Biosimilar Rituximab Compared to Originator Rituximab for Treatment of Patients With DLBCL

Results from a Phase 3 Trial

According to findings from a phase 3 trial conducted in India and recently published in Cancer Chemotherapy and Pharmacology, biosimilar rituximab had comparable efficacy, safety, pharmacokinetics, pharmacodynamics, and immunogenicity to originator rituximab among patients with diffuse large B-cell lymphoma (DLBCL). 

According to Ankit Patel, MD, Unique Hospital Multispecialty & Research Institute, Surat, India, and coauthors, in various trials among “patients with previously untreated DLBCL, event-free survival, failure-free survival, progression-free survival, and overall survival were improved to a significant extent by the addition of rituximab to [cyclophosphamide, doxorubicin hydrochloride, vincristine sulfate, and prednisone] (CHOP) or CHOP-like chemotherapy.” 

The biosimilar version of rituximab is made with the same natural sources as the originator version, and therefore is thought to have similar effects, but is a more affordable treatment option. 

The study authors aimed to compare the originator rituximab with the biosimilar rituximab among patients with DLBCL. The primary endpoint was objective response rate (ORR), and the secondary endpoints included the assessment of pharmacokinetics, pharmacodynamics, immunogenicity, and safety.

This phase 3 trial was conducted across 28 sites in India and utilized a randomized, assessor-blind, parallel-group design. 153 patients with newly diagnosed DLBCL were enrolled and randomized to receive either biosimilar rituximab (n=102) or originator rituximab (n=51), both administered at 375 mg/m2 every 3 weeks for a total of 6 cycles. 

At the end of cycle 6, the ORR was 82.1% in the biosimilar rituximab arm and 85.71% in the reference rituximab arm. The pharmacokinetics and pharmacodynamic parameters were highly similar across both arms. The incidence rate of immunogenicity was very low across both arms. Lastly, the safety assessments of both treatments were similar, with no major differences in terms of nature, frequency, or severity of treatment-related adverse events. The most commonly occurring treatment-related adverse events in both arms were neutropenia and skin rashes, the majority of which were mild in severity. 

As all endpoints were assessed, Dr Patel et al concluded that the results “demonstrated the biosimilarity between the biosimilar rituximab and the reference rituximab in terms of efficacy, safety, pharmacokinetics, pharmacodynamics and immunogenicity. Therefore, the biosimilar rituximab could add to the cost-effective treatment alternatives for patients with DLBCL in India.” 

Source: 

Patel, A., Bhatt, N., Prakash, S.S. et al. Rituximab biosimilar for the treatment of diffuse large B-cell lymphoma: a phase 3 randomized study in India. Cancer Chemother Pharmacol (2023). https://doi.org/10.1007/s00280-023-04530-x