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Allogeneic hematopoietic cell transplantation after myeloablative conditioning is an effective therapy for patients with hematologic malignancies. In an attempt to extend this therapy to older patients or those with comorbidities, reduced intensity or truly nonmyeloablative regimens have been developed over the last decade. The principle underlying reduced intensity regimens is to provide some tumor kill with lessened regimen-related morbidity and mortality, then rely on graft-versus-tumor (GVT) effects to eradicate remaining malignant cells, while nonmyeloablative regimens rely primarily on GVT effects. In this article, three representative approaches are described, demonstrating the clinical application for both hematopoietic and non-hematopoietic malignancies. Current challenges include controlling graft-versus-host disease while allowing GVT to occur. In the future, clinical trials using reduced intensity and nonmyeloablative conditioning will be compared to myeloablative conditioning in selected malignancies to extend the application to standard risk patients.
PMCID: PMC1829153  PMID: 17222778
reduced intensity; nonmyeloablative; allogeneic; hematopoietic cell transplantation
2.  Treatment of hematological malignancies with nonmyeloablative, HLA-haploidentical bone marrow transplantation and high dose, post-transplantation cyclophosphamide 
Hematopoietic stem cell transplantation provides the only potential curative option in many patients with hematological malignancies. Finding a suitably matched donor in a timely manner is often difficult. However, most patients have a partially HLA-mismatched (HLA-haploidentical) first-degree relative readily available. Historically, HLA-haploidentical bone marrow transplantation (BMT) has been considered extremely high risk due to high rates of life-threatening graft-versus-host disease (GVHD) and non-relapse mortality (NRM). Modifications of the stem cell graft, such as T-cell depletion, have resulted in poor rates of engraftment. We have recently completed a phase II clinical trial of nonmyeloablative HLA-haploidentical hematopoietic BMT followed by post-transplantation high-cyclophosphamide. High-dose cyclophosphamide has been shown to create immunogenic tolerance by specifically killing activated mature T-cells. As a result, alloreactive T-cells in the donor graft are selectively destroyed thereby decreasing the incidence of severe GVHD. As well, host-versus-graft reactive T-cells are also selectively eliminated thereby increasing rates of engraftment. Among 210 patients with hematological malignancies receiving nonmyeloablative, HLA-haploidentical BMT with post-transplantation cyclophosphamide, the rate of sustained donor cell engraftment has been 87%. The cumulative incidence of grade 2–4 acute GVHD is 27%, grade 3–4 acute GVHD is 5% and chronic GVHD is 15%. Interestingly, increasing HLA disparity between donor and recipient was not associated with increasing incidence of GVHD or decreased event-free survival. Nonmyeloablative haploidentical stem cell transplantation with post-transplantation cyclophosphamide seems to be a promising, potentially curative, option for patients with hematological malignancies who either lack an HLA-matched related or unrelated donor, or in whom a myeloablative preparative regimen is contraindicated due to significant co-morbidities or history of extensive pre-treatment.
PMCID: PMC3204344  PMID: 21925089
stem cell transplantation; nonmyeloablative; HLA-haploidentical; hematological malignancies; cyclophosphamide
3.  Phase II Study of Gonadotropin-Releasing Hormone Analog for Ovarian Function Preservation in Hematopoietic Stem Cell Transplantation Patients 
The Oncologist  2012;17(2):233-238.
Results of a phase II clinical trial of leuprolide administered before conditioning chemotherapy in hematopoietic stem cell transplantation patients to reduce the incidence of premature ovarian failure are presented. Leuprolide did not preserve ovarian function in patients who underwent hematopoietic stem cell transplantation using either myeloablative or nonmyeloablative regimens.
Premature ovarian failure occurs in 40%–70% of patients who receive conventional chemotherapy alone. However, the incidence is higher, 70%–100%, in patients who undergo myeloablative chemotherapy with hematopoietic stem cell transplantation (HSCT). Gonadotropin-releasing hormone (GnRH) analogs, such as leuprolide, in a continuous-release formulation, may protect the ovaries from the gonadotoxic effects of chemotherapy. In non-HSCT settings, GnRH analogs have reduced the risk for premature ovarian failure to <10%. We conducted a phase II clinical trial based on the hypothesis that giving leuprolide before conditioning chemotherapy in HSCT patients reduces premature ovarian failure incidence.
Patients and Methods.
Eligible patients were women aged ≤40 years who were HSCT candidates, were premenopausal, and had both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels ≤20 IU/L. Two 22.5-mg leuprolide doses were delivered in 3-month depot i.m. injections, the first within 2 months before HSCT. Patients were monitored for menstruation return, and ovarian function tests (FSH, LH, and estradiol) were done every 2 months starting 90 days after the last leuprolide dose.
Sixty eligible patients were enrolled, 59 underwent HSCT, and 44 were evaluable (median age, 25 years; median follow-up, 355 days). Only seven of 44 patients (16%) regained ovarian function. Of the 33 who received myeloablative regimens, six (18%) regained ovarian function. However, among the 11 who received nonmyeloablative regimens, only one (9%) regained ovarian function (p = .66).
Leuprolide did not preserve ovarian function in patients who underwent HSCT using either myeloablative or nonmyeloablative regimens. Other measures that protect ovarian function need to be investigated.
PMCID: PMC3286172  PMID: 22282904
Gonadotropin-releasing hormone analog; Premature ovarian failure; Ovarian function preservation; Hematopoietic stem cell transplantation
4.  The Impact of Donor Type and ABO Incompatibility on Transfusion Requirements after Nonmyeloablative Hematopoietic Cell Transplantation (HCT) 
British journal of haematology  2010;149(1):101-110.
We retrospectively analyzed transfusion requirements within the first 100 days among allogeneic hematopoietic cell transplantation (HCT) recipients with hematological malignancies given either myeloablative (n=1353) or nonmyeloablative conditioning (n=503). We confirmed that myeloablative recipients required more platelet and red blood cell (RBC) transfusions than nonmyeloablative recipients (both P< 0.0001). Myeloablative patients given peripheral blood stem cells required less platelet transfusions (P<0.0001) than those given marrow while RBC transfusion requirements did not differ significantly. Subsequent analyses were restricted to nonmyeloablative recipients. Related recipients required less platelet and RBC transfusions compared to unrelated recipients (P < 0.0001 for both), with comparable median numbers of transfused units. Major/bidirectionally ABO-mismatched recipients required more RBC transfusions than ABO-matched recipients (P=0.006). Rates of graft rejection/failure, grades II–IV acute and chronic graft-versus-host-disease (GVHD), 2-year relapse, 3-year survivals and non-relapse mortality were comparable among ABO-matched, minor-mismatched, and major/bidirectionally mismatched recipients (P=0.93, 0.72, 0.57, 0.36, 0.17 and 0.79, respectively). Times to disappearance of anti-donor IgG and IgM isohemagglutinins among major/bidirectionally ABO-mismatched recipients were affected by magnitude of pre-HCT titres (P<0.001 for both) but not GVHD (P=0.71 and 0.78, respectively). In conclusion, nonmyeloablative recipients required fewer platelet and RBC transfusions and among them, both unrelated and major/bidirectionally ABO-mismatched recipients required more RBC transfusions. ABO incompatibility did not affect nonmyeloablative HCT outcomes.
PMCID: PMC2864362  PMID: 20067562
nonmyeloablative conditioning; allogeneic HCT; ABO-incompatibility; transfusion
5.  Feasibility of low dose interleukin-2 therapy following T cell-depleted non-myeloablative allogeneic hematopoietic stem cell transplantation from HLA matched or mismatched family member donors 
Cancer investigation  2011;29(1):56-61.
High relapse rates and infections remain primary causes of failure in non-myeloablative transplantation. Interleukin-2 (IL-2) may stimulate the immune system and improve outcomes. The primary objective of this pilot study was to evaluate the feasibility of administering IL-2 following a T cell-depleted nonmyeloablative hematopoietic stem cell transplant.
Patients received T cell depleted nonmyeloablative transplant from a matched or mismatched related donor. Those with allogeneic engraftment, < grade 2 acute GVHD at time of study entry, and no severe end organ damage were eligible and received IL2 starting 6 weeks after the first day of stem cell infusion. Patients received 1 mu/m2 daily for 5 days each week for 4 weeks followed by a 2 week rest period for a 6 week cycle to continue for up to 1 year.
Eight patients aged 28–69 were treated. Significant toxicities were limited to GVHD of the skin ≤ grade 2 in 3 patients and severe fatigue in 4 patients, limiting the duration of therapy. Two of the 8 patients died of relapsed disease and one from CMV. With a median overall duration of follow up of survivors of 48 months, five patients (63%) remain alive and in continuous complete remission.
PMCID: PMC3619422  PMID: 21166499
Non-myeloablative Allogeneic Transplantation; Leukemia /Lymphoma; IL-2; NK cells
6.  In vivo protection of activated Tyr22-dihydrofolate reductase gene-modified canine T lymphocytes from methotrexate 
The journal of gene medicine  2013;15(0):10.1002/jgm.2713.
