New Data Support Switching to Biosimilar Rituximab in Treating RA

At the American College of Rheumatology's 2017 meeting in San Diego, California, 2 research groups presented findings from studies conducted in patients with rheumatoid arthritis (RA) who were switched from reference rituximab to a biosimilar therapy.

The first study,¹ by Hans-Peter Tony, MD, and colleagues and presented during an oral poster session, compared the safety and immunogenicity of switching from reference rituximab to GP2013 (Sandoz’s proposed rituximab biosimilar) to continued treatment with reference rituximab in patients with active RA.

The randomized, double-blind, parallel-group study was conducted at 28 centers in the United States and 26 centers in the European Union. Patients (n = 107) had previously received reference rituximab prior to randomization into 2 treatment arms: 1 arm (n = 53) switched treatment to GP2013, and the control arm (n = 54) continued to receive reference rituximab.

The incidence of hypersensitivity was 9.4% in the switch group and 11.1% in the control group. Infusion-related reactions occurred in 11.3% and 18.5% of patients in each group, respectively. Among patients who tested negative for anti-drug antibodies (ADAs) at the time of screening, only 1 patient (in the control group) tested positive for ADAs after the first infusion. The rate of adverse events was similar between the 2 treatment arms.

The researchers concluded that the safety profile of patients who switched from the reference to the biosimilar was comparable with that of the patients who remained on the reference therapy.

The second study,² presented during a poster session, was conducted by Seung-Cheol Shim, MD, and colleagues. The researchers in this study investigated the safety of CT-P10 (Celltrion and Teva’s proposed rituximab biosimilar) when used long-term after switching from the reference rituximab.

Patients (n = 295) who had completed a previous 48-week main study comparing the pharmacokinetics, safety, and efficacy of CT-P10 and reference rituximab entered into the extension period of this 72-week study. Those who had received CT-P10 or European-sourced reference rituximab during the initial period received CT-P10 in the extension period. Those who had received US-sourced rituximab in the initial period were randomized to receive CT-P10 or US-sourced reference rituximab.

In total, 122 patients continued with CT-P10, 64 continued with US-sourced reference rituximab, 62 switched from US-sourced rituximab to CT-P10, and 47 switched to CT-P10 from European-sourced reference rituximab.

The mean change in the patients’ Disease Activity Score 28 scale (DAS28) from the baseline established by the main study period, as well as the mean change in the American College of Rheumatology response rates, were comparable among all groups. B-cell depletion after the first infusion was also comparable, and was maintained throughout the extention period. The researchers reported no remarkable changes in immunogenicity profiles after switching, and noted that safety profiles were comparable among all groups.

The researchers concluded that long-term effectiveness and tolerability were achieved over 72 weeks of treatment with CT-P10, and that efficacy, pharmacodynamics, safety, and immunogenicity were also comparable among patients who switched their treatments and those who continued with their original therapy.

References

1. Tony HP, Schulze-Koops H, Kruger K, et al. Presented at the American College of Rheumatology 2017 meeting, November 7, 2017; San Diego, California. Abstract 2795. acrabstracts.org/abstract/comparison-of-switching-from-the-originator-rituximab-to-the-biosimilar-rituximab-gp2013-or-re‑treatment-with-the-originator-rituximab-in-patients-with-active-rheumatoid-arthritis-safety-and/

2. Shim SC, Majstorovic LB, Kasay AB, et al. Presented at the American College of Rheumatology 2017 meeting, November 7, 2017; San Diego, California. Abstract 2445. acrabstracts.org/abstract/efficacy-and-safety-of-rituximab-biosimilar-ct-p10-after-a-single-switch-from-innovator-rituximabs-in-patients-with-rheumatoid-arthritis-results-from-phase-3-randomized-controlled-trial-over-72-wee/