Nurix Therapeutics Presents New Data Demonstrating Durable, Deepening Responses in Phase 1 Trial of Bexobrutideg (NX-5948) in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia (CLL) at the 67th American Society of Hematology (ASH) Annual Meeting & Exposition

Rhea-AI Summary

Nurix (NASDAQ: NRIX) reported updated Phase 1a/1b data for bexobrutideg (NX-5948) in relapsed/refractory CLL/SLL presented at ASH 2025.

Key clinical metrics: ORR 83% (Phase 1a, n=47 evaluable) including 2 complete responses, median PFS 22.1 months, median DOR 20.1 months, and a DCR of 95.7%. Randomized Phase 1b cohort (200 mg vs 600 mg, n=42) showed higher ORR at 600 mg: 83.3% vs 73.7% and a trend toward longer PFS; 600 mg was selected as the RP2D. Safety was consistent across doses (n=126 overall; n=70 at 600 mg) with common TEAEs including purpura/contusion, neutropenia, and petechiae; no dose-limiting toxicities, no systemic fungal infections, and no Grade 4 infections reported.

DAYBreak-CLL-201 Phase 2 is enrolling globally; a company webcast is scheduled for Dec 8, 2025, 8:15 p.m. ET.

Positive

• Objective response rate 83.0% (Phase 1a, n=47 evaluable)
• Median progression-free survival 22.1 months
• Duration of response median 20.1 months
• 600 mg RP2D showed higher ORR 83.3% vs 73.7% (200 mg) in randomized cohort
• 600 mg selected as recommended Phase 2 dose with comparable safety (n=70 at RP2D)

Negative

• Randomized Phase 1b median follow-up is limited (9.8 months)
• Small efficacy cohorts: Phase 1a efficacy evaluable n=47, Phase 1b randomized n=42
• Common treatment-emergent adverse events include neutropenia and purpura/petechiae

Key Figures

CLL Phase 1a ORR 83.0% Objective response rate among 47 efficacy evaluable CLL patients

Complete responses 2 patients (4.3%) Complete responses in Phase 1a CLL efficacy evaluable population

Median PFS 22.1 months Phase 1a CLL population across 50–600 mg doses

Median DOR 20.1 months Duration of response in Phase 1a CLL patients

Disease control rate 95.7% Overall disease control in Phase 1a efficacy evaluable CLL patients

Phase 1b ORR 600 mg 83.3% ORR for 600 mg arm in randomized Phase 1b cohort

Phase 1b ORR 200 mg 73.7% ORR for 200 mg arm in randomized Phase 1b cohort

Phase 1a/1b sample size 126 patients Total CLL/SLL patients in ongoing Phase 1a/1b NX-5948-301 study

Market Reality Check

$18.09 Last Close

Volume Volume 1,228,459 is below the 20-day average of 1,560,618, suggesting no pre-news buildup. normal

Technical Shares at $18.09 are above the $11.54 200-day MA but 21.18% below the $22.95 52-week high.

Peers on Argus 2 Up

Key biotech peers showed mixed moves: RIGL up 2.84%, AVBP up 0.86%, while RLAY, DAWN, and PRME declined. Momentum scanners flagged DAWN and TBPH moving up, but with no same-day peer news and no clear direction match to NRIX, the bexobrutideg update appears stock-specific rather than part of a coordinated sector move.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 01	Clinical webcast notice	Positive	-4.4%	Announced webcast to review new BTK degrader Phase 1a/1b data.
Nov 25	Conference participation	Neutral	-0.9%	Planned fireside chat at a major healthcare investor conference.
Nov 10	Board appointment	Positive	-0.5%	Added oncology-focused biopharma leader Roger Dansey to board.
Nov 07	Clinical data update	Positive	-1.7%	Shared immune-activation data from Phase 1a CBL-B inhibitor NX-1607.
Nov 03	ASH presentations	Positive	-2.5%	Flagged upcoming ASH oral and poster presentations for NX-5948 program.

Pattern Detected

Recent positive or neutral clinical and corporate updates have often been followed by modestly negative price reactions, indicating a pattern of selling or profit-taking into news.