Nonmyeloablative allogeneic hematopoietic stem cell (HSC) transplantation can cure malignant and nonmalignant diseases affecting the hematopoietic system, such as severe combined immunodeficiencies, aplastic anemia and hemoglobinopathies. Although nonmyeloablative is favored over myeloablative transplantation for many patients, graft rejection remains problematic. One strategy to decrease rejection is to protect donor activated T cells in the graft from methotrexate (MTX) by genetically modifying the cells to express MTX-resistant dihydrofolate reductase (Tyr22-DHFR), leaving the immunosuppressive effects of MTX to act solely on activated host T lymphocytes, shifting the balance to favor allogeneic engraftment.
To evaluate MTX resistance of Tyr22-DHFR+ T lymphocytes in vivo, we transplanted dogs with autologous CD34+ cells modified with YFP and DHFR-GFP lentivirus vectors. Dogs were then treated with a standard MTX regimen (days 1, 3, 6, and 11) following immune activation with a foreign antigen as a surrogate assay to mimic early transplantation.
DHFR-GFP+ gene marking was maintained in CD3+CD25+ and CD4+ T lymphocytes after MTX treatment while the level of T lymphocytes that expressed only a fluorescent reporter (YFP+) decreased. These data show that Tyr22-DHFR expression protects T lymphocytes from MTX toxicity in dogs, highlighting a clinically relevant application for preserving donor T lymphocytes during post transplantation immunosuppression.
These findings have implications for clinical translation of MTX-resistant T cells to facilitate engraftment of allogeneic cells following nonmyeloablative conditioning and minimize the risk of rejection. In summary, Tyr22-DHFR expression in T lymphocytes provides chemoprotection from MTX-mediated elimination in the context of immune activation in vivo.
PMCID: PMC3886817  PMID: 23666780
gene therapy; chemotherapy; viral vector; transplantation; drug resistance; animal model
7.  Stable Hematopoietic Cell Engraftment after Low-Intensity Nonmyeloablative Conditioning in Patients with Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX) Syndrome 
Immune dysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX) syndrome is characterized by severe systemic autoimmunity caused by mutations in the FOXP3 (Forkhead Box P3) gene. Hematopoietic cell transplantation is currently the only viable option for long-term survival, but patients are frequently very ill and may not tolerate traditional myeloablative conditioning regimens.
Here, we present the outcome of hematopoietic cell transplantation using a low intensity, nonmyeloablative conditioning regimen in two patients with IPEX syndrome and significant pre-transplant risk factors.
Two high-risk patients with IPEX syndrome received HLA-matched related bone marrow or unrelated peripheral blood stem cell grafts following conditioning with 90 mg/m2 fludarabine and 4 Gy total body irradiation. Postgrafting immunosuppression consisted of mycophenolate mofetil and cyclosporine. Immune reconstitution and immune function was evaluated by measurement of donor chimerism, regulatory T-cell numbers, absolute lymphocyte subsets and T-cell proliferation assays.
Both patients experienced minimal conditioning toxicity and successfully engrafted after hematopoietic cell transplantation. With a follow-up of 1 and 4 years, respectively, patients 1 and 2 have full immune function and normal FOXP3 protein expression.
A low intensity, nonmyeloablative conditioning regimen can establish stable engraftment and correct the life-threatening immune deficiency and enteropathy of IPEX syndrome despite the presence of comorbidities that preclude conventional hematopoietic cell transplantation.
PMCID: PMC2962731  PMID: 20643476
Hematopoietic cell transplantation; Nonmyeloablative conditioning regimen; Immunodeficiency; Immune dysregulation; Autoimmunity; Regulatory T-cells; Immune reconstitution
8.  Similar and Promising Outcomes in Lymphoma Patients Treated with Myeloablative or Nonmyeloablative Conditioning and Allogeneic Hematopoietic Cell Transplantation 
We compared the outcomes of 141 consecutive patients who received allogeneic transplantation with either myeloablative (MA) or nonmyeloablative/reduced intensity (NMA) conditioning for non-Hodgkin and Hodgkin lymphoma at the University of Minnesota. All patients were transplanted between 1997 and 2004. NMA transplant recipients were older and received umbilical cord blood grafts more frequently (MA: 6 [9%]; NMA: 33 [43%], P < .001). NMA patients had more advanced disease and 30 (39%) patients had undergone prior autologous transplantation. The 4-year overall survival (OS) (MA: 46% versus NMA: 49%; p = .34) and the 3-year progression-free survival (PFS) (MA: 44% versus NMA: 31%; P = 0.82) were similar after MA or NMA conditioning. However, MA conditioning resulted in significantly higher 1-year treatment-related mortality (TRM) (MA: 43% versus NMA: 17%; P < .01) but a lower risk of relapse at 3 years (MA: 11% versus NMA: 36%; P < .01). We conclude that similar transplant outcomes are achieved after allogeneic hematopoietic stem cell transplantation using MA conditioning in younger patients and NMA conditioning in older patients or those with prior autologous transplantation not eligible for MA conditioning. Modifications to refine patient assignment to the preferred conditioning intensity and reduce relapse risks with NMA approaches are needed.
PMCID: PMC2423491  PMID: 18410896
Lymphoma; Allogeneic transplantation; Nonmyeloablative
9.  Assessment of the Hematopoietic Cell Transplantation Comorbidity Index in Non-Hodgkin Lymphoma Patients Receiving Reduced-Intensity Allogeneic Hematopoietic Stem Cell Transplantation 
The hematopoietic cell transplantation comorbidity index (HCT-CI), a weighted index of 17 pretransplantation comorbidities, has been validated in nonmyeloablative and myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) studies, but it has not been specifically tested in patients with non-Hodgkin lymphoma (NHL) receiving reduced-intensity conditioning (RIC). We performed a retrospective analysis to assess the impact of the HCT-CI on outcomes of NHL patients treated with HSCT relative to treatment-related mortality (TRM), disease-related mortality (DRM), with a specific emphasis on overall survival (OS). Individual pretransplantation and disease-related factors also were analyzed with HCT-CI relative to their impact on OS. All patients were uniformly treated with an identical pretransplantation induction regimen and an identical RIC regimen (cyclophosphamide [Cy]/fludarabine [Flu]), and received T cell–replete allografts from HLA-matched siblings. The analysis included 63 NHL patients with a median HCT-CI score of 2 (range, 0 to 11). The HCT-CI (0 to 2 comorbidities vs 3+ comorbidities) demonstrated a potential association with TRM, but not with DRM, at 100 days (4.5% vs 26.3%) and at 1 year (13.6% vs 36.8%) posttransplantation. The factor most strongly associated with OS was response to pretransplantation chemotherapy (P = .0001), based on a composite measure. In a Cox model, pretransplantation chemotherapy response remained the most important factor (P < .0001) relative to OS, and there was a trend (P = .056) toward HCT-CI adding predictive value for OS. Although HCT-CI may be useful for predicting TRM, our data further underscore the importance of response to chemotherapy before transplantation as a predictor of overall transplantation outcome in NHL patients being considered for RIC allogeneic HSCT.
PMCID: PMC2842937  PMID: 19167682
Comorbidity index; Non-Hodgkin lymphoma; Reduced intensity conditioning; Allogeneic
10.  Allogeneic Hematopoietic Stem-Cell Transplantation for Sickle Cell Disease 
The New England journal of medicine  2009;361(24):2309-2317.
Myeloablative allogeneic hematopoietic stem-cell transplantation is curative in children with sickle cell disease, but in adults the procedure is unduly toxic. Graft rejection and graft-versus-host disease (GVHD) are additional barriers to its success. We performed nonmyeloablative stem-cell transplantation in adults with sickle cell disease.
Ten adults (age range, 16 to 45 years) with severe sickle cell disease underwent nonmyeloablative transplantation with CD34+ peripheral-blood stem cells, mobilized by granulocyte colony-stimulating factor (G-CSF), which were obtained from HLA-matched siblings. The patients received 300 cGy of total-body irradiation plus alemtuzumab before transplantation, and sirolimus was administered afterward.
All 10 patients were alive at a median follow-up of 30 months after transplantation (range, 15 to 54). Nine patients had long-term, stable donor lymphohematopoietic engraftment at levels that sufficed to reverse the sickle cell disease phenotype. Mean (±SE) donor–recipient chimerism for T cells (CD3+) and myeloid cells (CD14+15+) was 53.3±8.6% and 83.3±10.3%, respectively, in the nine patients whose grafts were successful. Hemoglobin values before transplantation and at the last follow-up assessment were 9.0±0.3 and 12.6±0.5 g per deciliter, respectively. Serious adverse events included the narcotic-withdrawal syndrome and sirolimus-associated pneumonitis and arthralgia. Neither acute nor chronic GVHD developed in any patient.
A protocol for nonmyeloablative allogeneic hematopoietic stem-cell transplantation that includes total-body irradiation and treatment with alemtuzumab and sirolimus can achieve stable, mixed donor–recipient chimerism and reverse the sickle cell phenotype.
