Zanubrutinib in Chronic Lymphocytic Leukemia: Real-World Treatment Patterns and Outcomes

Introduction

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia in adults and has undergone notable changes in its treatment approach over the past decade. Management has evolved from primarily chemotherapy-based regimens to the increased use of targeted therapies, which are now commonly incorporated into treatment strategies for many patients. One of the next-generation Bruton’s tyrosine kinase (BTK) inhibitors, zanubrutinib, has recently been approved for the treatment of CLL. Zanubrutinib has been designed to target B-cell receptor signaling pathways while minimizing the off-target effects seen with earlier BTK inhibitors. This article aims to highlight the current treatment practices, clinical outcomes and experiences of zanubrutinib in CLL in routine clinical practice.

Understanding Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a malignancy of mature B lymphocytes characterized by a typically slow progression, and affects the blood, bone marrow, lymph nodes, and spleen. While some individuals remain asymptomatic for many years and do not require treatment, others will experience disease progression that requires early intervention.

With the variety of different CLL treatments available, physicians are not limited to choosing a treatment based on a patient’s stage of disease. Other biological and clinical features must also be taken into consideration when choosing the best treatment for a patient with CLL.

Important factors influencing treatment selection include:

• Age and overall health
• TP53 mutation or 17p deletion
• IGHV mutation status
• Previous treatment history
• Kidney and liver function
• Presence of cardiovascular disease
• Patient preferences and treatment goals

What Is Zanubrutinib?

Zanubrutinib is a small-molecule Bruton’s tyrosine kinase (BTK) inhibitor that targets BTK signaling pathways involved in the survival and proliferation of malignant B cells. In zanubrutinib chronic lymphocytic leukemia treatment, inhibiting the B-cell receptor complex leads to reduced proliferation of leukemic cells and ultimately promotes their death.

In addition to targeting BTK, zanubrutinib is designed to have minimal inhibition of other kinases, with the intention being to maximize the anti-leukemic activity while improving tolerability for long term treatment.

Some of its intended advantages include:

• High BTK selectivity
• Sustained target inhibition
• Oral administration
• Continuous disease control
• Reduced off-target kinase inhibition

Why Real-World Evidence Is Important

Clinical trials with new treatments are conducted under defined conditions and patients with certain characteristics are included in the studies while others are excluded from participation, for instance patients with severe concomitant diseases or with a complex medical history.

Real-world studies provide complementary evidence by evaluating how therapies perform across broader patient populations encountered in routine oncology practice. These studies also help physicians understand long-term treatment adherence, safety management, and healthcare utilization outside the clinical trial setting.

Real-world research commonly evaluates:

• Treatment persistence
• Dose modifications
• Reasons for discontinuation
• Long-term safety
• Overall survival
• Progression-free survival
• Healthcare resource utilization

Real-World Patient Characteristics

The patients treated with zanubrutinib in real life are typically different from those included in clinical trials. Many of them are older and have concomitant diseases for which they have been treated for a long time already. In addition, a substantial proportion of them have high-risk genetic abnormalities and as a result of this, their disease may have a different course or they may have a different treatment response.

As a result, patients in real life are very heterogeneous and can be best studied in real life setting using observational studies.

Common characteristics reported in real-world cohorts include:

• Advanced age
• Hypertension or diabetes
• Chronic kidney disease
• Cardiovascular disorders
• TP53 mutation
• 17p deletion
• Unmutated IGHV
• Prior exposure to targeted therapies

Real-World Treatment Patterns

The use of targeted therapies, including zanubrutinib, in routine clinical practice continues to evolve with increasing clinical experience. It is used in multiple treatment settings, including as an initial therapy for eligible patients with CLL and in those with relapsed or refractory disease following prior treatments.

Patients may be transitioned from other BTK inhibitors due to tolerability concerns or adverse events, with zanubrutinib often continued until disease progression or as part of ongoing long-term management.

