A recent real-world study has demonstrated comparable outcomes between the infliximab biosimilar CT-P13 (Inflectra) and the reference product (Remicade) in patients with rheumatoid arthritis (RA). The study, utilizing data from the CorEvitas RA Registry, a large observational clinical registry, provides valuable insights into the effectiveness of CT-P13 in routine clinical practice.
The anti-tumor necrosis factor (TNF)-α infliximab is approved for use in several inflammatory diseases including RA. While randomized controlled trials have previously established comparable clinical outcomes between CT-P13 and the reference product, this real-world study aimed to further characterize the outcomes of CT-P13 initiation and switching in a diverse patient population.
Study Design and Patient Population
The study included 176 RA patients from the CorEvitas RA Registry who initiated CT-P13 and had Clinical Disease Activity Index (CDAI) data recorded at baseline and 6 months. The patient cohort comprised individuals who switched from the reference product (41%), switched from another biologic or targeted synthetic disease-modifying antirheumatic drug (tsDMARD) (35%), were biologic-naive (18%), or switched from another infliximab biosimilar (6%). Notably, patients switching from the reference product had a longer disease duration than biologic-naive patients at baseline.
The primary outcome 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, the proportion of patients achieving remission (CDAI ≤ 2.8) at 6 months, and patient-reported outcomes (PROs) of pain and fatigue.
Key Findings
At 6 months, 68% of patients remained on CT-P13 therapy, while 20% discontinued the biosimilar and did not start another biologic, and 12.5% switched to another biologic.
In patients switching from the reference product or other infliximab biosimilars to CT-P13, changes in clinical outcomes were small. A non-statistically significant increase in CDAI was observed, along with a small numerical increase in patient global assessment (PGA) score of 2.1 (SD, 18.1; 95% CI, –1.8 to 6.0). Conversely, improvements in CDAI were observed 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). Changes in PROs were generally small across all patient groups.
Among patients with moderate or high disease activity at baseline, 32.9% (95% CI, 22.9-42.9) achieved low disease activity at 6 months. The greatest proportion achieving low disease activity was observed 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-naive 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%).
Clinical Implications
The investigators believe that these findings provide valuable insights for clinicians regarding expected disease effectiveness outcomes following switching to CT-P13 in RA, potentially alleviating hesitation in its use. They noted that this is the first real-world study of CT-P13 initiation in US patients with RA, and the findings suggest that real-world outcomes at 6 months of CT-P13 treatment are comparable with efficacy outcomes in clinical trials. The greater response observed in treatment-naive patients and those switching from non-infliximab treatments compared to those switching from the originator product or other biosimilars was expected, as switching from the originator product or another biosimilar effectively represents a continuation of therapy.
