Study of Zanubrutinib in Older Patients With Previously Untreated Chronic Lymphocytic Leukemia (CLL) (ZEN-CLL)

September 9, 2026 updated by: The Lymphoma Academic Research Organisation

ZEN-CLL - A Phase II Trial Evaluating Zanubrutinib in Elderly, Treatment-Naïve, CLL Patients

This phase II, open-label, multicenter study evaluates zanubrutinib in patients aged 80 years and older with previously untreated chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) who require treatment.

CLL and SLL are slow-growing blood cancers that mainly affect older adults. Although zanubrutinib is an effective treatment, taking it continuously at the full dose may increase the risk of side effects over time, particularly in elderly patients. The study aims to assess whether a planned reduction in the dose of zanubrutinib after an initial period of treatment can maintain disease control while improving long-term tolerability.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The ZEN-CLL study is evaluating a treatment strategy based on zanubrutinib in previously untreated elderly patients with CLL or small lymphocytic lymphoma (SLL). Approximately 95 participants will be enrolled in 17 LYSA centers in France.

All participants will receive zanubrutinib 160 mg twice daily for the first 18 months of treatment. After Month 18, the dose will be reduced according to the dose received at that time and the participant's tolerability. Treatment will continue until permanent treatment discontinuation or the end of study participation.

The study aims to determine whether this dose reduction strategy can maintain disease control while improving long-term tolerability in this elderly population.

Study Type

Interventional

Enrollment (Estimated)

95

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • France
      • Argenteuil, France, 95107
      • Avignon, France, 84000
        • Ch D'Avignon - Hopital Henri Duffaut
        • Contact:
        • Principal Investigator:
          • Safia CHEBREK, doctor
      • Bayonne, France, 64109
        • CH de la Côte Basque
        • Contact:
        • Principal Investigator:
          • Nathan MOTTAL, doctor
      • Bordeaux, France, 33076
      • Cergy-Pontoise, France, 95303
      • Corbeil-Essonnes, France, 91106
        • Ch Sud Francilien
        • Contact:
        • Principal Investigator:
          • Laurence SIMON, doctor
      • Estaing, France, - SITE ESTAING
      • Grenoble, France, 38700
        • CHU de GRENOBLE
        • Contact:
        • Principal Investigator:
          • Lysiane MOLINA, doctor
      • Le Chesnay, France, 78157
        • Ch de Versailles - Hopital Andre Mignot
        • Contact:
        • Principal Investigator:
          • Fatiha MERABET, doctor
      • Le Mans, France, 72000
        • Ch Du Mans-Centre de Cancerologie de La Sarthe
        • Contact:
        • Principal Investigator:
          • Kamel LARIBI, doctor
      • Lille, France, 59020
        • Hopital Saint Vincent-de-Paul
        • Contact:
        • Principal Investigator:
          • Bénédicte HIVERT, doctor
      • Lyon, France, 69373
      • Orléans, France, 45067
      • Rouen, France, 76038
      • Toulouse, France, 31059
      • Vandœuvre-lès-Nancy, France, 54511
        • CHRU Nancy - hôpital Brabois
        • Contact:
        • Principal Investigator:
          • Pierre FEUGIER, professor
    • Pierre Bénite
      • Lyon, Pierre Bénite, France, 69310

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Participant who understands and voluntarily signs and dates an informed consent form prior to any studyspecific assessments/procedures being conducted, including consent for specific biology analysis
  • Must be able to adhere to the trial visit schedule and other protocol requirements
  • ≥ 80 years at the time of signing the informed consent form (ICF) with no upper age limit
  • Previously untreated and documented CLL or small lymphocytic lymphoma (SLL), with a Royal Marsden Hospital (RMH) or Matutes Score of 4 or 5. For SLL a detectable clone with a CLL phenotype in the peripheral blood is a prerequisite for trial participation.
  • Participant requiring treatment according to 2018 IWCLL guidelines
  • ECOG performance status 0 to 2
  • Life expectancy > 6 months

  • Adequate hematopoietic function within 7 days before the participant's enrollment