PMCID: PMC3627532  PMID: 20007560
11.  Allogeneic Stem Cell Transplantation for Multiple Myeloma: A Review of Outcomes at a single Transplant Center 
Bone marrow transplantation  2012;47(10):1312-1317.
Allogeneic stem cell transplant for multiple myeloma (MM) is one treatment associated with long term disease free survival. The high incidence of treatment related mortality and relapses, however, are important reasons for controversy about the role of allografting in the management of MM. We reviewed our results of allografting for MM spanning a period of 34 years in order to better define long term outcomes and identify areas of progress as well as areas needing improvement. A total of 278 patients received allogeneic marrow or peripheral blood stem cells after high dose myeloablative (N=144) or reduced intensity, non-myeloablative (N=134) regimens. In multivariable analysis, adjusting for differences in patient groups, reduced intensity/nonmyeloablative transplants were associated with significantly less acute GVHD, lower transplant mortality, better progression free survival and overall survival. There were no significant differences in relapse, progression or chronic GVHD, when adjusted. In multivariable analysis of patients receiving only non-myeloablative transplants, decreased overall survival and progression free survival were associated with relapse after a prior autograft and a β2 microglobulin >4.0. Transplant mortality was reduced and only influenced by a prior tandem autograft.
PMCID: PMC3376198  PMID: 22327126
Multiple myeloma; Plasma cell disorders; Allogeneic bone marrow transplant; Allogeneic stem cell transplant
12.  Graft-versus-Leukemia Effect of Nonmyeloablative Stem Cell Transplantation 
Nonmyeloablative stem cell transplantation (NST) is increasingly used with beneficial effects because it can be applied to older patients with hematological malignancies and those with various complications who are not suitable for conventional myeloablative stem cell transplantation (CST). Various conditioning regimens differ in their myeloablative and immunosuppressive intensity. Regardless of the type of conditioning regimen, graft-versus- host disease (GVHD) in NST occurs almost equally in CST, although a slightly delayed development of acute GVHD is observed in NST. Although graft-versus-hematological malignancy effects (i.e., graft-versus-leukemia effect, graft-versus-lymphoma effect, and graft-versus-myeloma effect) also occur in NST, completely eradicating residual malignant cells through allogeneic immune responses is insufficient in cases with rapidly growing disease or uncontrolled progressive disease. Donor lymphocyte infusion (DLI) is sometimes combined to support engraftment and to augment the graft-versus-hematological malignancy effect, such as the graft-versus-leukemia effect. DLI is especially effective for controlling relapse in the chronic phase of chronic myelogenous leukemia, but not so effective against other diseases. Indeed, NST is a beneficial procedure for expanding the opportunity of allogeneic hematopoietic stem cell transplantation to many patients with hematological malignancies. However, a more sophisticated improvement in separating graft-versus-hematological malignancy effects from GVHD is required in the future.
PMCID: PMC2784970  PMID: 19949725
Nonmyeloablative stem cell transplantation; Graft-versus-host disease; Graft-versus-leukemia effect
13.  Five decades of progress in hematopoietic cell transplantation based on the preclinical canine model 
The preclinical canine model has proved valuable for the development of principles and techniques of hematopoietic cell transplantation (HCT) applicable to human patients. Studies in random-bred dogs concerning the impact of histocompatibility barriers on engraftment and graft-versus-host disease, the kinetics of immunological reconstitution, the efficacy of various pre-transplant conditioning regimens, post-transplantation immunosuppression protocols, treatment of malignant diseases, and graft-versus-tumor effects have advanced HCT from an investigational therapy with uncertain clinical benefit half a century ago to an important treatment choice for thousands of patients treated annually in transplantation centers worldwide. More recent preclinical canine studies have resulted in the clinical translation of nonmyeloablative, minimally invasive transplantation protocols that have extended allogeneic HCT to include older human patients with malignant and non-malignant, acquired or inherited hematological disorders, and those with comorbid conditions. Here we review the contributions of the canine model to modern HCT and describe the usefulness of HCT for the treatment of canine hematological disorders.
PMCID: PMC2752055  PMID: 19754798
dog; hematopoietic cell transplantation; hematological malignancies
14.  Extracorporeal Photophoresis 
Executive Summary
To assess the effectiveness, safety and cost-effectiveness of extracorporeal photophoresis (ECP) for the treatment of refractory erythrodermic cutaneous T cell lymphoma (CTCL) and refractory chronic graft versus host disease (cGvHD).
Cutaneous T Cell Lymphoma
Cutaneous T cell lymphoma (CTCL) is a general name for a group of skin affecting disorders caused by malignant white blood cells (T lymphocytes). Cutaneous T cell lymphoma is relatively uncommon and represents slightly more than 2% of all lymphomas in the United States. The most frequently diagnosed form of CTCL is mycosis fungoides (MF) and its leukemic variant Sezary syndrome (SS). The relative frequency and disease-specific 5-year survival of 1,905 primary cutaneous lymphomas classified according to the World Health Organization-European Organization for Research and Treatment of Cancer (WHO-EORTC) classification (Appendix 1). Mycosis fungoides had a frequency of 44% and a disease specific 5-year survival of 88%. Sezary syndrome had a frequency of 3% and a disease specific 5-year survival of 24%.
Cutaneous T cell lymphoma has an annual incidence of approximately 0.4 per 100,000 and it mainly occurs in the 5th to 6th decade of life, with a male/female ratio of 2:1. Mycosis fungoides is an indolent lymphoma with patients often having several years of eczematous or dermatitic skin lesions before the diagnosis is finally established. Mycosis fungoides commonly presents as chronic eczematous patches or plaques and can remain stable for many years. Early in the disease biopsies are often difficult to interpret and the diagnosis may only become apparent by observing the patient over time.
The clinical course of MF is unpredictable. Most patients will live normal lives and experience skin symptoms without serious complications. Approximately 10% of MF patients will experience progressive disease involving lymph nodes, peripheral blood, bone marrow and visceral organs. A particular syndrome in these patients involves erythroderma (intense and usually widespread reddening of the skin from dilation of blood vessels, often preceding or associated with exfoliation), and circulating tumour cells. This is known as SS. It has been estimated that approximately 5-10% of CTCL patients have SS. Patients with SS have a median survival of approximately 30 months.
Chronic Graft Versus Host Disease
Allogeneic hematopoietic cell transplantation (HCT) is a treatment used for a variety of malignant and nonmalignant disease of the bone marrow and immune system. The procedure is often associated with serious immunological complications, particularly graft versus host disease (GvHD). A chronic form of GvHD (cGvHD) afflicts many allogeneic HCT recipients, which results in dysfunction of numerous organ systems or even a profound state of immunodeficiency. Chronic GVHD is the most frequent cause of poor long-term outcome and quality of life after allogeneic HCT. The syndrome typically develops several months after transplantation, when the patient may no longer be under the direct care of the transplant team.
Approximately 50% of patients with cGvHD have limited disease and a good prognosis. Of the patients with extensive disease, approximately 60% will respond to treatment and eventually be able to discontinue immunosuppressive therapy. The remaining patients will develop opportunistic infection, or require prolonged treatment with immunosuppressive agents.
Chronic GvHD occurs in at least 30% to 50% of recipients of transplants from human leukocyte antigen matched siblings and at least 60% to 70% of recipients of transplants from unrelated donors. Risk factors include older age of patient or donor, higher degree of histoincompatibility, unrelated versus related donor, use of hematopoietic cells obtained from the blood rather than the marrow, and previous acute GvHD. Bhushan and Collins estimated that the incidence of severe cGvHD has probably increased in recent years because of the use of more unrelated transplants, donor leukocyte infusions, nonmyeloablative transplants and stem cells obtained from the blood rather than the marrow. The syndrome typically occurs 4 to 7 months after transplantation but may begin as early as 2 months or as late as 2 or more years after transplantation. Chronic GvHD may occur by itself, evolve from acute GvHD, or occur after resolution of acute GvHD.
The onset of the syndrome may be abrupt but is frequently insidious with manifestations evolving gradually for several weeks. The extent of involvement varies significantly from mild involvement limited to a few patches of skin to severe involvement of numerous organ systems and profound immunodeficiency. The most commonly involved tissues are the skin, liver, mouth, and eyes. Patients with limited disease have localized skin involvement, evidence of liver dysfunction, or both, whereas those with more involvement of the skin or involvement of other organs have extensive disease.
Cutaneous T Cell Lymphoma
The optimal management of MF is undetermined because of its low prevalence, and its highly variable natural history, with frequent spontaneous remissions and exacerbations and often prolonged survival.
Nonaggressive approaches to therapy are usually warranted with treatment aimed at improving symptoms and physical appearance while limiting toxicity. Given that multiple skin sites are usually involved, the initial treatment choices are usually topical or intralesional corticosteroids or phototherapy using psoralen (a compound found in plants which make the skin temporarily sensitive to ultraviolet A) (PUVA). PUVA is not curative and its influence on disease progression remains uncertain. Repeated courses are usually required which may lead to an increased risk of both melanoma and nonmelanoma skin cancer. For thicker plaques, particularly if localized, radiotherapy with superficial electrons is an option.
