Systematic review with meta-analysis: effectiveness of anti-inflammatory therapy in immune checkpoint inhibitor-induced enterocolitis

Background Immune checkpoint inhibitors have revolutionised cancer treatment, but at the cost of off-target immune-mediated organ damage. This includes checkpoint inhibitor-induced enterocolitis which frequently requires hospitalisation and may be life-threatening. Empirical treatment typically includes corticosteroids and infliximab, although, no large-scale studies have confirmed their effectiveness. Aim To investigate the effectiveness of anti-inflammatory therapy in checkpoint inhibitor-induced enterocolitis. Methods We performed a systematic review and meta-analysis of studies reporting clinical outcomes of checkpoint inhibitor-induced enterocolitis in adult cancer patients treated with anti-inflammatory agents. We searched Medline, EMBASE, and the Cochrane library through April and extracted the proportion of patients responding to anti-inflammatory therapy. Variation in effect size was studied using a random-effects meta-regression analysis, with checkpoint inhibitor agent and tumour type as the variables. Results Data were pooled from 1210 treated patients across 39 studies. Corticosteroids were effective in 59% (95% CI 54- 65) of patients, with response significantly more favourable in patients treated with anti-PD-1/L1 monotherapy, compared with anti-CTLA-4 containing regimens (78%, 95% CI 69-85 vs 56 %, 95% CI 49-63,P= 0.003), and more favourable in lung cancer patients compared with melanoma patients (88%, 95% CI 62-97 vs 55%, 95% CI 47-63,P= 0.04). Infliximab was effective in 81% (95% CI 73-87) of patients, and vedolizumab in 85% (95% CI 60-96). Conclusion Corticosteroids, infliximab and vedolizumab, are effective in the treatment of checkpoint inhibitor-induced enterocolitis. Checkpoint inhibitor regimen and cancer type were significant moderators in response to corticosteroid therapy.