Accepted Manuscript. HCT for Non Malignant Disorders. John F. Tisdale, MD Mary Eapen, MD, MS Riccardo Saccardi, MD

HCT for Non Malignant Disorders

John F. Tisdale, MD Mary Eapen, MD, MS Riccardo Saccardi, MD

PII: S1083-8791(12)00423-5 DOI: 10.1016/j.bbmt.2012.10.007 Reference: YBBMT 52905

To appear in: Biology of Blood and Marrow Transplantation

Please cite this article as: Tisdale JF, Eapen M, Saccardi R, HCT for Non Malignant Disorders, Biology of Blood and Marrow Transplantation (2012), doi: 10.1016/j.bbmt.2012.10.007.

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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HCT for Non Malignant Disorders Wednesday February 13, 2013 10:30-12:00

Salt Palace Convention Center

Chair: R. Saccardi, MD

1. John F. Tisdale: Allogeneic HCT in Sickle Cells Diseases: When and How 2. Mary Eapen: Choice of Alternative Donors for Aplastic Anemia

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ALLOGENEIC HCT IN SICKLE CELLS DISEASES: WHEN AND HOW

John F. Tisdale, MD

Molecular and Clinical Hematology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Heart, Lung and Blood Institute, National Institutes of Health,

Bethesda, MD

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The first successful HSC transplant in a patient with SCD was reported in 1984 in a pediatric patient with co-existing AML1 and established the curative potential of this approach. Myeloablative conditioning with busulfan and cyclophosphamide followed by HLA-matched marrow infusion was later successfully employed in Europe2,3 and the United States4 as primary treatment for severe SCD in children without an underlying malignancy. Antithymocyte globulin was subsequently added to decrease the risk of graft rejection in this frequently alloimmunized population4. While indications for transplant have remained controversial in the pediatric setting, in on series, patients were divided into 2 groups to reflect their access to care, those in Europe with access to care in whom severity criteria were used and those in Africa where access to such care is limited. In the second group, the only indication was SCD, and disease severity criteria were not employed. While overall results were favorable, the best results were seen in the second group, suggesting that transplantation before complications are observed results in better outcomes5. The most recent results reported in 2007 demonstrate that with the addition of ATG, rejection rates decreased from 22.6% to 3% and event-free survival rates rose to 95.3% among those transplanted after January 2000. These results establish HLA-matched transplants using myeloablative conditioning as the standard of care for eligible pediatric patients with SCD. Now, hundreds of affected pediatric subjects have undergone fully myeloablative allogeneic HSCT with favorable results.

Though these results in children are encouraging, procedural toxicities that increase with advancing age have limited this approach to pediatric patients. The ability to achieve engraftment of allogeneic HSCs without myleoablative conditioning prompted many to consider this strategy in nonmalignant disorders as increased safety was assumed, potentially allowing application to older patients and patients co-morbidities. In many such studies, prompt myeloid engraftment was observed in all, yet appeared to result from a donor T cell mediated alloimmune response that was associated with significant rates of graft versus host disease (GVHD) driving both morbidity and

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mortality. Furthermore, early studies attempting nonmyeloablative transplantation in SCD proved unsuccessful7. Others began to explore reduced intensity conditioning (RIC), which often contained agents that are ablative at near ablative doses, with improved success8. Based upon rapamycin’s ability to promote T cell tolerance even when T cells are stimulated in the presence of costimulation9 both in vitro and in vivo10, a clinical trial testing this approach was initiated in severely affected adults. The primary endpoint of the study was the proportion of patients with stable engraftment, with the incidence of GvHD as a secondary endpoint. HLA identical relatives underwent G-CSF mobilization and these unmanipulated hematopoietic stem cells (HSCs) were infused after conditioning with alemtuzumab 1mg/kg total, given over 5 days, a single dose of 300 cGy total body irradiation and oral sirolimus (rapamycin) initiated on day -1. Stable mixed chimerism and disease reversion was observed in 9 of the first 10 patients treated11. Additionally, no GvHD was observed among engrafted patients. Expansion of the cohort to now 25 patients has resulted in similar rates of engraftment, with 22 of 25 patients disease free again in the absence of GvHD. These data support mixed chimerism as a suitable goal for HSC transplantation in SCD.

