Safety of immune checkpoint blockade in patients with cancer and preexisting autoimmune diseases and/or chronic inflammatory disorders

Background: Checkpoint blockade therapy, in the form of immune checkpoint inhibitors (ICIs), is increasingly being used to prolong survival in cancer patients, but its use is limited by the occurrence of immune-related adverse events (irAEs). These can be serious and occasionally fatal. However, the safety of ICIs is currently unknown in cancer patients with preexisting autoimmune diseases (PADs) and/or chronic inflammatory disorders (CIDs) such as eczema. Aim: The aim of this study is to evaluate the safety of ICIs in cancer patients with PAD and/or eczema at our institution. Patients and Methods: A retrospective study of cancer patients who presented to the Emergency Department between March 1, 2011, and February 29, 2016, after ICI therapy was previously conducted. Among these patients, those with PAD and/or eczema were further evaluated for safety by determining the occurrences of de novo irAEs or preexisting disease exacerbation. Results: Twenty-two cancer patients with PAD and/or eczema who received ICIs were reviewed, in which 15 were male (68%). Their median age was 63 years (range: 40-78 years). Most patients received anti-PD-1drugs (68%). Melanoma was the most common malignancy (45%). Autoimmune thyroiditis/primary hypothyroidism was the most common PAD. Four patients were receiving treatment for PAD at baseline using systemic corticosteroids, anti-inflammatory agents, and other immunosuppressants. Nineteen patients experienced de novo irAEs and/or PAD exacerbation. In three patients, the irAE was severe (grade ≥3). In six patients, the irAE or exacerbation was managed with systemic corticosteroids. Twelve patients experienced resolution of the de novo irAE or PAD exacerbation without the need to withhold or discontinue ICI therapy. The median time to last follow-up or death from the first dose of ICI was 16.8 months (range: 2-80 months). Death due to cancer progression was reported in 17 patients. Conclusion: Although de novo irAEs and PAD exacerbation were common, most patients with PAD and/or CIDs tolerated ICI therapy well.