Infliximab Trough Levels Associated With Increased Clinical Response

Despite the effectiveness of infliximab, an anti-tumor necrosis factor (anti-TNF) antibody in the treatment of ulcerative colitis (UC) and Crohn disease (CD), a substantial number of patients eventually lose disease response.

Infliximab trough levels greater than 2-3 μg/ml have been associated with higher rates of sustained clinical and biochemical remission. A recent study looked to evaluate the association between infliximab trough levels, response to treatment, and quality of life in a cohort of Brazilian irritable bowel disease (IBD) patients.

A transversal study was conducted among 71 patients with CD (55) and UC (16) receiving infliximab maintenance therapy of 5mg/kg. Infliximab trough levels were measured from blood samples collected before drug infusion. Complete remission was evaluated using the Harvey Bradshaw Index and partial Mayo Score for CD and UC, respectively. Mucosal healing (MH) was considered Simple Endoscopic Score ≤2 in CD, or a Mayo Endoscopic Subscore of ≤1 in UC.

Of the 71 patients included in the study, 43 (60.5%) had unsatisfactory infliximab trough levels, 35 (49.3%) had active disease, 4 (5.6%) were in complete remission but not MH, and 32 (45%) were in complete response and MH.

Satisfactory trough level (≥3&thinsp;μg/mL) were associated with complete response and mucosal healing (P <.001). In addition, quality of life was increased if the trough concentration was higher than ≥3&thinsp;μg/mL3.

Researchers demonstrated that better quality of life in patients with UC and CD is associated with adequate serum levels of infliximab. Participants in the study displayed improvement in intestinal problems, social function, and systemic manifestations.

According to the study authors, while therapeutic drug monitoring is not routinely conducted within Brazil, it has been shown to improve treatment outcomes and have important economic benefits in patients with IBD. This is because while individualized therapy based on immunopharmacological evidence has similar complete response rates compared to dose intensification strategies.

However, when a physician looks to “blindly” optimize dosing instead of making the decision based off of the patient’s infliximab trough level, the treatment cost is much higher. Although therapeutic drug monitoring can be a useful tool in patients losing disease response, the researchers note that further prospective studies are needed to confirm the results.

Reference

Parra R, Feitosa M, Ribeiro L, Castro L, Rocha J, Feres O. Infliximab trough levels and quality of life in patients with inflammatory bowel disease in maintenance therapy [published online May 8, 2018]. Gastroenterol Res Pract. doi: 10.1155/2018/1952086.