The following is a summary of “Local and Systemic Immunity During Five Vaccinations Against SARS-CoV-2 in Zanubrutinib-Treated Patients With Chronic Lymphocytic Leukemia,” published in the August 2023 issue of Hematology by Andersson et al.
Patients with chronic lymphocytic leukemia (CLL) are vulnerable to coronavirus disease 2019 (COVID-19) and have a lower response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination, especially if treated with Bruton’s tyrosine kinase inhibitor (BTKi) ibrutinib.
Researchers started a retrospective study to evaluate the impact of Zanubrutinib, a third-generation BTKi, on systemic and mucosal response to SARS-CoV-2 vaccination.
They included 9 patients with CLL who were on Zanubrutinib therapy. Patients provided blood and saliva samples before and 2-3 weeks after SARS-CoV-2 vaccine doses 3, 4, and 5. Ibrutinib-treated control patients (n = 7) and healthy age-matched controls (n = 7) provided blood samples 2 – 3 weeks after vaccine dose 5. The reactivity and neutralization capacity of SARS-CoV-2-specific IgG and IgA antibodies (Abs) were assessed in both serum and saliva and the reactivity of T cells activated with viral peptides.
The results indicated that Zanubrutinib- and ibrutinib-treated patients had considerably lower total spike-specific antibody levels after the fifth dose, up to a 1,000-fold decrease, compared to healthy controls (P<0.01). Spike-IgG levels in the serum of Zanubrutinib-treated patients showed a strong correlation with neutralization capacity (r = 0.68; P<0.0001), indicating functionality. Zanubrutinib-treated patients had virtually no mucosal immunity after 5 vaccine doses, whereas healthy controls had significantly higher levels (P<0.05). In contrast, T-cell reactivity was equally high in both groups.
They concluded that Zanubrutinib-treated CLL patients had impaired systemic and mucosal humoral responses to SARS-CoV-2 vaccination despite normal T-cell responses.