Zanubrutinib for the treatment of Bing–Neel syndrome

Summary Infiltration of the central nervous system by malignant lymphoplasmacytic cells is a rare complication of Waldenström macroglobulinaemia (WM) and is referred to as Bing–Neel syndrome (BNS). Traditionally, the treatment of BNS included chemotherapy, but in more recent years, the oral Bruton tyrosine kinase (BTK) inhibitor ibrutinib has become a standard therapy for WM and the most common therapy for BNS due to the drugs tolerability and ability to cross the blood–brain barrier. Zanubrutinib, a second‐generation covalent BTK inhibitor with fewer off‐target effects, is also effective in WM. In this series, we report on the successful use of zanubrutinib in nine patients with BNS, of whom five had prior exposure to ibrutinib and four were naïve to BTK inhibitors.