Comparable outcomes after nonmyeloablative hematopoietic cell transplantation with unrelated and related donors

Allogeneic Hematopoietic Cell Transplantation for Older Adults with Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a disease that affects adults aged 65 years and above, and survival in this population is poor. Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative therapy for these patients but is underutilized due to frequent comorbidities and perceived higher risk of treatment-related mortality and non-relapse mortality. Increasing data supports the utility of allo-HCT in fit older patients after intensive chemotherapy resulting in improvement of outcomes. With the development of reduced intensity and non-myeloablative conditioning regimens that are associated with lower rates of treatment-related toxicity and mortality, this has allowed more older patients with AML to receive allo-HCT. In this review, we provide some guidance on appropriate selection of older patients as transplant candidates, benefits and risks associated with allo-HCT, conditioning regimen choice, and stem cell transplant sources as they relate to the conduct of stem cell transplantation in older patients.

HLA-C KIR-Ligands Determine the Impact of Anti-Thymocyte Globulin (ATG) on Graft versus Host and Graft versus Leukemia Effects Following Hematopoietic Stem Cell Transplantation

Rabbit anti-thymocyte globulins (ATGs) are widely used for the prevention of acute and chronic graft versus host disease (aGVHD, cGVHD) following allogeneic hematopoietic stem cell transplantation (HSCT). However, most prospective and retrospective studies did not reveal an overall survival (OS) benefit associated with ATG. Homozygosity for human leukocyte antigen (HLA)-C group 1 killer-cell immunoglobulin-like receptor ligands (KIR-L), i.e. C1/1 KIR-L status, was recently shown to be a risk factor for severe aGVHD. Congruously, we have previously reported favorable outcomes in C1/1 recipients after ATG-based transplants in a monocentric analysis. Here, within an extended cohort, we test the hypothesis that incorporation of ATG for GVHD prophylaxis may improve survival particularly in HSCT recipients with at least one C1 KIR-ligand. Retrospectively, 775 consecutive allogeneic (excluding haploidentical) HSCTs were analyzed, including peripheral blood and bone marrow grafts for adults with hematological diseases at two Austrian HSCT centers. ATG-Fresenius/Grafalon, Thymoglobuline, and alemtuzumab were applied in 256, 87, and 7 transplants, respectively (subsequently summarized as "ATG"), while 425 HSCT were performed without ATG. Median follow-up of surviving patients is 48 months. Adjusted for age, disease-risk, HLA-match, donor and graft type, sex match, cytomegalovirus serostatus, conditioning intensity, and type of post-grafting GVHD prophylaxis, Cox regression analysis of the entire cohort (n = 775) revealed a significant association of ATG with decreased non-relapse mortality (NRM) (risk ratio (RR), 0.57; p = 0.001), and overall mortality (RR, 0.71; p = 0.014). Upon stratification for HLA-C KIR-L, the greatest benefit for ATG emerged in C1/1 recipients (n = 291), by reduction of non-relapse (RR, 0.34; p = 0.0002) and overall mortality (RR, 0.50; p = 0.003). Less pronounced, ATG decreased NRM (RR, 0.60; p = 0.036) in HLA-C group 1/2 recipients (n = 364), without significantly influencing overall mortality (RR, 0.70; p = 0.065). After exclusion of higher-dose ATG-based transplants, serotherapy significantly improved both NRM (RR, 0.54; p = 0.019; n = 322) and overall mortality (RR, 0.60; p = 0.018) in C1/2 recipients as well. In both, C1/1 (RR, 1.70; p = 0.10) and particularly in C1/2 recipients (RR, 0.94; p = 0.81), there was no statistically significant impact of ATG on relapse incidence. By contrast, in C2/2 recipients (n = 121), ATG neither reduced NRM (RR, 1.10; p = 0.82) nor overall mortality (RR, 1.50; p = 0.17), but increased the risk for relapse (RR, 4.38; p = 0.02). These retrospective findings suggest ATG may provide a survival benefit in recipients with at least one C1 group KIR-L, by reducing NRM without significantly increasing the relapse risk.

