Diffuse large B-cell lymphoma (DLBCL) is an aggressive lymphoma with variable prognoses. Patients with primary refractory DLBCL tend to have poor outcomes with second-line therapy and beyond. Tafasitamab, a CD19-targeting immunotherapy, combined with lenalidomide, is approved by the US Food and Drug Administration for relapsed or refractory (R/R) DLBCL in adults ineligible for autologous stem cell transplantation. In a recent real-world study, over one in four patients receiving tafasitamab for R/R DLBCL had primary refractory disease. Here, we describe patient characteristics, treatment patterns, and clinical outcomes observed in this study by primary refractory status.

In this retrospective cohort study, participating physicians from Cardinal Health's Oncology Provider Extended Network abstracted data from eligible patients’ medical records into electronic case report forms. Eligible patients were aged ≥18 years, initiated tafasitamab for R/R DLBCL on or after October 21, 2020, and had ≥4 months of follow-up (however, otherwise eligible patients who died during follow-up were also included). Results were summarized by primary refractory status using descriptive statistics. Primary refractory was defined as disease progression while receiving or ≤6 months after completion of first-line therapy. Tafasitamab treatment duration was estimated using the Kaplan-Meier method.

The analysis included 181 patients, 47 (26%) with primary refractory and 134 (74%) with nonprimary refractory disease. At tafasitamab initiation, 43% of patients in the primary refractory and 49% in the nonprimary refractory subgroups had ECOG PS ≥2, and most patients had revised International Prognostic Index scores of 3-5 (primary refractory, 83%; nonprimary refractory, 80%). Median (Q1-Q3) follow-up from tafasitamab initiation in the primary refractory and nonprimary refractory subgroups was 5.7 (4.6-7.6) and 6.5 (5.1-9.2) months, respectively. Most patients received tafasitamab as second-line treatment (primary refractory, 70.2%; nonprimary refractory, 72.4%). Median (95% CI) duration of tafasitamab treatment in the primary refractory and nonprimary refractory subgroups was 11.0 (5.8-14.1) and 11.9 (10.5-16.8) months, respectively. Real-world overall response rate (95% CI) was 61.7% (47.8-75.6%) for the primary refractory and 73.1% (65.6-80.6%) for the nonprimary refractory subgroups. At the time of data collection, 35 patients (74.5%) with primary refractory disease and 109 patients (81.3%) with nonprimary refractory disease were still alive, of whom 27 (77.1%) and 94 (86.2%) were still receiving tafasitamab, respectively.

Findings from this study indicate that real-world overall response rates to tafasitamab were favorable among patients with primary refractory and nonprimary refractory DLBCL. Most patients who were alive at time of data collection were still receiving tafasitamab. A limitation is the relatively short follow-up time.

This analysis supports the clinical benefit of tafasitamab treatment for patients with primary refractory and nonprimary refractory disease. Longer follow-up is required to evaluate long-term outcomes with tafasitamab treatment among patients with primary refractory DLBCL.

Incyte Corporation.