Influence of induction therapy on rejection and survival in heart transplantation

Immunosuppressive therapy has undergone great changes in recent years as a result of the introduction of new drugs, presumed a prior to be more effective and better tolerated. The greatest advance seems to have been the introduction of interleukin-2 (IL-2) receptor antagonists. The objective of this study was to determine whether the use of IL-2 receptor antagonists in induction therapy has implications for the development of rejection and survival.

Three hundred sixty-five consecutive cardiac transplant patients who received induction therapy were included. Heart-lung and transplants in children under 10 years were excluded. Three groups were compared according to the induction therapy (OKT3, 10 days; OKT3, 7 days; and IL-2R antagonists). Each treatment corresponded to a time period: OKT3 10 days from June 1989 to April 1994; OKT3 7 days from May 1994 to October 2002; and IL-2R antagonists from November 2002 to May 2004. Baseline characteristics of recipient and donor, surgical times, postsurgical complications, maintenance immunosuppression, number of rejections, time (days) to first rejection, and probability of survival at 1 year were recorded. We used analysis of variance, chi(2) test, Kaplan-Meier curves, and log-rank test as appropriate. A P-value < .05 was considered significant.

There were significant differences in the characteristics of the transplanted patients in the various time periods. Thus, recipients in the OKT3 10 day group had worse status but better donors, whereas recipients in the IL-2R antagonists group had better status but older donors with longer duration of ischemia. The incidence of acute graft failure was similar in the three groups. The number of rejection episodes in the first year was higher among the OKT3 groups (OKT3 10 days, 1.7 +/- 1.3; OKT3 7 days, 1.2 +/- 1.2; IL-2R antagonists, 1.0 +/- 1.2; P = .02) and the probability of survival at 1 year was also lower (OKT3 10 days, 74%; OKT3 7 days, 77%; IL-2R antagonists, 94%; P = .0007).

Induction therapy with IL-2 antagonists offers important advantages over treatment with OKT3 in terms of survival, with absolute and relative risk reductions of 20% and 27%. Furthermore, it did not increase the number of rejections, although this may have been due to the greater use of MMF versus azathioprine.