Investigators Find the Optimal Cut-Off for Infliximab for Patients With Crohn’s Disease


In data presented at ECCO 2022, investigators identified the optimal infliximab cut-off level was 4 μg/ml.

Teresa Valdes

Teresa Valdes

While infliximab is a viable and safe treatment for patients with inflammatory bowel disease (IBD), finding the optimal cut-off level has proven challenging in the past.

However, in data presented during the 2022 European Crohn’s and Colitis Organisation annual meeting, investigators identified the most promising cut-off level for patients with Crohn’s disease.


Infliximab is a monoclonal antibody that can enhance and improve the immune system and has been used to treat rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn’s disease, plaque psoriasis, and ulcerative colitis.

A team, led by Teresa Valdes, University Hospital Virgen Macarena, identified the cut-off of infliximab serum levels in patients with Crohn’s disease in remission in clinical practice and attempted to identify other predictors of long-term benefit of infliximab therapy.

Therapeutic drug monitoring for patients with Crohn’s disease treated with infliximab is needed to optimize treatments, but infliximab serum levels are not well-defined.

The Study

In the observational, retrospective, single-center study, the investigators examined patients with Crohn’s disease on maintenance therapy with infliximab between January 2019 and July 2020.

The team measured infliximab trough levels and antibodies to infliximab at least 3 times following 6 months of treatment and performed tests using enzyme linked immunosorbent assays. They also defined clinical remission using the Harvey Bradshaw index of at least 4.

Overall there were 105 patients with Crohn’s disease included in the study with a median age at diagnosis of 26 years.

They found the optimal infliximab level cut-off point classifying patients in clinical remission was 4 μg/ml with an area under the curve of 0.801.

However, the median infliximab trough levels were significantly higher when patients achieved clinical remission (4.8; 95% CI, 3-8 μg/m) compared to when they did not (0.59; 95% CI, 0.1-2.4 μg/ml).

The investigators also conducted a multivariate analysis and found that age, time on infliximab treatment, and time of disease evolution were associated with non-remission.

“Infliximab levels are an objective parameter related to clinical remission in maintenance therapy in patients with Crohn's disease,” the authors wrote. “Our cut-off point associated with clinical remission was 4 μg/ml.”

While endoscopy is still the top option for assessing disease activity and infliximab efficacy in patients with IBD, it is still invasive, costly, and time-consuming. In addition, infliximab is 1 of the top biological therapies for patients with IBD, but also elevates the risk of serious infections from immunosuppression. Also, up to 40% of IBD patients do not respond to anti-tumor necrosis factor treatments.

The study, “P081 Therapeutic Drug Monitoring of infliximab in Crohn’s Disease: Cut-off points during maintenance therapy,” was published online by the European Crohn’s and Colitis Organisation.

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