Supplementary Material for: Zanubrutinib in the maintenance treatment of elderly people with primary central nervous system lymphoma (PCNSL): a report of two cases

Primary central nervous system lymphoma (PCNSL) is a rare and aggressive extranodal non-Hodgkin lymphoma. The predominant subtype is diffuse large B-cell lymphoma (DLBCL), and no systematic lesion is identified at diagnosis. BTKi (Bruton's tyrosine kinase inhibitor) has demonstrated significant clinical activity in DLBCL. We retrospectively reported two patients who began with memory deterioration or right limb movement disabilities. A cranial magnetic resonance imaging (MRI) scan and a brain biopsy were used to diagnose PCNSLs. For induction treatment, middle-dose methotrexate (HD-MTX) regimens were initiated. Due to the patients' inability to tolerate continuous MTX regimens due to severe infections, zanubrutinib was chosen as the maintenance regimen instead. For one patient, the drug was well-tolerated, he achieved sustained complete remission (CR) as demonstrated by MRI, and he survived 14 months after diagnosis. Another patient achieved partial remission (PR) and continued to live six months after diagnosis. As an intriguing possibility, we successfully extended the PFS and OS in elderly PCNSL patients treated with zanubrutinib.