Nurix Therapeutics, Inc. (NASDAQ:NRIX), a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of targeted protein degradation medicines, today announced updated clinical data from the Company's ongoing NX-5948-301 Phase 1a/b clinical trial evaluating bexobrutideg (NX-5948), an investigational oral CNS-penetrant BTK degrader, in patients with chronic lymphocytic leukemia (CLL). The data will be presented during an oral presentation at the 2026 EHA Congress taking place June 11–14, 2026, in Stockholm, Sweden.

"These updated data continue to demonstrate the differentiated profile of bexobrutideg, including durable responses in heavily pretreated patients and encouraging activity in patients earlier in their treatment journey," said Talha Munir, M.B. Ch.B., Ph.D., consultant hematologist at Leeds Teaching Hospitals NHS Trust and deputy chair of the United Kingdom National Cancer Research Institute CLL Study Group. "Importantly, responses were observed across patients with difficult-to-treat disease characteristics, including BTK inhibitor resistance mutations, high-risk molecular features and CNS involvement, while maintaining a favorable tolerability profile."

"With longer follow-up in relapsed/refractory CLL and expansion into earlier-line treatment settings, we continue to see a consistent efficacy and safety profile for bexobrutideg," said Paula O'Connor, M.D., chief medical officer of Nurix. "The durability of responses observed in heavily pretreated patients together with the promising activity seen in BCL2i-naïve and BTKi-naïve patients further support the broad potential of BTK degradation across all lines of therapy in CLL."

"These latest findings continue to reinforce our belief that bexobrutideg has the potential to redefine BTK-directed therapy and emerge as a potentially best-in-class treatment for CLL," said Arthur T. Sands, M.D., Ph.D., president and chief executive officer of Nurix Therapeutics. "The updated data to be presented at EHA across Phase 1 cohorts continue to support the launch of a broad Phase 3 monotherapy program and strengthen the rationale for exploring the use of combination regimens in first- and second-line patients. We look forward to advancing these programs through our recently announced collaboration with Roche."

Growing Safety Cohort Continues to Support Differentiated Profile

Across all Phase 1a/b CLL patients (n=142), bexobrutideg was well tolerated, consistent with prior disclosures, with safety findings generally comparable between patients treated at the 600 mg RP2D and the broader study population.

As of the January 1, 2026, data cutoff:

• No dose-limiting toxicities were observed
• No treatment-related Grade 5 adverse events were reported
• Treatment discontinuations due to adverse events occurred in only 5.6% of patients
• The most common treatment-emergent adverse events included purpura/contusion, neutropenia, petechiae, diarrhea, and fatigue.

Updated Phase 1a Data in Relapsed/Refractory CLL Continue to Support Durable Responses

The Phase 1a dose escalation study enrolled 48 patients with relapsed/refractory CLL/SLL treated with bexobrutideg at doses ranging from 50 mg to 600 mg once daily. Patients were heavily pretreated, having received a median of four prior lines of therapy (range 2–12), including prior BTK inhibitors (97.9%), prior BCL2 inhibitors (83.3%), and prior non-covalent BTK inhibitors (27.1%). Baseline high-risk features included BTK inhibitor resistance mutations (38.3%), TP53 mutations (44.7%), PLCG2 mutations (14.9%), and central nervous system (CNS) involvement (10.4%).

As of the January 1, 2026, data cutoff:

• Median follow-up was 22.4 months
• Median progression-free survival (PFS) was 22.1 months (95% CI: 14.0–NR)
• Objective response rate (ORR) was 83.0% (95% CI: 69.2–92.4)
• Responses included two complete responses, one nodal partial response, and 36 partial responses.
• Responses were observed across patients with BTK inhibitor resistance mutations, high-risk molecular features, and CNS involvement
  
  
  
   

Phase 1b Data Supports High ORR in Earlier-Line Cohorts

Nurix will also present new data from two of the Phase 1b cohorts evaluating bexobrutideg in earlier lines of treatment, including patients who had received prior BTKi treatment but were BCL2i-naïve (Cohort 5) and patients who were BTKi-naïve, including treatment-naïve patients (Cohort 15).

In Cohort 5 (n=19), patients had received prior BTK inhibitor therapy but no prior BCL2 inhibitor:

• ORR was 92.9% (95% CI: 66.1–99.8) among evaluable patients (n=14)
• 18 of 19 patients remained on treatment at data cutoff
• Median follow-up was 5.2 months
• Five patients have not yet reached their first scan but remain on treatment

In Cohort 15 (n=20), which included BTKi-naïve and treatment-naïve patients:

• ORR was 84.2% (95% CI: 60.4–96.6) among evaluable patients (n=19)
• 19 of 20 patients remained on treatment at data cutoff
• Median follow-up was 4.9 months
• Three patients with stable disease remain on treatment