Jumping translocations in myelodysplastic syndromes

Jumping translocations (JT) have been identified in numerous malignancies, including leukemia, but infrequently in patients with myelodysplastic syndromes (MDS). The responsible genetic region has been mapped to the JTB gene at 1q21, but breakpoints involving other chromosomal loci, such as 3q and 11q, have been described as well. We have characterized the pathological and mutational landscape, and the clinical course of 6 new MDS patients with jumping mutations using chromosome genomic array testing (CGAT) and target gene panel next generation sequencing. In addition, we have performed a literature review for other MDS cases with JTs as defined by ISCN 2013. Results support the concept that MDS in patients with jumping translocations has a poor prognosis with a high risk of progression to leukemia, and suggest that these patients warrant aggressive therapy, including HCT, early in the disease course.

Relapse after Allogeneic Hematopoietic Cell Transplantation for Myelodysplastic Syndromes: Analysis of Late Relapse Using Comparative Karyotype and Chromosome Genome Array Testing

Relapse is a major cause of failure after allogeneic hematopoietic cell transplantation (HCT) in patients with myelodysplastic syndromes (MDS). We analyzed the relapse pattern in 1007 patients who underwent transplantation for MDS to identify factors that may determine the timing of relapse. Overall, 254 patients relapsed: 213 before 18 months and 41 later than 18 months after HCT, a time point frequently used in clinical trials. The hazard of relapse declined progressively with time since transplantation. A higher proportion of patients with early relapse had high-risk cytogenetics compared with patients with late relapse (P = .009). Patients with late relapse had suggestively longer postrelapse survival than patients who relapsed early, although the difference was not statistically significant (P = .07). Among 41 late relapsing patients, sequential cytogenetic data were available in 36. In 41% of these, new clonal abnormalities in addition to pre-HCT findings were identified at relapse; in 30% pre-HCT abnormalities were replaced by new clones, in 17.3% the same clone was present before HCT and at relapse, and in 9.7%, no abnormalities were present either before HCT or at relapse. Comparative chromosomal genomic array testing in 3 patients with late relapse showed molecular differences not detectable by cytogenetics between the pre-HCT clones and the clones at relapse. These data show that late relapses are not infrequent in patients who undergo transplantation for MDS. The pattern of new cytogenetic alterations at late relapse is similar to that observed in patients with early relapse and supports the concept that MDS relapse early and late after HCT is frequently due to the emergence of clones not detectable before HCT.

Reduced-intensity conditioned allogeneic SCT in adults with AML

AML is currently the most common indication for reduced-intensity conditioned (RIC) allo-SCT. Reduced-intensity regimens allow a potent GVL response to occur with minimized treatment-related toxicity in patients of older age or with comorbidities that preclude the use of myeloablative conditioning. Whether RIC SCT is appropriate for younger and more standard risk patients is not well defined and the field is changing rapidly; a prospective randomized trial of myeloablative vs RIC (BMT-CTN 0901) was recently closed when early results indicated better outcomes for myeloablative regimens. However, detailed results are not available, and all patients in that study were eligible for myeloablative conditioning. RIC transplants will likely remain the standard of care as many patients with AML are not eligible for myeloablative conditioning. Recent publication of mature results from retrospective and prospective cohorts provide contemporary efficacy and toxicity data for these attenuated regimens. In addition, recent studies explore the use of alternative donors, introduce regimens that attempt to reduce toxicity without reducing intensity, and identify predictive factors that pave the way to personalized approaches. These studies paint a picture of the future of RIC transplants. Here we review the current status of RIC allogeneic SCT in AML.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia in older adults

