Posttransplant cyclophosphamide for haploidentical stem cell transplantation in children with Wiskott–Aldrich syndrome

Abstract

Abstract Background Hematopoietic stem cell transplantation (HSCT) is the curative treatment for Wiskott–Aldrich syndrome (WAS). However, it is difficult to find a matched donor for patients. Therefore, haploidentical donors should be considered for patients lacking a suitable donor. Our pilot study evaluated whether HSCT with posttransplantation cyclophosphamide (PTCy) is an effective treatment for WAS. Methods Haploidentical family donors were selected as donor sources for a total of five patients without a suitable donor between March 2015 and March 2017. A modified transplant protocol using PTCy (50 mg/kg/day on days +3 and +4) was performed, including busulfan (16 mg/kg), fludarabine (150 mg/m 2 ), and rabbit antihuman thymocyte globulin (7.5 mg/kg). Results The median time for neutrophil recovery over 1,000 × 10 3 /mm 3 was 15 days (range, 12–18 days), and that for keeping platelets counts over 50,000/mm 3 was 27.5 days (range, 20–35 days). The median follow‐up was 2.1 years (range, 1.4–2.5 years). Two patients developed grade I acute graft‐versus‐host disease (GVHD), and one patient had limited chronic GVHD. All five patients are alive and independent of platelet infusion with 100% donor chimerism. Conclusion Our pilot study suggests that HSCT with modified PTCy is a safe and effective treatment for WAS, which needs further clinical practice and research.