Real-World Use of Tafasitamab (tafa) for Relapsed or Refractory (R/R) Diffuse Large B-Cell Lymphoma (DLBCL) Among Racial and Ethnic Minorities in the United States

Introduction: Tafa, a CD19-targeting immunotherapy, received accelerated approval by the FDA in combination with lenalidomide (len) for the treatment of patients with R/R DLBCL ineligible for autologous stem cell transplantation. In a recent real-world study (RWS) of tafa for R/R DLBCL, nearly one-third of patients were from typically underrepresented racial groups (abstract submitted to ASH 2023). Research has shown that patient characteristics, risk factors, and outcomes for DLBCL can differ by race and ethnicity (Li Y, et al. Cancer Epidemiol. 2015;39:8-13; Ermann D et al. J Clin Oncol. 2022;40(suppl):7507). The purpose of this analysis is to understand the patient characteristics, treatment patterns, and outcomes observed in the tafa RWS by race and ethnicity.

Methods: This was a retrospective cohort study in which 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 ≥18 years of age who initiated tafa for R/R DLBCL on or after Oct 21, 2020. Included patients had ≥4 months of follow-up unless the patient died during this period. Use of tafa in combination with len was not a requirement for study eligibility. Patients who received tafa as part of a clinical trial were excluded. Results were summarized by race (White, Black/African American, “Other”) and ethnicity (Non-Hispanic, Hispanic) using descriptive statistics. The “Other” racial category included patients with mixed race or a race other than White, Black/African American, or Unknown. The Kaplan-Meier method was used to measure time to tafa discontinuation. Due to limited follow-up and small sample size, effectiveness outcomes for subgroups smaller than 20 patients are not presented.

Results: A total of 181 patients who initiated tafa for R/R DLBCL were included in this analysis. Table 1 shows patient characteristics, treatment patterns, and outcomes by racial and ethnic groups. The racial composition of the study population was 64% White, 22% Black/African American, 8% “Other,” and 6% Unknown (Unknown not displayed in Table), and ethnic composition was 82% non-Hispanic, 17% Hispanic, and 1% Unknown (Unknown not displayed in Table). Most physicians who participated in this study were from community oncology practices (83%). The median follow-up time from tafa initiation to data collection among all patients was 6.5 (interquartile range [IQR], 5.0-8.6) months. The majority of patients (96%) received tafa in combination with len. At the time of data collection, 144 patients (80%) were alive, among whom 121 (84%) were still receiving tafa.

The median age at which tafa was initiated ranged from 70 to 72 years for all racial and ethnic groups. Among the racial groups, the White cohort had the highest percentage of patients with an ECOG PS ≥2 (53%) and Ann Arbor Stage IV (68%) at time of tafa initiation. Among the racial categories, the median time (IQR) from initial DLBCL diagnosis to initiation of tafa was longest in Black/African Americans (23.3 [12.6-34.8] months) and shortest in the “Other” group (18.0 [15.0-21.4] months). In non-Hispanics and Hispanics, the median (IQR) duration from initial DLBCL diagnosis to tafa initiation was 20.0 (12.4-35.0) and 19.0 (14.0-34.0) months, respectively ( Table 1).

Among patients who had disease response data, the real-world overall response rate (95% CI) was 75.0% (66.8-83.2) and 77.5% (64.6-90.4) for the White and Black/African American cohorts, and 74.5% (67.3-81.7) and 80.8% (65.7-95.9) for non-Hispanic and Hispanic groups, respectively ( Figure 1).

Conclusions: The diverse population in this RWS is reflective of the heterogeneous patient population with R/R DLBCL treated primarily at community oncology centers in the United States. In addition, the study results support the clinical benefit of tafa across racial and ethnic groups. The majority of patients were still receiving tafa at data cutoff and follow-up was limited in duration; the median follow-up time in this study was shorter than the median time to complete response observed in L-MIND (NCT02399085; Duell J, et al. Haematologica. 2021;106:2417-2426), the pivotal phase 2 trial that contributed to the accelerated FDA approval of tafa for R/R DLBCL. A longer follow-up is required to better assess long-term outcomes of tafa treatment for R/R DLBCL among racial and ethnic patient groups.