GI infections fuel severe symptoms in immune-mediated diarrhoea, colitis

Concomitant gastrointestinal (GI) infections contribute to more severe symptoms in patients with immune-mediated diarrhoea and colitis (IMDC), a recent study has shown. Antimicrobial therapy neither shuns the need for immunosuppressive treatment for IMDC nor improves clinical outcomes.

In addition, concomitant GI infection is not associated with an increased risk of IMDC recurrence or poor overall survival.

The investigators retrospectively reviewed cancer patients administered with immune checkpoint inhibitors (ICIs) and developed IMDC between January 2015 and September 2019. GI infections were assessed using a GI multiplex panel.

Patients with positive infection were eligible, but those who were only positive for Clostridioides difficile or cytomegalovirus were not. In frequency matching, IMDC patients with negative infection served as controls. Between-group comparisons were done for patients’ disease course and outcome.

Of the 72 patients with IMDC included, 22 were in the study group and 50 in the control group. Seventeen patients were found to have Escherichia coli of different pathotypes, while five had viral infections, such as adenovirus, norovirus, and sapovirus.

Patients with GI infections more frequently had grade 3 or 4 colitis (43 percent vs 18 percent; p=0.041). GI infections, however, did not correlate with different risks of IMDC recurrence or overall survival. While antibiotics treatment did not influence the need for infliximab or vedolizumab, it was associated with a greater risk of IMDC recurrence (50.0 percent vs 0.0 percent; p=0.015).

IMDC is a common adverse event in cancer patients on ICIs, and GI infections can co-occur with IMDC, according to the investigators.