Successful use in lung transplantation of an immunosuppressive regimen aimed at reducing target blood levels of sirolimus and tacrolimus

Background: The primary aim of this study was to assess the safety and efficacy in lung transplantation of an immunosuppressive regimen aimed at achieving sirolimus and tacrolimus concentrations of 6 to 10 μg/ml and 5 to 7 ng/ml, respectively. Methods: We retrospectively identified 49 lung transplant recipients who were converted to an immunosuppressive regimen consisting of tacrolimus, sirolimus, and prednisone. Data collected included demographic information, laboratory work, episodes of rejection, bronchiolitis obliterans syndrome (BOS) grade, and adverse effects. Results: The most common reason for conversion to a sirolimus and tacrolimus regimen was BOS. The most common adverse effects were increased triglycerides (10%), leukopenia (8%), and skin rash (6%). Four patients (8%) experienced acute allograft rejection during the study period. We followed BOS grade for 1 year in 23 patients. Of these, BOS grade improved in 8, 13 patients remained unchanged, and 2 worsened. Eleven patients (22%) discontinued sirolimus because of adverse events. Conclusion: An immunosuppressive regimen consisting of sirolimus and tacrolimus that aims to keep the trough drug concentrations at 6 to 10 μg/ml and 5 to 7 ng/ml, respectively, provides effective lung allograft protection while maintaining an acceptable side-effect profile. The use of this immunosuppressive combination may have a benefit with regard to BOS.