Acute myeloid leukemia (AML) is primarily a disease of the elderly and the numbers of these patients are increasing. Patients ≥60 years of age continue to have poor prognosis. Preliminary results suggest benefit from reduced-intensity allogeneic hematopoietic cell transplantation (HCT) in selected patients 60-80 years of age. However, although patients in this age range comprise >50% of those with AML, they currently constitute only 17% of those offered HCT. In the absence of prospective randomized studies comparing HCT and chemotherapy, the decision to recommend HCT rests on retrospective analyses of the risks of relapse and nonrelapse mortality after each approach. There is strong evidence that pre-HCT comorbidities can predict HCT-related morbidity and mortality. Age alone does not appear predictive and, particularly if the risk of relapse with chemotherapy is high, should not be the sole basis for deciding against HCT. Use of geriatric assessment tools, inflammatory biomarkers, and genetic polymorphism data may further aid in predicting nonrelapse mortality after HCT. Disease status and pretreatment cytogenetics with FLT3-TID, NPM-1, and CEBP-α status are the main factors predicting relapse and these are likely to be supplemented by incorporation of other molecular markers and the level of minimal residual disease after chemotherapy. HLA-matched related and unrelated donor grafts seem preferable to those from other donor sources. Donor age is of no clear significance. Models combining comorbidities with AML risk factors are useful in risk assessment before HCT. In this chapter, we integrated information on AML-specific, HCT-specific, and patient-specific risk factors into a risk-adapted approach to guide decisions about HCT versus no HCT.

Continuous reduced nonrelapse mortality after allogeneic hematopoietic stem cell transplantation: a single-institution's three decade experience

This study analyzed changes in patients, transplantation, graft characteristics, and outcome among 827 patients who received their first allo-SCT in a single center between 1983 and 2010. In the 2001 to 2010 decade, compared with the 1983 to 1990 and 1991 to 2000 decades, patients were significantly older and presented with higher risk diseases, reduced intensity conditioning and alternative donors were used more often, and stem cell sources changed from bone marrow to peripheral blood stem cells and cord blood. In the 2001 to 2010 decade, we observed a significant decrease in nonrelapse mortality (NRM) (P = .0007 and P < .0001, respectively) and an increase in relapse incidence (P = .04 and P = .009, respectively), but overall survival (OS) was increased (P = .11 and P = .009, respectively), and there was a trend towards an increased progression-free survival (P = .30 and P = .09, respectively), as compared with the 1983 to 1990 and 1991 to 2000 decades. Chronic graft-versus-host disease (GVHD) was significantly increased, whereas grades III to IV acute GVHD remained stable. These data suggest that, despite the fact that older and higher risk patients with more comorbidities underwent transplantation in the last 10 years, NRM decreased while the incidence of relapse increased and the OS improved.

Transplantation for myelodysplastic syndromes 2013

PURPOSE OF REVIEW

The only current treatment capable of curing patients with myelodysplastic syndromes (MDS) is allogeneic haematopoietic stem cell transplantation (HCT). However, many MDS patients are older, often with substantial comorbid conditions, and the disease is heterogeneous. As a consequence, results of HCT vary considerably, and the practices of HCT for MDS are evolving.

RECENT FINDINGS

The newly published modified International Prognostic Scoring System (IPSS-R), developed for nontransplanted patients, also correlates with post-HCT outcome, with the patient's karyotype having the strongest impact. The presence of monosomal karyotype and various genetic and molecular markers have also been shown to have a prognostic value. The use of hypomethylating agents, before or after HCT, may reduce the post-HCT relapse risk or delay relapse. Low and reduced-intensity conditioning regimens have allowed to transplant growing numbers of older patients with MDS, and the development of novel regimens may lead to improved relapse-free survival even in patients with high-risk cytogenetics. The optimal stem cell source may differ for different patient populations and different disease risk categories.

SUMMARY

Transplant results for MDS have improved in recent years. Some patients even in the eighth decade of life have been transplanted successfully. Ongoing studies are aimed at further reducing transplant-related toxicity, graft-versus-host disease and post-HCT relapse.