The success of this regimen provides indirect evidence for graft specific tolerance, opening the possibility of expanding to alternative donor sources. Indeed, the main limitation has been a lack of HLA-matched sibling donors in the majority of patients with SCD. To determine availability of alternative donor sources, ten patients who met all study criteria on full screening for sibling matched HSCT but who did not have a suitable donor were selected for alternative donor searching in the National Marrow Donor Program (NMDP) and Bone Marrow Donors Worldwide (BMDW). Though 7 of 10 had a potential 6/6 matched unrelated donor, only 1 of 7 had a greater than 1% probability of having a 6/6 HLA match according to Haplogic. When cord blood units were searched, 9 of 10 had at least one 4/6 cord blood match identified (>1.5 x 107 total nucleated cells per kilogram body weight and ABO-matched). When higher degrees of matching (5/6) and higher cell doses were queried (2.5 x 107 total nucleated cells per kilogram body weight and ABO-matched) only 2 patients had a suitable cord product (Hsieh, personal communication).

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Thus nonmyeloablative haplo-identical HSC transplantation strategies are currently being explored as they appear the only current reliably obtainable stem cell source. Though extension of the low dose TBI/Campath/Rapamycin approach may be feasible in the haplo-identical setting, additional methods aimed at reducing the risk of both rejection and GVHD will likely be required. Cyclophosphamide given from two to three days after bone marrow transplantation has been shown to facilitate engraftment and prevent the development of GVHD by targeting activated lymphocytes. Recently, 14 individuals with sickle cell disease who received nonmyeloablative haploidentical bone marrow transplantation employing post-graft cyclophosphamide were reported, with engraftment in just over half of the subjects. Though higher rates of engraftment would be desirable, these results are encouraging as they were achieved in the absence of significant GvHD and no mortality was seen12. Additionally, a haplo-identical protocol employing TBI/Campath/Rapamycin has also recently opened to accrual at the National Institutes of Health. The study is designed as a dose escalation study testing post graft cyclophosphamide and accrual is ongoing.

In summary, HSCT for patients with SCD is highly effective, reversing the phenotype even when low levels of donor engraftment are achieved with newer, less toxic regimens. Results in children with myeloablative conditioning in the current era suggest that this therapy is underutilized. Future well designed studies testing nonmyeloablative conditioning regimens and alternative donor sources are poised to expand the application of the approach and lead the field in immune tolerance. Continued efforts to develop allogeneic transplantation for SCD with the goal of maximizing engraftment rates while minimizing morbidity and mortality are indeed justified.

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1. Johnson FL, Look AT, Gockerman J, Ruggiero MR, Dalla-Pozza L, Billings FT, 3rd. Bone-marrow transplantation in a patient with sickle-cell anemia. The New England journal of medicine 1984;311:780-3.

2. Vermylen C, Cornu G, Ferster A, Ninane J, Sariban E. Bone marrow transplantation in sickle cell disease: the Belgian experience. Bone Marrow Transplant 1993;12:116-7.

3. Bernaudin F, Souillet G, Vannier JP, et al. Bone marrow transplantation (BMT) in 14 children with severe sickle cell disease (SCD): the French experience. GEGMO. Bone Marrow Transplant 1993;12:118-21.

4. Walters MC, Patience M, Leisenring W, et al. Bone Marrow Transplantation for Sickle Cell Disease. The New England journal of medicine 1996;335:369-76.