“Second line” therapy for early stage disease is often topical chemotherapy, radiotherapy or total skin electron beam radiation (TSEB).
Treatment of advanced stage (IIB-IV) MF usually consists of topical or systemic therapy in refractory or rapidly progressive SS.
Bone marrow transplantation and peripheral blood stem cell transplantation have been used to treat many malignant hematologic disorders (e.g., leukemias) that are refractory to conventional treatment. Reports on the use of these procedures for the treatment of CTCL are limited and mostly consist of case reports or small case series.
Chronic Graft Versus Host Disease
Patients who develop cGvHD require reinstitution of immunosuppressive medication (if already discontinued) or an increase in dosage and possibly addition of other agents. The current literature regarding cGvHD therapy is less than optimal and many recommendations about therapy are based on common practices that await definitive testing. Patients with disease that is extensive by definition but is indolent in clinical appearance may respond to prednisone. However, patients with more aggressive disease are treated with higher doses of corticosteroids and/or cyclosporine.
Numerous salvage therapies have been considered in patients with refractory cGvHD, including ECP. Due to uncertainty around salvage therapies, Bhushan and Collins suggested that ideally, patients with refractory cGvHD should be entered into clinical trials.
Two Ontario expert consultants jointly estimated that there may be approximately 30 new erythrodermic treatment resistant CTCL patients and 30 new treatment resistant cGvHD patients per year who are unresponsive to other forms of therapy and may be candidates for ECP.
Extracorporeal photopheresis is a procedure that was initially developed as a treatment for CTCL, particularly SS.
Current Technique
Extracorporeal photopheresis is an immunomodulatory technique based on pheresis of light sensitive cells. Whole blood is removed from patients followed by pheresis. Lymphocytes are separated by centrifugation to create a concentrated layer of white blood cells. The lymphocyte layer is treated with methoxsalen (a drug that sensitizes the lymphocytes to light) and exposed to UVA, following which the lymphocytes are returned to the patient. Red blood cells and plasma are returned to the patient between each cycle.
Photosensitization is achieved by administering methoxsalen to the patient orally 2 hours before the procedure, or by injecting methoxsalen directly ino the leucocyte rich fraction. The latter approach avoids potential side effects such as nausea, and provides a more consistent drug level within the machine.
In general, from the time the intravenous line is inserted until the white blood cells are returned to the patient takes approximately 2.5-3.5 hours.
For CTCL, the treatment schedule is generally 2 consecutive days every 4 weeks for a median of 6 months. For cGvHD, an expert in the field estimated that the treatment schedule would be 3 times a week for the 1st month, then 2 consecutive days every 2 weeks after that (i.e., 4 treatments a month) for a median of 6 to 9 months.
Regulatory Status
The UVAR XTS Photopheresis System is licensed by Health Canada as a Class 3 medical device (license # 7703) for the “palliative treatment of skin manifestations of CTCL.” It is not licensed for the treatment of cGvHD.
UVADEX (sterile solution methoxsalen) is not licensed by Health Canada, but can be used in Canada via the Special Access Program. (Personal communication, Therakos, February 16, 2006)
According to the manufacturer, the UVAR XTS photopheresis system licensed by Health Canada can also be used with oral methoxsalen. (Personal communication, Therakos, February 16, 2006) However, oral methoxsalen is associated with side effects, must be taken by the patient in advance of ECP, and has variable absorption in the gastrointestinal tract.
According to Health Canada, UVADEX is not approved for use in Canada. In addition, a review of the Product Monographs of the methoxsalen products that have been approved in Canada showed that none of them have been approved for oral administration in combination with the UVAR XTS photophoresis system for “the palliative treatment of the skin manifestations of cutaneous T-cell Lymphoma”.
In the United States, the UVAR XTS Photopheresis System is approved by the Food and Drug Administration (FDA) for “use in the ultraviolet-A (UVA) irradiation in the presence of the photoactive drug methoxsalen of extracorporeally circulating leukocyte-enriched blood in the palliative treatment of the skin manifestations of CTCL in persons who have not been responsive to other therapy.”
UVADEX is approved by the FDA for use in conjunction with UVR XTS photopheresis system for “use in the ultraviolet-A (UVA) irradiation in the presence of the photoactive drug methoxsalen of extracorporeally circulating leukocyte-enriched blood in the palliative treatment of the skin manifestations of CTCL in persons who have not been responsive to other therapy.”
The use of the UVAR XTS photopheresis system or UVADEX for cGvHD is an off-label use of a FDA approved device/drug.
Summary of Findings
The quality of the trials was examined.
As stated by the GRADE Working Group, the following definitions were used in grading the quality of the evidence.
Cutaneous T Cell Lymphoma
Overall, there is low-quality evidence that ECP improves response rates and survival in patients with refractory erythrodermic CTCL (Table 1).
Limitations in the literature related to ECP for the treatment of refractory erythrodermic CTCL include the following:
Different treatment regimens.
Variety of forms of CTCL (and not necessarily treatment resistant) - MF, erythrodermic MF, SS.
SS with peripheral blood involvement → role of T cell clonality reporting?
Case series (1 small crossover RCT with several limitations)
Small sample sizes.
Response criteria not clearly defined/consistent.
Unclear how concomitant therapy contributed to responses.
Variation in definitions of concomitant therapy
Comparison to historical controls.
Some patients were excluded from analysis because of progression of disease, toxicity and other reasons.
Unclear/strange statistics
Quality of life not reported as an outcome of interest.
The reported CR range is ~ 16% to 23% and the overall reported CR/PR range is ~ 33% to 80%.
The wide range in reported responses to ECP appears to be due to the variability of the patients treated and the way in which the data were presented and analyzed.
Many patients, in mostly retrospective case series, were concurrently on other therapies and were not assessed for comparability of diagnosis or disease stage (MF versus SS; erythrodermic versus not erythrodermic). Blood involvement in patients receiving ECP (e.g., T cell clonality) was not consistently reported, especially in earlier studies. The definitions of partial and complete response also are not standardized or consistent between studies.
Quality of life was reported in one study; however, the scale was developed by the authors and is not a standard validated scale.
Adverse events associated with ECP appear to be uncommon and most involve catheter related infections and hypotension caused by volume depletion.
GRADE Quality of Studies – Extracorporeal Photopheresis for Refractory Erythrodermic Cutaneous T-Cell Lymphoma
Chronic Graft-Versus-Host Disease
Overall, there is low-quality evidence that ECP improves response rates and survival in patients with refractory cGvHD (Table 2).
Patients in the studies had stem cell transplants due to a variety of hematological disorders (e.g., leukemias, aplastic anemia, thalassemia major, Hodgkin’s lymphoma, non Hodgkin’s lymphoma).
In 2001, The Blue Cross Blue Shield Technology Evaluation Centre concluded that ECP meets the TEC criteria as treatment of cGvHD that is refractory to established therapy.
The Catalan health technology assessment (also published in 2001) concluded that ECP is a new but experimental therapeutic alternative for the treatment of the erythrodermal phase of CTCL and cGvHD in allogenic HPTC and that this therapy should be evaluated in the framework of a RCT.
Quality of life (Lansky/Karnofsky play performance score) was reported in 1 study.
The patients in the studies were all refractory to steroids and other immunosuppressive agents, and these drugs were frequently continued concomitantly with ECP.
Criteria for assessment of organ improvement in cGvHD are variable, but PR was typically defined as >50% improvement from baseline parameters and CR as complete resolution of organ involvement.
Followup was variable and incomplete among the studies.
GRADE Quality of Studies – ECP for Refractory cGvHD
As per the GRADE Working Group, overall recommendations consider 4 main factors.
The tradeoffs, taking into account the estimated size of the effect for the main outcome, the confidence limits around those estimates and the relative value placed on the outcome.
The quality of the evidence (Tables 1 and 2).
Translation of the evidence into practice in a specific setting, taking into consideration important factors that could be expected to modify the size of the expected effects such as proximity to a hospital or availability of necessary expertise.
Uncertainty about the baseline risk for the population of interest.
The GRADE Working Group also recommends that incremental costs of healthcare alternatives should be considered explicitly alongside the expected health benefits and harms. Recommendations rely on judgments about the value of the incremental health benefits in relation to the incremental costs. The last column in Table 3 is the overall trade-off between benefits and harms and incorporates any risk/uncertainty.
For refractory erythrodermic CTCL, the overall GRADE and strength of the recommendation is “weak” – the quality of the evidence is “low” (uncertainties due to methodological limitations in the study design in terms of study quality and directness), and the corresponding risk/uncertainty is increased due to an annual budget impact of approximately $1.5M Cdn (based on 30 patients) while the cost-effectiveness of ECP is unknown and difficult to estimate considering that there are no high quality studies of effectiveness. The device is licensed by Health Canada, but the sterile solution of methoxsalen is not licensed.
