Unmanipulated Graft Transplantation From Family Haploidentical Donors: A Survey On 183 Adult Patients with Acute Leukemias On Behalf of the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation (EBMT)

Allogeneic stem cell transplantation from an haploidentical family donor has been recently developed through unmanipulated graft platforms.

We collected in 57 EBMT centers 183 haploidentical transplants (haploSCT) from unmanipulated peripheral blood (PB) and bone marrow (BM) graft in adults patients (pts) with de novo acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) reported to EBMT registry from 2007 to 2010 and analysed the outcome according to the known risk factors.

Overall, 120 AML patients underwent transplantation in CR1 (39), CR2 (22) or in advanced disease (54). Overall, 63 ALL pts underwent transplantation in CR1 (26), CR2 (14) or in advanced disease (22). Median age was 42y (18–75). Graft composition was based on non ex-vivo T-cell depleted BM in 52 (28%) or PB in 131 (72%). Conditioning regimen was myeloablative (MAC) in 95 and reduced-intensity (RIC) in 88 pts. Primary engraftment was documented in 160 pts (88%), with ANC 0.5 ×10⁹/L in a median of 19 days (BM) and 16 days (PB). Graft-versus-Host Disease (GvHD) prophylaxis was based on Anti-thymocyte globulins (ATG) + cyclosporine-methotrexate (24%) or cyclosporine-mycophenolate (18%), rapamycine-mycophenolate (25%), tacrolimus-mycophenolate (15%), others (7%). The cumulative incidence of acute GvHD >=II was 26%. With a median follow-up of 13 months (1–49), the estimated leukemia-free survival (LFS) at 1 years i was 53 +/−7%, 36 +/−8% and 22 +/−5% for CR1, CR2 and advanced patients respectively. In multivariate analysis for competing risks, relapse incidence (RI) at 1 y was 23 +/−5%, 20 +/−7%, 48 +/−6% for CR1, CR2 and advanced. The non-relapse mortality (NRM) at 1 y was 23 +/−6%, 43 +/−5%, 29 +/−6% for CR1, CR2 and advanced patients. On multivariate analysis, the only factor relevant for LFS was disease status at transplant.

EBMT registry analysis of haploidentical transplantation from unmanipulated donor graft confirms relevant LFS for patients with high risk acute leukemia. These results suggest that this procedure should be considered prospectively int treatment algorithm for high risk adults patients in early stages.

No relevant conflicts of interest to declare.