5. Vermylen C, Cornu G, Ferster A, et al. Haematopoietic stem cell transplantation for sickle cell anaemia: the first 50 patients transplanted in Belgium. Bone Marrow Transplant 1998;22:1-6. 6. Childs R, Clave E, Contentin N, et al. Engraftment kinetics after nonmyeloablative allogeneic peripheral blood stem cell transplantation: full donor T-cell chimerism precedes alloimmune responses. Blood 1999;94:3234-41.

7. Iannone R, Casella JF, Fuchs EJ, et al. Results of minimally toxic nonmyeloablative transplantation in patients with sickle cell anemia and beta-thalassemia. Biol Blood Marrow Transplant 2003;9:519-28.

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8. Krishnamurti L, Kharbanda S, Biernacki MA, et al. Stable long-term donor engraftment following reduced-intensity hematopoietic cell transplantation for sickle cell disease. Biol Blood Marrow Transplant 2008;14:1270-8.

9. Powell JD, Lerner CG, Schwartz RH. Inhibition of cell cycle progression by rapamycin induces T cell clonal anergy even in the presence of costimulation. J Immunol 1999;162:2775-84. 10. Powell JD, Fitzhugh C, Kang EM, Hsieh M, Schwartz RH, Tisdale JF. Low-dose radiation plus rapamycin promotes long-term bone marrow chimerism. Transplantation 2005;80:1541-5. 11. Hsieh MM, Kang EM, Fitzhugh CD, et al. Allogeneic hematopoietic stem-cell transplantation for sickle cell disease. N Engl J Med 2009;361:2309-17.

12. Bolanos-Meade J, Fuchs EJ, Luznik L, et al. HLA-haploidentical bone marrow transplantation with post-transplant cyclophosphamide expands the donor pool for patients with sickle cell disease. Blood 2012.

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CHOICE OF ALTERNATIVE DONORS FOR APLASTIC ANEMIA

Mary Eapen, MD, MS Medical College of Wisconsin

Milwaukee, WI Email: meapen@mcw.edu

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Treatments for aplastic anemia include immune suppressive therapy (IST) with anti-thymocyte globulin (ATG), which lyses lymphocytes, and cyclosporine, which blocks T lymphocyte function, and hematopoietic stem cell transplantation (HCT), which replaces all hematopoietic progenitor cells, including lymphopoietic cells.1 There is general agreement that, when a human leukocyte antigen (HLA) matched sibling is available, HCT is first-line treatment for most patients with severe aplastic anemia (SAA). On the other hand, IST is used as first-line therapy is employed for patients who do not have an HLA-matched sibling and must seek an alternative donor2. Whether alternative donor HCT should be done after the failing one or more than one course of IST is uncertain and depends, in part, on patient factors predicting the likelihood of further response to IST and the likelihood of good outcome with HCT, as well as timely availability of a suitable donor.

Unrelated adult donor transplantation

Unrelated donor transplantation is an effective therapy for SAA but is limited by the availability of a suitably matched unrelated donor and is associated with higher risks of graft failure, GVHD and mortality than HLA-matched sibling transplantation. Selecting an appropriately matched donor for HCT is an important component of success. Several groups have attempted to compare outcomes of transplantation for aplastic anemia using 8/8 HLA matched versus HLA-mismatched grafts. Among 118 children and adolescents with aplastic anemia transplanted between 1989 and 2003 with unrelated adult donor bone marrow (BM) grafts, mortality risks were lower after HLA-matched versus misHLA-matched transplants.3 Ten-year probabilities of overall survival were 57% after 8/8 HLA- matched transplants compared to 39% after ≤7/8 HLA matched transplants.3 In a more recent report, survival probabilities after 8/8 HLA-matched unrelated donor bone marrow transplantation was higher at 75%.4 In that report, lower survival rates were 61% after peripheral blood stem cell transplantation. These observations support bone marrow is the preferred graft when considering unrelated donor transplantation. Importantly, advances in transplantation

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strategies including selection of better-matched donors have resulted in substantial improvements in survival after unrelated donor transplantation (32% before 1998; 61% before 2005 and now 75%). In the absence of a suitably matched adult unrelated donor, umbilical cord blood (UCB) has been used as an alternative graft. Data from Eurocord and the Japan Cord Blood Bank Network suggest survival probabilities of about 40%. In addition to HLA disparity and the less than optimal cell dose in UCB grafts it is likely that in some cases the reason for inferior survival is the fact that these transplantations are often done for patients who have failed multiple courses of IST. To-date there are no direct comparisons of outcomes after a second (or third) course of IST and unrelated donor transplantations.

