Long-term follow-up of myeloablative allogeneic stem cell transplantation using Campath ‘in the bag’ as T-cell depletion: the Leiden experience

Bone Marrow Transplantation (2006) 37, 1129–1134 & 2006 Nature Publishing Group All rights reserved 0268-3369/06 $30.00 www.nature.com/bmt ORIGINAL ARTICLE Long-term follow-up of myeloablative allogeneic stem cell transplantation using Campath ‘in the bag’ as T-cell depletion: the Leiden experience RMY Barge, CWJ Starrenburg, JHF Falkenburg, WE Fibbe, EW Marijt and R Willemze Department of Hematology, Leiden University Medical Center, Leiden, The Netherlands Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity after allogeneic stem cell transplantation (alloSCT) but can be prevented by removing T-lymphocytes from the graft. Campath (antiCD52) antibodies have been widely used in vivo for T-cell depletion following conventional and reduced intensity conditioning regimens. The use of Campath in vivo was associated with a significant reduction in GVHD but at the cost of impaired immune reconstitution. We evaluated the long-term outcome of 73 myeloablative allogeneic stem cell transplants with HLA-identical sibling donors using Campath ‘in the bag’ as method of in vitro T-cell depletion. All patients engrafted and hematopoietic recovery was uneventful, resulting in a median of 99% donor chimerism at 3 months after alloSCT. Cytomegalovirus (CMV) reactivation occurred in 53% of the patients. No CMV disease was observed probably as a result of pre-emptive (val)ganciclovir treatment. The incidence of aGVHD was low (22% grade II). No grades III–IV aGVHD was observed and extensive chronic GVHD (cGVHD) occurred in 19% of the patients. The low incidence of GVHD and successful pre-emptive antiviral therapy resulted in low TRM of 8%. Sixteen patients died due to disease relapse after alloSCT, resulting in an overall survival of 48% at 5-years after alloSCT. Bone Marrow Transplantation (2006) 37, 1129–1134. doi:10.1038/sj.bmt.1705385 Keywords: T-cell depletion; allogeneic stem cell transplantation; long-term follow up Introduction Allogeneic stem cell transplantation (alloSCT) is a curative treatment modality for many patients with malignant and non-malignant diseases. Graft-versus-host disease (GVHD) remains the main complication after conventional myeloablative as well as after non-myeloablative conditioning.1–6 Post-transplant immune suppression and techniques to deplete the graft and/or the patient for T lymphocytes have been applied for many years. Anti-CD52 antibodies, directed against the CD52 antigen expressed on human T- and B-lymphocytes, monocytes and dendritic cells, have been successfully used for T-cell depletion. Initially rat antibodies Campath-1M and Campath-1G, and later the humanized form Campath-1H (alemtuzumab), have been administered in different in vivo and in vitro treatment protocols.7–12 The main technical advantage to using Campath in vitro is its easy applicability, compared to the time-consuming procedure of CD34 selection using an affinity-column. At 30 min after addition of the Campath antibody to the graft, the stem cells are infused into the patient. A drawback of using Campath is impaired immune reconstitution. Recently the use of in vivo administration of high-dose alemtuzumab in combination with fludarabine and melphalan as a non-myeloablative conditioning regimen has been extensively investigated. Despite the significant decrease in the incidence of GVHD, poor immune reconstitution and an increased incidence of infectious complications was observed.13–14 Immune incompetence is probably caused by infusion of high-dose alemtuzumab since pharmacokinetic studies have shown that, in contrast to Campath-1G with an earlier reported half-life of approximately 12–13 h, alemtuzumab has a half-life of 15–21 days in the setting of the transplantation protocol.15 In vitro T-cell depletion with Campath ‘in the bag’ has predominantly been used after myeloablative conditioning. Only limited information is available on long-term results of in vitro usage of Campath for T-cell depletion. In this report, we describe our single centre long-term experience with in vitro T-cell depletion of the stem cell graft by Campath in 73 patients with a hematological malignancy receiving a conventional myeloablative alloSCT from an HLA identical family donor. Patients and methods Correspondence: Dr RMY Barge, Department of Hematology, Leiden University Medical Center, C2R, PO Box 9600, 2300 RC Leiden, The Netherlands. E-mail: Received 15 November 2005; revised 21 March 2006; accepted 22 March 2006 Patients Between January 1998 and December 2004, 73 adults with hematological malignancies received a first alloSCT after standard cyclophosphamide/TBI conditioning, using Campath in the bag as T-cell depletion RMY Barge et al 1130 Table 1 Patient and transplantation characteristics Number Age at alloSCT (years) Median (range) 44.5 (19–61) Gender Female Male 40 33 Diagnosis Acute myeloid leukemia Acute lymphoid leukemia Myelodysplastic syndrome Chronic myeloid leukemia Multiple myeloma Lymphoma Other Standard risk/high riska 21 13 5 16 11 4 3 53/20 CD34+ cells in the graft (
106/kg) Median (range) a 7.5 (0.5–18.6) Standard risk: acute leukemia in first CR or CML in first chronic phase. peripheral blood stem cells from an HLA-identical sibling donor, at the Leiden University Medical Center. The transplant protocol was approved by the institutional Ethics Committee. The main clinical characteristics of the 73 patients are shown in Table 1. All patients were nursed in HEPA-filtered rooms. Donors All patients were transplanted with stem cells from a fully HLA-matched sibling donor. Donor stem cells were mobilized with filgrastim (Amgen, Thousand Oaks, CA, USA), 10 mg/kg/day s.c. for 4 or 5 days. On day 4, donors received two injections of filgrastim. Apheresis was performed on day 5, using a continuous flow blood cell separator (Cobe Spectra; Gambro BCT; Lakewood, CO, USA). A minimum dose of 5
106 CD34 þ cells/kg of the recipient body weight was targeted for transplantation. After filtering and centrifugation, the buffy coat was harvested. T-cell depletion of the stem cell product was performed by incubation with alemtuzumab (20 mg) for 30 min at room temperature under continuous gentle agitation.7 The number of CD34 þ cells was analyzed by flow cytometry. Transplantation Patients were conditioned with a standard myeloablative regimen. They received cyclophosphamide (Cy) at 60 mg/ kg/day i.v. administered for 2 consecutive days (days 6 and 5) and single dose TBI (9 Gy; 25 cGy/min with lungand eye-shielding) at day 1. Immediately following incubation with alemtuzumab, the stem cell product was infused intravenously on day 0. No post-transplant GVHD prophylaxis, cytomegalovirus (CMV) prophylaxis or hematopoietic growth factors were administered. All patients received supportive care, that is antimicrobial prophylaxis, hydration, blood component support, parenteral nutrition, according to institutional protocols. Bone Marrow Transplantation Post-trans (...truncated)