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Kezar Life Sciences

A clinical-stage biopharmaceutical company developing novel small-molecule therapeutics targeting the immunoproteasome for the treatment of autoimmune diseases and cancer.

Company Overview

A clinical-stage biopharmaceutical company developing novel small-molecule therapeutics targeting the immunoproteasome for the treatment of autoimmune diseases and cancer. Kezar's lead program, zetomipzomib (KZR-616), is a selective immunoproteasome inhibitor in late-stage clinical trials for lupus nephritis and autoimmune hepatitis. In March 2026, Aurinia Pharmaceuticals announced its acquisition of Kezar for $6.955 per share in cash plus contingent value rights, with closing expected in Q2 2026.

Headquarters and Global Presence

Kezar is headquartered in South San Francisco, California. The company's operations are centered in the San Francisco Bay Area, where it maintains its research and corporate functions. Kezar conducts global clinical trials, including the PALIZADE Phase IIb study in lupus nephritis and the PORTOLA Phase IIa study in autoimmune hepatitis.

Founding and History

Kezar was founded in 2015 by John Fowler, Jack Taunton, and Christopher Kirk. The company was built around a licensing agreement with Amgen for intellectual property from its Onyx/Proteolix acquisition relating to an immunoproteasome program. Kirk, who previously served as VP of Research at Onyx Pharmaceuticals and played a key role in the development of carfilzomib (KYPROLIS), was appointed CEO in October 2023 following a strategic restructuring. The company raised a $28.4 million Series A in 2015 to fund initial development.

Therapy Areas and Focus

Kezar's primary focus is autoimmune diseases, with clinical programs in lupus nephritis and autoimmune hepatitis. The company's immunoproteasome platform has potential applications across a range of immune-mediated conditions, including systemic lupus erythematosus. Kezar also maintains an oncology program targeting the Sec61 translocon pathway for solid tumors.

Technology Platforms and Modalities

Kezar's core platform is selective immunoproteasome inhibition, a potentially first-in-class approach that modulates pathological immune responses by targeting the immunoproteasome's role in antigen processing and immune cell activation. The company's second platform targets the Sec61 translocon and protein secretion pathway, with applications in oncology. Both platforms are based on small-molecule therapeutics.

Key Pipeline and Programs

Zetomipzomib (KZR-616) is Kezar's lead asset, a selective immunoproteasome inhibitor being evaluated in the global Phase IIb PALIZADE trial for lupus nephritis and the Phase IIa PORTOLA trial for autoimmune hepatitis. The PORTOLA trial has shown clinically meaningful, durable, steroid-sparing remissions. Topline data from both studies are expected mid-2026. KZR-261, targeting the Sec61 translocon, is in a Phase I open-label dose-escalation trial for solid tumors.

Key Personnel

Christopher Kirk, Ph.D., co-founder, serves as Chief Executive Officer, having been appointed in October 2023. Kirk previously served as President and Chief Scientific Officer at Kezar and before that as VP of Research at Onyx Pharmaceuticals, where he contributed to the development of carfilzomib.

Strategic Partnerships

Kezar has an active collaboration with Everest Medicines for development of its programs. The company sold its Sec61-based discovery and development program to Enodia Therapeutics. The original immunoproteasome intellectual property was licensed from Amgen. In March 2026, Aurinia Pharmaceuticals announced the acquisition of Kezar, with contingent value rights linked to clinical milestones for zetomipzomib, proceeds from the Everest Medicines collaboration, and the Enodia Therapeutics asset sale.

FAQ Section

Kezar must deliver positive topline data from its PALIZADE and PORTOLA trials mid-2026 while navigating integration into Aurinia Pharmaceuticals following the acquisition expected to close in Q2 2026.

The immunoproteasome is selectively expressed in immune cells and plays a central role in antigen processing, making it a differentiated target for modulating autoimmune disease without broadly suppressing normal proteasome function in non-immune tissues.

Kezar developed a potentially first-in-class selective immunoproteasome inhibitor, building on deep expertise from the carfilzomib proteasome inhibitor program at Onyx Pharmaceuticals to create a more targeted approach for autoimmune diseases.

Zetomipzomib could become the first selective immunoproteasome inhibitor approved for autoimmune diseases, offering a novel mechanism distinct from existing immunosuppressants, with demonstrated steroid-sparing activity in autoimmune hepatitis.

The pipeline spans autoimmune diseases, primarily lupus nephritis and autoimmune hepatitis through the immunoproteasome platform, and solid tumor oncology through the Sec61 translocon program.

Kezar is a late clinical-stage company with its lead asset zetomipzomib in Phase IIb for lupus nephritis and Phase IIa for autoimmune hepatitis, and an earlier-stage Phase I oncology program.

Key watchpoints are the mid-2026 topline data from the PALIZADE and PORTOLA trials, successful completion of the Aurinia acquisition, and regulatory progression of zetomipzomib toward potential registration-enabling studies.

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