ALBERT

Description: Abstract 3234 Haemopoietic stem cell transplantation is the only proven curative treatment available for haemoglobinopathies. From 2000 to 2010 severty-four consecutive transplants were conditioned with busulfan 14 mg/kg, cyclophosphamide 200 mg/kg and alemtuzumab (Bu/Cy) achieving a DFS of 94.5%. In order to reduce busulfan toxicity, minimise mixed chimerism and enable the use of related mismatched and unrelated donors, the conditioning regimen was modified: fludarabine 160 mg/m2, treosulfan 42 g/m2, thiotepa 10 mg/kg and ATG (Thymoglobulin) 7.5 mg/kg or 11.25 mg/kg (FTTA). 18 patients [13 with β thalassaemia major and 5 with sickle cell disease, median age 6.5 years (2 – 16)] received a related transplant: fifteen 10/10 matched sibling, one 10/10 matched related and two 9/10 mismatched sibling. The source of stem cells was BM in 16 patients and mixed cord blood and BM in 2 with a median cell dose of 3.85 ×108 TNC.kg (range 1.50 – 6.87). Median follow-up was 6.7 months (2.40 – 20). Two patients received an unrelated transplant (α thalassaemia major, 12 years, 10/10 matched BM, 2.4 ×108 TNC/kg, survival +5 months; sickle cell disease, 7 years, 9/10 matched PBSC, 6 ×106CD34+/kg, survival +1.8 months). Endogenous haemopoiesis was suppressed with hypertransfusions. GvHD prophylaxis: ciclosporin and MMF. Patients with thalassaemia were Pesaro class I or II. Patients with sickle cell disease were transplanted for stroke or recurrent vaso-oclusive crisis and/or acute chest syndrome not responding to hydroxycarbamide. All patients are alive with transfusion-independence and donor haematological values (DFS 100%, OS 100%). Acute GvHD ≥grade 2 occurred in 1 related patient (5.6%) and both unrelated patients; chronic limited GvHD in 2 related patients (11.1%), all with resolution following steroid treatment. Neutrophil engraftment was achieved at a median of 12 days (9 – 21) in comparison to 19.5 days (12 – 28 days) with the previous protocol. Chimerism studies in whole blood demonstrated that donor haemopoiesis was higher for FTTA v Bu/Cy at all-time points (day +28: 100% 〉95% for FTTA v 81.4% 〉95%, 16% 〉90–95% and 2.4% 〉50–80%; day +90: 91.6% 〉95% and 8.3% 〉90–95% v 67.1% 〉95%, 12.8% 〉90–95%, 12.8% 〉80–90% and 12.8% 〉50–80%; day +150: 50% 〉95%, 37.5% 〉90–95% and 12.5% 〉50–80% v 55.8% 〉95%, 10.8% 〉90–95%, 14.7% 〉80–90%, 8.8% 〉50–80%, 2.9% 〉30–50% and 2.9% 〉20–30%). Donor T-cell lymphopotiesis is FTTA was day +28: 100% (68 – 100), day +90: 98.5% (55–100) and day +150: 98% (73–100). In conclusion, FTTA leads to earlier engraftment and higher donor chimerism than Bu/Cy, no graft failure, and enables the use of mismatched and unrelated donors for transplantation in haemoglobinopathies, whilst the incidence of GvHD is low. Disclosures: No relevant conflicts of interest to declare.

