Ten-year trend of rituximab use for hematological malignancies: a multiregional real-world study using the Italian valore distributed database network

Objectives: To assess the use of rituximab in non-Hodgkin lymphoma (nHL) and chronic lymphocytic leukemia (CLL) in light of the evolving regulatory landscape, including the introduction of subcutaneous and biosimilar formulations in the past decade. Methods: A retrospective cohort study was conducted using the VALORE distributed database network covering nine Italian regions (2012-2022). Patients with at least one rituximab dispensing and a previous nHL or CLL diagnosis were included. Annual prevalence rates (per 10,000 inhabitants) were estimated for intravenous originator, biosimilar, and subcutaneous formulations. Switch rates between originator and biosimilar were assessed by index year at 1 year of follow-up. Results: We selected 73,870 prevalent rituximab users. Prevalence peaked in 2019 (4.6/10,000) and declined in 2022 (3.4/10,000), with originator use dropping from 4.2 to 0.2/10,000. Among 24,258 incident users (nHL: 21,001; CLL: 3,257), originator-to-biosimilar switch rates rose from 12.5% (2017) to 33.3% (2022) in nHL(p < 0.05) and from 10.3% (2017) to 78.3% (2020) in CLL(p < 0.05). Biosimilar-to-originator switches were rare in CLL (3.8%) but more frequent in nHL (15.3%), due to subcutaneous switch. Conclusions: These findings show a shift from originator to biosimilar rituximab in Italy, alongside a recent decline in its use, likely driven by COVID-19 pandemic and new treatment strategies.