Nurix Therapeutics Enrolls First Patient In Phase 3 Trial Of Bexobrutideg For Relapsed Or Refractory CLL/SLL

Nurix Therapeutics, Inc. has announced the enrollment of the first patient in the global Phase 3 DAYBreak CLL-306 clinical trial evaluating bexobrutideg, an investigational targeted protein degrader of Bruton’s tyrosine kinase (BTK), for the treatment of relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). The study is being conducted in collaboration with Roche and marks the first Phase 3 trial for bexobrutideg.

The registrational study is designed to compare bexobrutideg directly with pirtobrutinib, the current standard non-covalent BTK inhibitor used in patients whose disease has progressed after treatment with a covalent BTK inhibitor. Nurix said the trial aims to determine whether targeted protein degradation can provide better clinical outcomes than traditional BTK inhibition in this patient population while supporting future global regulatory submissions.

The Phase 3 trial is expected to enroll approximately 620 patients with relapsed or refractory CLL/SLL who have previously received and progressed on a covalent BTK inhibitor. Participants will be randomly assigned in a 1:1 ratio to receive either a once-daily 600 mg oral dose of bexobrutideg or pirtobrutinib. The study's dual primary endpoints are objective response rate (ORR) and progression-free survival (PFS), both of which will be assessed by an independent review committee.

President and Chief Executive Officer Dr. Arthur Sands said the start of the Phase 3 trial represents a significant milestone for the global development program of bexobrutideg. He noted that the study has the potential to reshape the treatment landscape for patients with CLL by directly comparing BTK protein degradation with non-covalent BTK inhibition. He added that the collaboration with Roche reflects the companies' commitment to exploring the broader potential of BTK degradation across oncology, immunology, and neurology.

Chief Medical Officer Dr. Paula O'Connor said bexobrutideg has already demonstrated encouraging clinical activity in patients with relapsed or refractory CLL, along with a favorable safety and tolerability profile. She added that launching the DAYBreak CLL-306 trial is an important step toward developing new treatment options for patients who continue to face limited therapeutic choices after disease progression.

If successful, the Phase 3 study could position bexobrutideg as a new treatment option for patients with relapsed or refractory CLL/SLL who have exhausted earlier BTK inhibitor therapies. The trial is expected to generate the data needed to support regulatory submissions while further evaluating the potential advantages of targeted protein degradation over existing BTK inhibitor treatments.