Kezar Life Sciences Discontinues Unpromising Phase 1 Solid Tumor Drug

In its second-quarter earnings release, Kezar Life Sciences Inc. KZR announced that it had dropped its phase 1 solid tumor drug.

The company said it stopped patient enrollment in the KZR-261 Phase 1 study, and clinical resources are being reallocated toward developing zetomipzomib in autoimmune hepatitis (AIH) and lupus nephritis (LN).

Patients already enrolled in the study will continue to have access to KZR-261.

A total of 61 patients were enrolled across the dose-escalation and expansion portions of the study, including seven patients enrolled in the melanoma cohort of the dose-expansion portion at a dose level of 60 mg/m2.

No objective responses have been observed in the study to date. The company adds that five patients (two with melanoma) within the dose escalation portion of the study experienced stable disease for four months or longer, of which two patients (melanoma; head and neck) experienced stable disease for twelve months or longer.

Instead, the biotech will focus on the selective immunoproteasome inhibitor called zetomipzomib.

Kezar has enrolled all 24 patients in the phase 2 PORTOLA trial of zetomipzomib in patients with autoimmune hepatitis. Topline data are expected to be available in the first half of 2025.

A global PALIZADE Phase 2b trial of zetomipzomib in active lupus nephritis patients is expected to share topline data in mid-2026.

"We are thrilled to announce completion of enrollment to our PORTOLA trial and look forward to sharing topline results earlier than expected in the first half of 2025," said CEO Chris Kirk.

KZR-261 survived a pipeline restructuring in 2023, during which the biotech cut its workforce by 41% and resigned John Fowler as CEO, with Christopher Kirk appointed as the new CEO.

Kezar said it was also evaluating its Phase 1 trial of KZR-261 in solid tumors and expects to reduce the number of planned expansion cohorts to conserve cash resources while it evaluates safety and biologic activity in the ongoing trial.

Initial data from its KZR-261 Phase 1 trial was expected in 2024.

Price Action: KZR stock is up 1.38% at $0.58 at the last check on Wednesday.

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Illustration of Phrama lab worker created with MidJourney.