Haploidentical Transplantation (HAPLO) with Post-Transplant High-Dose Cyclophosphamide for Graft Vs Host Disease (GVHD) Prevention in the Treatment of High Risk Hematological Neoplasms

Allogeneic transplantation is the only curative option in the treatment of multiple high risk hematologic neoplasms. Only 25–30% of patients have an HLA identical sibling donor and searching for a compatible unrelated donor or cord blood renders satisfactory results in around 60–70%. Haploidentical transplantation (HAPLO) offers a therapeutic alternative to more than 95% of such patients with the advantages of quick availability, easy programming and a committed donor.

We evaluate the results of HAPLO with a reduced intensity conditioning regimen (Fludarabine 30 mg/m2 ×5 days (-6 to -2), Cyclophosphamide 14,5 mg/kg ×2 days (-6 and -5), IV Busulfan 3,2 mg/kg × 1–3 days (BUX, days -4 to -2) employing high doses of Cyclophosphamide post graft infussion (50 mg/kg days +3 and +4) as GVHD prophylaxis together with standard doses of cyclosporine and mycophenolate from day +5.

From Dec-2007, we have done 26 HAPLO in 4 spanish centers. Median age was 38 years (16–57), 20 were male and all were in advanced phases of their diseases (12 Hodgkin′s, 6 AML, 3 ALL, 2 MM, 1 MDS, 1 MF y 1 NHL). Previous autologous HSCT has been employed in 13 and allogeneic HSCT in 6 (2 MURD and 4 UCB). Disease status at HAPLO was CR in 8, PR in 14 and refractory in 4. Bone marrow was used in 16 and unmodified peripheral blood in 10. The haploidentical donor was patient′s mother (8), father (3), siblings (11) or other relatives (4). BUX was used in 1 dose (15), 2 doses (8) or 3 doses (2) and TBI 200 cGy in 1 case. Mean neutrophils engraftment was achieved on day +18 (13–26) and platelets >50K on day +27 (17–150) in all but 2 cases of graft failure (7.7%) due to progression (MF) or relapse (M7-AML). Main toxicities were grade 1–2 mucositis in 50%, febrile neutropenia in 75% and CMV reactivations in 58% with a 100 days NRM of 3.8% (1/26, VOD and MOF) and 10% NRM at 6 months (2/20). Grade II-IV acute GVHD appeared in 10/23 patients at risk (43%) and grade III-IV in 4/23 (17%). Chronic GVHD affected to 4/15 (27%), being extensive in 1/15 (6.7%). With a median follow-up of 9 months (1–38), 13/22 (59%) are alive in CR, progression or relapse has ocurred in 6/24 (25%). Immune reconstitution seems fast and complete in those evaluated.

HAPLO with high-dose cyclophosphamide as GVHD prophylaxis is a useful alternative in the treatment of high risk hematologic tumours, with low toxicity, acceptable GVHD incidence and severity, long lasting remissions, and fast immunological reconstitution.

No relevant conflicts of interest to declare.