Haploidentical Transplantation Using High Dose Post-Transplant Cyclophosphamide for Patients with Aplastic Anemia : The European Group for Blood and Marrow Transplantation Experience

• Published in: Blood 2018-11, Vol.132 (Supplement 1), p.486-486
• Main Authors: Prata, Pedro H, Afanasyev, Boris, Eikema, Dirk-Jan, Smiers, Frans, Knol, Cora, Diez-Martin, Jose L., Rocha, Vanderson G., Koc, Yener, Poire, Xavier, Fegueux, Nathalie, Kröger, Nicolaus, Holter, Wolfgang, Bloor, Adrian, Jubert, Charlotte, Al-Seraihy, Amal, Ganser, Arnold, Tilly, Herve, Pioltelli, Pietro, Pérez-Simón, José A., Ho, Aloysius YL, Aljurf, Mahmoud, Russell, Nigel H., Labussière-Wallet, Hélène, Kerre, Tessa, Dufour, Carlo, Peffault De Latour, Regis
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2018-99-114033

The outcome of patients with severe aplastic anemia (SAA) has greatly improved in recent years but is still poor for patients who failed or relapsed after immunosuppressive therapy (IST) and don't have a matched donor. Recent use of eltrombopag shows blood count improvements in 40% of cases, but most patients refractory to immunosuppressive therapy, are also unresponsive to eltrombopag. In this situation, hematopoietic stem cell transplantation (HSCT) using alternative donor sources (mismatched unrelated donors, cord blood, and haploidentical family donors) may be curative but are also associated with a high risk of morbidity and mortality. Moreover, ethnic minorities have limited access to an alternative donor, especially in the adult population. Haploidentical transplantation using post-transplant cyclophosphamide (Haplo-PTCy) has been shown to facilitate engraftment and shows GvHD rates comparable to those of matched sibling HSCT in hematologic malignancies. However, few papers have been published on Haplo-PTCy in the context of aplastic anemia. We conducted a retrospective analysis of 36 patients (72% male), who received an haplo-PTCy for aplastic anemia in 22 EBMT centers from June 2010 to March 2017. Haplo-PTCy was the first transplantation for 81% patients (second, 11%; third, 8%). The non-myeloablative preparatory regimen included anti-thymocyte globulin in 33% of patients and low dose TBI in 58% of patients. Donors were father (n=12, 35%), mother (n=12, 35%), brother (n=5, 15%), sister (n=3, 9%), cousin (n=1, 3%) and daughter (n=1, 3%). The stem cell source was mainly bone marrow (55%). All patients received cyclophosphamide 50mg/kg/day IV on days +3, and +4 post-transplant and 75% received tacrolimus or cyclosporine plus mycophenolic acid. The primary endpoint was the probability of OS. Secondary study endpoints included probability of neutrophil recovery (ANC 500/ μL for at least 3 consecutive days), platelet recovery (platelets 20 000/ μL for at least 3 consecutive days, and 7 days after the last transfusion), cumulative incidences of acute and chronic GVHD and relapse-free survival without Grade III-IV acute GvHD and without extensive chronic (GRFS). Thirty-two patients were diagnosed with moderate (7%), severe (52%) or very severe idiopathic aplastic anemia (41%), while 4 patients were transplanted for congenital aplastic anemia (3 Fanconi Anemia and 1 Diamond Blackfan). The median age was 19.4 years (range 2.5-45.4 years; 58% adults). Median