Prospective comprehensive profiling of immune responses to COVID-19 vaccination in patients on zanubrutinib therapy.

Zanubrutinib-treated and treatment-naïve patients with chronic lymphocytic leukaemia (CLL) or Waldenstrom's macroglobulinaemia were recruited in this prospective study to comprehensively profile humoral and cellular immune responses to COVID-19 vaccination. Overall, 45 patients (median 72 years old) were recruited; the majority were male (71%), had CLL (76%) and were on zanubrutinib (78%). Seroconversion rates were 65% and 77% following two and three doses, respectively. CD4+ and CD8+ T-cell response rates increased with third dose. In zanubrutinib-treated patients, 86% developed either a humoral or cellular response. Patients on zanubrutinib developed substantial immune responses following two COVID-19 vaccine doses, which further improved following a third dose.