At ASH, Data on Truxima Underscore the Biosimilar's Safety and Efficacy

Celltrion and Teva’s biosimilar rituximab, CT-P10, Truxima, recently launched in the United States. The product is the first rituximab biosimilar to become available to US patients, and during this week’s 61st meeting of the American Society of Hematology (ASH), 2 research teams presented data that highlight the biosimilar’s safety and efficacy in patients with lymphoma.

New phase 3 data show similar efficacy and safety between CT-P10, reference

First, a team presented on updated phase 3 study results from a clinical trial of the biosimilar in 140 patients with newly diagnosed advanced-stage follicular lymphoma.¹ Previously reported results from the same trial showed similarity between the biosimilar and the reference product, Rituxan, in terms of progression-free survival (PFS) and overall survival (OS) at a median follow-up of 22.6 months.

In the study, 70 patients received biosimilar rituximab with cyclophosphamide, vincristine, and prednisone, and 70 patients received the reference with the same regimen, for 8 cycles. Of these patients, 62 patients in the biosimilar group and 60 in the reference group entered the rituximab monotherapy maintenance period after induction therapy, and 46 and 38 of them, respectively, completed the maintenance period of 2 years. After 2 years, patients were followed for tumor evaluation up to 3 years from the last patient’s first infusion.

For investigator-assessed PFS, time to progression (TTP), and OS, medians have not been reached in either group (median follow-up durations: 40 months in the CT-P10 group and 39 months in the reference group).

There were no significant differences between the groups in terms of PFS (hazard ratio [HR], 1.33; 95% CI, 0.67-2.63; 4-year PFS for CT-P10, 60.9%; 95% CI, 46.5%-72.5%; 4-year PFS for reference, 54.7%; 95% CI, 36.1%-70.0%).

There were also no significant differences in TTP (HR, 1.17; 95% CI, 0.58-2.37; 4-year TTP for CT-P10, 64.2%; 95% CI, 49.4%-75.7%; 4-year TTP for reference, 55.8%; 95% CI, 36.8%-71.1%).

OS was comparable between the groups (4-year OS for CT-P10, 88.0%; 95% CI, 77.5%-93.8%; 4-year OS for reference, 93.3%; 95% CI, 83.2%-97.4%; P = .287).

In total, 30% of patients in each group experienced disease progression. Five patients in the biosimilar group and 2 patients in the reference group died during the study period. No new safety signals were identified, and similar numbers of patients in each group experienced at least 1 treatment-emergent adverse event.

Rapid infusion with CT-P10 is well tolerated

Second, another group of researchers reported on a postauthorization safety study of the biosimilar that is currently underway in several European nations.² The study concerns rapid infusion of the biosimilar, over a period of 90 minutes or less, during routine clinical practice.

In Europe, the recommended protocol for infusion of rituximab is a slow initial infusion rate with a gradual upward titration, but rapid infusion is often used in second or subsequent infusions for patients who had no serious complications with a first infusion.

In the study, 112 with lymphoma who had between 1 and 4 prior infusions with CT-P10 were given subsequent rapid infusions over a 6-month observation. In total, 19 patients experienced 1 or more infusion-related reactions (IRRs). Of these patients, 9 had 1 IRR, 5 had 2 IRRs, and 5 had 3 or more IRRs.

The best responses to rituximab therapy during the observation period were complete response in 74% of patients, partial response in 21% of patients, stable disease in 3% of patients, and progressive disease in 2% of patients, say the investigators.

References

1. Buske C, Kwak LW, Jurczak W, et al. Long-term efficacy and safety results of CT-P10 and reference rituximab in patients with newly diagnosed advanced stage follicular lymphoma: phase III updated study results with median follow-up of 40 months. Presented at: The 61th Annual Meeting and Exposition of the American Society of Hematology; December 7-10, 2019; Orlando, FL. Abstract 1528.

2. Bishton M, Zinzani PL, Marshall S, et al. Rapid infusion with CT-P10 in patients with non-Hodgkin’s lymphoma or chronic lymphocytic leukemia: interim six month follow-up from a European non-interventional post-authorization study. Presented at: The 61th Annual Meeting and Exposition of the American Society of Hematology; December 7-10, 2019; Orlando, FL. Abstract 4135.