Recent Company History

Over the past six months, Nurix has repeatedly highlighted its clinical pipeline. On Jun 12 (news 866445), it reported durable, deepening responses for bexobrutideg with strong ORRs in CLL and WM, yet the stock fell 5.3%. Subsequent clinical and translational updates on NX-5948, NX-1607, and other programs (news 874458, 906519, 932472, 941807) also saw mostly negative single-day moves. Today’s detailed Phase 1a/1b CLL data extends this clinical story, providing more mature efficacy and safety results for the same lead asset.

Market Pulse Summary

This announcement details mature Phase 1a/1b data for bexobrutideg, showing an ORR of 83.0%, a disease control rate of 95.7%, and median PFS of 22.1 months in heavily pretreated CLL patients. The randomized Phase 1b results support 600 mg as the RP2D with maintained tolerability, feeding into the pivotal DAYBreak program. In light of past clinical updates that saw mixed stock reactions, investors may track longer-term durability, enrollment progress, and future regulatory milestones as key markers of execution.

Key Terms

objective response rate medical

"Objective response rate (ORR) of 83% including two complete responses..."

The objective response rate (ORR) is the percentage of patients in a clinical trial whose tumors measurably shrink or disappear according to preset rules. Investors use it as a quick, objective signal of a drug’s ability to produce a clear treatment effect—like counting how many plants visibly respond after applying a new fertilizer—and higher ORR can improve odds of regulatory approval, commercial success, and company valuation.

progression free survival medical

"...median progression free survival (PFS) of 22.1 months across all doses..."

Progression free survival is the length of time during and after a treatment when a disease, such as cancer, does not get worse or spread. It is an important measure because longer periods of stability can indicate that a treatment is effectively controlling the condition. For investors, it provides insight into the potential durability and success of a therapy or medication.

disease control rate medical

"Overall, the disease control rate (DCR) was 95.7%."

The disease control rate is the share of patients in a clinical trial whose cancer or condition either shrinks or stops getting worse for a specified period after treatment. Think of it like the percentage of people for whom a treatment hits pause or nudges back the problem rather than letting it progress; higher rates suggest the therapy can meaningfully limit disease, which matters to investors assessing a drug’s potential efficacy and commercial value.

central nervous system (CNS) medical

"Of the five patients (4.0%) in the trial who had central nervous system (CNS) involvement..."

The central nervous system (CNS) is the part of the body that includes the brain and spinal cord, acting as the control center for processing information and directing actions. It is essential for coordinating all bodily functions, from movement to thinking. For investors, understanding the CNS is important because it illustrates how complex systems—like markets or organizations—rely on core components to operate smoothly.

AI-generated analysis. Not financial advice.

Objective response rate (ORR) of 83% including two complete responses in CLL patients in Phase 1a study with median progression free survival (PFS) of 22.1 months across all doses tested

Emerging data from randomized Phase 1b cohorts points to higher ORR and longer progression free survival at the 600 mg recommended Phase 2 dose (RP2D) compared to the 200 mg dose

Bexobrutideg was well tolerated with a consistent safety profile between the 600 mg RP2D and the overall study population

Phase 2 clinical trial of bexobrutideg (DAYBreak-CLL-201) currently enrolling globally

Company will host a webcast to discuss the data on Monday, December 8, 2025, at 8:15 p.m. ET

BRISBANE, Calif., Dec. 06, 2025 (GLOBE NEWSWIRE) -- 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, today announced new clinical data from the Company’s ongoing Phase 1a/1b NX-5948-301 study of bexobrutideg (NX-5948) in patients with relapsed or refractory B-cell malignancies. These data will be presented in an oral session at the 67th American Society of Hematology (ASH) Annual Meeting and Exposition in Orlando, FL, on December 6, 2025, at 9:45 a.m. ET, by Zulfa Omer, M.D., Assistant Professor of Internal Medicine at the University of Cincinnati and a principal investigator in the study.

