A study published in Blood Advances found the three-year rate of overall survival (OS) was similar between Dutch patients with diffuse large B-cell lymphoma (DLBCL) who were treated with first-line rituximab biosimilars (R-biosimilars) versus those treated with rituximab (R-originator). According to researchers led by Marcel Nijland, MD, of the University of Groningen in the Netherlands, these findings support the wider use of R-biosimilars, considering their equivalent survival benefit compared with R-originator.
The Netherlands was one of the first countries to implement R-biosimilars within its health-care system, largely because of their considerably lower purchase cost. Dr. Nijland and colleagues examined whether the 2017 endorsement of biosimilars by the Dutch Association of Medical Specialists was merited for R-biosimilars in 4,429 patients with newly diagnosed DLBCL. Data for these patients were found in the Netherlands Cancer Registry. All patients identified in the registry had received at least one cycle of rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP).
Data obtained from a central repository of the Dutch medicinal drug market were used to categorize patients into groups based on whether they received R-originator (n=3,553) or R-biosimilars (n=876). The investigators compared three-year OS rates between the groups, defined as duration between DLBCL diagnosis and all-cause death.
Between January 2014 and the April 2017 approval of R-biosimilars by the European Medicines Agency, a total of 3,183 patients were prescribed R-originator. By the end of 2018, the purchase percentage of R-biosimilars, compared with R-originator, had risen to 91%. During this period, 370 patients received R-originator and 876 received R-biosimilars.
The median age of patients in both the R-originator and R-biosimilar groups was 68 years. However, a significantly greater proportion of patients in the R-originator group were age 60 or younger (30.7% vs. 26.5%; p=0.014). In addition, a significantly greater proportion of patients treated with R-biosimilars had a World Health Organization performance status score of 0 to 2 (57.4% vs. 52.9%; p=0.044), while a significantly smaller proportion of patients in the R-biosimilars arm received >6 cycles of R-CHOP (23.9% vs. 29.9%; p=0.004).
There was no difference in overall response rate between the R-originator and R-biosimilar groups (85% vs. 84%; p=0.326). The proportion of patients who experienced a partial response was the same in both groups (11%). Approximately 74% of patients treated with R-originator had a complete response compared with 72% in the R-biosimilars arm.
Median follow-up periods for patients with DLBCL were 61.7 months for those treated with R-originator and 32.3 months for those treated with R-biosimilars. At three years, the OS rates were 73% (95% CI 72%-74%) in the R-originator group and 73% (95% CI 70%-76%; p=0.855) in the R-biosimilars group.
In an analysis adjusted for age at diagnosis, sex, International Prognostic Index score, and the number of R-CHOP cycles, the researchers found no difference between the two groups in mortality risk (hazard ratio = 0.89; 95% CI 0.76-1.05; p=0.182).
“These results favor the use of R-biosimilars in the first-line treatment of DLBCL because this helps to constrain worldwide health-care spending without negatively affecting OS,” the authors wrote.
The authors report no relevant conflicts of interest.
Brink M, Kahle XU, Vermaat JSP, et al. Impact of rituximab biosimilars on overall survival in diffuse large B-cell lymphoma: a Dutch population-based study. Blood Adv. 2021;5(15):2958-2964.