Pre-transplant prognostic factors of long-term survival after allogeneic peripheral blood stem cell transplantation with matched related/unrelated donors

Mobilized peripheral blood has become the predominant stem cell source for allogeneic hematopoietic cell transplantation. In this retrospective single center study of 442 patients with hematologic malignancies, we analyzed prognostic factors for long-term survival after peripheral blood stem cell transplantation from HLA-matched related or unrelated donors. To account for disease/status heterogeneity, patients were risk-stratified according to the Disease Risk Index. Five-year overall survival was similar after transplants with matched related and unrelated donors (45% and 46%, respectively; P=0.49). Because donor age ≥60 years impacted outcome during model building, we further considered 3 groups of donors: matched unrelated (aged <60 years by definition), matched related aged <60 years and matched related aged ≥60 years. In multivariate analysis, the donor type/age group and the graft CD34(+) and CD3(+) cell doses impacted long-term survival. Compared with matched unrelated donor transplant, transplant from matched related donor <60 years resulted in similar long-term survival (P=0.67) while transplant from matched related donor ≥60 years was associated with higher risks for late mortality (hazard ratio (HR) 4.41; P=0.006) and treatment failure (HR: 6.33; P=0.009). Lower mortality risks were observed after transplant with CD34(+) cell dose more than 4.5×10(6)/kg (HR: 0.56; P=0.002) and CD3(+) cell dose more than 3×10(8)/kg (HR: 0.61; P=0.01). The Disease Risk Index failed to predict survival. We built an "adapted Disease Risk Index" by modifying risks for myeloproliferative neoplasms and multiple myeloma that improved stratification ability for progression-free survival (P=0.04) but not for overall survival (P=0.82).

Risk assessment before allogeneic hematopoietic cell transplantation for older adults with acute myeloid leukemia

Acute myeloid leukemia (AML) most commonly affects patients older than 60 years. Outcomes of treatment of older AML patients have been poor. The advent of reduced-intensity conditioning (RIC) regimens made allogeneic hematopoietic cell transplantation (HCT) an available treatment option with curative intent for older AML patients. Because older patients are often excluded from clinical trials, little is known about the stratification of their risks before allogeneic HCT. While recent studies of RIC and allogeneic HCT have shown little impact of age on outcomes, other variables such as the recipient health status and the AML disease status and chromosomal aberrations have proven to be of prognostic significance. Here, the authors review recent studies of allogeneic HCT for older patients with AML with detailed evaluation of risk factors for relapse as well as non-relapse mortality. The authors have integrated the currently available information on transplant risks into a five-category risk-benefit system that could aid in the decision-making in this patient population.

Prospective study of one- vs two-unit umbilical cord blood transplantation following reduced intensity conditioning in adults with hematological malignancies

As the threshold nucleated cell dose for one-unit umbilical cord blood (UCB) in adults has not to date been firmly established, we prospectively compared one- vs two-unit UCB transplantation after reduced intensity conditioning (RIC) in adult patients with hematological malignancies. Study design specified one-UCB unit if the cryopreserved total nucleated cell (TNC) dose was 2.5 × 10(7)/kg recipient weight, otherwise two units matched at minima of 4/6 HLA loci to the patient and 3/6 to each other were infused. A total of 27 patients received one unit; 23 patients received two units. Median time to ANC >500/μL was 24 days (95% confidence interval 22-28 days), 25 days for one unit and 23 days for two units (P=0.99). At day 100, ANC >500/μL was 88.4 and 91.3% in the one- and two-unit groups (P=0.99), respectively. Three-year EFS was 28.6% and 39.1% in the one- and two-unit groups (P=0.71), respectively. Infusion of two units was associated with a significantly lower relapse risk, 30.4% vs 59.3% (P=0.045). Infused cell doses (TNC, CD3(+), CD34(+) and CD56(+)CD3(neg)) did not impact on engraftment, OS or EFS. Taken together, one-unit UCB transplantation with a threshold cell dose 2.5 × 10(7)/kg recipient weight after RIC is a viable option for adults, although infusion of two units confers a lower relapse incidence.