Transplantation strategies – conditioning regimen

Alternative donor transplants have higher rates of graft failure, regimen-related toxicity and GVHD than HLA matched sibling transplants, even when the donor and recipient are 8/8 HLA matched. Unrelated donor transplantations performed in the eighties and nineties incorporated high doses of total body irradiation (TBI) to prevent graft failure. However, high dose TBI containing regimens are associated with severe acute toxicity and secondary malignancies. Therefore, to lower early toxicity and secondary malignancy, recent transplant conditioning regimens have used lower doses of TBI in combination with cyclophosphamide and ATG. Deeg and colleagues5 identified 200 cGy of TBI administered as a single dose together with cyclophosphamide (200 mg/kg) and equine ATG (90 mg/kg) as the optimal regimen in a radiation dose de-escalation study; graft failure occurred in 5% of patients and 5-year survival was 55%. Regimen-related toxicity (grade 3 or higher) and death decreased with de-escalation of the TBI dose. Age was an important predictor of survival; the 5-year probability of overall survival in younger patients (≤20 years) was 73% compared to 46% in older patients (p=0.05). Lowering the dose of TBI had no impact on graft failure. Further attempts at deescalating the dose of cyclophosphamide had yielded mixed results. A recent report from on on-going clinical trial in the United States showed excess mortality in the

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TBI (200cGy), cyclophosphamide 150 mg/kg, fludarabine 120 mg/m , ATG 9 mg/kg or ATGAM 90 mg/kg and excess graft failure when cyclophosphamide was eliminated from the regimen.6 Accrual to the cyclophosphamide 100 mg/kg and 50 mg/kg continue and the trial is expected to complete accrual early 2013.

Conclusion

The selection of more closely HLA-matched unrelated donors and lowering the intensity of transplant conditioning regimens, have had a significant impact on survival after transplantation for SAA. Bone marrow is the preferred graft source. The role of UCB transplantation in patients without an HLA-matched adult donor needs further exploration.

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1. Young NS, Bacigalupo A, Marsh JC. Aplastic Anemia: Pathophysiology and treatment. Biol Blood Marrow Transplant 2010; 16:S119-S125

2. Deeg HJ, O’Donnell M, Tolar J, et al. Optimization of conditioning for marrow transplantation from unrelated donors for patients with aplastic anemia after failure of immunosuppressive therapy. Blood. 2006; 108: 1485-1491

3. Perez-Albuerne ED, Eapen M, Klein J, et al. Outcome of unrelated donor stem cell transplantation for children with severe aplastic anemia. B J Haematol. 2008; 141: 216-223 4. Eapen M, Le Rademacher J, Antin JH et al. Effect of stem cell source on outcomes after

unrelated donor transplantation in severe aplastic anemia. Blood. 2001; 118: 2618-2621 5. Deeg HJ, Socie G, Schoch G, et al. Malignancies after marrow transplantation for aplastic

anemia and Fanconi anemia: a joint Seattle and Paris analysis of results in 700 patients. Blood. 1996; 87: 386-392

6. Tolar J, Deeg HJ, Arai S, et al. Fludarabine-based conditioning for marrow transplantation from unrelated donors in severe aplastic anemia: early results of a cyclophosphamide dose de-escalation study show life threatening adverse events at predefined cyclophosphamide dose levels. Biol Blood Marrow Transplant. 2012; 18: 1007-1011

