Summary Checkpoint inhibitor (CPI) therapy has vastly improved long‐term outcomes in metastatic malignant melanoma (MMM). Therapy takes the form of monoclonal antibody infusions that target immune cell checkpoint proteins, such as cytotoxic T‐lymphocyte‐associated protein 4 (CTLA4) and programmed death 1/programmed death ligand 1 (PD1/PDL1). Cutaneous immune‐related adverse effects (IrAEs) are frequent in patients with MMM treated with CPIs. Our aim was to review the clinical presentations of cutaneous IrAEs associated with CPI therapy in adult patients with MMM. We carried out a literature review of clinical trials, case series and case reports of patients with melanoma and those with other cancers treated with anti‐CTLA4, anti‐PD1/PDL1, or a combination of these therapies. Diverse clinical presentations of cutaneous IrAEs are recognized. Anti‐CTLA4 therapy has a higher associated rate of cutaneous IrAEs than anti‐PD1/PDL1 therapies. Low‐grade cutaneous IrAEs are common and are usually managed supportively while continuing CPI therapy. Delayed presentations arising after established use of CPIs can make therapy‐associated cutaneous IrAEs difficult to distinguish from coincidental dermatological disease. Vitiligo‐like depigmentation is a good prognostic indicator of outcome in patients with melanoma. Life‐threatening adverse events including toxic epidermal necrolysis are rare. The identification of predictive biomarkers that highlight patients at risk of life‐threatening IrAEs remains an unmet need. The involvement of dermatologists in the multidisciplinary assessment of cutaneous IrAEs is increasingly pertinent in the management and care of CPI‐treated patients with melanoma.

Summary Patients with haematological malignancies have a high risk of severe infection and death from SARS‐CoV‐2. In this prospective observational study, we investigated the impact of cancer type, disease activity, and treatment in 877 unvaccinated UK patients with SARS‐CoV‐2 infection and active haematological cancer. The primary end‐point was all‐cause mortality. In a multivariate analysis adjusted for age, sex and comorbidities, the highest mortality was in patients with acute leukaemia [odds ratio (OR) = 1·73, 95% confidence interval (CI) 1·1–2·72, P = 0·017] and myeloma (OR 1·3, 95% CI 0·96–1·76, P = 0·08). Having uncontrolled cancer (newly diagnosed awaiting treatment as well as relapsed or progressive disease) was associated with increased mortality risk (OR = 2·45, 95% CI 1·09–5·5, P = 0·03), as was receiving second or beyond line of treatment (OR = 1·7, 95% CI 1·08–2·67, P = 0·023). We found no association between recent cytotoxic chemotherapy or anti‐CD19/anti‐CD20 treatment and increased risk of death within the limitations of the cohort size. Therefore, disease control is an important factor predicting mortality in the context of SARS‐CoV‐2 infection alongside the possible risks of therapies such as cytotoxic treatment or anti‐CD19/anti‐CD20 treatments.

Checkpoint inhibitors (CPIs) are monoclonal antibodies which, by disrupting interactions of immune checkpoint molecules with their ligands, block regulatory immune signals otherwise exploited by cancers. Despite revolutionary clinical benefits, CPI use is associated with an array of immune-related adverse events (irAEs) that mirror spontaneous autoreactivity. Severe irAEs necessitate pausing or stopping of CPI therapy and use of corticosteroids and/or other immunomodulatory interventions. Despite increasingly widespread CPI use, irAE pathobiology remains poorly understood; its elucidation may point to targeted mitigation strategies and uncover predictive biomarkers for irAE onset in patients, whilst casting new light on mechanisms of spontaneous immune-mediated disease. This review focuses on common CPI-induced irAEs of the gut, skin and synovial joints, and how these compare to immune-mediated diseases such as ulcerative colitis, vitiligo and inflammatory arthritis. We review current understanding of the immunological changes reported following CPI therapy at the level of peripheral blood and tissue. Many studies highlight dysregulation of cytokines in irAE-affected tissue, particularly IFNγ and TNF. IrAE-affected tissues are also predominantly infiltrated by T-cells, with low B-cell infiltration. Whilst there is variability between studies, patients treated with anti-programmed cell death-1 (PD-1)/PDL-1 therapies seem to exhibit CD8+ T-cell dominance, with CD4+ T-cells dominating in those treated with anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) monotherapy. Interestingly, CD8+CXCR3+ T-cells have been reported to be elevated in gastrointestinal, dermatological and musculoskeletal -irAE affected tissues. These findings may highlight potential opportunities for therapeutic development or re-deployment of existing therapies to prevent and/or improve the outcome of irAEs.