Use of matched unrelated donors compared with matched related donors is associated with lower relapse and superior progression-free survival after reduced-intensity conditioning hematopoietic stem cell transplantation

As success of reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (HSCT) relies primarily on graft-versus-leukemia (GVL) activity, increased minor HLA disparity in unrelated compared to related donors could have a significant impact on transplant outcomes. To assess whether use of unrelated donors (URD) engenders more potent GVL in RIC HSCT compared to matched related donors (MRD), we retrospectively studied 433 consecutive T-replete 6/6 HLA matched URD (n = 246) and MRD (n = 187) RIC HSCT for hematologic malignancies at our institution. Diseases included: acute myelogenous leukemia (AML) (127), non-Hodgkin lymphoma (NHL) (71), chronic lymphocytic leukemia (CLL) (68), myelodysplastic syndrome (MDS) (64), Hodgkin disease (HD) (40), chronic myeloid leukemia (CML) (25), multiple myeloma (MM) (23), myeloproliferative disorder (MPD) (12), acute lymphoblastic leukemia (ALL) (7), and other leukemia (1). All received uniform fludarabine and intravenous busulfan conditioning, and GVHD prophylaxis with tacrolimus/mini-methroxate (mini-MTX) or tacrolimus/sirolimus ± mini-MTX. Unrelated donors were younger compared to MRD (median donor age: 33 years versus 52 years, P < .0001), and provided larger CD34(+) products (median CD34(+) cells infused: 8.7 × 10(6)/kg versus 7.5 × 10(6)/kg, P = .002). Distribution of diseases, disease risk, prior transplant, and cytomegalovirus (CMV) status was similar in both cohorts. Cumulative incidence of grade II-IV acute GVHD (at day +180), 2-year chronic GVHD, and 2-year nonrelapse mortality (NRM) were 20% versus 16%, 55% versus 50%, and 8% versus 6% in URD and MRD, respectively (P = NS). Cumulative incidence of relapse at 2 years was lower in URD, 52% versus 65% (P = .005). With median follow-up of 26.5 and 35.8 months, 2-year progression-free survival (PFS) was significantly better in unrelated donor transplants, 39.5% for URD, and 29% for MRD (P = .01). Overall survival (OS) at 2 years were 56% for URD versus 50% for MRD (P = .53). In multivariable analysis, URD was associated with a lower risk of relapse (hazard ratio [HR] 0.67, P = .002) and superior PFS (HR 0.69, P = .002). These results suggest that URD is associated with greater GVL activity than MRD, and could have practice changing impact on future donor selection in RIC HSCT.

High cytogenetic or molecular genetic risk acute myeloid leukemia

Resistance, manifested as failure to enter remission despite living long enough to do so or as relapse from remission, is the principal cause of therapeutic failure in acute myeloid leukemia, even in patients age ≥ 75. Recently, a "monosomal karyotype" in acute myeloid leukemia blasts has been found to be a principal predictor of resistance. It is also clear that patients with a normal karyotype, and other intermediate prognosis karyotypes, can be placed into a high-risk group based on the absence of a mutation in the NPM1 gene or the presence of an internal tandem duplication (ITD) of the Fms-like tyrosine kinase 3 gene (FLT3) gene, particularly if there is loss of the wild-type FLT3 allele. The effects of other genetic abnormalities have been inconsistent, perhaps reflecting differences in expression of the abnormality and its translation into protein. Several reports have shown the prognostic potential of profiling global gene expression, micro-RNA expression, DNA methylation, and proteomics. Although routine application of these approaches is still premature, pretreatment assessment of the nucleophosmin 1 (NPM1) mutation and FLT3 ITD status, as well as cytogenetics, should be routine. These results can be used to guide the choice of remission induction therapy, for example, by placing patients with monosomal karyotype or FLT3 ITDs on clinical trials. Allogeneic hematopoietic cell transplant in first complete remission is generally indicated for high-risk patients. However, new approaches are needed to reduce the high rates of relapse, even after hematopoietic cell transplant.

A modified EBMT risk score and the hematopoietic cell transplantation-specific comorbidity index for pre-transplant risk assessment in adult acute lymphoblastic leukemia

BACKGROUND

Disease stage is the most important prognostic parameter in allogeneic hematopoietic cell transplantation (HCT) for acute lymphoblastic leukemia, but other factors such as donor/host histocompatibility and gender combination, recipient age, performance status and comorbidities need to be considered. Several scoring systems are available to predict outcome in HCT recipients; however, their prognostic relevance in acute lymphoblastic leukemia is not well defined.

