On October 22, 2025 Nurix Therapeutics, Inc. (Nasdaq: NRIX), a clinical stage biopharmaceutical company focused on the discovery, development, and commercialization of targeted protein degradation medicines in oncology and autoimmune disease, reported the initiation of the DAYBreak clinical trial, a pivotal single-arm Phase 2 study of bexobrutideg (NX-5948) in patients with relapsed or refractory chronic lymphocytic leukemia.

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DAYBreak and the planned Phase 3 confirmatory study of bexobrutideg will evaluate the 600 mg dose taken once daily (QD). The selection of the 600 mg dose follows the completion of the analysis of data from a randomized cohort within the Phase 1b study comparing 200 mg and 600 mg in accordance with Project Optimus and reflects alignment with global regulators including the U.S. Food and Drug Administration, the U.K Medicines and Healthcare products Regulatory Agency, and the European Medicines Agency.

In an investor webcast at 8:00 a.m. ET, today, Wednesday, October 22, 2025, Nurix will provide a program update including a review of new preclinical data supporting the potential best-in-class BTK degrader profile of bexobrutideg and discuss the DAYBreak and planned Phase 3 confirmatory studies.

"The initiation of the DAYBreak study marks Nurix’s transition to a pivotal-stage company and a major milestone for bexobrutideg, which our data demonstrate has a potential best-in-class profile," said Arthur T. Sands, M.D., Ph.D., president and chief executive officer of Nurix. "With the DAYBreak study underway, we are advancing the development of bexobrutideg and are one step closer to registration and commercialization."

The DAYBreak study will enroll patients with r/r CLL who have experienced disease progression following treatment with a covalent BTK inhibitor (cBTKi), a BCL-2 inhibitor (BCL-2i), and a non-covalent BTK inhibitor (ncBTKi). The DAYBreak study aims to evaluate bexobrutideg’s potential to address an unmet medical need in this patient population and generate data to support a potential Accelerated Approval submission.

Nurix plans to initiate a randomized confirmatory Phase 3 trial in the first half of 2026 in r/r CLL patients whose disease has previously progressed while receiving a cBTKi. This global Phase 3 confirmatory trial in patients treated in the second line or later setting will compare bexobrutideg monotherapy to an investigator’s choice of pirtobrutinib monotherapy (a ncBTKi), bendamustine + rituximab, or idelalisib + rituximab.

"The favorable safety profile observed at the 600 mg bexobrutideg dose allows us to optimize its therapeutic effect, providing patients the opportunity to regain control of CLL that has progressed or has failed to respond to other therapies," said Paula O’Connor, M.D., chief medical officer of Nurix. "With regulatory alignment, we are advancing a global registrational program intended to address a large unmet need for patients with relapsed or refractory CLL. We look forward to completing this pivotal Phase 2 study and our confirmatory Phase 3 trial as part of our comprehensive development plan designed to provide patients with a much-needed therapeutic alternative.

As an innovator in the field of targeted protein degradation, Nurix has generated significant data to support bexobrutideg’s potential best-in-class BTK degrader profile.

"During our upcoming conference call, we will share highlights from our latest, unpublished preclinical data demonstrating superior degradation potency, broad coverage of clinically relevant BTK mutations, and exquisite selectivity, which together set a high bar for this class of medicines," said Gwenn Hansen, Ph.D., chief scientific officer of Nurix. "These superior attributes strengthen our conviction that bexobrutideg may prove to be a clinically superior medicine for the treatment of patients with CLL and other B-cell driven diseases."

Investor webcast
Nurix will host an investor webcast today, October 22, 2025, at 8:00 a.m. EDT. A live webcast and replay of today’s event will be available on the Investors section of the Nurix website at View Source A copy of the materials to be presented at the Investor Update will be filed in an accompanying Form 8-K filing and may be found at View Source

(Press release, Nurix Therapeutics, OCT 22, 2025, View Source [SID1234656899])