Chronic lymphocytic leukemia (CLL) is a common hematologic malignancy affecting adults worldwide. Although targeted therapies have improved the management of CLL, relapse and resistance to therapy remain major clinical challenges for patients with this disease. The introduction of next generation Bruton’s tyrosine kinase (BTK) inhibitors has transformed the management of relapsed or refractory CLL. Alpine zanubrutinib, a highly selective BTK inhibitor, has been shown to have long lasting BTK inhibition with sustained BTK target occupancy and less off-target kinase inhibition compared to first generation BTK inhibitors. As a result, alpine zanubrutinib has been studied for its pharmacologic activity and duration of BTK inhibition and allow for continued treatment of patients with CLL.
In terms of the studies to date that have assessed the use of alpine zanubrutinib in CLL that has relapsed or is refractory, clinical studies have evaluated zanubrutinib as a treatment option for CLL for the period for which it is required.
Understanding Relapsed/Refractory CLL
Relapsed CLL refers to a situation where CLL has relapsed or come back after a period of time where the patient had responded to a treatment. Refractory CLL refers to a situation where a patient’s CLL does not respond to a treatment. In both situations patients are in need of an alternative treatment that can help to overcome mechanisms of resistance of the leukemic cells and that has an acceptable side effect profile allowing for long-term administration.
BTK inhibitors have recently been introduced to the treatment options for patients with CLL and have significantly improved the results for patients with relapsed or refractory disease. BTK inhibitors target key signal-transduction pathways essential for the development, survival and spread of CLL cells.
Challenges in Relapsed/Refractory CLL
- Disease progression after prior therapy
- Development of treatment resistance
- Increased comorbidity burden in older patients
- Need for long-term treatment adherence
- Management of treatment-related adverse events
What Is Alpine Zanubrutinib?
Alpine Zanubrutinib refers to the Alpine clinical development program of zanubrutinib, a next generation BTK inhibitor with enhanced selectivity for BTK compared to first generation BTK inhibitors, such as ibrutinib, which are active against a panel of related kinases in addition to BTK.
Zanubrutinib is different from first generation BTK inhibitors, which are active against other kinases. Zanubrutinib was designed to increase BTK occupancy while reducing the level of activity against other kinases, thereby providing enhanced efficacy and improved safety for patients required to take long-term therapy.
Key Features of Alpine Zanubrutinib
- Highly selective BTK inhibitor
- Sustained BTK target occupancy
- Reduced off-target kinase inhibition
- Designed for continuous treatment
- Zanubrutinib has been evaluated in certain B-cell malignancies in clinical research
Clinical Outcomes in Relapsed/Refractory CLL
Studies conducted with the Alpine Zanubrutinib compound have demonstrated has demonstrated activity against leukemic cells in clinical studies
in CLL patients with relapsed or refractory disease. Responses are achieved in a broad patient population, including patients with highly aggressive disease and prior therapies. Durable responses are particularly important in relapsed or refractory CLL as patients are typically treated for long periods of time and need disease to be controlled to maintain a good quality of life.
Reported Clinical Benefits
- High overall response rates
- Durable clinical responses
- Prolonged progression-free survival
- Effective disease control in heavily pretreated patients
- Consistent therapeutic activity across risk groups
Many clinical investigators believe that the depth and duration of responses to zanubrutinib may be considered among treatment options based on clinical evaluation for patients with CLL who are treated in the modern era.
Progression-Free Survival and Disease Control
In the treatment of CLL that has relapsed or is refractory, the main goals of treatment are to delay the time to disease progression and to maintain the patient’s quality of life. The results for the end point of progression-free survival (PFS) for alpine zanubrutinib support the use of this agent for the treatment of long duration.
Prolonged suppression has been associated with disease control in clinical investigations by preventing the proliferation and death of malignant B cells.
Treatment Goals Achieved with Zanubrutinib
- Reduction in disease burden
- Delayed disease progression
- Long-term disease stabilization
- Improved treatment durability
- Ongoing disease monitoring and management
Safety Profile of Alpine Zanubrutinib
Safety remains important when considering the use of any new therapy for CLL patients that are in a relapsed/refractory state and are on extended duration therapy.
Selective inhibition of BTK with zanubrutinib is designed to minimize interference with other non-BTK kinases potentially responsible for many of the adverse events associated with initial BTK inhibitors. Experience with zanubrutinib suggests that it may have a more favorable safety profile compared with other BTK inhibitors on the market.
Common Safety Considerations
- Monitoring for infections
- Regular hematologic assessment
- Blood pressure monitoring
- Evaluation of bleeding risk
- Assessment of cardiovascular health
All known side effects with zanubrutinib can generally be managed with monitoring and adequate supportive care.
Cardiovascular Safety Considerations
In several BTK inhibitors, there have been reports of cardiovascular adverse events. The CLL patient is usually of an older age and has pre-existing cardiovascular risk factors. As such, BTK inhibitors can result in severe and even long-lasting treatment-induced cardiac defects, which may greatly affect a patient’s long-term outcome.
The improved selectivity of zanubrutinib may lead to a lower incidence of some of the cardiovascular complications, typically seen with less selective BTK inhibitors. The impact of zanubrutinib on the cardiovascular system in patients with CLL could be most pronounced in patients with prior cardiovascular disease or risk factors and could be an important consideration in the risk/benefit assessment for these patients.
Cardiovascular Events Commonly Monitored
- Atrial fibrillation
- Hypertension
- Cardiac arrhythmias
- Palpitations
- Cardiac-related treatment interruptions
Patient Management and Monitoring
Monitoring of the patients treated with alpine zanubrutinib is crucial to maximize efficacy of treatment and to promptly address potential risks or side effects of treatment in order to continue treatment effectively and achieve best long term outcome.
Recommended Monitoring Parameters
- Complete blood count (CBC)
- Liver function tests
- Kidney function assessment
- Blood pressure monitoring
- Infection surveillance
- Cardiovascular evaluation when appropriate
Monitoring is part of clinical management and may support treatment decisions of the treatment over the long-term and for the patient to remain on treatment.
Future Perspectives
The success of alpine zanubrutinib in relapsed/refractory CLL will pave the way for future research. While first data on alpine zanubrutinib in relapsed/refractory CLL is promising and supports the use of alpine zanubrutinib as a further targeted treatment option for this patient group, most likely future studies will investigate alpine zanubrutinib in combination with other drugs, for earlier stage patient populations as well as in so called “high risk” patient populations.
Future Investigations Are Expected to Focus On:
- Combination treatment strategies
- Personalized therapy approaches
- Resistance mechanisms
- Long-term survival outcomes
- Optimization of treatment sequencing
Conclusion
Alpine Zanubrutinib is a BTK inhibitor evaluated in patients with relapsed/refractory CLL for patients with relapsed/refractory CLL given its ability to generate durable responses in patients with relapsed/refractory CLL who have received prior therapies with outcomes such as disease control and patient-reported quality of life evaluated in clinical studies of time until disease progression. With a favorable safety profile, alpine Zanubrutinib will continue to be an important BTK inhibitor in the management of patients with this disease, as more data become available clinicians will be able to manage patients with relapsed or refractory CLL in the best way. This content has been reviewed by a qualified medical reviewer to support accuracy and balance. For individualized guidance and more detailed information, healthcare professionals should be consulted.