With an annual budget impact of $1.5 M Cdn (based on 30 patients), and the current expenditure is $1.3M Cdn (for out of country for 7 patients), the potential cost savings based on 30 patients with refractory erythrodermic CTCL is about $3.8 M Cdn (annual).
For refractory cGvHD, the overall GRADE and strength of the recommendation is “weak” – the quality of the evidence is “low” (uncertainties due to methodological limitations in the study design in terms of study quality and directness), and the corresponding risk/uncertainty is increased due to a budget impact of approximately $1.5M Cdn while the cost-effectiveness of ECP is unknown and difficult to estimate considering that there are no high quality studies of effectiveness. Both the device and sterile solution are not licensed by Health Canada for the treatment of cGvHD.
If all the ECP procedures for patients with refractory erythrodermic CTCL and refractory cGvHD were performed in Ontario, the annual budget impact would be approximately $3M Cdn.
Overall GRADE and Strength of Recommendation (Including Uncertainty)
PMCID: PMC3379535  PMID: 23074497
15.  Limbal Stem Cell Transplantation 
Executive Summary
The objective of this analysis is to systematically review limbal stem cell transplantation (LSCT) for the treatment of patients with limbal stem cell deficiency (LSCD). This evidence-based analysis reviews LSCT as a primary treatment for nonpterygium LSCD conditions, and LSCT as an adjuvant therapy to excision for the treatment of pterygium.
Clinical Need: Condition and Target Population
The outer surface of the eye is covered by 2 distinct cell layers: the corneal epithelial layer that overlies the cornea, and the conjunctival epithelial layer that overlies the sclera. These cell types are separated by a transitional zone known as the limbus. The corneal epithelial cells are renewed every 3 to 10 days by a population of stem cells located in the limbus.
Nonpterygium Limbal Stem Cell Deficiency
When the limbal stem cells are depleted or destroyed, LSCD develops. In LSCD, the conjunctival epithelium migrates onto the cornea (a process called conjunctivalization), resulting in a thickened, irregular, unstable corneal surface that is prone to defects, ulceration, corneal scarring, vascularization, and opacity. Patients experience symptoms including severe irritation, discomfort, photophobia, tearing, blepharospasm, chronic inflammation and redness, and severely decreased vision.
Depending on the degree of limbal stem cell loss, LSCD may be total (diffuse) or partial (local). In total LSCD, the limbal stem cell population is completed destroyed and conjunctival epithelium covers the entire cornea. In partial LSCD, some areas of the limbus are unharmed, and the corresponding areas on the cornea maintain phenotypically normal corneal epithelium.
Confirmation of the presence of conjunctivalization is necessary for LSCD diagnosis as the other characteristics and symptoms are nonspecific and indicate a variety of diseases. The definitive test for LSCD is impression cytology, which detects the presence of conjunctival epithelium and its goblet cells on the cornea. However, in the opinion of a corneal expert, diagnosis is often based on clinical assessment, and in the expert’s opinion, it is unclear whether impression cytology is more accurate and reliable than clinical assessment, especially for patients with severe LSCD.
The incidence of LSCD is not well understood. A variety of underlying disorders are associated with LSCD including chemical or thermal injuries, ultraviolet and ionizing radiation, Stevens-Johnson syndrome, multiple surgeries or cryotherapies, contact lens wear, extensive microbial infection, advanced ocular cicatricial pemphigoid, and aniridia. In addition, some LSCD cases are idiopathic. These conditions are uncommon (e.g., the prevalence of aniridia ranges from 1 in 40,000 to 1 in 100,000 people).
Pterygium is a wing-shaped fibrovascular tissue growth from the conjunctiva onto the cornea. Pterygium is the result of partial LSCD caused by localized ultraviolet damage to limbal stem cells. As the pterygium invades the cornea, it may cause irregular astigmatism, loss of visual acuity, chronic irritation, recurrent inflammation, double vision, and impaired ocular motility.
Pterygium occurs worldwide. Incidence and prevalence rates are highest in the “pterygium belt,” which ranges from 30 degrees north to 30 degrees south of the equator, and lower prevalence rates are found at latitudes greater than 40 degrees. The prevalence of pterygium for Caucasians residing in urban, temperate climates is estimated at 1.2%.
Existing Treatments Other Than Technology Being Reviewed
Nonpterygium Limbal Stem Cell Deficiency
In total LSCD, a patient’s limbal stem cells are completely depleted, so any successful treatment must include new stem cells. Autologous oral mucosal epithelium transplantation has been proposed as an alternative to LSCT. However, this procedure is investigational, and there is very limited level 4c evidence1 to support this technique (fewer than 20 eyes examined in 4 case series and 1 case report).
For patients with partial LSCD, treatment may not be necessary if their visual axis is not affected. However, if the visual axis is conjunctivalized, several disease management options exist including repeated mechanical debridement of the abnormal epithelium; intensive, nonpreserved lubrication; bandage contact lenses; autologous serum eye drops; other investigational medical treatments; and transplantation of an amniotic membrane inlay. However, these are all disease management treatments; LSCT is the only curative option.
The primary treatment for pterygium is surgical excision. However, recurrence is a common problem after excision using the bare sclera technique: reported recurrence rates range from 24% to 89%. Thus, a variety of adjuvant therapies have been used to reduce the risk of pterygium recurrence including LSCT, amniotic membrane transplantation (AMT), conjunctival autologous (CAU) transplantation, and mitomycin C (MMC, an antimetabolite drug).
New Technology Being Reviewed
To successfully treat LSCD, the limbal stem cell population must be repopulated. To achieve this, 4 LSCT procedures have been developed: conjunctival-limbal autologous (CLAU) transplantation; living-related conjunctival-limbal allogeneic (lr-CLAL) transplantation; keratolimbal allogeneic (KLAL) transplantation; and ex vivo expansion of limbal stem cells transplantation. Since the ex vivo expansion of limbal stem cells transplantation procedure is considered experimental, it has been excluded from the systematic review. These procedures vary by the source of donor cells and the amount of limbal tissue used. For CLAU transplants, limbal stem cells are obtained from the patient’s healthy eye. For lr-CLAL and KLAL transplants, stem cells are obtained from living-related and cadaveric donor eyes, respectively.
In CLAU and lr-CLAL transplants, 2 to 4 limbal grafts are removed from the superior and inferior limbus of the donor eye. In KLAL transplants, the entire limbus from the donor eye is used.
The recipient eye is prepared by removing the abnormal conjunctival and scar tissue. An incision is made into the conjunctival tissue into which the graft is placed, and the graft is then secured to the neighbouring limbal and scleral tissue with sutures. Some LSCT protocols include concurrent transplantation of an amniotic membrane onto the cornea.
Regulatory Status
Health Canada does not require premarket licensure for stem cells. However, they are subject to Health Canada’s clinical trial regulations until the procedure is considered accepted transplantation practice, at which time it will be covered by the Safety of Human Cells, Tissues and Organs for Transplantation Regulations (CTO Regulations).
Review Strategy
The Medical Advisory Secretariat systematically reviewed the literature to assess the effectiveness and safety of LSCT for the treatment of patients with nonpterygium LSCD and pterygium. A comprehensive search method was used to retrieve English-language journal articles from selected databases.
The GRADE approach was used to systematically and explicitly evaluate the quality of evidence and strength of recommendations.
Summary of Findings
Nonpterygium Limbal Stem Cell Deficiency
The search identified 873 citations published between January 1, 2000, and March 31, 2008. Nine studies met the inclusion criteria, and 1 additional citation was identified through a bibliography review. The review included 10 case series (3 prospective and 7 retrospective).
Patients who received autologous transplants (i.e., CLAU) achieved significantly better long-term corneal surface results compared with patients who received allogeneic transplants (lr-CLAL, P< .001; KLAL, P< .001). There was no significant difference in corneal surface outcomes between the allogeneic transplant options, lr-CLAL and KLAL (P = .328). However, human leukocyte antigen matching and systemic immunosuppression may improve the outcome of lr-CLAL compared with KLAL. Regardless of graft type, patients with Stevens-Johnson syndrome had poorer long-term corneal surface outcomes.
Concurrent AMT was associated with poorer long-term corneal surface improvements. When the effect of the AMT was removed, the difference between autologous and allogeneic transplants was much smaller.
Patients who received CLAU transplants had a significantly higher rate of visual acuity improvements compared with those who received lr-CLAL transplants (P = .002). However, to achieve adequate improvements in vision, patients with deep corneal scarring will require a corneal transplant several months after the LSCT.
No donor eye complications were observed.
Epithelial rejection and microbial keratitis were the most common long-term complications associated with LSCT (complications occurred in 6%–15% of transplantations). These complications can result in graft failure, so patients should be monitored regularly following LSCT.
The search yielded 152 citations published between January 1, 2000 and May 16, 2008. Six randomized controlled trials (RCTs) that evaluated LSCT as an adjuvant therapy for the treatment of pterygium met the inclusion criteria and were included in the review.
