8-K: Kezar Life Sciences Provides Update on Zetomipzomib Clinical Development, Cites PALIZADE Trial Safety Data

Kezar Life Sciences presented an update on zetomipzomib's clinical development, including safety data from the PALIZADE Phase 2b trial in lupus nephritis and the design of the PORTOLA trial in autoimmune hepatitis, during a virtual Key Opinion Leader event.

Summary

• Kezar Life Sciences presented at a virtual Key Opinion Leader event on February 27, 2025, discussing the clinical development of zetomipzomib.
• The presentation included a safety update from the PALIZADE Phase 2b clinical trial in patients with active lupus nephritis (LN).
• The company also discussed the design of the PORTOLA Phase 2 clinical trial evaluating zetomipzomib in autoimmune hepatitis (AIH).
• The PALIZADE trial enrolled 84 patients before termination, and analysis showed an approximately 80% reduction in median urine to protein creatinine ratio (UPCR) in patients reaching 6 months of treatment with the 60 mg dose.
• Four fatalities occurred in the PALIZADE trial, with patients having pre-existing conditions such as adrenal insufficiency and potential systemic infections.
• The PORTOLA trial is a Phase 2 placebo-controlled study evaluating zetomipzomib in AIH patients who have relapsed or are insufficient responders to standard-of-care therapy, with topline data expected in the first half of 2025.
• The company plans to submit PALIZADE data to a medical conference in the second half of 2025.
• Kezar intends to respond to FDA hold comments and propose a potential registrational study in AIH following the PORTOLA readout.

Sentiment

Score: 5

Explanation: The document presents mixed signals. While there's encouraging clinical activity in some patients, the trial's early termination and reported fatalities raise concerns. The future development of zetomipzomib hinges on the PORTOLA trial results.

Positives

• The PALIZADE trial showed encouraging clinical activity, with an approximately 80% reduction in median UPCR in patients treated with 60 mg of zetomipzomib for 6 months.
• Improvements in serologic markers of SLE were observed in both zetomipzomib treatment arms.
• The PORTOLA trial has completed enrollment and has the potential to be the first randomized study in relapsed AIH patients to report safety and efficacy results.
• The IDMC overseeing the AIH PORTOLA trial recommended that the trial may proceed without modification.
• No Grade 4 or fatal events were observed in 69 patients across PORTOLA, PRESIDIO or MISSION trials.

Negatives

• Four fatalities occurred in the PALIZADE trial, with patients having pre-existing conditions such as adrenal insufficiency and potential systemic infections.
• The PALIZADE trial was terminated early, limiting the amount of data available.
• The discontinuation rate in the PALIZADE trial was less than 15% prior to termination.
• 15 SAEs (18% of enrolled patients) were reported in the PALIZADE trial, leading to the IDMC recommending suspending enrollment and dosing.

Risks

• The PALIZADE trial was terminated early due to safety concerns, which could impact the future development of zetomipzomib in lupus nephritis.
• The small sample sizes in the PALIZADE trial and its early termination make rigorous statistical analysis of response rates impossible.
• The safety data from the PALIZADE trial requires further confirmation and analysis.
• The development of zetomipzomib is subject to regulatory approval, which is not guaranteed.
• The company faces competition from other companies developing treatments for autoimmune diseases.

Future Outlook

Kezar plans to report topline data from the Phase 2 PORTOLA study in the first half of 2025 and will use this data to inform the design of a potential registrational study in AIH. The company also plans to respond to FDA hold comments prior to proposing this study.

Management Comments

• Kezar assessment of PALIZADE safety and efficacy data to date and data from >200 patients across multiple trials support continued development of zetomipzomib in autoimmune hepatitis and other autoimmune diseases.

Industry Context

The presentation highlights Kezar's efforts to develop novel treatments for autoimmune diseases, a field with significant unmet medical need. The company is focusing on zetomipzomib, a selective immunoproteasome inhibitor, as a potential treatment for lupus nephritis and autoimmune hepatitis. The results of the PALIZADE and PORTOLA trials will be important in determining the future development path for zetomipzomib.

Comparison to Industry Standards

• The PALIZADE trial's fatality rates of up to 5% were observed across multiple trials of novel agents (e.g., voclosporin, belimumab, obinutuzumab).
• SAE rates in these trials were as high as 30%, with infection being the most common.
• In one trial, the majority of AEs occurred within the first 6 months of trial and the majority of deaths occurred within the first 2 months.

Stakeholder Impact

• Shareholders: The clinical trial results and future development plans for zetomipzomib will impact shareholder value.
• Patients: The development of zetomipzomib could provide a new treatment option for patients with lupus nephritis and autoimmune hepatitis.
• Employees: The company's clinical development programs impact employee workload and job security.
• Regulatory agencies: The FDA will review the clinical trial data and determine whether to approve zetomipzomib.

Next Steps

• Kezar plans to report topline data from the Phase 2 PORTOLA study in the first half of 2025.
• The company plans to submit PALIZADE data to a medical conference in the second half of 2025.
• Kezar intends to respond to FDA hold comments and propose a potential registrational study in AIH following the PORTOLA readout.

Key Dates