Clinical outcomes of coronavirus disease 2019 (COVID‐19) in cancer patients with prior exposure to immune checkpoint inhibitors

Dear Editor, The coronavirus disease 2019 (COVID-19) pandemic has affected over 6,000,000 people globally [1]. Patients with COVID-19 manifest with symptoms of fever, dry cough, dyspnea, and present with radiological changes that are consistent with atypical pneumonia [2]. Pathogenetic mechanisms for these abnormalities involve the systemic immune response that is associated with the hyperactivation of peripheral CD8 and CD4 T cells, and a cytokine storm [3]. Globally, the reported prevalence of patients with COVID-19 and cancer ranges from 0.5% to 6.0% in the different case series [4]. Consistent with these studies, we had previously reported that patients with cancer harbored an approximately 2-fold higher risk of COVID-19 than non-cancer patients, thereby indicating that this group of patients represents a susceptible population [5]. Immune checkpoint inhibitors (ICI) targeting the cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed death-ligand 1 (PD-L1) immuno-inhibitory axis have demonstrated single-agent activity in treatment-refractory cancers, and have also demonstrated synergism with chemotherapy and radiotherapy in the first-line setting [6]. Anti-CTLA-4 and anti-PD-1/-PD-L1 antibodies work by targeting the T-cell exhaustion pathways, thereby resulting in reactivation of cytotoxic CD8 T cells for antitumor activity [6]. Given the convergence of the downstream effects on the innate immunity by both ICI and severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infections, we therefore queried whether patients with cancer and prior exposure to ICI would present with