Program DHC-Virtual
20 - 21 January 2021
Clinical Abstracts session 1
Abstract
Impact of rituximab biosimilars on overall survival in DLBCL
20 January
09:06 09:18
M. Brink
Paper

impact of rituximab biosimilars on overall survival among PATIENTS WITH DIFFUSE LARGE B-CELL LYMPHOMA IN THE NETHERLANDS; a nationwide, population-based cohort study

Mirian Brink (1), Xaver U. Kahle (2), Joost S.P. Vermaat (3), Josee M. Zijlstra (4), Martine Chamuleau (4), Marie José Kersten (4), Müjde Durmaz (1), Wouter J. Plattel (2), Pieternella J. Lugtenburg (5), Wendy Stevens (6), Rogier Mous (7), Elisabeth G.E. de Vries (8), Marjolein W.M. van der Poel (9), Prashant V. Nannan Panday (10), Gerwin Huls (2), Tom van Meerten (2), Marcel Nijland (2)
(1) Netherlands Comprehensive Cancer Organisation (IKNL), Department of Research, Utrecht, (2) University Medical Center Groningen, Department of Hematology, Groningen, (3) Leiden University Medical Center, Department of Hematology, Leiden, (4) Amsterdam University Medical Center, Department of Hematology, Amsterdam, (5) Erasmus MC Cancer Institute, Department of Hematology, Rotterdam, (6) Radboud University Medical Center, Department of Hematology, Nijmegen, (7) University Medical Center Utrecht, Department of Hematology, Utrecht, (8) University Medical Center Groningen, Department of Medical Oncology, Groningen, (9) Maastricht University Medical Center, Department of Hematology, Maastricht, (10) University Medical Center Groningen, Department of Clinical Pharmacy and Pharmacology, Groningen
No potential conflicts of interest
Introduction

In 2017, rituximab biosimilars (R-biosimilars) for treatment of diffuse large B-cell lymphoma (DLBCL) was approved. Until now, safety regarding treatment-related toxicities of R-biosimilars was evaluated in prospective studies on rheumatoid arthritis and naïve follicular lymphoma. However, patient numbers were limited in order to assess non-inferiority in efficacy of R-biosimilar¾in combination with cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP)¾of patients with DLBCL. Therefore, this population-based study aimed to assess the 2-year overall survival (OS) of patients with DLBCL treated with R-biosimilars or rituximab originator (R-originator) in the Netherlands.

Methods

All DLBCL patients ≥18 years diagnosed between 2014-2018 with at least one cycle of R-CHOP were identified in the Netherlands Cancer Registry. Detailed information on baseline characteristics,  diagnostics and first-line therapy was available for all patients. Patients were categorized into R-originator and R-biosimilars groups using data from a central repository of the Dutch medicinal drug market. The primary endpoint was 2-year OS, defined as the date from DLBCL diagnosis to all-cause death. Patients alive were censored at February 1, 2020. Multivariable evaluation was performed using Cox regression. P<0.05 indicates statistical significance. Due to time dependency, differences in follow-up time between R-originator and R-biosimilars was unavoidable. Therefore, a sensitivity analysis was performed by excluding all patients in the R-originator group diagnosed in the pre-EMA approval period of R-biosimilars.   

Results

By the end of 2018, 91% of purchased rituximab by the Dutch hospitals were biosimilars. In total, 4,430 patients with DLBCL who received at least one cycle of R-CHOP were identified. Of these patients, 876 (20%) were categorized in the R-biosimilars group and 3,554 (80%) in the R-originator group. Sex and age distribution was similar between the two subgroups. Patients in the R-biosimilars group less frequently received >6 cycles of R-CHOP as compared to patients treated with R-originator (24% vs. 30%, P=0·003). The 2-year OS did not differ between patients treated with R-originator or R-biosimilars (77% vs. 78%, P=0·775). Risk of survival between R-originator and R-biosimilars remained similar after adjustment for sex, age, International Prognostic Index (IPI) score and number of R-CHOP cycles. In the sensitivity analysis, the frequency of >6 cycles of R-CHOP as well as the 2-year OS was similar for patients treated with R-originator or with R-biosimilars.  

Conclusion

The results in this independent validation 'real world' population study confirm equivalent efficacy in patients with DLBCL treated with either R-originator or R-biosimilars¾in combination with CHOP¾resulting in a significant reduction of costs in the Dutch healthcare system. Thus, our conclusion has far-reaching consequences at the level of global implementation of rituximab biosimilars, and consequently, containment of global health care expenditure in treatment of hematological malignancies.

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