Abstract
CD20 expression is a hallmark of B-cell lymphomas and the target of anti-CD20 monoclonal antibodies. Although CD20 negativity at second-line therapy initiation has been reported, its prevalence and prognostic impact in diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and mantle cell lymphoma (MCL) remain uncertain. We assessed the prevalence of CD20 negativity at second-line initiation and its association with overall survival (OS) in a nationwide cohort. We included consecutive Danish adults with DLBCL, FL, or MCL who received rituximab-based first-line therapy and were diagnosed between 2005 and 2023, for whom CD20 expression was evaluated at second-line initiation. The primary endpoint was OS from second-line therapy, stratified by CD20 status. Multivariable Cox regression analysis was adjusted for age, sex, and subtype-specific international prognostic indices. Among 1375 patients (814 with DLBCL, 339 with FL, 222 with MCL), 168 (12.2%) were CD20(-) at second-line initiation. Patients who were CD20(-) had lower complete remission rates to first-line therapy (61.5% vs 72.9%; P < .001) and shorter time to second-line therapy compared with patients who were CD20(+) (25.4 vs 35.2 months, respectively; P < .001). Median OS from second-line therapy was 0.9 years for patients who were CD20(-) and 3.1 years for patients who were CD20(+). CD20 negativity was independently associated with shorter OS from second-line therapy in multivariable analysis (hazard ratio, 1.44; 95% confidence interval, 1.18-1.74; P < .001). In conclusion, CD20 negativity is observed in 1 in 8 patients with B-cell lymphomas at second-line initiation and is independently associated with poorer OS from second-line therapy. This underscores an unmet need for therapies targeting non-CD20-dependent antigens.