A recent study (full text link: “Loss of Infliximab into feces is associated with lack of response to therapy in patients with severe ulcerative colitis” Gastroenterol 2015; 149; 350-55.e2) provides information about patients with ulcerative colitis who do not respond well to infliximab therapy.
In this study, the authors obtained fecal samples from 30 consecutive patients with moderate to severe UC during the 1st 2 weeks of therapy. In addition, they obtained serum infliximab levels as well as assessed clinical and endoscopic response at 2 weeks, 8 weeks, and 3 months after treatment began.
- Fecal infliximab was detected in 129 of 195 (66%) samples. The greatest loss was observed approximately 2 days after infusion. Low serum albumin was associated with greater infliximab levels in the stool.
- Clinical nonresponders at week 2 had significantly higher fecal infliximab
- The authors did not observe a correlation between fecal and serum infliximab concentrations. However, it is possible that stool losses could indicate lower mucosal concentrations of infliximab.
Bottomline: It is not clear whether stool losses of infliximab directly contribute to drug failure or whether the loss is another biomarker of disease activity/high-risk patients.
The study authors note that “intestinal loss of IFX in moderate to severely active UC is associated with a diminished response to this treatment. Patients with severe disease can, therefore, benefit from more intensive dosing regiments. This strategy warrants a prospective clinical trial.”
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