Real-World Study Shows Comparable Outcomes Between CT-P13, Remicade in RA

A real-world study of the biosimilar infliximab-dyyb (CT-P13; Inflectra) in rheumatoid arthritis (RA) reported the majority of patients who initiated CT-P13 switched from the reference product or another biologic or targeted synthetic disease-modifying antirheumatic drug (tsDMARD).

They observed disease activity “remained stable” in patients who switched from the reference product or another infliximab biosimilar and improved in patients switching from a non-infliximab biologic or tsDMARD and in biologic/tsDMARD-naive patients. The study used data from CorEvitas RA Registry, a large, observational clinical registry including data collected from patients and their rheumatologists at routine visits.

The anti-tumor necrosis factor (TNF)-α infliximab is approved for use in several inflammatory diseases including RA. According to the authors, randomized controlled trials have established “comparable clinical outcomes” in CT-P13 and the reference product. However, they said, “better characterization” of real-world patients with RA beginning treatment with CT-P13 and switching from the reference product, “is warranted to confirm that clinical trial data may be extrapolated to the real-world setting.”

Patients with RA in the CorEvitas RA Registry treated with CT-P13 who had Clinical Disease Activity Index (CDAI) data recorded at baseline and 6 months were included in the study. Of 318 patients who initiated CT-P13, 176 had CDAI scores recorded at baseline and 6 months. Of these, 73 (41%) switched from the reference product, 61 (35%) switched from another biologic or tsDMARD, 32 (18%) were biologic-naive, and 10 (6%) switched from another infliximab biosimilar. The authors noted patients who had switched from the reference product had a longer disease duration than biologic-naive patients at baseline.

The primary outcome of the study was the proportion of patients with moderate or high disease activity (CDAI > 10) at baseline achieving low disease activity (CDAI ≤ 10) at 6 months. Secondary outcomes included change in CDAI from baseline to 6 months, proportion of patients achieving remission (CDAI ≤ 2.8) at 6 months, and patient-reported outcomes (PROs) of pain and fatigue.

At 6 months, 119 (68%) patients remained on CT-P13 therapy, 35 (20%) discontinued the biosimilar and did not start another biologic, and 22 (12.5%) switched to another biologic.

In patients switching from the reference product or other infliximab biosimilars to CT-P13, the changes in clinical outcomes were “small,” the authors said. In these patients, a not statistically significant increase in CDAI was observed, as well as a “small numerical increase” patient global assessment (PGA) score of 2.1 (SD, 18.1; 95% CI, –1.8 to 6.0). There were improvements in CDAI in patients switching from another biologic or tsDMARD (–4.7; SD, 11.9; 95% CI, –7.6 to –1.7) and in biologic/tsDMARD-naive patients (–4.1; SD, 10.9; 95% CI, –7.8 to –0.3). PGA scores decreased by 3.6 (SD, 25.9; 95% CI, –10.2 to 2.9) in those switching from non-infliximab biologics or tsDMARDs and by 4.1 (SD, 23.4; 95% CI, –12.2 to 4.0) in patients naive to biologics and tsDMARDs. Changes in PROs were “generally small” in all patients, according to the investigators.

In patients with moderate or high disease activity at baseline, 32.9% (95% CI, 22.9-42.9) achieved low disease activity at 6 months. Among groups of patients, the greatest proportion achieving low disease activity was in those who had switched to CT-P13 from another biologic (38%), compared to those who switched from the reference product or another biosimilar (26%), and biologic/tsDMARD-naïve patients (29%).

The lowest rate of remission was observed in patients who had switched from a non-infliximab biologic or tsDMARD (7.4%), compared to patients who had switched from the reference product or another infliximab biosimilar (18%) and those who were naive to biologics or tsDMARDs (19%). The authors commented that the greater response they observed in the treatment-naive and switching from non-infliximab treatment groups than the group switching from the reference product or other infliximab biosimilars was expected, “since changing from the originator product or other biosimilar product should effectively represent a continuation of therapy.”

The investigators said their findings “provide insights for clinicians regarding expected disease effectiveness outcomes following switching” to CT-P13 in RA, which could “potentially alleviate hesitation in its use.” To their knowledge, this is the first real-world study of CT-P13 initiation in US patients with RA, and they said their findings suggest real-world outcomes at 6 months of CT-P13 treatment “are comparable with efficacy outcomes in clinical trials.”

Reference

Baker JF, Bakewell C, Dikranian A, et al. Characteristics and 6-month outcomes in patients with rheumatoid arthritis initiating infliximab biosimilar IFX-dyyb in a real-world setting. Rheumatol Ther. 2024;11(3):841-853. doi:10.1007/s40744-024-00653-6