Steven-Johnson Syndrome/Toxic Epidermal Necrolysis is Associated with PD-1/PD-L1 Inhibitors Usage: A Case Series

<b>Aims/Background</b> The increasing adoption of inhibitors of programmed cell death-1 (PD-1) and its ligand, programmed death-ligand 1 (PD-L1), in the treatment of multiple cancer types in China has started to garner broader attention due to the occurrence of immune-related adverse events (irAEs), especially life-threatening skin reactions such as Steven-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). Isolated case reports have described SJS/TEN associated with PD-1/PD-L1 inhibitors usage. In this paper, we presented a series of cases of SJS/TEN following the use of PD-1/PD-L1 inhibitors in a dermatology hospital located in Zhejiang Province of China in the past several years, summarizing characteristics of these cases and providing a reference of management. <b>Methods</b> We retrospectively reviewed all the medical records of inpatients diagnosed with SJS/TEN in the Hangzhou Third People's Hospital from 2012 to 2024. We analyzed and compared the situation of SJS/TEN onset, types of PD-1/PD-L1 inhibitors used, score of severity, laboratory findings, and essential therapies of the patients who had received PD-1/PD-L1. <b>Results</b> We identified 12 SJS/TEN patients who had been treated with PD1/PD-L1 inhibitors: sintilimab had been used in six patients; tislelizumab in two cases; toripalimab, keytruda and cadonilimab each in one case; and an unknown prescription in one case. The longest duration between the first PD-1/PD-L1 inhibitor dose and the SJS/TEN diagnosis recorded was nine months whereas the shortest was 11 days. Half of the selected patients received chemotherapy at the same time. More than two types of therapies were applied to the cases, except for two cases with mild SJS. <b>Conclusion</b> This study unveils a potential, under-recognized cause of SJS/TEN in the cancer patients after analyzing the cases of SJS/TEN in cancer patients with prior exposure to PD-1/PD-L1 inhibitors. This paper also provides clue about the prominent features of SJS/TEN aforesaid, offering insights on the effective management measures for optimizing clinical safety.