SUBCUTANEOUS INFLIXIMAB IN REFRACTORY CROHN'S DISEASE PATIENTS AFTER THE MULTIPLE TREATMENT FAILURES - SHORT TREATMENT OUTCOMES
Authors: Lukas Milan , Jirsa Jakub , Lukas Martin , Kolar Martin , Machkova Nadezda , Duricova Dana , Hruba Veronika , Kastylova Kristyna , Cerna Karin 
Published: January 2023

Abstract

BACKGROUND
Subcutaneous administration of infliximab shows an increased benefit in terms of pharmacokinetics and pharmacodynamics effects compared to the intravenous infliximab.
The practical question arises whether routine administration in refractory CD patients who have failed prior biological therapy will provide "biobetter" clinical efficacy.

AIMS
We propose a single center study designed to evaluate SC-IFX treatment outcomes in patients with active CD after the previous failures of other biologicals (TMAbs). Such a refractory CD cohort was chosen because there is currently insufficient appropriate medication therapy available for these patients and the identification of parameters predicting response to SC-IFX treatment could be of great benefit to some of them.

PATIENTS & METHODS
A total of 32 CD patients were included, with the median age of 34.5 years and median CD duration of 11 years; &gt;90% of them with stricturing and/or penetrating disease behavior, &gt;80% with ileocolic involvement, and about 40% with the active perianal disease. Eighteen of 32 patients (56%) have failed on ≥3 previous TMAbs, the rest on 2 previous TMAbs. Twenty (62.5%) of n = 32 have had IV-IFX in past; in this sub-cohort, 85% of patients have positive anti-IFX antibodies (ATI). In ATI-positive sub-cohort, induction of SC-IFX was realized with four 120 mg SC doses weekly. Two induction IV infusions of 5 mg/kg IFX were administered in 2-week intervals in ATI-negative sub-cohort. Maintenance treatment in whole cohort consisted of 120 mg SC IFX bi-weekly.

RESULTS
Of the 32 patients, 7 individuals have failed the treatment during the induction phase: one because of heart disease progression, and 6 patients due to delayed hypersensitivity reactions with systemic manifestation. In 25/32 patients who continued their treatment up to W14, the initial median Harvey-Bradshaw index (HBI) of 6 (min 1, max 28) did not decrease significantly within the 14 weeks of treatment (p=0.067). However, both the serum CRP level (p=0.039) and fecal calprotectin level (p=0.027) have shown significant decrease. Median trough IFX levels have increased from 6 μg/mL at W2 to 10 μg/mL at W14 (p&lt;0.001), and median ATI levels dropped from median of 38 ng/mL to 5 ng/mL (p= 0.0004). None of the patients with initial zero ATI levels have shown new ATI formation. Moreover, in 10 of 17 patients (59%) with the initial ATI positivity, ATI serum levels have decreased significantly even to the cut-off levels. The only risk factor for SC-IFX discontinuation before W14 was a high serum levels of ATIs (p &lt; 0.001).

CONCLUSIONS
Our short-term experience with SC-IFX shows the treatment efficacy and tolerability in complicated CD patients after multiple TMAbs failures.The research gap in information about biobetters in patients with IBD must be filled and predictive factors for the response to SC-IFX must be found.