Kezar Life Sciences is a clinical-stage biotechnology company developing a single drug candidate, zetomipzomib, a selective inhibitor of the immunoproteasome. The immunoproteasome regulates immune activity across multiple cell types, and Kezar argues that zetomipzomib can modulate a broad range of immune processes without causing the broad immunosuppression associated with conventional therapies. Kezar's lead target indication is autoimmune hepatitis (AIH), a rare chronic disease where the immune system attacks the liver. Current AIH treatment relies on corticosteroids and immunosuppressants, which carry significant side effects and often fail patients over time; Kezar focuses on patients who are relapsed or refractory to these standard therapies, a population with no approved alternatives. Kezar has no approved products and generates no product revenue. The company licensed zetomipzomib rights in Greater China and several Asian markets to Everest Medicines, receiving a $7M upfront payment and eligibility for up to $125.5M in milestones plus royalties. Kezar itself holds an in-license from Onyx Therapeutics and owes up to $167.5M in future milestones. The company is effectively in wind-down mode following a clinical hold tied to patient deaths in a lupus nephritis trial, and has reduced to 9 employees. A 2026 Type C FDA meeting provided guidance on a potential Phase 2b AIH trial design, keeping the program alive, but Kezar's most likely path forward is a partnership, asset sale, or reverse merger rather than independent development.