Study Observes Equivalence Between CT-P10 Biosimilar and Reference Rituximab

CT-P10 is the first biosimilar of the reference monoclonal anti-CD20 antibody rituximab. At the 2018 American Society of Hematology Annual Meeting, and simultaneously published in The Lancet Haematology, researchers reported that both agents were therapeutically equivalent and well-tolerated among patients with follicular lymphoma (FL).

The ongoing, randomized, double-blind, parallel-group, active-controlled, phase III study compared the efficacy and safety between CT-P10 and rituximab as monotherapy in adult patients with newly diagnosed FL with stage II-IV, grade 1-3a, and low tumor burden disease. Between November 9, 2015, and January 4, 2018, 258 patients were randomized 1:1 to receive CT-P10 (n=130) or rituximab 375 mg/m² intravenously (n=128) monotherapy weekly for four weeks as induction therapy. Patients who achieved complete response (CR), had unconfirmed CR, had partial response, or had stable disease after induction therapy went on to receive maintenance therapy every two months for two years. A total of 231 patients completed up to seven months of treatment: 119 (92%) of those receiving CT-P10 and 112 (88%) receiving rituximab.

Over seven months, the overall response rate (ORR; primary endpoint) was 83.1% in the CT-P10 group and 81.3% in the rituximab group (treatment difference estimate = 1.8%; 90% confidence interval [CI] = −6.43-10.20). Therapeutic equivalence was shown, as 90% CIs were within the prespecified margin of 17%, according to the authors.

The study results indicated that CT-P10 was well tolerated, and both agents had a similar safety profile: The adverse event (AE) rate was 71% with CT-P10 and 67% with rituximab. Infections and infusion-related reactions occurred in a similar proportion of patients in both groups, and no patients experienced progressive multifocal leukoencephalopathy or hepatitis B virus reactivation.

The most common grade 3 or 4 treatment-related AEs were decreased neutrophil count and neutropenia. Six (5%) patients receiving CT-P10 and three (2%) receiving rituximab experienced at least one treatment-related serious AE.

“CT-P10 monotherapy is suggested as a new therapeutic option for patients with low tumor burden FL,” the authors concluded.