P468 Switching from adalimumab originator to ABP 501 biosimilar: a multicentre North Italian study

B. Barberio1, P. Melatti1, F. Zingone1, L. Bertani2, A. Ferronato3, A. GUBBIOTTI1, D. Massimi4, R. D’Incà1, E.V. Savarino5

1Department of Surgery Oncology Gastroenterology, University of Padua, Padua, Italy, 2Department of Gastroenterology, University of Padua, Pisa, Italy, 3Gastroenterology Unit, Santorso Hospital, Santorso, Italy, 4Department of Surgery- Oncology- Gastroenterology, Univeristy of Padua, Padua, Italy, 5Department of Surgery- Oncology- Gastroenterology, University of Padua, Padua, Italy

Background

In late 2018, adalimumab (ADA) biosimilars have been approved by the EMA with the same indications of the reference product (RP), that is Humira. However, while their efficacy and safety have been proven in patients with rheumatoid arthritis and psoriasis showing no differences compared with the RP, data on inflammatory bowel disease (IBD) is lacking. The primary aim of this study was to verify the ability of ABP501 to maintain the clinical response induced by the RP after switching to the biosimilar.

Methods

We retrospectively enrolled all consecutive patients who switched to ABP501 by ADA Originator at the IBD Units of Veneto Region (Padua, Santorso) from December 2018 to November 2019. We collected data on partial Mayo (p-Mayo) Score, Harvey–Bradshaw Index (HBI), C Reactive Protein (CRP), faecal calprotectin (FC), concomitant steroid and azathioprine therapy at the time of the switch (T0) and after six months. Continuous and categorical variables were expressed as mean with standard deviation (SD) and frequency with percentages respectively. Comparisons among variables were conducted using one-way ANOVA and chi-square. Data were analysed using STATA11 software.

Results

Forty IBD patients switched to biosimilar [7 with ulcerative colitis (UC) and 33 with Crohn’s disease (CD)] were included in the study. All switched patients were in remission or in mild clinical activity at the time of the switch. We observed a clinical worsening and clinical improvement in 8 and 2 patients, respectively (p = 0.001) from T0 to T1. FC value increases at T1 compared with T0 (from a mean value of 98.32 to 137.9 μg/g) but without significant difference. Seven patients needed to add steroids at T1 (p = 0.04) and five (12.5%) needed therapeutic optimisation. Finally, 8 (20%) patients stopped therapy: 7 for loss of response and 1 for an adverse event.

Conclusion

Our data show that after switching, one out of three of the patients may experience disease relapse, requiring treatment optimisation (i.e. addiction of steroids or increasing the dose to once a week) or treatment discontinuation. Thus, patients should be strictly observed in order to prevent or, at least, early manage such clinical relapses. Larger and longer studies are mandatory to understand the clinical implications of these findings.