Kezar Life Sciences, Inc.

Kezar Life Sciences, Inc. is a clinical-stage biotechnology company focused on developing new small molecule drugs for immune-mediated diseases. In October 2025, the company announced plans to explore strategic alternatives to maximize stockholder value after not reaching an agreement with the U.S. Food and Drug Administration (FDA) on a potential registrational clinical trial for zetomipzomib. Zetomipzomib is a novel, selective inhibitor of the immunoproteasome intended for patients with relapsed and refractory autoimmune hepatitis (AIH). Following this announcement, Kezar began a restructuring plan and wind-down of business operations to concentrate on strategic alternatives for zetomipzomib's development. In January 2026, Kezar announced that the FDA Division of Hepatology and Nutrition granted a new Type C meeting to discuss zetomipzomib's development in AIH patients. This meeting involved reviewing a potential global, randomized Phase 2b clinical study of zetomipzomib in patients with relapsed and refractory AIH. Kezar submitted pharmacokinetic and hepatic safety data analyses from prior clinical trials to support a proposal for parallel AIH and hepatic impairment studies. The company also provided additional safety data and an updated risk-mitigation plan to modify the FDA's previous requirement for 48-hour in-unit patient monitoring in future AIH studies. In March 2026, Kezar completed a successful Type C meeting with the FDA, where the FDA provided feedback and guidance on the regulatory pathway for zetomipzomib in AIH, including agreement on treatment duration, endpoints, and enrollment criteria. The FDA also offered additional guidance on safety monitoring. Zetomipzomib is currently the only investigative agent that has shown steroid-sparing clinical activity in AIH patients who are refractory or intolerant to standard care therapies. Zetomipzomib is a first-in-class selective immunoproteasome inhibitor being developed for severe autoimmune diseases with high unmet medical need.