Tacrolimus as an alternative to cyclosporine in the maintenance phase of immunosuppressive therapy for severe aplastic anemia in children

Abstract

Given the paucity of data on the use of agents other than cyclosporine (CsA) in the maintenance phase of immunosuppressive therapy (IST) for severe aplastic anemia (SAA) in children, we sought to describe our experience with tacrolimus in pediatric SAA, and to compare outcomes with a preceding series of patients who received CsA. Eight patients with SAA diagnosed between 2003 and 2008 for whom no human leukocyte antigen (HLA)-matched sibling donor was identified underwent tacrolimus-based IST. These children were compared with a previously described series of 13 patients who had undergone CsA-based IST at our institution between 1990 and 2003. All patients initially received equine antithymocyte globulin (ATG) and corticosteroids. Complete response (CR) rate was 88% for tacrolimus and 85% for CsA. Median time to CR was approximately 7 months in both groups. Median follow-up duration was 2.4 years for tacrolimus and 8.4 years for CsA. Among responders with de novo SAA, relapse rate was 25% (n = 1) at 2 years for tacrolimus and 0% at 2 years and 23% (n = 3) at 5 years for CsA; no significant difference in relapse-free survival was detected between the two groups (P = 0.07). Paroxysmal nocturnal hemoglobinuria was seen in one patient on tacrolimus who had relapsed after CsA-based IST. Tacrolimus-based IST was well-tolerated. These data provide evidence that tacrolimus may be a suitable alternative to CsA as part of an IST regimen for SAA in children who lack an HLA-matched sibling and may have a more favorable profile of side effects than CsA.