    • ANC ≥ 0.75 G/L
    • And Platelets ≥ 50 G/L Note: Platelets transfusions may be administered during screening to meet this requirement
  • Hemoglobin level > 9g/dL, regardless of transfusion
  • Adequate renal function defined by a Creatinine Clearance ≥ 30 ml/min calculated according to MDRD or CKD-EPI or Cockcroft-Gault (using actual body weight).
  • Adequate liver function, as indicated by a total bilirubin <1.5 x ULN, AST and ALT <3 x ULN value, unless directly attributed to the participant's CLL/SLL or to Gilbert's Syndrome (the ULN is based on institutionalvalues)
  • Participant covered by any social security system
  • Participant who understands and speaks the country official language unless local regulation authorizes independent translator

Exclusion Criteria:

  • Any prior CLL or SLL-specific therapies, even including rituximab used for autoimmune cytopenias.

  • Clinically significant cardiovascular disease including the following:

    1. Myocardial infarction within 6 months prior to ICF signature
    2. Unstable angina within 3 months prior to ICF signature
    3. NYHA class III or IV heart failure
    4. Uncontrolled hypertension
    5. History of clinically significant arrhythmias (including sustained ventricular tachycardia, ventricular fibrillation, or torsades de pointes).
    6. History of Mobitz II second- or third-degree heart block without permanent pacemaker
    7. Known LVEF <50% as determined by echocardiography or multiple uptake gated acquisition (MUGA) scan
  • Child-Pugh liver cirrhosis
  • Clinical evidence for Central Nervous System involvement by CLL
  • Severe chronic obstructive lung disease with hypoxemia
  • Severe diabetes mellitus
  • Disease significantly affecting gastrointestinal function (malabsorption syndrome, stomach or small bowel resection)
  • Active or non-active autoimmune hemolytic anemia (AIHA) (isolated positive DAT is not an exclusion criterion, but reticulocytes/haptoglobin levels must be in lab normal ranges) or idiopathic thrombocytopenic purpura (ITP), requiring steroid therapy with > 20 mg daily of prednisone dose or equivalent.
  • Any prior history of Richter transformation or DLBCL
  • Any evidence or suspicion of Richter transformation or DLBCL during screening
  • Active malignancy other than the one treated in this trial. Prior history of malignancies unless the participant has been free of the disease for ≥ 2 years.

However, participants with the following history /conditions that have been treated with a curative intent are allowed:

  1. Non-invasive basal cell or epidermoid carcinoma (non melanoma)
  2. In situ carcinoma of the cervix
  3. In situ carcinoma of the breast
  4. Incidental histologic finding of prostate cancer (T1a or T1b) using the tumor, nodes, metastasis [TNM] clinical staging system

  5. Woman with adjuvant endocrine therapy (I.e., hormonotherapy) after breast cancer treatment can be enrolled if hormonotherapy was started for ≥ 2 years

    • History of stroke or intracranial hemorrhage within 6 months prior to ICF signature.
    • Major surgery 28 days before the ICF signature
    • History or known bleeding disorders (e.g hemophilia or von Willebrand disease)
    • Active Hepatitis C Virus (HCV) infection (RNA PCR-positive). Participants who received treatment for HCV infection that was intended to eradicate the virus may participate if hepatitis C RNA levels are undetectable
    • Active Hepatitis B Virus (HBV) infection (DNA PCR-positive). Participants with evidence of prior HBV infection but who are PCR-negative are permitted in the trial but should receive prophylactic antiviral therapy during the entire treatment with active monitoring of viral load in the blood
    • Patient with a positive HIV test before enrollment are eligible provided that they are stable on antiretroviral therapy for at least 4 weeks, have a CD4 count ≥ 200/uL, have an undetectable viral load, and have not had a history of opportunistic infection attributable to AIDS within the last 12 months.Known or suspected hypersensitivity or anaphylaxis to trial intervention including active substance or to any of the excipients.
    • Requires or receiving anticoagulation with warfarin or dual antiplatelets therapy equivalent vitamin K antagonists (other anticoagulants allowed: novel oral anticoagulant alone, aspirin alone, heparin alone).
    • Requires treatment with a strong/moderate cytochrome CYP3A4 inhibitor/inducer.
    • Participation in another clinical study who would compromise the participation to the current study.
    • Vaccinated with live, attenuated vaccines within 6 months of ICF
    • Use of any standard or experimental anti-cancer drug therapy within 28 days before the start (Day 1) of study treatment
    • Corticosteroid use > 20 mg per day within 1 week before the first dose of trial intervention, except as indicated for other medical conditions, such as inhaled steroid for asthma, topical steroid use, or as premedication for administration of trial intervention or contrast.
    • Any significant medical conditions, or laboratory abnormality or psychiatric illness likely to interfere with participation in this clinical trial or affect interpretation of trial outcomes (according to the investigator's decision)
    • Any uncontrolled and/or active significant infection (eg, bacterial, viral, or fungal; including participants with positive cytomegalovirus PCR).
    • Participant deprived of their liberty by a judicial or administrative decision
    • Participant hospitalized without consent
    • Adult participant under legal protection

