Alemtuzumab Associated With Higher Mortality Than Basiliximab in Older Kidney Transplant Recipients.

Introduction: Kidney transplantation (KT) in older age is increasingly common as more elderly patients live with end-stage renal disease. Immunosuppression (IS) after KT confers additional risk in aging patients with weakened immune systems. We hypothesized that 1-year mortality among KT recipients aged 70 y and older would be higher in those receiving induction IS with alemtuzumab lymphocyte depletion versus basiliximab interleukin-2 inhibition.

Methods: This single-institution retrospective analysis enrolled KT recipients aged 70 y and older who underwent transplantation between January 2010 and June 2022. Data were obtained from the United Network for Organ Sharing and the electronic medical record. Descriptive comparisons were performed using chi-squared, Fisher's exact, and Wilcoxon rank-sum tests as appropriate. The primary outcome was a risk-adjusted analysis to assess the association of induction IS type with 1-year mortality.

Results: The median age was 72 y [IQR 70-74] among 146 eligible KT recipients. Induction IS was achieved with alemtuzumab in 47 recipients and basiliximab in 99 recipients. At 1 y, higher rates of mortality (17.0% versus 3.0%, P = 0.005), infectious death (12.8% versus 1%, P = 0.005), and graft failure (21.3% versus 6.1%, P = 0.006) were observed among alemtuzumab compared to basiliximab recipients, with no significant difference in biopsy-proven acute rejection rate. On multivariate analysis, alemtuzumab was independently associated with 1-year mortality (P = 0.012).

Conclusions: Alemtuzumab is associated with increased 1-year mortality over basiliximab induction among KT recipients 70 y and older. Lymphocyte-depleting induction may contribute to inferior outcomes via infectious risk. Alemtuzumab induction should be approached with caution in this high-risk population.