Immune-related adverse events in patients with solid-organ tumours treated with immunotherapy: a 3-year study of 102 cases from a single centre.

OBJECTIVES: Immune checkpoint blockade therapy (ICBT) increases the anti-tumoural function of the immune system, but it can also induce immune-related adverse events (irAEs). Our aim was to assess the irAEs due to ICBT in patients from a single centre of Northern Spain. METHODS: We set up an observational study of patients treated in monotherapy with ICBT targeted against cytotoxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death 1 (PD-1) or its ligand (PD-L1) for solid organ tumours. All patients were followed up in a single University Hospital from March 2015 to September 2018. RESULTS: We studied 102 patients (63 men/39 women); mean age 60.6±9.7 years, with lung (n=63), melanoma (n=21), kidney (n=11), gastric (n=3), colon (n=3) or bladder (n=1) cancer. Only 7 patients had a previous diagnosis of an immune-mediated disease, specifically: psoriasis (n=2), psoriatic arthritis (n=1), systemic lupus erythematosus (n=1), spondyloarthitis (n=1), rheumatoid arthritis (n=1) and cutaneous lupus (n=1). One of the following ICBT was administered: nivolumab (n=52), pembrolizumab (n=35), atezolizumab (n=10) and ipilimumab (n=5). After a mean follow-up time of 14.4±7.7 months since ICBT onset, 87 (85.3%) patients had experienced irAEs, mostly gastrointestinal, thyroid and musculskeletal manifestations including inflammatory arthralgia (n= 8), arthritis (n= 6) and myositis (n=2). ICBT was discontinued in 41 patients but it was reintroduced in 30 of them after resolution of the adverse event, with a good tolerance in all cases. Thirty-six (41.4%) of the 87 patients required specific treatment (prednisone, levothyroxine, and thiamazol) for the irAEs. CONCLUSIONS: irAEs are frequent in patients undergoing ICBT. Almost half of the patients that have irAEs require treatment. Musculoskeletal manifestations are not uncommon.