Description: Long-term survival in Diamond Blackfan Anaemia (DBA) is compromised by transfusional iron overload and/or side effects of high-dose steroids as well as increasing recognition of the increased risks of aplasia and malignancy. Allogeneic haemopoietic stem cell transplantation (HSCT) can cure the haematological manifestations of DBA, but the optimal conditioning protocol is yet to be defined, particularly avoiding irradiation in view of the increased risk of malignancy. Four consecutive children with DBA were conditioned with oral busulfan 14 mg/kg (days-9 to -6), cyclophosphamide 200 mg/kg (days-5 to -2) and horse ALG 45 mg/kg (days-4 to -2) prior to HLA-matched sibling donor HSCT. Graft-versus-host disease (GvHD) prophylaxis was provided with ciclosporin from day-1 for six months to a target range of 100–150 ng/mL and methotrexate 10 mg/m2 on days +4 and +7. P1: 10 years old boy who was transfusion dependent for two years having lost the response to steroids. In addition, he had deafness, short stature, gastrooesophageal reflux and cleft palate. He received bone marrow (8 × 108 TNC/kg). P2: 10 years old boy who was steroid dependent and had developed diffuse liver steatosis and bone fractures. In addition, he had short stature and undescended testis. He received bone marrow (1.91 × 108 TNC/kg). P3: four year old girl who was transfusion dependent with no associated abnormalities. She received a combination of cord blood (0.83 × 107 TNC/kg) and bone marrow (0.738 × 108 TNC/kg) from a sibling born following pre-implantation genetic diagnosis and HLA typing. P4: six year old boy born at 34 weeks of gestation who was transfusion dependent. He received a combination of cord blood (1.4 × 107 TNC/kg) and bone marrow (2.73 × 108 TNC/kg). Neutrophil and platelet engraftment were prompt in all 4 patients (neutrophils: day 15–22; platelets day 10–33). Stable complete donor haemopoiesis was confirmed in all four patients using peripheral blood genomic DNA microsatellites markers by genescanning on day +28, 6 months and 1 year post-transplantation. The conditioning protocol was well tolerated by all patients with no life-threatening infections, though one patient had moderate veno-occlusive disease responding to defibrotide followed by gastrointestinal haemorrhage and another suffered reversible ciclosporin-associated posterior leucoencephalopathy and stage IV, steroid-responsive, acute gut GvHD. All four patients are alive with full donor haemopoiesis and normal haematological parameters at 11, 12, 15 and 24 months post-transplantation. Sibling allogeneic HSCT with this non-TBI protocol is a reasonable and feasible option for DBA patients suffering from unacceptable steroid side effects or chronic transfusion therapy.

Description: Blood and marrow transplantation (BMT) is the only proven curative treatment available for haemoglobinopathies. From October 2010 to May 2013 thirty-eight patients with haemoglobinoapathies received a BMT at St. Mary’s Hospital, London. The conditioning included fludarabine 160 mg/m2, treosulfan 42 g/m2, thiotepa 10 mg/kg and ATG (Thymoglobulin) 7.5 mg/kg or 11.25 mg/kg (FTTA). GvHD prophylaxis was ciclosporin for six months and MMF until molecular evidence of donor engraftment. Patients with SCD received clonazepam CNS prophylaxis whilst on immunosuppression. Endogenous haemopoiesis was suppressed with hypertransfusions for at least six weeks pre-transplantation to minimise the risk of rejection. All patients had iron load assessed by MRI T2* and FerriScan and hepatic fibrosis staged by liver biopsy pre-transplantation. Patients with liver fibrosis Ishak ≥3 were given defibrotide prophylaxis. Twenty-six patients suffered from thalassaemia major (TM) and from 12 sickle cell disease (SCD). Patients with TM were Pesaro class I or II. Patients with SCD were transplanted for stroke or recurrent vaso-oclusive crisis and/or acute chest syndrome not responding to hydroxycarbamide. The median age was 7 years (range 2-17). The median follow-up was 10.18 months (range 1.02 -25.1). Thirty-six patients