Nurix Therapeutics, Inc. has announced a significant stride in the development of its investigational therapy, bexobrutideg (NX-5948), with the European Medicines Agency (EMA) granting it Orphan Drug Designation (ODD) for the treatment of lymphoplasmacytic lymphoma, commonly known as Waldenström macroglobulinemia (WM). This rare blood cancer, characterized by the abnormal proliferation of B lymphocytes and the overproduction of a specific blood protein (IgM paraprotein), can lead to serious complications including blood thickening, vision issues, and heart and neurological problems, highlighting a profound unmet medical need.

Bexobrutideg stands out as an orally bioavailable, brain-penetrant Bruton's tyrosine kinase (BTK) degrader. Unlike traditional BTK inhibitors that merely block the enzyme's activity, bexobrutideg works by inducing the complete degradation of the BTK protein. This targeted protein degradation approach is designed to offer more profound and potentially durable therapeutic effects by eliminating the BTK protein, which is crucial for the survival and growth of malignant B-cells in WM and other B-cell malignancies. Currently, bexobrutideg is being evaluated in an ongoing Phase 1a/b clinical trial in adults with relapsed or refractory B-cell malignancies, where Nurix has already reported encouraging safety and efficacy data, demonstrating early signs of clinical benefit and the potential for long-lasting outcomes in WM patients.

The EMA's ODD is a strong endorsement of bexobrutideg's potential, providing crucial incentives for its development in the EU, including 10 years of market exclusivity upon approval, reduced regulatory fees, and access to specialized regulatory assistance. This follows previous Fast Track designations from the U.S. FDA for bexobrutideg in both WM and relapsed or refractory chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), as well as an EMA PRIME designation for CLL/SLL, collectively underscoring the broad potential and expedited development pathway for this innovative BTK degrader across multiple challenging B-cell cancers.