Limbal stem cell transplantation was compared with CAU, AMT, and MMC. The results showed that CLAU significantly reduced the risk of pterygium recurrence compared with CAU (relative risk [RR], 0.09; 95% confidence interval [CI], 0.01–0.69; P = .02). CLAU reduced the risk of pterygium recurrence for primary pterygium compared with MMC, but this comparison did not reach statistical significance (RR, 0.48; 95% CI, 0.21–1.10; P = .08). Both AMT and CLAU had similar low rates of recurrence (2 recurrences in 43 patients and 4 in 46, respectively), and the RR was not significant (RR, 1.88; 95% CI, 0.37–9.5; P = .45). Since sample sizes in the included studies were small, failure to detect a significant difference between LSCT and AMT or MMC could be the result of type II error. Limbal stem cell transplantation as an adjuvant to excision is a relatively safe procedure as long-term complications were rare (< 2%).
GRADE Quality of Evidence
Nonpterygium Limbal Stem Cell Deficiency
The evidence for the analyses related to nonpterygium LSCD was based on 3 prospective and 7 retrospective case series. Thus, the GRADE quality of evidence is very low, and any estimate of effect is very uncertain.
The analyses examining LSCT as an adjuvant treatment option for pterygium were based on 6 RCTs. The quality of evidence for the overall body of evidence for each treatment option comparison was assessed using the GRADE approach. In each of the comparisons, the quality of evidence was downgraded due to serious or very serious limitations in study quality (individual study quality was assessed using the Jadad scale, and an assessment of allocation concealment and the degree of loss to follow-up), which resulted in low- to moderate-quality GRADE evidence ratings (low-quality evidence for the CLAU and AMT and CLAU and MMC comparisons, and moderate-quality evidence for the CLAU and CAU comparison).
Ontario Health System Impact Analysis
Nonpterygium Limbal Stem Cell Deficiency
Since 1999, Ontario’s out-of-country (OOC) program has approved and reimbursed 8 patients for LSCTs and 1 patient for LSCT consultations. Similarly, most Canadian provinces have covered OOC or out-of-province LSCTs. Several corneal experts in Ontario have the expertise to perform LSCTs.
As there are no standard guidelines for LSCT, patients who receive transplants OOC may not receive care aligned with the best evidence. To date, many of the patients from Ontario who received OOC LSCTs received concurrent AMTs, and the evidence from this analysis questions the use of this procedure. In addition, 1 patient received a cultured LSCT, a procedure that is considered investigational. Many patients with LSCD have bilateral disease and therefore require allogeneic transplants. These patients will require systemic and topical immunosuppression for several years after the transplant, perhaps indefinitely. Thus, systemic side effects associated with immunosuppression are a potential concern, and patients must be monitored regularly.
Amniotic membrane transplantation is a common addition to many ocular surface reconstruction procedures, including LSCT. Amniotic membranes are recovered from human placentas from planned, uneventful caesarean sections. Before use, serological screening of the donor’s blood should be conducted. However, there is still a theoretical risk of disease transmission associated with this procedure.
Financial Impact
For the patients who were reimbursed for OOC LSCTs, the average cost of LSCT per eye was $18,735.20 Cdn (range, $8,219.54–$33,933.32). However, the actual cost per patient is much higher as these costs do not include consultations and follow-up visits, multiple LSCTs, and any additional procedures (e.g., corneal transplants) received during the course of treatment OOC. When these additional costs were considered, the average cost per patient was $57,583 Cdn (range, $8,219.54–$130,628.20).
The estimated average total cost per patient for performing LSCT in Ontario is $2,291.48 Cdn (range, $951.48–$4,538.48) including hospital and physician fees. This cost is based on the assumption that LSCT is technically similar to a corneal transplant, an assumption which needs to be verified. The cost does not include corneal transplantations, which some proportion of patients receiving a LSCT will require within several months of the limbal transplant.
Pterygium recurrence rates after surgical excision are high, ranging from 24% to 89%. However, according to clinical experts, the rate of recurrence is low in Ontario. While there is evidence that the prevalence of pterygium is higher in the “pterygium belt,” there was no evidence to suggest different recurrence rates or disease severity by location or climate.
Nonpterygium Limbal Stem Cell Deficiency
Successful LSCTs result in corneal re-epithelialization and improved vision in patients with LSCD. However, patients who received concurrent AMT had poorer long-term corneal surface improvements. Conjunctival-limbal autologous transplantation is the treatment option of choice, but if it is not possible, living-related or cadaveric allogeneic transplants can be used. The benefits of LSCT outweigh the risks and burdens, as shown in Executive Summary Table 1. According to GRADE, these recommendations are strong with low- to very low-quality evidence.
Benefits, Risks, and Burdens – Nonpterygium Limbal Stem Cell Deficiency
Short- and long-term improvement in corneal surface (stable, normal corneal epithelium and decreased vascularization and opacity)
Improvement in vision (visual acuity and functional vision)
Long-term complications are experienced by 8% to 16% of patients
Risks associated with long-term immunosuppression for recipients of allogeneic grafts
Potential risk of induced LSCD in donor eyes
High cost of treatment (average cost per patient via OOC program is $57,583; estimated cost of procedure in Ontario is $2,291.48)
Costs are expressed in Canadian dollars.
GRADE of recommendation: Strong recommendation, low-quality or very low-quality evidence
benefits clearly outweigh risks and burdens
case series studies
strong, but may change if higher-quality evidence becomes available
Conjunctival-limbal autologous transplantations significantly reduced the risk of pterygium recurrence compared with CAU. No other comparison yielded statistically significant results, but CLAU reduced the risk of recurrence compared with MMC. However, the benefit of LSCT in Ontario is uncertain as the severity and recurrence of pterygium in Ontario is unknown. The complication rates suggest that CLAU is a safe treatment option to prevent the recurrence of pterygium. According to GRADE, given the balance of the benefits, risks, and burdens, the recommendations are very weak with moderate quality evidence, as shown in Executive Summary Table 2.
Benefits, Risks, and Burdens – Pterygium
Reduced recurrence; however, if recurrence is low in Ontario, this benefit might be minimal
Long-term complications rare
Increased cost
GRADE of recommendation: Very weak recommendations, moderate quality evidence.
uncertainty in the estimates of benefits, risks, and burden; benefits, risks, and burden may be closely balanced
very weak, other alternatives may be equally reasonable
PMCID: PMC3377549  PMID: 23074512
16.  High prevalence of potential drug interactions affecting mycophenolic acid pharmacokinetics in nonmyeloablative hematopoietic stem cell transplant recipients 
Mycophenolic acid (MPA) exposure is associated with clinical outcomes in hematopoietic cell transplant (HCT) recipients. Various drug interaction studies, predominantly in healthy volunteers or solid organ transplant recipients, have identified medications which impact MPA pharmacokinetics. Recipients of nonmyeloablative HCT, however, have an increased burden of comordities, potentially increasing the number of concomitant medications and potential drug interactions (PDI) affecting MPA exposure. Thus, we sought to be the first to characterize these PDI in nonmyeloablative HCT recipients.
Materials and methods
We compiled PDI affecting MPA pharmacokinetics and characterized the prevalence of PDI in nonmyeloablative HCT recipients. A comprehensive literature evaluation of four databases and PubMed was conducted to identify medications with PDI affecting MPA pharmacokinetics. Subsequently, a retrospective medication review was conducted to characterize the cumulative PDI burden, defined as the number of PDI for an individual patient over the first 21 days after allogeneic graft infusion, in 84 nonmyeloablative HCT recipients.
Of the 187 concomitant medications, 11 (5.9%) had a PDI affecting MPA pharmacokinetics. Eighty-seven percent of 84 patients had one PDI, with a median cumulative PDI burden of 2 (range: 0 to 4). The most common PDI, in descending order, were cyclosporine, omeprazole, and pantoprazole.
Only a minority of medications (5.9%) have a PDI affecting MPA pharmacokinetics. However, the majority of nonmyeloablative HCT recipients had a PDI, with cyclosporine and the proton pump inhibitors being the most common. A better understanding of PDI and their management should lead to safer medication regimens for nonmyeloablative HCT recipients.
PMCID: PMC3758456  PMID: 23782584
Mycophenolic acid; drug interactions; hematopoietic cell transplantation
17.  Association between calcineurin inhibitor blood concentrations and outcomes after allogeneic hematopoietic cell transplantation 
To determine whether calcineurin inhibitor (CNI) blood concentrations within the first month after allogeneic hematopoietic cell transplantation (HCT) correlated with the incidence of graft-versus-host disease (GVHD) and other outcomes, we retrospectively analyzed data from 1181 patients with hematologic malignancies who had HCT from HLA-matched related (n=634) or unrelated (n=547) donors at a single institution between 2001 and 2009. After myeloablative HCT (n=774), higher CNI concentrations were not associated with lower risks of acute or chronic GVHD. After nonmyeloablative HCT (n=407), higher cyclosporine concentrations were associated with decreased risks of grade 2–4 and 3–4 acute GVHD (hazard ratio [HR] per 100 ng/ml change in cyclosporine concentrations, 0.7; 95% confidence interval [CI], 0.6–0.82; and HR, 0.66, 95%CI, 0.49–0.9, respectively), non-relapse mortality (HR, 0.6, 95% CI, 0.41–0.88), and overall mortality (HR, 0.83, 95%CI, 0.71–0.99). Cyclosporine concentrations were not associated with risks of chronic GVHD and recurrent malignancy after nonmyeloablative HCT. Among patients given tacrolimus after nonmyeloablative HCT, a similar trend of CNI-associated GVHD-protection was observed. Higher CNI concentrations were not associated with apparent renal toxicity. We conclude that higher cyclosporine concentrations relatively early after nonmyeloablative HCT confer protection against acute GVHD that translates into reduced risks of non-relapse and overall mortality.
