Mycophenolate mofetil versus azathioprine in patients surviving the initial cardiac transplant hospitalization: an analysis of the Joint UNOS/ISHLT Thoracic Registry.

Background. Although the randomized mycophenolate mofetil- (MMF) azathioprine (AZA) trial is likely applicable to cardiac transplantation in general, it was limited to select and usually larger cardiac transplant centers and suffered from substantial cross-over and failure of many patients to receive assigned treatment drug. Methods. The Joint ISHLT/UNOS Thoracic Registry was analyzed for the effects of MMF versus AZA in patients 1) on a cyclosporine- (CsA) based immunosuppression protocol; 2) having survived long enough to be discharged from the transplant hospitalization. Results. A total of 5599 patients (4942 CsA/AZA and 657 CsA/MMF) were included with no significant differences between the MMF and AZA groups in baseline characteristics with the exception of recipient age (50 vs. 47 years), donor age (29 vs. 28 years), ischemic time (3.0 vs. 2.9 hr), and pretransplant medical condition (more AZA patients in ICU, more MMF patients on VAD). Actuarial survival was greater in the MMF group compared to the AZA group in patients surviving the initial transplant hospitalization (1 year 96 vs. 93%, 3 years 91 vs. 86%, P=0.0012). This difference was confirmed in the logistic regression analysis of 3-year mortality showing a relative risk of 0.62 (P=0.011). Conclusions. These data provide independent support for the broad applicability of the positive results from the randomized MMF-AZA clinical trial in a substantially larger patient population and confirm improved survival in patients using mycophenolate mofetil compared to azathioprine late after cardiac transplantation.