Outcomes in lung transplant recipients on azathioprine compared to mycophenolate

A three-drug immunosuppression regimen to prevent graft loss is the cornerstone of therapy following lung transplantation. Direct comparisons between maintenance regimens including mycophenolate (MMF) and azathioprine (AZA) are limited in the lung transplant population.

We completed a retrospective cohort study of adult (≥18 years of age) lung transplant recipients at Mayo Clinic (Rochester, MN) from January 1, 2009 through July 1, 2022 and compared outcomes in patients on AZA vs MMF. Our primary outcome was clinically significant acute cellular rejection. Secondary outcomes included graft loss, drug interruption, chronic lung allograft dysfunction (CLAD), and infection. Analyses were performed with Multivariable Cox Regression with transplant era and induction immunosuppression agent as covariables.

224 patients were included, 88 on AZA and 136 on MMF. The risk of clinically significant rejection was greater in the AZA group compared to the MMF group (HR, 1.76; 95 % CI 1.12-2.79; P = 0.02). Medication interruption was also higher in the AZA (HR, 1.47; 95 % CI 1.04-2.08; P = 0.026). Rates of CLAD, graft loss, and infection were similar between the groups.

In this cohort, MMF was associated with lower risk of clinically significant acute cellular rejection and drug interruption when compared to AZA. Similar rates of CLAD, graft loss, and infection were observed.