Kezar Announces Presentations During Upcoming Scientific Conferences

Kezar Life Sciences, Inc. (Nasdaq: KZR ), a clinical-stage biotechnology company discovering and developing novel small molecule therapeutics to treat unmet needs in autoimmune disease and cancer, today announced presentations during upcoming major scientific conferences.

“Kezar’s unique ability to translate novel science into viable treatment options is underscored by the selection of three abstracts featuring data from both of our programs targeting protein homeostasis,” said Christopher Kirk, PhD, Kezar’s President and Chief Scientific Officer. “The acceptance of a pre-clinical abstract to ASCO serves as a testament to the innovative mechanism and potential of KZR-261 to target a number of solid and liquid tumor types. Furthermore, the growing body of clinical data demonstrating the broad immunomodulatory effects of KZR-616 supports its potential to treat a wide range of severe autoimmune diseases.”

Following is an overview of Kezar’s upcoming scientific presentations, which will also be made available on the Company’s website:

American Society of Clinical Oncology (ASCO20 Virtual)

Title: Preclinical evaluation of KZR-261, a novel small molecule inhibitor of Sec61 Abstract N°: 3582 (poster presentation) Session: Developmental Therapeutics—Molecularly Targeted Agents and Tumor Biology Authors: Eric Lowe, R . Andrea Fan, Jing Jiang, Henry W.B. Johnson, Christopher J. Kirk, Dustin McMinn, Beatriz Millare, Tony Muchamuel, Yu Qian, Brian Tuch, Jennifer A. Whang, Patricia Zuno Date: Available beginning May 29, 2020, 8:00 AM ET

European League Against Rheumatism (EULAR 2020 E-Congress)

Title: Treatment of SLE with the Immunoproteasome Inhibitor KZR-616: Results from the First 4 Cohorts of the MISSION Study, an Open-Label Phase 1b Dose Escalation Trial Abstract N°: AB0373 (abstract publication) Session: SLE, Sjögren’s and APS - treatment Authors: Richard Furie, S.V. Parikh, Adonis Maiquez, Amber Khan, Orlando Moreno, Miguel Soneira, Christopher Kirk, Darrin Bomba, Ken Harvey, Mary Katherine Farmer Date: Additional data available on June 3, 2020 on Kezar’s corporate website

25 th Annual European Hematology Association (EHA25 Virtual)

Title: Selective Immunoproteasome Inhibitor, KZR-616, A Novel Therapy for Autoimmune Hemolytic Anemia and Immune Thrombocytopenia: Biomarker Activity and Phase II Clinical Trial In Progress (MARINA) Abstract N°: S318 (oral presentation) Session : ITP: What's new in 2020 Authors: Andrea Fan, Janet Anderl, Brian Tuch, Ken Harvey, Darrin Bomba, Chris Kirk, Julia Lawrence Date: June 11-14, 2020

About KZR-616

KZR-616 is a novel, first-in-class, selective immunoproteasome inhibitor with broad therapeutic potential across multiple autoimmune diseases. Preclinical research demonstrates that selective immunoproteasome inhibition results in a broad anti-inflammatory response in animal models of several autoimmune diseases, while avoiding immunosuppression. Data generated from Phase 1a and 1b trials provide evidence that KZR-616 potentially avoids adverse effects caused by currently marketed non-selective proteasome inhibitors, which we believe prevent them from being utilized as a chronic treatment in autoimmune disorders. Phase 2 trials are underway for the treatment of lupus nephritis ( MISSION - NCT03393013 ), dermatomyositis and polymyositis ( PRESIDIO - NCT04033926 ), and autoimmune hemolytic anemia and immune thrombocytopenia ( MARINA - NCT04039477 ).

About KZR-261

KZR-261, a novel, first-in-class protein secretion inhibitor, is the first clinical candidate to be nominated from Kezar’s research and discovery efforts targeting protein secretion pathways. KZR-261 is a broad-spectrum anti-tumor agent that acts through direct interaction and inhibition of Sec61 activity. The compound was discovered at Kezar through a robust medicinal chemistry campaign in which several scaffolds were progressed through the company’s proprietary platform evaluating Sec61 modulation. As a result, Kezar has established a broad library of protein secretion inhibitors. KZR-261 has demonstrated several encouraging properties that lead to its potential to be an anti-cancer agent for the treatment of solid and hematologic malignancies. IND-enabling activities are currently underway, and an IND submission in solid tumors is expected in the first quarter of 2021.

About Kezar Life Sciences

Based in South San Francisco, Kezar Life Sciences is a clinical-stage biotechnology company committed to revolutionizing treatments for patients with autoimmune diseases and cancer. Kezar is translating its innovative research on the immunoproteasome and protein secretion pathways to advance novel therapeutic approaches. KZR-616, a first-in-class selective immunoproteasome inhibitor, is being evaluated in severe and underserved autoimmune diseases. Additionally, KZR-261, the first clinical candidate for the treatment of cancer from Kezar’s protein secretion program, is undergoing IND-enabling activities. For more information, visit www.kezarlifesciences.com .

Cautionary Note on Forward-looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Words such as “may,” “will,” “should,” “expect,” “believe” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) are intended to identify forward-looking statements. These forward-looking statements are based on Kezar’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties that could cause Kezar’s clinical development programs, future results or performance to differ materially from those expressed or implied by the forward-looking statements. Forward-looking statements contained in this press release include, but are not limited to, statements about the design, progress, timing, scope and results of clinical trials, the likelihood data will support future development, the association of data with treatment outcomes, the likelihood of obtaining regulatory approval of Kezar’s product candidates, the timing of regulatory filings, and the discovery and development of new product candidates. Many factors may cause differences between current expectations and actual results, including the impacts of the COVID-19 pandemic on the company’s business, clinical trials and financial position, unexpected safety or efficacy data observed during preclinical or clinical studies, clinical trial site activation or enrollment rates that are lower than expected, changes in expected or existing competition, changes in the regulatory environment, the uncertainties and timing of the regulatory approval process, and unexpected litigation or other disputes. Other factors that may cause actual results to differ from those expressed or implied in the forward-looking statements in this press release are discussed in Kezar’s filings with the U.S. Securities and Exchange Commission, including the “Risk Factors” contained therein. Except as required by law, Kezar assumes no obligation to update any forward-looking statements contained herein to reflect any change in expectations, even as new information becomes available.

CONTACT: Celia Economides SVP, Strategy & External Affairs [email protected]