Background: Therapeutic response to Infliximab (IFX) and Adalimumab (ADA) in patients affected by Crohn's Disease (CD) has been assessed for many years by clinical indices of disease activity; however, recently it has been shown that a combination of both clinical and endoscopic remission leads to a better outcome. As CD involves the whole wall thickness, a transmural healing could be an even more important long-term target in order to reduce the risk of clinical relapse. A gold standard to assess transmural healing is still lacking.
The primary aim of our study was to analyze if fecal calprotectin (FC) values correlates with mucosal and parietal healing evaluated by Ultrasound Imaging (US) or Magnetic Resonance Imaging (MRI). The secondary aim was to evaluate mucosal and parietal healing in CD patients treated with anti-TNF with clinical response.
Methods: We enrolled 21 consecutive ileal CD patients who reached clinical remission at W6 with IFX or ADA. All patients performed colonoscopy, US and MRI at 1 year. Fecal calprotectin (FC) was evaluated at 6 months and at 1 year.
Absence of ulcers was considered as endoscopic healing. A bowel wall thickness (≤3 mm) was considered as transmural healing in MRI and in US. The value of 150mg/Kg of FC was considered the best cut off to identify patients at high risk of clinical relapse. Statistical analysis was performed by Fisher Exact Test.
Results: We recruited 21 CD patients (8M), 10 (48%) treated with IFX, 11 (52%) with ADA.
After one year of treatment, 9 (42%) patients showed mucosal healing, 7 (33%) patients showed transmural healing with US and 5 (23%) patients showed transmural healing with MRI. Five (23%) patients had FC values ≤150 mg/Kg at 6 months, 10 (48%) patients at one year. We found a correlation between FC values at 6 months and mucosal and parietal healing both with MRI and US.
On the other hand, FC values at one year correlated with mucosal healing and with parietal healing with US, but not with parietal healing with MRI.
Conclusions: Our results showed that, even adopting restrictive criteria, a good response to anti-TNF therapy was observed both for mucosal and transmural healing. Above all, we found a correlation between FC values at 6 months and mucosal and transmural healing, suggesting that FC could be a prognostic marker of therapeutic response and a possible future target of therapy.