Bortezomib, sold under the brand name Velcade among others, is an anti-cancer medication used to treat multiple myeloma and mantle cell lymphoma.

[7] The phase III demonstrated the superiority of bortezomib over a high-dose dexamethasone regimen (e.g. median TTP 6.2 vs 3.5 months, and 1-year survival 80% vs 66%).

However, these side effects are usually mild relative to bone marrow transplantation and other treatment options for people with advanced disease.

[12] Ocular side effects such as chalazion or hordeolum (stye) may be more common in women and have led to discontinuation of treatment.

The boron atom in bortezomib is proposed to bind the catalytic site of the 26S proteasome[16] with high affinity and specificity.

Bortezomib causes a rapid and dramatic change in the levels of intracellular peptides that are produced by the proteasome.

[20] The pharmacodynamics of bortezomib are determined by quantifying proteasome inhibition in peripheral blood mononuclear cells taken from people receiving the drug.

[21] In May 2003, bortezomib (marketed as Velcade by Millennium Pharmaceuticals Inc.) was approved in the United States by the Food and Drug Administration (FDA) for use in multiple myeloma, based on the results from the SUMMIT Phase II trial.

[24] The 2008 approval was based on an international, multicenter, open label, active-control trial in previously untreated people with symptomatic multiple myeloma.

[24] In August 2014, bortezomib was approved in the United States for the retreatment of adults with multiple myeloma[25][26] who had previously responded to Velcade therapy and relapsed at least six months following completion of prior treatment.

[26] In October 2014, bortezomib was approved in the United States for the treatment of treatment-naïve people with mantle cell lymphoma.