onyx Pharmaceuticals of Emeryville, California, announced positive phase 2 results for its proteasome inhibitor carfilzomib, which is currently being tested in multiple myeloma. The drug achieved a 24% response rate in individuals with advanced cancer, who had failed on all prior therapies, more than double the expected response rate (11%). This was not only good news for the company—whose stock jumped 21% and which clinched a marketing deal worth >$300 million with Japanese firm Ono Pharmaceuticals of Osada—but also a boost for the field of proteasome inhibition, which thus far has only a single success story, Velcade (bortezomib), which was first approved in multiple myeloma in 2003.