Oprozomib

Oprozomib (ONX 0912, PR-047) is an orally bioavailable and selective proteasome inhibitor. Oprozomib (ONX 0912) selectively inhibited CT-L activity of both the constitutive proteasome (beta5) and immunoproteasome (LMP7) and demonstrated an absolute bioavailability of up to 39% in rodents and dogs. Oprozomib inhibits growth and induces apoptosis in MM cells resistant to conventional and bortezomib therapies. The anti-MM activity of Oprozomib (ONX 0912) is associated with activation of caspase-8, caspase-9, caspase-3, and poly(ADP) ribose polymerase, as well as inhibition of migration of MM cells and angiogenesis. Oprozomib significantly reduced tumor progression and prolonged survival in animal tumor model studies. Immununostaining of MM tumors from ONX 0912-treated mice showed growth inhibition, apoptosis, and a decrease in associated angiogenesis. Finally, Oprozomib (ONX 0912) enhances anti-MM activity of bortezomib, lenalidomide dexamethasone, or pan-histone deacetylase inhibitor.