Background
Infliximab (IFX) demonstrated its effectiveness in perianal CD (pCD) and represents the first-line medical treatment. A subcutaneous (SC) formulation has recently been developed, however so far it has not been specifically investigated in pCD. The aim of our study was to evaluate the effectiveness and safety of SC IFX in pCD.
Methods
We conducted a multicentre retrospective cohort study in the French GETAID, in patients with either active (group 1) or inactive (group 2) pCD who received SC IFX. Inclusion criteria were, for group 1: active pCD in the 6 months prior to initiation of SC IFX; and for group 2: inactive pCD for > 6 months at the time of IV to SC switch, but with a history of seton drainage. The primary endpoint in group 1 was clinical remission at 6 months (absence of anal ulcers, and absence of draining fistula). Univariate and multivariable logistic regression analyses were performed to identify predictors of clinical remission. In group 2, the primary endpoint was perianal clinical recurrence during follow-up.
Results
A total of 192 patients were included in 24 centres. Mean age was 38.9 years, 43.2% were women, 25.1% were smokers. 66 patients were included in group 1, 117 in group 2. In 9 patients, pCD had a > 6 months persistent activity on IV IFX when switched to SC.
In group 1, median follow-up was 46 (26.6-64.6) weeks, 51/66(77.3%) patients received combination therapy, surgical drainage was performed in 40(60.6%) patients. One(1.5%), 1(1.5%), 32(48.5%), 20(30.3%) and 12(18.2%) patients received 0, 1, 2, 3 and ≥ 4 IV perfusions respectively before SC switch. At M6, 27/61(44.3%) patients were in clinical remission and 53/61(86.9%) in clinical response. MRI remission or response was achieved in 19/28(68%) patients. In univariate analysis, factors inversely associated with remission were BMI, previous pCD surgery, initial seton drainage, and SC dose optimization. In multivariable analysis, prior exposure to ≥1 biologic (OR 0.248;CI95% [0.071-0.861]p= 0.0243) was predictive of clinical remission.
In group 2, median follow-up was 53.6(36.7-67) weeks. The pCD recurrence rate at 6 months was 3.1%. The recurrence-free survival curve is shown in Figure1.
Overall, SC IFX was discontinued in 20(10.4%) patients, 8 switched back to IV. Two cases of immunization were observed. Median IFX serum concentration was > 20(17.1- > 20) µg/l. There were 16(8.3%) cases of adverse events related to pain/injection-site reaction: 4 switched back to IV, 1 stopped IFX. There were 5 cases of infection, no case of cancer.
Conclusion
Our results are in line with those reported in the literature on the effectiveness of IV IFX in pCD. The SC formulation appears to be effective and safe for active pCD, and for maintaining remission in inactive pCD

Perianal CD recurrence free survival in Group 2

Stéphane NAHON

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