Abstract
BACKGROUND: Programmed-cell death protein 1 (PD-1) inhibitors have emerged as a standard of care treatment among advanced-stage or metastatic cutaneous squamous cell carcinoma (cSCC). Immune-compromised patients and particularly solid organ transplant recipients (SOTRs) are considered at high risk for cSCC. When treated with PD-1 inhibitors, the possibility of organ rejection, autoimmune flare, or insufficient response to treatment is feared. As these patients were excluded from past prospective clinical trials, we aim to describe our institute's experience regarding these patients. METHODS: A retrospective analysis was conducted on cSCC patients treated with PD-1 inhibitors. Comparisons were made between immune-compromised and immune-competent groups, with a subgroup analysis of SOTR. RESULTS: The study cohort comprised of 133 patients, including 97.8% receiving Cemiplimab with a mean age of 77.2 ± 11.7 years. Immune-compromised patients constituted 26.9% (n = 35) of the cohort, including 10 SOTR (all kidney transplant recipients). Objective response rates (ORRs) and disease control rates (DCR) were comparable between immunocompetent and immunosuppressed patients receiving Cemiplimab (ORR: 76.8% vs 62.9%, P = .12; DCR: 81.1% vs 68.6%, P = .13). SOTR demonstrated an 80% ORR and DCR. Progression-free survival was comparable across all groups. Toxicity rates were similar between immunosuppressed and immunocompetent subgroups (68.6% vs 62.1%, P = .5). Two OTRs (20%) experienced acute graft rejection. CONCLUSIONS: PD-1 inhibitors demonstrate efficacy and safety in immunosuppressed cSCC patients. While effective in SOTR, treatment requires multidisciplinary management due to the potential risk of organ rejection. These findings provide valuable insights into this understudied population and support the use of PD-1 inhibitors in immunosuppressed patients with advanced cSCC.