Optimizing outcomes with maintenance IV UST in highly bio-exposed patients with IBD. Efficacy and adjusted regimen in real world.

Background and aims: Ustekinumab is an effective treatment for inflammatory bowel diseases. However, some patients do not respond to conventional doses. The aim of the study was to evaluate the effectiveness of intravenous maintenance ustekinumab in patients with secondary failure.

Methods: Single-center, retrospective study in adult patients with intravenous maintenance ustekinumab. The reduction of biochemical activity markers, ustekinumab trough levels and clinical indices of activity were evaluated. Biological remission was defined as the percentage decrease fecal calprotectin ≥80% and/or final fecal calprotectin ≤250 and C reactive protein <5mg/L.

Results: Thirty-one patients were included: Crohn's disease 77.4%. All included patients were bio-exposed and 61.3% had carried ≥2 biologics. Pre-intravenous maintenance mean Harvey-Bradshaw Index was 6.5±4.38 vs 5±3.1 at week 8 (p=0.024) vs 4.1±3.1 at week 24 (p=0.019). The median ustekinumab trough level pre-intravenous maintenance was 1.40μg/ml [IQR 2.3] vs 5.35μg/ml [IQR 4.1] at week 8 (p<0.001) vs 4.8μg/ml [IQR 3.9] at week 24 (p<0.001). The pre-intravenous maintenance median fecal calprotectin was 809μg/g [IQR: 2256] vs 423μg/g [IQR: 999] at week 8 (p=0.025) vs 333μg/g [508] (p=0.001) at week 24. At the end of follow-up 48% went into biological remission. The presence of perianal disease was associated with lower biological remission (70.6% vs 27.3%, p=0.025). Median intravenous ustekinumab maintenance time was 8.55 [IQR 23.9] months. In 83.9% of patients no serious infections or malignancy were documented.

Conclusions: The use of maintenance intravenous ustekinumab appears to be an effective and safe strategy that can be evaluated as a salvage treatment especially in highly bio-exposed patients.