Retreatment with rabbit anti‐thymocyte globulin and ciclosporin for patients with relapsed or refractory severe aplastic anaemia

The management of patients with severe aplastic anaemia (SAA) who do not have a matched sibling donor and fail a course of horse anti-thymocyte globulin (h-ATG)/ciclosporin (CsA) is uncertain. Repeated courses of ATG-based immunosuppression are often employed; in children and increasingly in adults, alternative donor haematopoietic stem cell transplantation is an option. We analysed the success rate of retreatment with rabbit ATG (r-ATG)/CsA in 43 patients treated at our institution in the last 5 years; 22 were refractory (20 adults; two children) to h-ATG/CsA-based regimens and 21 (17 adults; four children) had relapsed after h-ATG/CsA-based regimens. The overall response rate was 30% in patients who were refractory to h-ATG and 65% in patients who had relapsed following h-ATG. The 1000-d survival in patients who responded to r-ATG was 90% compared with 65% in non-responders. Six patients developed a clonal haematological disorder; two were responders, two were non-responders and in two the evolution occurred before the response could be assessed at 3 months following r-ATG. Thirteen patients died; three were responders, six were non-responders and four patients died prior to 3 months when response was assessed. In our study, the response rate in refractory patients was inferior to what has been previously reported.