Targeting Bruton Tyrosine Kinase With Zanubrutinib for Treatment of Vitreoretinal Lymphoma: Report of 3 Cases

Updates of primary central nervous system lymphoma

Lymphoma occurring in the central nervous system is considered primary central nervous system lymphoma (PCNSL), usually without systematic lesions. Over the last few decades, a deep understanding of PCNSL has been lacking due to the low incidence rate, and the overall survival and progression-free survival of patients with PCNSL are lower than those with other types of non-Hodgkin lymphoma. Recently, there have been several advancements in research on PCNSL. Advances in diagnosis of the disease are primarily reflected in the promising diagnostic efficiency of novel biomarkers. Pathogenesis mainly involves abnormal activation of nuclear factor kappa-B signaling pathways, copy number variations, and DNA methylation. Novel therapies such as Bruton's tyrosine kinase inhibitors, immunomodulatory drugs, immune checkpoint inhibitors, and phosphoinositide 3-kinase/mammalian target of rapamycin inhibitors are being evaluated as possible treatment options for PCNSL, especially for relapsed/refractory (R/R) cases. Several clinical trials also indicated the promising feasibility and efficacy of chimeric antigen receptor T-cell therapy for selected R/R PCNSL patients. This review focuses on discussing recent updates, including the diagnosis, pathogenesis, and novel therapy of PCNSL.

Bilateral Cystoid Macular Edema with Zanubrutinib Therapy: A Case Report

We present a patient with recurrent mantle cell lymphoma (MCL) who was treated with zanubrutinib, a Bruton's tyrosine kinase inhibitor. He subsequently developed bilateral cystoid macular edema (CME) in both eyes. This is the first report of CME in a patient with MCL who was treated with zanubrutinib. CME was refractory to topical corticosteroid therapy, but sub-Tenon's steroid injections and holding off zanubrutinib managed to decrease the CME. Treatment managed to prevent further vision loss but did not restore lost vision. The prompt ophthalmic exam is recommended for patients on zanubrutinib with decreased vision.

Targeting Bruton’s tyrosine kinase in vitreoretinal lymphoma: an open-label, prospective, single-center, phase 2 study

Vitreoretinal lymphoma (VRL) is strongly linked to central nervous system (CNS) progression with no standard treatment approaches. Commonly used strategies include repeated intraocular injections of low-dose methotrexate or local radiotherapy, with great inconvenience, long-term side effects, and high risk of CNS relapse. In this study, we evaluated the efficacy and safety of bruton’s tyrosine kinase inhibitors (BTKi) in the treatment of VRL. This prospective single-center study enrolled patients with relapsed or newly diagnosed VRL between October 2020 and April 2022. Patients received BTKi monotherapy until disease progression or unacceptable toxicity. The primary endpoint was the disease control (DC) rate after one month of treatment; secondary endpoints include toxicity, overall survival (OS), and progression-free survival (PFS). Ten consecutive patients with VRL were enrolled into this study. After 1-month treatment, 9 patients (90%) achieved a DC, with 7 patients (70%) achieving a complete response (CR). With a median follow-up of 8.3 (2.5–21.4) months, 4 patients were confirmed to have disease progression, with a PFS of 1.2, 7.5, 9.1, and 11.6 months, respectively. The remaining 6 patients have durable control of disease and were still on treatment at time of the analysis. BTKi were well-tolerated and no patients discontinued the drug because of adverse events. In conclusion, targeting BTK in VRL is viable, and our findings could pave the way for a paradigm change in VRL therapy choices. Further large-scale studies, however, are required to give stronger evidence about the efficacy and safety.

A Canadian Perspective on the Treatment of Waldenström Macroglobulinemia

Waldenström macroglobulinemia (WM) is a slowly progressing B-cell non-Hodgkin lymphoma characterized by monoclonal IgM gammopathy in the blood and infiltration of the bone marrow by clonal lymphoplasmacytic cells. As an incurable disease, the goals for therapy for WM are to relieve symptoms, slow disease progression, prevent organ damage, and maintain quality of life. However, given the rarity of WM, clinical trials comparing treatments for WM are limited and there is no definitive standard of care. The selection of first-line WM therapy is thus based on patient factors, disease characteristics, and drug access, with bendamustine-rituximab and Bruton's tyrosine kinase (BTK) inhibitor therapy considered preferred treatments. Other treatments such as proteasome inhibitor- or purine analogue-based therapy, alternative chemoimmunotherapy, and autologous stem cell transplantation are generally reserved for the relapsed setting but may be used in rare circumstances in earlier lines of therapy. This paper summarizes the efficacy and safety of these WM therapies and discusses considerations for treatment from a Canadian perspective.