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HCT FOR SEVERE MULTIPLE SCLEROSIS

Riccardo Saccardi, MD

Hematology Department, Careggi University Hospital Florence, Italy

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Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease believed to be mediated by autoreactive lymphocytes that invade the Central Nervous System (CNS) and cause oligodendrocyte, axonal and neuronal damage as well as glial scarring, resulting in demyelination, neuronal death and brain atrophy. In the majority of patients the onset of the disease is characterized by recurrent attacks, with or without incomplete recovery, resulting in an accumulation of disability, intermediated by clinical remissions (Relapsing-Remitting phase, RR). This phase is pathologically characterized by focal perivenular infiltrates dominated by T- and monocytoid cells. After years to decades, the inflammatory component gradually becomes more diffuse, the attacks become less apparent and more often disappear whilst the disability tends to slowly progress (Secondary-Progressive phase, SP). During this phase the continuous clinical deterioration is mainly sustained by degenerative changes including axonal and neuronal loss and a more diffuse microglial infiltration 1.

Neurological monitoring is carried out through both clinical and MRI parameters. A number of indexes have been developed to assess the clinical disability according to different performance scores; the most popular is the Kurtzke Expanded Disability Status Scale (EDSS), ranging from 0 (normal neurological examination) to 10 (MS-related death). Progression of the disability is defined as an increase of the EDSS score, confirmed after 3-6 months. Magnetic resonance imaging (MRI) has become the most important diagnostic tool in MS and as of a number of years, the diagnosis of MS is largely based on MRI alterations that show brain lesions disseminated in space. Conventional MRI metrics include Gadolinium-enhancing lesions (Gd+), a measure of blood-brain barrier disruption associated with acute inflammatory lesions and T2 lesions, a sensitive measure of demyelinating lesions. Loss of brain tissue or atrophy is determined by measuring decreased brain volume.

Available treatments for MS include high-dose steroids for the treatment of acute phases and immunomodulatory/immunosuppressive drugs chronically administered to reduce the number of

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relapses, decrease their severity and slow down the progression of disability. However, no disease modifying agent has been shown to modify long-term outcome; moreover a subset of patients shows an aggressive clinical pattern at the onset associated with a poor response to the conventional treatments. It is particularly this group of patients, i.e. those failing multiple treatments and accumulating clinical disability rapidly, for which treatment alternatives are needed.

Autologous Hematopoietic Stem Cell Transplantation (HSCT) has been experimented with over the last fifteen years in the treatment of severe autoimmune diseases (AD), that progress despite the administration of standard treatments. The rationale is derived both from experimental models and from the observations of positive effects of transplants for conventional indications and a coincidental AD. Autologous HSCT for MS has been employed since 1997 2,3 and currently approximately 1,000 patients have been treated worldwide, who are either in the Registry of the European Group for Blood and Marrow Transplantation (EBMT, www.ebmt.org) or in that of the Center for International Blood & Marrow Transplant Research (CIBMTR, www.cibmtr.org). This HSCT procedure results in a profound renewal of the immune system 4 and in a drop of inflammatory activity, as assessed by MRI5. Most patients were included in small, either single-center or multi-centre, phase 1–2 trials and no data are currently available from prospective comparative trials. A major clinical response was reported in most of the published studies, the neurological outcome being particularly favorable in patients transplanted in the RR phase and/or showing an inflammatory pattern at MRI during the pre-transplant screening. Case series, and reports about the excellent outcome in particularly aggressive forms of MS, support the efficacy of HSCT in MS patients with prominent inflammatory activity. In particular, a sustained EDSS improvement was reported more frequently in RR patients over SP patients6.

