On Monday, Onyx Pharmaceuticals agreed to purchase Proteolix, the developer of the cancer drug carfilzomib (Kyprolis), for $276 million. Carfilzomib, which is Proteolix’s leading cancer drug, has dem­onstrated significant tumor-reduction activity in Phase 1 trials of patients with re­lapsed multiple myeloma.

Similar to Velcade (bor­tez­o­mib), car­filz­o­mib is a proteasome inhibitor that blocks the activity of these protein-destroying enzymes and induces cancer cell death. Carfilzomib is cur­rently undergoing Phase 2 trials on patients with re­lapsed multiple myeloma, for which data will be reported in late 2010. Phase 3 trials combining car­filz­o­mib with Revlimid (lena­lido­mide) and dexamethasone (Decadron) will begin next year. Carfilzomib is also undergoing early-stage clinical trials for solid tumor cancers.

“There is a tremendous need for new agents in multiple myeloma that can extend and improve the lives of patients and be used in com­bi­na­tion with existing ther­a­pies,” said Todd Yancey, vice president of clinical devel­op­ment at Onyx.

Onyx could potentially pay up to an addi­tional $535 million to cover devel­op­ment of car­filz­o­mib, including $170 million for accelerated approval by the U.S. Food and Drug Administration. Onyx expects to expand its research and devel­op­ment budget to con­tinue the devel­op­ment of car­filz­o­mib.

For more in­­for­ma­tion about Onyx’s purchase plan, please read the Onyx press release. For in­­for­ma­tion about car­filz­o­mib clinical trials, please see The Myeloma Beacon research summary about car­filz­o­mib's Phase 1 trial results or the National Institutes of Health's directory of ongoing car­filz­o­mib clinical trials.