Common treatment scenarios include:

• First-line therapy
• Relapsed or refractory CLL
• Switching because of intolerance
• Sequential targeted therapy
• Long-term continuous treatment

Clinical Outcomes in Routine Practice

Most studies have found the outcomes from treatment with zanubrutinib in routine practice to be consistent with those from studies that were undertaken as clinical trials. Thus, many patients have experienced a durable response with reduction in both the size and number of affected lymph nodes, together with a recovery of the blood cell count and relief from all of the associated symptoms.

The progression free survival and overall survival are being monitored by patient registries and by follow-up studies of long term treatment. Patients with different CLL phenotypes and pretreatment therapies show variable results but in many cases a long term control of the disease is achieved and patients are kept on treatment.

Reported real-world benefits include:

• Durable clinical responses
• Symptom improvement
• Reduced lymphadenopathy
• Long treatment persistence
• Consistent disease control

Safety Profile in Everyday Clinical Practice

As many BTK inhibitors are administered on a continuous basis for a long period of time, monitoring of long-term adverse events with due attention to their management is crucial. Zanubrutinib has been shown to have a manageable safety profile in routine practice.

Blood count abnormalities as well as infections and bleeding can occur and need monitoring. As with all cardiovascular drugs, monitoring of blood pressure as well as of potential changes in cardiac rhythm or conduction is indicated and appropriate modification of supportive measures and of other medications as necessary.

Frequently monitored adverse events include:

• Neutropenia
• Anemia
• Thrombocytopenia
• Respiratory infections
• Mild bleeding events
• Gastrointestinal symptoms
• Hypertension
• Cardiac rhythm abnormalities

Factors That Influence Treatment Decisions

When selecting initial therapy for CLL, treatment considerations typically involve evaluating disease-specific characteristics alongside individual patient factors, including overall health status and lifestyle. The choice between short-term and continuous therapy approaches may also depend on the patient’s ability to tolerate longer-duration treatment.

Shared decision-making is increasingly recognized as an integral component of CLL management, supporting treatment selection that aligns with individual patient goals and quality-of-life considerations.

Key decision factors include:

• Genetic risk profile
• Patient age
• Existing comorbidities
• Previous treatment exposure
• Medication interactions
• Patient preferences
• Expected treatment duration

Monitoring During Zanubrutinib Therapy

Monitoring the patient during the treatment with Zanubrutinib allows the health care team to check the treatment response as well as detect any potential complications early.

Periodic monitoring may include assessment of complete blood counts, kidney and liver function, blood pressure, and evaluation of disease-related symptoms. Image studies or other additional diagnostic tests may also be performed from time to time, depending on the patient’s clinical status.

Monitoring commonly includes:

• Blood counts
• Liver function
• Kidney function
• Blood pressure
• Infection surveillance
• Medication adherence
• Symptom assessment

Limitations of Real-World Studies

Even though real-world evidence is a very powerful tool for gathering clinical experience in real life situations, the findings obtained in observational studies have a number of limitations.

In addition, the data may be affected by variables not recorded or by patient selection bias. Thus, Real-World Evidence should be analyzed in conjunction with data from Randomized Clinical Trials, with due consideration of their respective strengths and limitations.

Future Perspectives

Further clinical research on zanubrutinib in CLL is being conducted to test the potential of the drug as a single agent as well as in combination with other treatments for this disease. There is also growing interest in the use of this agent for earlier stages of disease and for use on an individualized basis. Ongoing registries and long term follow-up of patients treated with zanubrutinib will provide further insight into the duration of response to this treatment as well as its safety and quality of life for patients with this disease.

Future research priorities include:

• Combination regimens
• Fixed-duration therapy
• Biomarker-guided treatment
• Long-term safety evaluation
• Comparative effectiveness studies
• Patient-reported outcomes

Conclusion

The expanding body of real-world evidence on zanubrutinib has contributed to a broader understanding of its use in the management of CLL. In routine clinical practice, its use has been observed across diverse patient populations, with data describing patterns of treatment persistence as well as safety and efficacy profile.

Additional observational data may further inform the use of zanubrutinib in patients with CLL. Integrating findings from clinical trials and real-world practice may support more informed, evidence-based approaches to individualized long-term disease management.

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