A comprehensive study conducted between December 2021 and January 2024 has revealed that Brukinsa (zanubrutinib) demonstrates a more favorable safety profile compared to Imbruvica (ibrutinib) in patients with chronic lymphocytic leukemia (CLL). The findings, published in Hematological Oncology, analyzed data from 200 patients equally divided between the two treatment arms.
Safety Profile Comparison
The research showed significant differences in adverse event rates between the two BTK inhibitors. Patients treated with Brukinsa experienced fewer severe side effects (4% versus 9%) and serious adverse events (8% versus 17%) compared to those on Imbruvica. Notably, neutropenia occurred exclusively in the Imbruvica group (3% of patients), while sepsis rates were lower in the Brukinsa group (4% versus 8%).
"One of the most striking findings in our study was the absence of neutropenia in the [Brukinsa] group," researchers noted, emphasizing the clinical significance for vulnerable patients where maintaining neutrophil counts is crucial.
Patient Demographics and Treatment Details
The study population had comparable baseline characteristics, with mean ages of 49.65 and 49.16 years in the Imbruvica and Brukinsa arms, respectively. Brukinsa was administered at 160mg twice daily, while Imbruvica was given as 420mg once daily. The Brukinsa arm included more patients with worse ECOG status (71% versus 57%).
Treatment Modifications and Outcomes
Treatment modifications were less frequent in the Brukinsa group, with lower rates of dose reductions (2% versus 5%) and treatment discontinuation (3% versus 7%) compared to Imbruvica. Importantly, while the Imbruvica group recorded two treatment-related deaths, no such fatalities occurred in the Brukinsa group.
Subgroup Analysis and Clinical Implications
The study revealed important nuances in treatment responses across different patient subgroups. Brukinsa showed higher complication rates in patients with non-refractory disease (11.4% versus 5.26%). Stage 3 CLL emerged as a protective factor against severe side effects, while chromosome 17p deletion was identified as the primary risk factor for serious adverse events.
Personalized Treatment Considerations
Despite Brukinsa's generally favorable safety profile, researchers emphasized the importance of individualized treatment approaches. The study found that Brukinsa may carry higher risks in certain populations, particularly patients with elevated beta2-microglobulin levels and longer disease duration.
"These findings provide valuable insights for clinicians managing patients with CLL," the researchers concluded, suggesting that Brukinsa might be preferable for patients at higher infection risk or requiring long-term treatment, while Imbruvica could remain the choice for patients with better performance status.