“The clinical activity and durability observed with bexobrutideg in this study are highly encouraging for patients with relapsed or refractory CLL/SLL, many of whom have limited treatment options,” said Dr. Omer. “The responses we are seeing across heavily pretreated patients, including those with prior exposure to both covalent and non-covalent BTK inhibitors and BCL-2 inhibitors, support continued evaluation of bexobrutideg as a therapeutic approach for patients with relapsed or refractory CLL/SLL and ultimately earlier line patients.”

The new and updated data from the Phase 1a/1b study (NX-5948-301) in patients with relapsed or refractory chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) include safety findings across all patients, safety findings for patients treated at the RP2D of 600 mg once daily, updated Phase 1a results with extended follow-up, and emerging efficacy results from the randomized Phase 1b cohort 1 comparing 200 mg and 600 mg once-daily dosing. Collectively, these results provide a maturing clinical picture of bexobrutideg’s efficacy, durability, and tolerability, which form the foundation for Nurix’s advancing pivotal clinical program.

“We are excited to share this important data update for bexobrutideg, which continues to demonstrate compelling efficacy and durability for patients with relapsed or refractory CLL/SLL” said Paula O’Connor, M.D., chief medical officer of Nurix. “Advancing the 600 mg dose into our pivotal DAYBreak program reflects our conviction that this regimen offers patients the greatest opportunity for sustained clinical benefit, supported by a favorable safety profile.”

Data presented at the 2025 ASH Annual Meeting include baseline demographics and safety findings for all patients with CLL/SLL in the ongoing Phase 1a/1b study (n=126) and safety findings for patients treated at the RP2D of 600 mg (n=70). Efficacy results are presented for patients treated with bexobrutideg at doses ranging from 50 mg to 600 mg in the Phase 1a study (n=48) and for patients in the Phase 1b cohort 1, who were randomized and treated with either a 200 mg or 600 mg dose (n=42) in accordance with FDA’s Project Optimus.

Phase 1a/1b demographics and safety findings
Overall, the heavily pretreated Phase 1a/1b population had received a median of three prior lines of therapy (range = 1–17) including prior BTK inhibitors (85.7%), prior BCL-2 inhibitors (61.9%), and prior non-covalent BTK inhibitors (27.0%). The Phase 1a population was more heavily pretreated with a median of four prior lines of therapy (range = 2-12) including prior BTK inhibitors (97.9%), prior BCL-2 inhibitors (83.3%), and prior non-covalent BTK inhibitors (27.1%). At baseline, many patients had mutations associated with BTK inhibitor resistance, including mutations in BTK (39.6% overall, 38.3% in the Phase 1a population) and PLCG2 (8.1% overall, 14.9% in the Phase 1a population). Poor prognostic features were common, including TP53 mutations (39.6% overall, 44.7% in the Phase 1a population). Of the five patients (4.0%) in the trial who had central nervous system (CNS) involvement, all five were in the Phase 1a population.

Bexobrutideg was well tolerated across all dose levels evaluated, consistent with prior disclosures. The treatment emergent adverse event (TEAE) profile was similar between the RP2D of 600 mg and the overall study population with the most common treatment emergent adverse events being purpura/contusion, neutropenia, and petechiae. There were no dose-limiting toxicities, no systemic fungal infections or Grade 4 infections of any kind, and a single event of new onset atrial fibrillation was consistent with the rate in the age-matched general population.

Phase 1a efficacy update (n=48)
The updated Phase 1a dataset includes patients treated at starting dose levels ranging from 50 mg to 600 mg once daily with a median follow-up of 19.0 months (range = 13.5 – 32.3). Among the 47 efficacy evaluable patients, the objective response rate (ORR) was 83.0% including two patients (4.3%) with a complete response, an improvement from earlier disclosures due to additional follow-up and deepening of response. Overall, the disease control rate (DCR) was 95.7%. Importantly, the median progression-free survival was 22.1 months, and the median duration of response (DOR) was 20.1 months. Responses were observed across clinically challenging subgroups including patients who had progressed on prior BTK inhibitors, patients who were double-exposed to both BTK inhibitors and BCL-2 inhibitors, patients who had received prior non-covalent BTK inhibitors, patients with baselines mutations associated with BTK inhibitor resistance including non-C481 BTK mutations, and patients with high-risk molecular features such as TP53 mutations. Meaningful reductions in lymph node burden were also observed independent of baseline mutations associated with BTK inhibitor resistance and poor prognosis.

