Clinical stage biopharma Kezar Life Sciences will drop its Phase I solid tumour drug to streamline focus on its lead autoimmune disease drug zetomipzomib.

The San Francisco-based biotech shared this update in its 2Q financial results. The candidate, dubbed KZR-261, was being investigated in a Phase I trial (NCT05047536) in patients with solid tumours.

Of the 61 enrolled patients, five experienced stable disease for four months or longer, with two of these patients experiencing stable disease for a year or longer. No objective responses have been reported. Enrolment in the trial has been halted, but the 61 patients will continue to have access to KZR-261.

All eyes will now be on zetomipzomib, a selective immunoproteasome inhibitor. The candidate is being evaluated in a Phase IIb PALIZADE clinical trial (NCT05781750) for lupus nephritis and a Phase IIa PORTOLA clinical trial (NCT05569759) for autoimmune hepatitis.

Everest Medicines secured the Greater China, South Korea, and South-East Asia rights for zetomipzomib in September 2023. The first patient in China has already been dosed with zetomipzomib as part of the PALIZADE trial, with topline data expected in mid-2026, as per Kezar.

The PORTOLA trial has enrolled 24 patients so far, randomised to receive 60mg of zetomipzomib or a placebo for 24 weeks. Kezar said that topline data from this trial is anticipated in the first half of next year.

Zetomipzomib has previously been studied in lupus nephritis, with the company reporting positive data from the Phase II MISSION trial investigating zetomipzomib in 69 patients with that autoimmune condition. Data highlighted that 64.7% of the trial subjects attained the trial’s primary efficacy endpoint of overall renal response (ORR).

Kezar, a spinout from Amgen, slashed its workforce by 41% back in October 2023 to extend its cash runway. Though clinical development of zetomipzomib and KZR-261 survived the restructuring, the company halted all of its preclinical programmes. The company ended the 2Q with $164m in cash and equivalents.

According to GlobalData’s Pharma Intelligence Center, if approved, zetomipzomib could be set to pull in sales of $498m in 2030.

GlobalData is the parent company of Pharmaceutical Technology.

In the announcement accompanying the business update, Kezar’s CEO Chris Kirk said: “We are thrilled to announce the completion of enrolment to our PORTOLA trial and look forward to sharing topline results earlier than expected in the first half of 2025.

"This important milestone brings us one step closer to delivering zetomipzomib as a new treatment option for patients suffering from autoimmune hepatitis, a disease of significant unmet medical need.”

"Kezar stalls solid tumour trial to focus on autoimmune disease candidate" was originally created and published by Pharmaceutical Technology, a GlobalData owned brand.

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