PMCID: PMC3276708  PMID: 21875504
18.  Low-dose parenteral busulfan provides an extended window for the infusion of hematopoietic stem cells in murine hosts 
Experimental hematology  2007;35(9):1415-1420.
Myeloablative total body irradiation (TBI) in the setting of autologous transplantation of genetically modified hematopoietic stem cells (HSC) is associated with substantial toxicity. Nonmyeloablative doses of TBI are less toxic, but result in low-level engraftment of genetically modified HSCs. As an alternative to TBI, escalating doses of parenteral busulfan were tested for their hematologic toxicity, their ability to promote donor leukocyte engraftment, and the time window for such engraftment.
Materials and Methods
Hematologic toxicity of busulfan was assessed in C57BL6 mice after single nonmyeloablative doses of intraperitoneal busulfan ranging from 1 to 40 mg/kg by serial complete blood counts monitored up to 40 days. The level of donor engraftment attainable after nonmyeloablative busulfan was determined by infusion of 20 million congenic murine bone marrow nucleated cells (BMNC) following 5 to 40 mg/kg of busulfan. To determine the effects of delayed HSC infusions, BMNCs were infused 1, 10, 15, and 20 days after a single dose of 10 mg/kg of busulfan.
Busulfan doses from 1 to 40 mg/kg produced hematologic toxicity that was most pronounced in the 2nd to 3rd week. In transplantation experiments, dose-dependent donor leukocyte engraftment was attained with levels >70% after only 20 mg/kg of busulfan. Similar levels of engraftment were achieved even when infusion of BMNCs was delayed up to 20 days after busulfan injection.
Nonmyeloablative parenteral busulfan produced transient myelosuppressive effects, clinically relevant levels of engraftment, and an extended time window for HSC infusion in murine hosts.
PMCID: PMC2676902  PMID: 17618036
19.  Nonmyeloablative Conditioning with Busulfan before Matched Littermate Bone Marrow Transplantation Results in Reversal of the Disease Phenotype in Canine Leukocyte Adhesion Deficiency 
Leukocyte adhesion deficiency (LAD)–1, a primary immunodeficiency disease caused by molecular defects in the leukocyte integrin CD18 molecule, is characterized by recurrent, life-threatening bacterial infections. Myeloablative hematopoietic stem cell transplantation is the only curative treatment for LAD-1. Recently, canine LAD (CLAD) has been shown to be a valuable animal model for the preclinical testing of nonmyeloablative transplantation regimens for the treatment of children with LAD-1. To develop new allogeneic transplantation approaches for LAD-1, we assessed a nonmyeloablative conditioning regimen consisting of busulfan as a single agent before matched littermate allogeneic bone marrow transplantation in CLAD. Three CLAD dogs received busulfan 10 mg/kg intravenously before infusion of matched littermate bone marrow, and all dogs received posttransplantation immunosuppression with cyclosporin A and mycophenolate mofetil. Initially, all 3 dogs became mixed chimeras, and levels of donor chimerism sufficient to reverse the CLAD phenotype persisted in 2 animals. The third dog maintained donor microchimerism with an attenuated CLAD phenotype. These 3 dogs have all been followed up for at least 1 year after transplantation. These results indicate that a nonmyeloablative conditioning regimen with chemotherapy alone is capable of generating stable mixed chimerism and reversal of the disease phenotype in CLAD.
PMCID: PMC1351378  PMID: 16182176
Canine leukocyte adhesion deficiency; Nonmyeloablative conditioning; Busulfan; Bone marrow transplantation
20.  Lack of utility of chimerism studies obtained two to three months after myeloablative haematopoietic cell transplantation for acute lymphocytic leukaemia 
Bone marrow transplantation  2008;42(4):271-274.
Lineage specific chimerism studies are commonly obtained at several time points after nonmyeloablative haematopoietic cell transplantation to assess the tempo and degree of engraftment, and to monitor graft rejection. For patients who receive myeloablative transplants, the value of frequent chimerism analyses using sensitive molecular techniques is less certain. In this study, a retrospective analysis was performed to assess the transplant outcome of 89 adult patients with acute lymphocytic leukaemia who had chimerism studies of unfractionated bone marrow cells or peripheral blood subsets performed approximately 80 days after transplantation. These patients received unmanipulated, myeloablative transplants using either HLA-identical or HLA-mismatched, related or unrelated donor stem cells. Incomplete donor engraftment was present only in the CD3+ peripheral blood T-cells in a small percentage of patients. There was no correlation of mixed chimerism with transplant outcome. Routine “Day 80” chimerism studies in this group of patients who receive intensive, myeloablative conditioning regimens are not recommended.
PMCID: PMC3044127  PMID: 18500370
ALL; myeloablative transplant; chimerism analysis
21.  Isoform-Specific Potentiation of Stem and Progenitor Cell Engraftment by AML1/RUNX1  
PLoS Medicine  2007;4(5):e172.
AML1/RUNX1 is the most frequently mutated gene in leukaemia and is central to the normal biology of hematopoietic stem and progenitor cells. However, the role of different AML1 isoforms within these primitive compartments is unclear. Here we investigate whether altering relative expression of AML1 isoforms impacts the balance between cell self-renewal and differentiation in vitro and in vivo.
Methods and Findings
The human AML1a isoform encodes a truncated molecule with DNA-binding but no transactivation capacity. We used a retrovirus-based approach to transduce AML1a into primitive haematopoietic cells isolated from the mouse. We observed that enforced AML1a expression increased the competitive engraftment potential of murine long-term reconstituting stem cells with the proportion of AML1a-expressing cells increasing over time in both primary and secondary recipients. Furthermore, AML1a expression dramatically increased primitive and committed progenitor activity in engrafted animals as assessed by long-term culture, cobblestone formation, and colony assays. In contrast, expression of the full-length isoform AML1b abrogated engraftment potential. In vitro, AML1b promoted differentiation while AML1a promoted proliferation of progenitors capable of short-term lymphomyeloid engraftment. Consistent with these findings, the relative abundance of AML1a was highest in the primitive stem/progenitor compartment of human cord blood, and forced expression of AML1a in these cells enhanced maintenance of primitive potential both in vitro and in vivo.
These data demonstrate that the “a” isoform of AML1 has the capacity to potentiate stem and progenitor cell engraftment, both of which are required for successful clinical transplantation. This activity is consistent with its expression pattern in both normal and leukaemic cells. Manipulating the balance of AML1 isoform expression may offer novel therapeutic strategies, exploitable in the contexts of leukaemia and also in cord blood transplantation in adults, in whom stem and progenitor cell numbers are often limiting.
The truncated "a" isoform of AML1 is shown to have the capacity to potentiate stem and progenitor cell engraftment, both of which are required for successful clinical transplantation.
Editors' Summary
Blood contains red blood cells (which carry oxygen round the body), platelets (which help the blood to clot), and white blood cells (which fight off infections). All these cells, which are regularly replaced, are derived from hematopoietic stem cells, blood-forming cells present in the bone marrow. Like all stem cells, hematopoietic stem cells self-renew (reproduce themselves) and produce committed progenitor cells, which develop into mature blood cells in a process called hematopoiesis. Many proteins control hematopoiesis, some of which are called transcription factors; these factors bind to DNA through their DNA-binding domain and then control the expression of genes (that is, how DNA is turned into proteins) through particular parts of the protein (their transcription regulatory domains). An important hematopoietic transcription factor is AML1—a protein first identified because of its involvement in acute myelogenous leukemia (AML, a form of blood cancer). Mutations (changes) in the AML1 gene are now known to be present in other types of leukemia, which are often characterized by overproliferation of immature blood cells.
Why Was This Study Done?
Because of AML1′s crucial role in hematopoiesis, knowing more about which genes it regulates and how its activity is regulated could provide clues to treating leukemia and to improving hematopoietic cell transplantation. Many cancer treatments destroy hematopoietic stem cells, leaving patients vulnerable to infection. Transplants of bone marrow or cord blood (the cord that links mother and baby during pregnancy contains peripheral blood stem cells) can replace the missing cells, but cord blood in particular often contains insufficient stem cells for successful transplantation. It would be useful, therefore, to expand the stem cell content of these tissues before transplantation. In this study, the researchers investigated the effect of AML1 on self-renewal and differentiation of hematopoietic stem and progenitor cells in the laboratory (in vitro) and in animals (in vivo). In particular, they have asked how two isoforms (closely related versions) of AML1 affect the ability of these cells to grow and differentiate (engraft) in mice after transplantation.
