Oprozomib[1] (codenamed ONX 0912 and PR-047) is an orally active second-generation proteasome inhibitor developed by Proteolix, which was acquired by Onyx Pharmaceuticals, an Amgen subsidiary, in 2009. It selectively inhibits chymotrypsin-like activity of both the constitutive proteasome (PSMB5) and immunoproteasome (LMP7).[2]
It is being investigated for the treatment of hematologic malignancies, specifically, multiple myeloma, with Phase 1b studies ongoing (as of February 16, 2016).[3] Being an epoxyketone derivative, oprozomib is structurally related to carfilzomib and has the added benefit of being orally bioavailable. Like carfilzomib, it is active against bortezomib-resistant multiple myeloma cells.[4]
^Zhou HJ, Aujay MA, Bennett MK, Dajee M, Demo SD, Fang Y, et al. (May 2009). "Design and synthesis of an orally bioavailable and selective peptide epoxyketone proteasome inhibitor (PR-047)". Journal of Medicinal Chemistry. 52 (9): 3028–38. doi:10.1021/jm801329v. PMID19348473.