A retrospective study from British Columbia, Canada, indicates that switching from the infliximab reference product (Remicade) to biosimilars CT-P13 (Inflectra) or SB2 (Renflexis) does not significantly impact treatment persistence, loss of response, or adverse events in patients with inflammatory bowel disease (IBD). The findings, published in the Journal of the Canadian Association of Gastroenterology, offer reassurance regarding the safety and efficacy of biosimilar switching in IBD management.
The study, which analyzed data from stable IBD patients at the IBD Centre of British Columbia, compared outcomes of 265 patients who underwent a mandatory non-medical infliximab switch with those of 99 patients who remained on the reference product. The primary outcome was treatment persistence at 12 months post-switch, with secondary outcomes including loss of response, adverse events, and immunogenicity.
Comparable Treatment Persistence
The results showed that at 12 months, treatment persistence was similar between the two groups, with 90% of patients in the biosimilar group and 95% in the reference product group remaining on infliximab treatment. Specifically, 92% of Crohn's disease (CD) patients and 87% of ulcerative colitis (UC) patients in the switch group continued treatment, compared to 95% and 91% in the reference group, respectively.
Discontinuation and Adverse Events
Reasons for discontinuation were also similar between the groups. Loss of response was reported in 4% and 5% of patients on biosimilars and the reference product, respectively. Immunogenicity was observed in approximately 1% of each group, and adverse effects led to discontinuation in 1% and 2% of patients, respectively. Although not statistically significant, there was a numerical increase in the likelihood of treatment discontinuation in switchers compared to the control group (HR, 2.11; 95% CI, 0.57-1.04; P = .148).
Mitigating the Nocebo Effect
Interestingly, the study reported lower treatment discontinuation rates compared to some previous studies, which the authors attributed to the involvement of clinical IBD nurses who counseled patients regarding the switch, potentially mitigating the nocebo effect. The nocebo effect refers to negative expectations leading to adverse outcomes.
Implications for Clinical Practice
The authors concluded that the non-medical switch of infliximab in British Columbia demonstrated similar clinical outcomes between patients who switched to biosimilars and those who remained on the reference product. These findings support existing clinical data from Europe and Asia, informing future practice guidelines and reassuring healthcare providers about the safety and efficacy of biosimilar switching in IBD.
Limitations of the study included the inability to objectively determine remission at the time of switching and the inability to control for factors such as objective disease activity and serum inflammatory markers.
