Significant clinical impact of immunosuppressive therapy termination after allogeneic haematopoietic stem cell transplantation

The clinical impact of immunosuppression termination (IST) after allogeneic haematopoietic stem cell transplantation (allo-HSCT) remains to be fully elucidated. This study was aimed at assessing the impact of IST within 2 years after transplantation on subsequent clinical outcomes. We analysed data for patients from the Transplant Registry Unified Management Program 2 (TRUMP 2) database who survived without progression for at least 2 years after allo-HSCT. Of the 5061 patients whose median age was 48 (range: 0-79) years, 2320 discontinued immunosuppressive therapy within 2 years (IST group), while 2741 did not (non-IST group). The 4-year overall survival (OS) rate was significantly higher in the IST group than in the non-IST group (95.3% vs. 90.8%; p < 0.01). The 4-year cumulative incidence of non-relapse mortality (NRM) was significantly lower in the IST group than in the non-IST group (3.5% vs. 8.6%; p < 0.01). This reduction in NRM was consistent across major causes, including graft-versus-host disease (GVHD)-related mortality, infection-related mortality and organ failure-related mortality. Immunosuppressive therapy beyond 2 years after allo-HSCT was associated with inferior OS. Our findings suggest that the optimal transplant strategy is necessary to avoid long-term immunosuppression for improving clinical outcomes in allo-HSCT recipients.