Background and Importance Ustekinumab has been shown to be effective and safe in the long term in inflammatory bowel disease. However, its use in advanced treatment stages is associated with a loss of effectiveness, leading to intensified usage and an associated additional cost.

Aim and Objectives The objective is to analyse the posological intensification of ustekinumab in ulcerative colitis (UC) and Crohn’s disease (CD) in real clinical practice according to the line of treatment used.

Material and Methods Retrospective observational study in which all patients treated with ustekinumab in a tertiary hospital were included during the period January 2017, to September 15, 2023.

The analysed variables included age, sex, previous anti-TNF therapy, intensified patients, months from the start of Ustekinumab until needing intensification to 6 weeks and 4 weeks, causes of Ustekinumab use in first line treatment. The sources used to obtain data were the electronic prescription application Prisma® and the computerised medical record system Diraya®.

Results A total of 177 patients were included (48.1% women), with a mean age of 48 years (range 19–85). Among them, 37.3% (n=66) had been previously treated with two anti-tnf, either exclusively with Adalimumab (n=71. 40.1%), exclusively with Infliximab (n=20. 11.3%) or had no prior anti-tnf treatment (n=20, 11.3%).

Intensification of the regimen with ustekinumab was necessary in 54.5% of those previously treated with two anti-tnf, 49.3% only adalimumab, 50% only infliximab, 45% no previous anti-TNF.

The initial posology of ustekinumab was 8 weeks. The median number of months for the intensification of ustekinumab to 6 weeks and 4 weeks was 10.5 months and 19.9 months (two anti-TNF), 11.4 months and 20.6 months (adalimumab), 12.3 months and 20.6 months ( infliximab) and 19.7 months and 26.5 months ( non anti-TNF).

In our hospital, patients who had not previously undergone any anti-TNF treatment did so due to neoplasia (46.6%), infections (20%), HLA-DQA1*05 (13.3%) or multiple sclerosis (13.3%).

Conclusion and Relevance The percentage of patients intensified with ustekinumab is higher in those treated with anti-TNF than in those not treated.

In addition, patients treated with one anti-TNF or no anti-TNF required more time to intensify than patients treated with two anti-TNFs.

Conflict of Interest No conflict of interest.