PBSC are usually well mobilized in MS patients; mobilization with the administration of G-CSF and without chemotherapy (i.e. Cyclophosphamide) results in a high incidence of disease

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recurrences and must be prevented by the administration of steroids. High intensity conditioning regimens, including either Busulphan or TBI, were not shown to result in a more efficient control of the disease7. Reduced-intensity regimens (Cyclophosphamide and ATG) showed a low transplant-related toxicity but a higher incidence of relapses8. BEAM plus ATG is the most frequent regimen reported to the EBMT Registry, showing a satisfactory equipoise of toxicity and efficacy9. Transplant-related mortality dropped from 7.3% in the years 1995-2000 to 1.3% in the years 2001-20072, probably due to a better patient selection and the use of less intense conditioning regimens. Indications for HSCT in MS have been recently reviewed by the EBMT9 in light of the clinical outcomes reported in the literature. The ideal target patient for autologous HSCT is one who is in the RR phase, shows high inflammatory activity, both clinically and with an MRI. SP patients should only be considered when some inflammatory activity is still present, either clinically (evidence of relapses in the previous year) of by MRI (accumulation of lesion in T2 scans in the previous year), therefore representing the transition phase between the RR and the SP, respectively. Data reported in prospective phase 1-2 studies show that an 80-90% progression-free survival (PFS) at 3 years from HSCT is expected in RR patients, whilst it drops to 50% in SP forms. An EBMT retrospective analysis on 143 MS patients showed that 63% of patients, mostly transplanted in the SP phase, were stable or improved at a median of 41.7 months after HSCT 10.However, MS is a chronic, progressive disease and assessment of long-term outcome is needed to provide a realistic evidence of efficacy of any treatment.. A joint EBMT/CIBMTR retrospective study, collecting data from patients with a follow-up ranging between 4 and 12 years, is currently ongoing. A prospective, comparative trial is also in preparation11.

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1. Compston A, Coles A. Multiple sclerosis. Lancet 2008;372:1502-17.

2. Mancardi G, Saccardi R. Autologous haematopoietic stem-cell transplantation in multiple sclerosis. Lancet Neurol 2008;7:626-36.

3. Atkins H. Hematopoietic SCT for the treatment of multiple sclerosis. Bone Marrow Transplant 2010;45:1671-81.

4. Muraro PA, Douek DC, Packer A, et al. Thymic output generates a new and diverse TCR repertoire after autologous stem cell transplantation in multiple sclerosis patients. J Exp Med 2005;201:805-16.

5. Saccardi R, Mancardi GL, Solari A, et al. Autologous HSCT for severe progressive multiple sclerosis in a multicenter trial: impact on disease activity and quality of life. Blood 2005;105:2601-7.

6. Mancardi GL, Sormani MP, Di Gioia M, et al. Autologous haematopoietic stem cell transplantation with an intermediate intensity conditioning regimen in multiple sclerosis: the Italian multi-centre experience. Mult Scler 2012;18:835-42.

7. Reston JT, Uhl S, Treadwell JR, Nash RA, Schoelles K. Autologous hematopoietic cell transplantation for multiple sclerosis: a systematic review. Mult Scler 2011;17:204-13.

8. Burt RK, Loh Y, Cohen B, et al. Autologous non-myeloablative haemopoietic stem cell transplantation in relapsing-remitting multiple sclerosis: a phase I/II study. Lancet Neurol 2009;8:244-53.

9. Snowden J, Saccardi R, Allez M, et al. Haematopoietic stem cell transplantation (HSCT) in severe autoimmune diseases: updated guidelines of the European Group for Blood and Marrow Transplantation (EBMT). In: Bone Marrow Transplant; 2011.

10. Saccardi R, Kozak T, Bocelli-Tyndall C, et al. Autologous stem cell transplantation for progressive multiple sclerosis: update of the European Group for Blood and Marrow Transplantation autoimmune diseases working party database. Mult Scler 2006;12:814-23.

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11. Saccardi R, Freedman MS, Sormani MP, et al. A prospective, randomized, controlled trial of autologous haematopoietic stem cell transplantation for aggressive multiple sclerosis: a position paper. Mult Scler 2012;18:825-34.