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Zanubrutinib
Participants will receive oral zanubrutinib followed by a predefined dose reduction strategy. Treatment will continue until disease progression, permanent treatment discontinuation, withdrawal of consent, loss to follow-up, or the end of study participation.
Drug: Zanubrutinib
Zanubrutinib is a Bruton tyrosine kinase (BTK) inhibitor administered orally.
Other Names:
  • BRUKINSA

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Progression-Free Survival (PFS)
Time Frame: 30 months and 5 years
The primary endpoint is the Progression-Free Survival (PFS).
30 months and 5 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Permanent Treatment Discontinuation (PTD) Rate
Time Frame: 18 months
The key secondary endpoint is the rate of permanent treatment discontinuation (PTD).
18 months
Overall Survival (OS)
Time Frame: At 30 months and at 5 years
The secondary efficacy endpoint 1 is the Overall Survival (OS).
At 30 months and at 5 years
Time to Next Anti-Leukemia Treatment
Time Frame: At 30 months and at 5 years
The secondary efficacy endpoint 2 is the Time to Next Anti-Leukemia Treatment (TTNLT).
At 30 months and at 5 years
Overall Response Rate
Time Frame: At 18 months and at 30 months
The secondary efficacy endpoints 3 and 4 are Overall Response Rate (ORR) at 18 months and at 30 months, respectively.
At 18 months and at 30 months
Change From Baseline in Geriatric Assessment Scores
Time Frame: at baseline, at 18 months, at 30 months and at 42 months
Geriatric condition will be evaluated using minimal nurse-delivered scales recommended by the SIOG.
at baseline, at 18 months, at 30 months and at 42 months
Health-Related Quality of Life
Time Frame: At baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Health-Related Quality of Life as assessed by Questionnaire
At baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Frailty Assessment Score
Time Frame: At baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Frailty status will be assessed using a validated frailty scale.
At baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Patient-Reported Treatment Side Effect Burden
Time Frame: Baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Treatment side effect burden will be assessed using a patient-reported questionnaire.
Baseline, every 3 months for the first 2 years, and every 6 months thereafter for 3 years.
Incidence and Severity of Adverse Events (AEs), Serious Adverse Events (SAEs), and Adverse Events of Special Interest (AESIs)
Time Frame: From first dose of study treatment until the end of study participation (up to 5 years).
Safety will be assessed by the incidence, severity, and seriousness of adverse events, including serious adverse events and adverse events of special interest.
From first dose of study treatment until the end of study participation (up to 5 years).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

The Lymphoma Academic Research Organisation

Collaborators

Lymphoma Study Association
BeOne Medicines

Investigators

  • Principal Investigator: Loïc YSEBAERT, Professor, IUCT Oncopole
  • Principal Investigator: Emmanuelle FERRANT, Doctor, Hospices Civils de Lyon

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

December 1, 2026

Primary Completion (Estimated)

April 1, 2029

Study Completion (Estimated)

December 1, 2032

Study Registration Dates

First Submitted

July 28, 2026

First Submitted That Met QC Criteria

July 28, 2026

First Posted (Actual)

July 31, 2026

Study Record Updates

Last Update Posted (Actual)

September 14, 2026

Last Update Submitted That Met QC Criteria

September 9, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ZEN-CLL
  • 2025 (U.S. NIH Grant/Contract: Faculty of Social Sciences Scientific Grant at the University of Gdańsk)
  • 2025-525080-32-00 (Ctis)

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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