DESIGN AND METHODS

In the present study we evaluated a modified EBMT risk score (mEBMT) and the HCT-specific comorbidity index (HCT-CI) in 151 adult acute lymphoblastic leukemia patients who received allogeneic HCT from 1995 until 2007 at our center.

RESULTS

Disease status was first complete remission (CR1) (47%), CR>1 (21%) or no CR (32%). Overall survival (OS) at one, two and five years was 62%, 51% and 40% and non-relapse mortality (NRM) was 21%, 24% and 32%. Median mEBMT was 3 (0-6). Higher mEBMT was associated with inferior OS (hazard ratio per score unit (HR): 1.50, P<0.001), higher NRM (HR: 1.36, P=0.042) and higher relapse mortality (HR: 1.68, P<0.001). Disease stage was the predominant prognostic factor in this score. Comorbidities were present in 71% of patients with mild hepatic disease (29%), moderate pulmonary disease (28%) and infections (23%) being the most common. Median HCT-CI was 1 (0-9). In univariate analysis a trend for inferior OS (HR: 1.08, P=0.20) and higher NRM (HR: 1.14, P=0.11) with increasing HCT-CI was observed but the level of significance was not reached. In additional analyses we found that reduced Karnofsky Performance Status (KPS) was associated with inferior OS (HR: 1.34, P=0.023) and higher relapse mortality (HR: 1.71, P=0.001) when analyzed univariately. However, KPS was associated with disease stage and significance was lost in multivariate analysis.

CONCLUSIONS

The mEBMT was prognostic in our patient cohort with predominant influence of disease stage, whereas a trend but no significant prognostic value was observed for the HCT-CI.

Infections in non-myeloablative hematopoietic stem cell transplantation patients with lymphoid malignancies: spectrum of infections, predictors of outcome and proposed guidelines for fungal infection prevention

The overall risk of infections is lower in patients undergoing non-myeloablative allogeneic stem cell transplantation (NST) than in conventional stem cell transplant recipients. We sought to evaluate conditions associated with increased risk of infections after NST. In 81 patients, 187 infection episodes were noted; chronic lymphocytic leukemia (138 episodes/100 person-years) and recipients of matched unrelated donor graft (128 episodes/100 person-years) had higher risk of infection. Only half of the cytomegalovirus (CMV) infections occurred 31-100 days after transplantation. Most patients with CMV infection were non-neutropenic (100%), had lymphoma (76%), were younger (<55 years; 72%) and had received matched related donor (MRD) graft (72%). However, graft-versus-host disease (GVHD) was present in only 15% of these patients. Seven (78%) of nine invasive fungal infections (IFI) were diagnosed >100 days after NST and were associated with high mortality (78%). Most patients with IFI were also not neutropenic (100%), had received MRD graft (100%), had lymphoma (78%) and were given systemic steroids (78%); unlike CMV infection, 67% of these patients also had GVHD. On the basis of our results, we propose that NST recipients with lymphoma treated with high-dose corticosteroids for GVHD be considered for antifungal prophylaxis or pre-emptive antifungal therapy.

TLI and ATG conditioning with low risk of graft-versus-host disease retains antitumor reactions after allogeneic hematopoietic cell transplantation from related and unrelated donors

A hematopoietic cell transplantation regimen was adapted from a preclinical model that used reduced-intensity conditioning (RIC) and protected against graft-versus-host disease (GVHD) by skewing residual host T-cell subsets to favor regulatory natural killer T cells. One hundred eleven patients with lymphoid (64) and myeloid (47) malignancies received RIC using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) followed by the infusion of granulocyte colony-stimulating factor-mobilized grafts. Included were 34 patients at least 60 years of age, 32 patients at high risk of lymphoma relapse after disease recurrence following prior autologous transplantation, and 51 patients at high risk of developing GVHD due to lack of a fully human leukocyte antigen (HLA)-matched related donor. Durable chimerism was achieved in 97% of patients. Cumulative probabilities of acute GVHD (grades II-IV) were 2 and 10% of patients receiving related and unrelated donor grafts. Nonrelapse mortality (NRM) at 1 year was less than 4%. Cumulative incidence of chronic GVHD was 27%. The 36-month probability of overall and event-free survival was 60% and 40%, respectively. Disease status at start of conditioning and the level of chimerism achieved after transplantation significantly impacted clinical outcome. The high incidence of sustained remission among patients with active disease at time of transplantation suggests retained graft-versus-tumor reactions. Active trial registration currently at clinicaltrials.gov under IDs of NCT00185640 and NCT00186615.

