Several aspects of the study protocol are likely to have contributed to the preservation of efficacy despite the steroid-free regimen. Patients with high PRA levels or an extended cold ischemia time were excluded. 92.4% of the population is Caucasian. The feasibility of this type of steroid avoidance regimen in higher-risk individuals, such as patients with donor specific antibodies, African-American promotion recipients, or those receiving a marginal graft from an extended criteria donor, is questionable. An intensified regimen of EC-MPS was administered during the first six weeks after transplantation. Such a regimen has previously been shown to reduce the risk of BPAR when administered to patients receiving CsA and IL-2RA induction [7].

Moreover, protocol biopsies at three months after transplantation ensured detection of subclinical pathology, permitting reevaluation of the immunosuppressive regimen and reintroduction of steroids or other revisions if necessary. This approach improves the security of steroid avoidance. An alternative option may be to continue steroids indefinitely and withdraw long-term MPA therapy although comparative data from randomized controlled trials is relatively sparse [20]. In terms of renal function, mean creatinine clearance at month 36 was 44.7mL/min/1.73m2. Comparison of renal function between our population and other steroid avoidance studies is hampered by the fact that eGFR has not always been reported [3, 5] and that, where available, values extend only to month 6 [4] or month 12 [2], but published values at those time points are broadly similar to those observed in our study.

Moreover, there was no significant difference in renal function between the two treatment groups at any time point. The potential concern that steroid avoidance could ultimately lead to chronic rejection seems to be addressed by the finding that renal function, proteinuria, and the reported incidence of chronic rejection were similar in both arms to 36 months after transplant. It would also have been interesting to assess the presence of donor specific antibodies to evaluate whether this was promoted by steroid withdrawal, but the study protocol did not address this question. Other aspects of the study merit discussion. The INFINITY study was observational in design, with investigators free to manage patients according to local protocol after month 6 after transplant. Nevertheless, there were Carfilzomib relatively few changes to immunosuppressive regimens after month 6, with steroids being introduced in only three patients (4.3%) in the steroid avoidance arm and being discontinued in only four patients (6.5%) in the steroid withdrawal arm.