What Did the Researchers Do and Find?
The researchers artificially expressed AML1a and AML1b (both isoforms contain a DNA binding domain, but only AML1b has transcription regulatory domains) in mouse hematopoietic stem and progenitor cells and then tested the cells' ability to engraft in mice. AML1a-expressing cells engrafted better than unaltered cells and outgrew unaltered cells when transplanted as a mixture. AML1b-expressing cells, however, did not engraft. In vitro, AML1a-expressing cells grew more than AML1b-expressing cells, whereas differentiation was promoted in AML1b-expressing cells. To investigate whether the isoforms have the same effects in human cells, the researchers measured the amount of AML1a and AML1b mRNA (the template for protein production) made by progenitor cells in human cord blood. Although AML1b (together with AML1c, an isoform with similar characteristics) mRNA predominated in all the progenitor cell types, the relative abundance of AML1a was greatest in the stem and progenitor cells. Furthermore, forced expression of AML1a in these cells improved their ability to divide in vitro and to engraft in mice.
What Do These Findings Mean?
These findings indicate that AML1a expression increases the self-renewal capacity of hematopoietic stem and progenitor cells and consequently improves their ability to engraft in mice, whereas AML1b expression encourages the differentiation of these cell types. These activities are consistent with the expression patterns of the two isoforms in normal hematopoietic cells and in leukemic cells—the mutated AML made by many leukemic cells resembles AML1a. Because the AML1 isoforms were expressed at higher than normal levels in these experiments, the physiological relevance of these findings needs to be confirmed by showing that normal levels of AML1a and AML1b produce similar results. Nevertheless, these results suggest that manipulating the balance of AML1 isoforms made by hematopoietic cells might be useful clinically. In leukemia, a shift toward AML1b expression might slow the proliferation of leukemic cells and encourage their differentiation. Conversely, in cord blood transplantation, a shift toward AML1a expression might improve patient outcomes by expanding the stem and progenitor cell populations.
Additional Information.
Please access these Web sites via the online version of this summary at
Wikipedia has pages on hematopoiesis and hematopoietic stem cells (note: Wikipedia is a free online encyclopedia that anyone can edit; available in several languages)
The US National Cancer Institute has a fact sheet on bone marrow and peripheral blood stem cell transplantation (in English and Spanish) and information for patients and professionals on leukemia (in English)
The American Society of Hematology provides patient information about blood diseases, including information on bone marrow and stem cell transplantation
PMCID: PMC1868041  PMID: 17503961
Myeloablative allogeneic hematopoietic cell transplantation (HCT) may cure patients with relapsed or refractory Hodgkin Lymphoma (HL), but is associated with a high treatment-related mortality (TRM). Reduced intensity and nonmyeloablative (RIC/NST) conditioning regimens aim to lower TRM. We analyzed the outcomes of 143 patients undergoing unrelated donor RIC/NST HCT for relapsed and refractory HL between 1999 and 2004 reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Patients were heavily pretreated, including autologous HCT in 89%. With a median follow-up of 25 months, the probability of TRM at day 100 and 2 years was 15% (95% CI 10-21%) and 33% (95% CI 25-41%) respectively. The probabilities of progression free survival (PFS) and overall survival (OS) were 30% and 56% at 1 year and 20% and 37% at 2 years. The presence of extranodal disease and KPS < 90 were significant risk factors for TRM, PFS and OS, whereas chemosensitivity at transplantation was not. Dose intensity of the conditioning regimen (RIC vs NST) did not impact outcomes. Unrelated donor HCT with RIC/NST can salvage some patients with relapsed/refractory HL, but relapse remains a common reason for treatment failure. Clinical studies should be aimed at reducing the incidence of acute Graft-versus-Host Disease and relapse.
PMCID: PMC2929570  PMID: 19135949
unrelated; allogeneic transplantation; Hodgkin Lymphoma
23.  Long-Term Outcomes Among Older Patients Following Nonmyeloablative Conditioning and Allogeneic Hematopoietic Cell Transplantation for Advanced Hematologic Malignancies 
A minimally toxic nonmyeloablative regimen was developed for allogeneic hematopoietic cell transplantation (HCT) to treat patients with advanced hematologic malignancies who are older or have comorbidities.
To describe outcomes of patients ≥ 60 years.
Design, Setting, and Participants
From 1998 to 2008, 372 patients, 60–75 years old were enrolled in prospective clinical HCT trials at 18 collaborating institutions using conditioning with low-dose total body irradiation alone or combined with fludarabine 90 mg/m2 before related (n=184) or unrelated (n=188) donor transplants. Post-grafting immunosuppression included mycophenolate mofetil and a calcineurin inhibitor.
Main Outcome Measures
Overall and progression-free survivals were estimated by Kaplan-Meier method. Cumulative incidence estimates were calculated for acute and chronic GVHD, toxicities, achievement of full donor chimerism, complete remission, relapse, and non-relapse mortality. Hazard ratios (HR) were estimated from Cox regression models.
Overall, 5-year cumulative incidences of non-relapse mortality and relapse were 27% (95% CI, 22%–32%) and 41% (95% CI, 36%–46%), respectively, leading to overall and progression-free 5-year survivals of 35% (95% CI, 30%–40%) and 32% (95% CI, 27%–37%), respectively. These outcomes were not statistically significantly different when stratified by age groups. Furthermore, increasing age was not associated with increases in acute or chronic graft-versus-host disease (GVHD) or organ toxicities. In multivariate models, HCT-CI scores of 1–2 [HR, 1.58 (95% CI,1.08–2.31)] and ≥3 [HR, 1.97 (95% CI,1.38–2.80)] were associated with worse survival compared to HCT-CI score of 0 (overall P = 0.003). Similarly, standard relapse risk [HR, 1.67 (95% CI, 1.10–2.54)] and high relapse risk [HR, 2.22 (95% CI, 1.43–3.43)] were associated with worse survival compared to low relapse risk (overall P = 0.0008).
Among patients aged 60–75 years and treated with nonmyeloablative allogeneic HCT, 5-year overall and progression-free survivals were 35% (95% CI, 30%–40%) and 32% (95% CI, 27%–37%), respectively.
PMCID: PMC3217787  PMID: 22045765
Marrow transplantation; hematopoietic cell transplantation; age; comorbidities; toxicities; infections; performance status; graft-versus-host disease; withdrawal of immunosuppression; mortality; survival; comparative outcomes research
24.  Role of Comorbidities in Optimizing Decision-Making for Allogeneic Hematopoietic Cell Transplantation 
Allogeneic conventional hematopoietic cell transplantation (HCT) following high-dose, myeloablative conditioning regimens has been used since the 1970’s as potentially curative treatment for patients with malignant, hematological disorders. The toxicities of conditioning regimens have limited conventional HCT to relatively young patients in otherwise good medical condition. With the development of less toxic nonmyeloablative regimens and improvements in supportive care, increasing numbers of older and medically infirm patients have been treated by allogeneic HCT. Until recently, there has been almost no effort to evaluate the prevalence of comorbidities among HCT recipients and their impact on outcomes. We first evaluated the Charlson Comorbidity Index (CCI) developed for patients with solid malignancies, for this purpose. While useful, it lacked sensitivity and specificity for the HCT setting. We next introduced the HCT-specific comorbidity index (HCT-CI) which was based on objective laboratory data to better define comorbidities. Here, we describe this development and illustrate the usefulness of the HCT-CI in predicting HCT outcomes in patients with myeloid and lymphoid malignancies undergoing allogeneic transplantation.
PMCID: PMC2997746  PMID: 21152378
25.  Role of Comorbidities in Optimizing Decision-Making for Allogeneic Hematopoietic Cell Transplantation 
Allogeneic conventional hematopoietic cell transplantation (HCT) following high-dose, myeloablative conditioning regimens has been used since the 1970’s as potentially curative treatment for patients with malignant, hematological disorders. The toxicities of conditioning regimens have limited conventional HCT to relatively young patients in otherwise good medical condition. With the development of less toxic nonmyeloablative regimens and improvements in supportive care, increasing numbers of older and medically infirm patients have been treated by allogeneic HCT. Until recently, there has been almost no effort to evaluate the prevalence of comorbidities among HCT recipients and their impact on outcomes. We first evaluated the Charlson Comorbidity Index (CCI) developed for patients with solid malignancies, for this purpose. While useful, it lacked sensitivity and specificity for the HCT setting. We next introduced the HCT-specific comorbidity index (HCT-CI) which was based on objective laboratory data to better define comorbidities. Here, we describe this development and illustrate the usefulness of the HCT-CI in predicting HCT outcomes in patients with myeloid and lymphoid malignancies undergoing allogeneic transplantation.
PMCID: PMC2997746  PMID: 21152378

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