Small vessel vasculitis and dry gangrene secondary to combined CTLA-4 and PD-1 blockade in malignant mesothelioma.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a rare and aggressive tumour with an overall poor prognosis. In October 2020, first line treatment with the PD-1 antagonist nivolumab and the CTLA-4 antagonist ipilimumab for unresectable disease was FDA approved-the first approved treatment regime since 2004. Interim analyses from the phase 3 CHECKMATE-743 study shows improvements in overall survival. Skin-related toxicities are the most commonly reported any-grade treatment-related adverse event from combined nivolumab and ipilimumab therapy. CASE PRESENTATION: Here we report a case of a 35-year-old white male who developed digital ischaemia secondary to small vessel vasculitis after receiving PD-1 and CTLA-4 blockade therapy for MPM. His progressive ischaemia became gangrenous, and he required multi-speciality input and treatment with prednisolone, prostacyclin, mycophenolate mofetil and hydroxychloroquine. CONCLUSIONS: Our case highlights the importance of early detection, intervention, and a multispecialty approach to managing such complications in order to minimise the associated morbidity and mortality.