Onyx is developing oprozomib, a novel oral proteasome inhibitor. In preclinical studies, oprozomib has been shown to inhibit the 20S proteasome that primarily targets chymotrypsin-like activity. Oprozomib is distinct from Kyprolis® (carfilzomib) for Injection, although the compound is based on the same chemistry that is employed to selectively target the proteasome. As an orally-dosed agent, oprozomib is designed to provide prolonged proteasome inhibition and combinability with other available therapies with the convenience of an oral therapy.
Oprozomib has demonstrated preclinical anti-tumor activity and a broad therapeutic window in preclinical models. Oprozomib is currently being studied in two trials, including a Phase 1b/2 study evaluating oprozomib in hematologic malignancies including multiple myeloma. The second trial is a Phase 1 study in patients with recurrent or refractory solid tumors.