received stem cells from a related donor (31 matched sibling bone marrow, 2 matched other relatives, two 9/10 mismatched siblings, and one 9/10 mismatched other relative) and 2 from unrelated donors (1 fully matched and one 9/10 mismatch). The source of stem cells was bone marrow (BM) in 32 patients, mixed BM and cord blood (CB) in 3 patients, CB in 2 patients and PBSC in one patient. The median cell dose 3.61 x108 TNC/kg (range 0.58 -9.77) and 5.99 x108 TNC/kg (range 1.15 -14.23). All patients engrafted, though one related CB transplant suffered secondary graft failure on day +26 due to disseminated adenovirus infection. The median neutrophil engraftment occurred on day +12 (range 9-21). Three patients (7.8%) suffered VOD, presenting at a median of 9 days (7-11) which was successfully treated with defibrotide. Acute GvHD grade 1 occurred in 1 patient (2.6%) and grade ≥2 in 5 patients (13.2%), which resolved in all patients including 2 who received MSC. cGVHD 〉day +100 post-transplantation was limited in 2 (7.9%) and extensive in 2 patients (5.3%) and fully resolved in all cases with appropriate treatment. Two patients have died of a transplant related cause: a related CB transplant for TM of disseminated adenovirus infection on day +31 and a related BM transplant for SCD of an intracranial haemorrhage on day +185 due to immune thrombocytopenia and parvovirus B19 infection. Chimerism studies in whole blood demonstrated donor haemopoiesis as follows: day +28: 94% 〉95% and 6% 〉90-95%; day +90: 93.2% 〉95%, 3.4% 〉90-95% and 3.4% 〉80-90%; day +120: 84% 〉95%, 8% 〉90-95%, 4% 〉50-80% and 4% 95%, 24% 〉90-95%, 4% 〉80-90%, 4% 〉50-80% and 4% 95%, 25% 〉90-95%, 8.3% 〉80-90% and 4.3% 〉50-80%; day +360: 61.5% 〉95%, 30.8% 〉90-95% and 7.7% 〉30-50%. Donor T-cell lymphopoiesis was day +28: 100% (28 – 100), day +90: 99% (16-100), day +150: 96% (36-100), day +180: 96% (54-100) and day +360: 94.5% (78-100). In conclusion, FTTA leads to high levels of long-term donor engraftment and enables the use of mismatched and unrelated donors for transplantation in haemoglobinopathies with limited toxicity Disclosures: No relevant conflicts of interest to declare.

Description: Haemopoietic stem cell transplantation (HSCT) is the only proven curative treatment available for haemoglobinopathies. To reduce transplant-related mortality and morbidity associated with graft-versus-host disease (GvHD) and facilitate donor engraftment we have used low-dose alemtuzumab in 43 consecutive patients (36 with thalassaemia and 7 with sickle cell disease; median age 6 years; range 2 to 16 years) transplanted since 2000. Donors were HLA-matched family donors in all cases. All patients were conditioned with oral busulfan 14 mg/kg (days -9 to -6), cyclophosphamide 200 mg/kg (days -5 to -2) and alemtuzumab 0.3 mg/kg (days -8 to -6) with post-HSCT methotrexate (10 mg/m2 days +4 and +7) and ciclosporin for six months. Hypertransfusion was initiated six weeks before conditioning and maintained until day +28 to suppress endogenous haemopoiesis and minimise graft rejection. Patients with thalassaemia were Pesaro class I or II. Patients with sickle cell disease were transplanted for stroke or recurrent vasooclusive crisis and/or acute chest syndrome not responding to hydroxycarbamide. The source of stem cells was bone marrow in all cases except one patient who received PBSC with a median cell dose of 3.08 x 108 TNC/kg (range 1.69 – 10.90 x 108 TNC/kg). Median follow up was 25.8 months (range 6.5 – 94.3 months). Chimerism studies were performed on peripheral blood genomic DNA using 8 microsatellites markers by genescanning. All patients are alive (43/43), 42 with long-term transfusion-independence and donor haematological values (5 years DFS 97.7%). One patient failed to engraft and was re-infused with autologous cells. Donor haemopoiesis was ≥ 95% on day +28 in all 42 patients who engrafted and was maintained at ≥ 95% in the majority of patients at 12 months post-HSCT. Eleven patients (11/42; 31%) have stable mixed chimerism at ≥ 12 months post-HSCT: donor haemopoiesis 90–94% (n=4);