Unrelated donor hematopoietic cell transplantation for non-hodgkin lymphoma: long-term outcomes

We analyzed the outcomes of 283 patients receiving unrelated donor allogeneic hematopoietic cell transplantation for non-Hodgkin lymphoma (NHL) facilitated by the Center for International Blood and Marrow Transplant Research/National Marrow Donor Program (CIBMTR/NMDP) between 1991 and 2004. All patients received myeloablative conditioning regimens. The median follow-up of survivors is 5 years. Seventy-three (26%) patients are alive. The day 100 probability of death from all causes is estimated at 39%. The cumulative incidence of developing grade III-IV acute graft-versus-host disease (aGVHD) at day 100 is 25%. The estimated 5-year survival and failure free survival are 24% (95% confidence interval [CI]: 19-30) and 22% (95% CI: 17-28), respectively. Factors adversely associated with overall survival (OS) included increasing age, decreased performance status, and refractory disease. Follicular lymphoma (FL) and peripheral T cell lymphoma had improved survival compared to aggressive B cell lymphomas. Factors adversely associated with progression-free survival (PFS) included performance status, histology, and disease status at transplant. Long-term failure-free survival is possible following unrelated donor transplantation for NHL, although early mortality was high in this large cohort.

Does the hematopoietic cell transplantation specific comorbidity index predict transplant outcomes? A validation study in a large cohort of umbilical cord blood and matched related donor transplants

The hematopoietic cell transplantation specific comorbidity index (HCT-CI) has been recently proposed to predict the probability of nonrelapse mortality (NRM) and overall survival (OS) in allogeneic HCT recipients while taking into account any pretransplant comorbidity. We tested the validity of the HCT-CI in a cohort of 373 adult HCT recipients (184 matched-related donor and 189 unrelated umbilical cord blood) who received a myeloablative (N = 150) or nonmyeloablative (N = 223) conditioning regimen. HCT-CI scores of 0, 1, 2, and > or =3 were present in 58 (16%), 56 (15%), 64 (17%), and 195 (52%) patients, respectively. Pulmonary conditions were the most common comorbidity. Cumulative incidence of NRM at 2 years was 10%, 20%, 24%, and 28% for HCT-CI scores of 0, 1, 2, and > or =3, respectively (P = .01). The corresponding probability of OS at 2 years was 72%, 67%, 51%, and 48%, respectively (P < .01). On multivariate analyses adjusted for recipient age, disease risk, donor source, and conditioning regimen intensity, the relative risks for NRM for HCT-CI scores of 1, 2, and > or =3 (compared to a score of 0) were 2.0 (95% confidence intervals, 0.8-5.3), 2.6 (1.0-6.7), and 3.2 (1.4-7.4), respectively. The risks for overall mortality were 1.2 (0.6-2.1), 2.0 (1.1-3.4), and 2.1 (1.3-3.3), respectively. In subgroup analyses, the HCT-CI score did not consistently predict NRM and OS among different donor sources and conditioning regimens. The HCT-CI, although a useful tool for capturing pretransplant comorbidity and risk-assessment, needs to be further validated prior to adopting it for routine clinical use.

