Crohn's disease is a chronic multifactorial disease for which therapeutic options have expanded in the last decades. However there are still patients who lack or lose response to current standard treatment strategies. A unicentric, retrospective, study was performed in order to evaluate the clinical and biochemical response to intravenous ustekinumab manteinance therapy (IVUMT) in patients with refractory CD. We included 12 patients from our centre who started IVUMT between September 2018 and November 2021. 75% started IV treatment after previous subcutaneous (SC) treatment. At week 8 (n=8), 63% had clinical response, with 25% in clinical remission. At week 16 (n=10), 60% had clinical response, with 50% in clinical remission. At week 26 (n=10), 90% had clinical response, with 60% in clinical remission. At week 52 (n=11), 91% had clinical response, with 64% in clinical remission (Fig. 2). Basal faecal calprotectin (FCP) median level was 684µg/g, with a significant reduction at 52 weeks, with median FCP 97µg/g (p=0,017). Basal C-reactive protein (CRP) median level was 11,6mg/L. A significant reduction was observed at week 26, with median CRP 2,8mg/L (p=0,008); and 52 weeks, with median CRP 2,7 (p=0,013). Average follow-up was 117,1 weeks, average treatment survival was 105,9 weeks. There were no severe adverse events. Our results suggest IVUMT is a safe and effective treatment for most patients with refractory and complex CD and should be considered as an option in selected patients.