Treatments and Outcomes of Newly Diagnosed CD5-Positive Diffuse Large B-Cell Lymphoma: A Multi-Institutional Observational Study.

CD5-positive diffuse large B-cell lymphoma (CD5+ DLBCL) is characterized by a poor prognosis and frequent central nervous system (CNS) relapse. Sandwich therapy comprising dose-adjusted (DA)-EPOCH-R (etoposide, prednisolone, vincristine, cyclophosphamide, doxorubicin, and rituximab) and high-dose methotrexate (HD-MTX) (DA-EPOCH-R/HD-MTX) showed excellent efficacy and manageable safety in a phase II study of patients diagnosed with stage II-IV CD5+ DLBCL. To validate the results of that study and elucidate the current state of treatment for CD5+ DLBCL, we retrospectively analyzed the outcomes of patients with CD5+ DLBCL diagnosed between 2016 and 2021 who received anthracycline-containing chemotherapy with rituximab. Among the 346 patients evaluated, 62 (18%) received DA-EPOCH-R/HD-MTX. The median follow-up time was 43 months. In 55 patients with stage II-IV disease treated with DA-EPOCH-R/HD-MTX, the 2-year overall survival (OS), progression-free survival, and cumulative incidence of CNS relapse were 87% (95% CI, 73%-94%), 76% (95% CI, 61%-86%), and 7.3% (95% CI, 2.4%-16%), respectively. There were no treatment-related deaths. Febrile neutropenia occurred in 18 (33%) patients. Multivariate analysis of the 346 patients identified elevated serum lactate dehydrogenase levels, multiple extranodal involvement, no intrathecal MTX (IT-MTX), and no DA-EPOCH-R/HD-MTX as independent risk factors for OS. Only one CNS relapse event was observed in 28 patients who received both HD-MTX and IT-MTX. Our study provides real-world data on the treatments and outcomes of a large number of patients. The favorable survival and manageable toxicity of DA-EPOCH-R/HD-MTX have been validated in clinical settings. The use of HD-MTX and IT-MTX might be effective for preventing CNS relapse in patients with CD5+ DLBCL.