5PSQ-112 Evaluation of the use of infliximab in immune checkpoint inhibitor-induced adverse reactions

<h3>Background and Importance</h3> Immune checkpoint inhibitors (ICIs) have transformed cancer treatment. However, their use can lead to immune-related adverse events (irAEs). Corticosteroids are the first-line treatment for irAEs; in refractory cases, selective immunosuppressive therapies such as infliximab (off-label use) can be administered. <h3>Aim and Objectives</h3> To evaluate the efficacy of infliximab in treating irAEs in cancer patients receiving ICIs. <h3>Material and Methods</h3> A retrospective observational study was conducted at a tertiary hospital, including demographic, clinical, and efficacy data of patients treated with infliximab for irAEs from January 2011 to October 2024. <h3>Results</h3> Thirty-one patients were included; 58.1% (n=18) were men, with a median age of 61 years(range: 28–84). ICIs responsible for irAEs included ipilimumab plus nivolumab(45.2%, n=14), ipilimumab(22.6%, n=7), nivolumab(9.7%, n=3), pembrolizumab(9.7%, n=3), and other ICIs(12.9%, n=4). Infliximab was used to treat colitis (confirmed by fibrocolonoscopy) in 48.4% of patients (n=15; grade 4 in 2 patients, grade 3 in 8 patients, and grade 1–2 in 5 patients). It was indicated for diarrhoea (without colitis) in 35.5% (n=11; grade 3 in 9 patients and grade 1–2 in 2 patients). Infliximab was indicated for pneumonitis in 16.1% (n=5) of patients, all presenting with grade 4. Reactions occurred after the first administration of ICIs in 16.1% (n=5), after the second in 25.8% (n=8), after the third in 22.6% (n=7), and after at least the fourth dose in 35.5% (n=11). During ICI treatment, 32.3% of patients experienced more than one irAE. All patients received steroids (1mg/kg/d) as first-line therapy, with an initial response in 54.8% (n=17) and a median treatment duration of 11 days. The number of infliximab doses (5mg/kg, with 2 patients receiving 10mg/kg) administered was one in 71% of patients (n=22), two in 22.6% (n=7), and three doses in 6.5% (n=2). Complete resolution was achieved in 61.3% of patients (n=19), partial improvement in 22.6% (n=7), and no improvement in 16.1% (n=5, all failures in pneumonitis). Infliximab was administered during hospitalisation in 58.1% of patients. Only 29.1% resumed immunotherapy after infliximab treatment, with one patient experiencing a recurrence of the irAE. <h3>Conclusion and Relevance</h3> Infliximab was effective in treating immune-mediated colitis and diarrhoea, reducing steroid dosages. However, it was not beneficial in cases of immune-mediated pneumonitis. <h3>References and/or Acknowledgements</h3> <h3>Conflict of Interest</h3> No conflict of interest