A new prospective cohort study reveals that patients with inflammatory bowel disease (IBD) can safely transition back to reference infliximab (Remicade) after using the biosimilar SB2, with no significant impact on clinical outcomes or safety profiles.
The single-center observational study followed patients who were initially switched from Remicade to biosimilar SB2 for 96 weeks, then reversed back to Remicade for an additional 48 weeks. This research addresses a critical knowledge gap regarding multiple switches between reference biologics and their biosimilars in IBD treatment.
Clinical Outcomes and Disease Activity
Disease activity remained stable throughout the reverse switch period. For Crohn's disease patients, the median Harvey-Bradshaw Index (HBI) stayed consistent at 2 from baseline to week 48. Similarly, ulcerative colitis patients showed stable partial Mayo scores, shifting marginally from 1 at baseline to 0.5 at week 48.
The study demonstrated robust disease control, with 80% of patients in remission at baseline and 82% maintaining remission at week 48. Notably, no patients experienced severe disease flares during the observation period.
Biomarker Stability and Drug Levels
Inflammatory markers remained well-controlled throughout the study. C-reactive protein (CRP) levels showed minimal variation, with median values of 2.0 mg/L at baseline and 2.4 mg/L at week 48, staying below the normal threshold of 5 mg/L.
Drug trough levels demonstrated stability, with median values of 7.2 μg/ml at baseline and 5.5 μg/ml at week 48. The percentage of patients maintaining therapeutic trough levels slightly improved from 31% at baseline to 37% at week 48.
Immunogenicity and Safety Profile
The study revealed low immunogenicity rates, with only 3.4% of patients developing new anti-drug antibodies during the reverse switch period. The majority of patients (87%) remained antibody-negative throughout the study duration.
Safety outcomes aligned with previous infliximab studies. Among 95 patients, 46 experienced adverse events, with seven classified as serious. The overall treatment discontinuation rate was 14.7%, with most discontinuations occurring in patients who had either positive anti-drug antibodies or sub-therapeutic drug levels.
Treatment Modifications and Dosing
Treatment adaptability was demonstrated through various dosing adjustments. By week 48, 40% of patients maintained stable dosing, while 39% required lower doses and 21% needed higher doses. The majority of patients (67%) maintained their original treatment schedule, with some requiring shorter (11%) or longer (22%) dosing intervals.
Study Implications
While the research provides valuable insights into reverse switching in IBD treatment, the investigators acknowledged certain limitations, including a modest sample size and the absence of a control group continuing SB2 therapy. Additionally, the study population consisted primarily of patients with established responses to infliximab, potentially introducing selection bias.
Despite these limitations, the findings provide important evidence supporting the practice of switching between reference infliximab and its biosimilars in IBD management. This data may help inform clinical decision-making and healthcare policy regarding biologic therapy options in IBD treatment.
