Use of Rituximab Biosimilar With CHOP to Treat DLBCL Is Effective, EHA Abstracts Find

The combination regimen rituximab (Rituxan), cyclophosphamide (Cytoxan), doxorubicin (Adriamycin), vincristine (Oncovin), and prednisone (R-CHOP) is a common treatment for diffuse large B-cell lymphoma (DLBCL). Two abstracts at the 2022 European Hematology Association (EHA) Congress evaluated the use of biosimilar rituximab to replace the reference product.

The first abstract presented data from the REFLECT study,¹ which is a real-world, multicenter, open-label, single-arm, noninterventional trial evaluating the 2-year effectiveness and safety of SDZ-RTX, a rituximab biosimilar from Sandoz. SDZ-RTX was granted European Union marketing authorization in June 2017 and is sold under the name Rixathon or Riximyo.

The study evaluated 169 patients with DLBCL who were not previously treated. Half of the patients (52.1%) were female, and the median (SD) age was 67.3 (13.4) years. They were treated with SDZ-RTX-CHOP every 2 or 3 weeks for 6 to 8 cycles.

At baseline 19.5% of patients had Ann Arbor disease stage III and 24.3% had stage IV, plus 80.5% of patients had an Eastern Cooperative Oncology Group performance score of 0 or 1. Overall, 100 patients completed the 24-month observation period.

Nearly two-thirds (65.1%, n = 110) achieved a complete response and 29.6% achieved a partial response. The authors found:

• Overall response rate was 94.7%
• 1-year progression-free survival (PFS) was 84.9% and 2-year PFS was 78.5%
• Median PFS was not reached

While a majority (84.3%) of patients experienced an adverse event (AE), only 31.4% were suspected to be related to the therapy.

The researchers wrote that the study confirmed that SDZ-RTX is effective as a first-line treatment of CD20-positive DLBCL along with CHOP.

“These data may help to broaden patient access to rituximab-based chemotherapy and support the sustainability of cancer care,” they wrote.

The second abstract also evaluated R-CHOP, comparing biosimilar rituximab with reference rituximab in a Danish population.² In 2018, Danish hospitals implemented biosimilar rituximab to treat non-Hodgkin lymphoma and DLBCL because of the lower cost of the biosimilar.

“Biosimilar rituximab has shown noninferiority in randomized trials, but population-based analyses of the efficacy are still lacking,” the authors noted.

They used LYFO, a population-based lymphoma registry in Denmark, to identify patients with newly diagnosed DLBCL between January 2015 and January 2022. They identified 2372 patients, with 1049 patients treated with rituximab and 1343 patients treated with a rituximab biosimilar. The median age in the rituximab group was 69 years compared with 71 years in the biosimilar group.

Among the biosimilar group, 94% of patients were receiving CHOP compared with 98% in the rituximab group. The 3-year PFS was similar between the 2 groups: 71.8% (95% CI, 69.1%-74.3%) in the rituximab group vs 72.2% (95% CI, 69.3%-74.0%) in the biosimilar group. In multivariate analyses, there was no difference in PFS or overall survival.

The authors speculated that fewer patients in the biosimilar group were treated with CHOP because of an increased use of mini-CHOP, a reduced-dose regimen of CHOP, and more intensive regimens. Overall, however, the results of the study found no significant difference in PFS or overall survival between the 2 groups.

“These results substantiate the continued use of biosimilar rituximab in patients with DLBCL,” they concluded.

References

1. Welslau M, Kubuschok B, Topaly J, Otremba B, Wolff T, Bryn G. REFLECT: prospective noninterventional study on the effectiveness and safety of Sandoz rituximab (SDZ-RTX) with CHOP for patients with previously untreated CD20-positive diffuse large B-cell lymphoma. Presented at: EHA2022 Congress; June 9-12, 2022; Vienna, Austria. Abstract P1171.

2. Haujir A, Tøstesen M, El-Galaly TC, et al. Efficacy of rituximab and biosimilar rituximab in untreated diffuse large B-cell lymphoma, a Danish population based analysis. Presented at: EHA2022 Congress; June 9-12, 2022; Vienna, Austria. Abstract P1224.