Background and importance Adalimumab is an antitumour necrosis factor-α (anti-TNF) agent indicated in ulcerative colitis (UC) and Crohn’s disease (CD). Primary non-response to anti-TNF has been suggested as predictive of poor response to re-treatment with another anti-TNF.

Aim and objectives To assess the effectiveness of adalimumab as the second anti-TNF agent administered, evaluating the influence of response to the first anti-TNF agent.

Material and methods A descriptive retrospective study to July 2019 was conducted. All patients with inflammatory bowel diseases (IBD) treated with adalimumab as the second anti-TNF agent were selected. Variables collected were age, gender, diagnosis, previous anti-TNF therapy, reason for switch, response to anti-TNF, therapy duration and Mayo clinic score (MCS). Effectiveness was measured by MCS at 12, 36 and 60 months. Clinical remission (R) was MCS ≤2 points, clinical response (CR) was a decrease from baseline in MCS ≥3 points and lack of response (LOR) was none of the above. Patients with LOR and treatment suspension in 1 week were considered as LOR in the following weeks. Influence of response to the first anti-TNF agent was evaluated using the relationship between types of response to the first and second treatments. Primary non-response to anti-TNF was defined as LOR after induction of anti-TNF treatment: before week 10 for infliximab and before week 4 for adalimumab. Secondary non-response to anti-TNF treatment was considered as LOR after induction therapy.

Results Fifty-eight patients were included: 39.6% men and 60.4% women. Mean age was 41.6 (86–17) years. Diagnoses: 34.5% UC and 65.5% CD. All patients were pretreated with infliximab (first anti-TNF). Switching to adalimumab was caused by: 2 (3.4%) primary non-response, 45 (77.6%) secondary non-response and 11 (19%) intolerance. Mean adalimumab treatment duration was 29.7 (1–120) months. MCS at 12 months: 43.9% R, 19.3% CR and 36.8% LOR. MCS at 36 months: 29% R, 7.9% CR and 63.1% LOR. MCS at 60 months: 22.9% R, 2.8% CR and 74.3% LOR. One patient with primary non-response to infliximab (1/2, 50%) presented primary non-response to adalimumab; and another with secondary non-response to infliximab (1/45, 2.2%) had primary non-response to adalimumab.

Conclusion and relevance Adalimumab showed long term effectiveness in IBD patients pretreated with another anti-TNF, maintaining >20% of patients in clinical remission at 60 months. Adalimumab’s primary non-response proportion was lower in patients with secondary non-response to a first anti-TNF than in those who had a primary non-response, but studies with larger sample sizes are necessary.

References and/or acknowledgements No conflict of interest.