Phase 1b Cohort 1: Randomized evaluation of 200 mg vs 600 mg once daily (n=42)
In the randomized Phase 1b cohort, 42 patients were assigned to receive either 200 mg (n = 22) or 600 mg (n = 20) once daily. Among the 37 efficacy evaluable patients, preliminary data showed the 600 mg dose with an ORR of 83.3% compared to 73.7% for the 200 mg dose. With a median follow up of 9.8 months, the preliminary PFS curves suggest longer progression free survival for the 600 mg group compared to the 200 mg group.

Across Phase 1a and Phase 1b, the totality of clinical data supports 600 mg once daily as the optimal dose for further development. At this dose level, bexobrutideg demonstrated the strongest clinical activity observed to date, including higher response rates and a favorable trend toward longer progression-free survival in the randomized Phase 1b cohort. Importantly, the 600 mg dose maintained a tolerable safety profile comparable to the overall study population, with no dose-limiting toxicities, no systemic fungal infections, and no Grade 4 infections reported. Taken together, in accordance with FDA’s Project Optimus, these results provide a robust foundation for advancing 600 mg as the recommended Phase 2 dose and for the ongoing pivotal DAYBreak development program.

“These exciting, positive results reinforce the potential for bexobrutideg to be best-in-class and form a strong foundation to support our pivotal development program,” said Arthur T. Sands, M.D., Ph.D., president and chief executive officer, Nurix. “Nurix has entered this next phase of clinical development with momentum and a commitment to deliver a transformative new medicine for patients with B-cell malignancies.”

Webcast Details
Date and time: Monday, December 8, 2025, 8:15 p.m. ET
Access Details: The live webcast and subsequent archived replay will be available in the Investors section of the Nurix website under Events.

About Bexobrutideg (NX-5948)
Bexobrutideg is an investigational, orally bioavailable, brain penetrant, highly selective small molecule degrader of BTK currently being evaluated in the DAYBreak CLL-201 clinical trial (NCT07221500), a pivotal single-arm Phase 2 study of bexobrutideg in patients with relapsed or refractory chronic lymphocytic leukemia. Nurix also continues enrollment in the NX-5948-301 Phase 1a/1b clinical trial (NCT05131022) of bexobrutideg in patients with relapsed or refractory B cell malignancies. Additional information on the ongoing clinical trials can be accessed at clinicaltrials.gov.

About Nurix Therapeutics, Inc.
Nurix Therapeutics is a clinical stage biopharmaceutical company focused on the discovery, development and commercialization of targeted protein degradation medicines, the next frontier in innovative drug design aimed at improving treatment options for patients with cancer and autoimmune diseases. Nurix’s wholly owned, clinical stage pipeline includes degraders of Bruton’s tyrosine kinase (BTK), a B-cell signaling protein, and inhibitors of Casitas B-lineage lymphoma proto-oncogene B (CBL-B), an E3 ligase that regulates activation of multiple immune cell types including T cells and NK cells. Nurix also is advancing multiple potentially first-in-class or best-in-class degraders and degrader antibody conjugates (DACs) in its preclinical pipeline. Nurix’s partnered drug discovery pipeline consists of a preclinical stage degrader of STAT6 in collaboration with Sanofi, and a clinical stage degrader of IRAK4 in collaboration with Gilead, as well as multiple additional programs under collaboration agreements with Gilead Sciences, Inc., Sanofi S.A. and Pfizer Inc., within which Nurix retains certain options for co-development, co-commercialization and profit sharing in the United States for multiple drug candidates. Powered by a fully AI-integrated discovery engine capable of tackling any protein class, and coupled with unparalleled ligase expertise, Nurix’s dedicated team has built a formidable advantage in translating the science of targeted protein degradation into clinical advancements. Nurix aims to establish degrader-based treatments at the forefront of patient care, writing medicine’s next chapter with a new script to outmatch disease. Nurix is headquartered in Brisbane, California. For additional information visit http://www.nurixtx.com.

Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995 and other federal securities laws. When or if used in this press release, the words “anticipate,” “believe,” “could,” “estimate,” “expect,” “intend,” “may,” “outlook,” “plan,” “predict,” “should,” “will,” and similar expressions and their variants, as they relate to Nurix, may identify forward-looking statements. All statements that reflect Nurix’s expectations, assumptions or projections about the future, other than statements of historical fact, are forward-looking statements, including, without limitation, statements regarding: the tolerability, safety profile, therapeutic potential and other advantages of bexobrutideg; the potential role of bexobrutideg in the treatment of patients with CLL and SLL, and Nurix’s plans and expectations for the development of bexobrutideg. Forward-looking statements reflect Nurix’s current beliefs, expectations, and assumptions. Although Nurix believes the expectations and assumptions reflected in such forward-looking statements are reasonable, Nurix can give no assurance that they will prove to be correct. Forward-looking statements are not guarantees of future performance and are subject to risks, uncertainties and changes in circumstances that are difficult to predict, which could cause Nurix’s actual activities and results to differ materially from those expressed in any forward-looking statement. Such risks and uncertainties include, but are not limited to: (i) the risks inherent in the drug development process, including the unexpected emergence of adverse events or other undesirable side effects during clinical development; (ii) uncertainties related to the timing and results of clinical trials; (iii) whether Nurix will be able to fund its research and development activities and achieve its research and development goals; (iv) the impact of economic and market conditions and global and regional events on Nurix’s business, clinical trials, financial condition, liquidity and results of operations; (v) whether Nurix will be able to protect intellectual property and (vi) other risks and uncertainties described under the heading “Risk Factors” in Nurix’s Quarterly Report on Form 10-Q for the fiscal period ended August 31, 2025, and other SEC filings. Accordingly, readers are cautioned not to place undue reliance on these forward-looking statements. The statements in this press release speak only as of the date of this press release, even if subsequently made available by Nurix on its website or otherwise. Nurix disclaims any intention or obligation to update publicly any forward-looking statements, whether in response to new information, future events, or otherwise, except as required by applicable law.

Contacts:

Investors
Kris Fortner
Nurix Therapeutics, Inc.
Kfortner@nurixtx.com

Elizabeth Wolffe, Ph.D.
Wheelhouse Life Science Advisors
lwolffe@wheelhouselsa.com

Media
Aljanae Reynolds
Wheelhouse Life Science Advisors
areynolds@wheelhouselsa.com

FAQ

What were the key efficacy results for Nurix's NX-5948 (NRIX) in the Phase 1a CLL cohort?

Phase 1a (n=47 efficacy evaluable) showed an ORR of 83.0%, median PFS 22.1 months, and median DOR of 20.1 months.

Why did Nurix select 600 mg as the RP2D for bexobrutideg (NRIX)?

The 600 mg dose produced higher ORR (83.3% vs 73.7% at 200 mg) and a favorable trend in PFS with a comparable safety profile.

What safety findings were reported for bexobrutideg (NX-5948) at the 600 mg RP2D?

Safety at 600 mg (n=70) was consistent with the overall study: common TEAEs were purpura/contusion, neutropenia, and petechiae; no DLTs, no systemic fungal infections, and no Grade 4 infections.

How large were the patient populations reported for Nurix's CLL data (NRIX)?

The overall Phase 1a/1b dataset included n=126 for demographics/safety, Phase 1a efficacy cohorts were n=48 (47 evaluable), and Phase 1b randomized cohort was n=42.

Is Nurix advancing to a pivotal trial for bexobrutideg (NRIX) and is it enrolling?

Yes; Nurix is advancing a pivotal DAYBreak program and the Phase 2 DAYBreak-CLL-201 trial is currently enrolling globally.

When can investors view Nurix's webcast discussing the ASH data for NX-5948 (NRIX)?

The company will host a webcast on December 8, 2025 at 8:15 p.m. ET, with a replay available in the Investors Events section of the company website.