Value of cemiplimab in progressive metastatic cutaneous squamous cell carcinoma after kidney transplantation: a case report.

Cutaneous squamous cell carcinoma (CSCC) is the most frequent post-transplant tumour entity resulting from immunosuppression treatment that is needed to prevent organ rejection. Solid organ transplant (SOT) recipients are at higher risk for CSCC and vulnerable for aggressive disease or a fatal course. Here, we report on a case of post-kidney transplant metastatic CSCC, demonstrating efficacy of cemiplimab in achieving complete remission after previous disease progression under cetuximab treatment. Unfortunately, the patient developed severe pneumonia, which was only later diagnosed as cemiplimab-associated pneumonitis. Due to a rapidly evolving septic condition, intensive care treatment was required and resulted in a fatal outcome. The patient's transplant remained intact, yet first-line treatment of advanced CSCC, such as with cemiplimab, should be weighed critically in SOT recipients, as transplant rejection may occur. However, the present case underlines the feasibility of cemiplimab as a second-line treatment option in this patient collective.