587 Safety of immune checkpoint inhibitors in kidney transplant recipients

Background Recent advancements in solid organ transplant (SOT) care have significantly improved long-term survival rates through enhanced clinical practices and refined immunosuppressive therapies. However, a growing number of SOT recipients are facing challenges related to malignancies, for which immune checkpoint inhibitors (ICI) have emerged as standard treatment options. Historically, transplant patients have been excluded from ICI clinical trials, resulting in a lack of clear guidelines regarding their safe use in this population, with conflicting evidence in the literature. Early phase clinical trials have reported an 11.7% rejection rate associated with ICI use in kidney transplant recipients, suggesting potential variability based on the specific ICI and immunosuppressive regimen employed. Methods This study aims to investigate the rejection rates of kidney transplants in patients receiving ICIs. We conducted a retrospective analysis using the TriNetX Research Network (TriNetX LLC., Cambridge, Massachusetts, USA), identifying patients with a history of kidney transplant and malignancy who received ICIs post-transplant (specifically Cemiplimab, Nivolumab, Pembrolizumab, Atezolizumab, Avelumab, or Durvalumab). Kidney transplant rejection was documented using ICD-10 codes (T86.11). Propensity score matching was employed to control for medical comorbidities, comparing patients with kidney transplant and malignancy receiving ICIs (group 1) against those receiving no ICIs (group 2). Results Our analysis included 111 patients, predominantly with Melanoma (n=51), followed by Lung cancer (n=41) and kidney cancer (n=19). The mean age was 72 years (range 43 to 92), with 71% male representation (see table 1 for baseline characteristics). Following propensity score matching, 17 patients (15.3%) in group 1 experienced documented rejection compared to 22 patients (19.8%) in group 2, with no statistically significant difference observed between the two groups (p=0.38). Conclusions In conclusion, this study represents the largest reported cohort investigating ICI use in kidney transplant recipients. Our findings suggest that the rejection rates associated with ICIs are comparable to those reported in early phase studies, implying a potential safety profile for ICI use in this population. However, larger randomized trials are warranted to validate these findings and establish definitive guidelines for clinical practice.