Acute graft-versus-host disease: differing risk with differing graft sources and conditioning intensity

Acute graft-versus-host disease (aGVHD) is a constant component of allogeneic hematopoietic cell transplantation (HCT), with variations in incidence and severity affected by the graft source, human leukocyte antigen (HLA) compatibility, and the preparative regimen. The graft source - related versus unrelated donors, bone marrow (BM) versus peripheral blood (PB), umbilical cord blood (UCB) versus unrelated donor BM - are discussed in this review, as well as myeloablative versus reduced-intensity (RI) preparative regimens. Recent comparisons of matched related versus matched unrelated donor HCT support a minimal difference in aGVHD between these two donor sources. The use of BM versus mobilized PB in the matched related donor (MRD) setting has been compared in randomized as well as phase-II comparative clinical trials which support a slight increase in aGVHD in the adult population. Similar results have been seen in the unrelated donor (URD) setting, although based on minimal comparative data to date. Preliminary comparisons of UCB versus URD BM have shown a decreased incidence of aGVHD with UCB, despite increased HLA mismatching. Haploidentical HCT has continued to be explored, with limitations due to delayed immune reconstitution and disease relapse. Many reduced-intensity preparative regimens have been published, with a reduced or minimal difference in incidence of aGVHD when historically compared to myleoablative preparative regimens. More formal comparisons of the different graft sources as well as preparative regimen intensities will be required to determine a more accurate picture of the differences between these transplantation alternatives.

Five-year follow-up of patients with advanced chronic lymphocytic leukemia treated with allogeneic hematopoietic cell transplantation after nonmyeloablative conditioning

PURPOSE

We reported encouraging early results of allogeneic hematopoietic cell transplantation (HCT) after nonmyeloablative conditioning in 64 patients who had advanced chronic lymphocytic leukemia (CLL). Here, we have extended the follow-up to a median of 5 years and have included data on an additional 18 patients.

PATIENTS AND METHODS

Eighty-two patients, age 42 to 72 years, who had fludarabine-refractory CLL were conditioned with 2 Gy total-body irradiation alone or combined with fludarabine followed by HCT from related (n = 52) or unrelated (n = 30) donors.

RESULTS

Complete remission (CR) and partial remission were achieved in 55% and 15% of patients, respectively. Higher CR rates were noted after unrelated HCT (67% v 48%). The 5-year incidences of nonrelapse mortality (NRM), progression/relapse, overall survival, and progression-free survival were 23%, 38%, 50%, and 39%, respectively. Among 25 patients initially reported in CR, 8% relapsed and 8% died as a result of NRM, whereas 84% have remained alive and in CR. Among 14 responding patients who were tested and who had molecular eradication of their disease, two died as a result of NRM, two relapsed, and 10 have remained negative. At 5 years, 76% of living patients were entirely well, whereas 24% continued to receive immunosuppression for chronic graft-versus-host disease; the median performance status in each group was 100% and 90%, respectively. Lymphadenopathy > or = 5 cm, but not cytogenetic abnormalities at HCT, predicted relapse. In a risk-stratification model, patients who had lymphadenopathy less than 5 cm and no comorbidities had a 5-year OS of 71%.

CONCLUSION

Nonmyeloablative HCT resulted in a median survival of 5 years for patients who had fludarabine-refractory CLL with sustained remissions and in the continued resolution of chronic graft-versus-host disease in surviving patients.

Prophylaxis of acute GVHD: manipulate the graft or the environment?

Graft-versus-host disease (GVHD) is the immune response of donor T lymphocytes responding to the recipient's alloantigens. The cellular and cytokine mechanisms driving GVHD are now well defined and have led to several prophylactic approaches. Selective allodepletion techniques promise to prevent GVHD without causing immune deficiency provoked by global T-cell depletion. Targeted dosing of other (non-T-cells) cells in the graft - such as CD34+ progenitors, regulatory T cells, natural killer cells and mesenchymal stromal cells - can also lead to transplants designed to retain immune capability without causing GVHD. Immunosuppressive drugs such as methotrexate, cyclosporine and anti-lymphocyte antibodies are the mainstay in the prevention of GVHD and can be used in conjunction with engineered grafts to eliminate GVHD. In future it is anticipated that further refinements in targeting the elimination or suppression of the GVHD reacting T cells should be selective enough to preserve the important graft-versus-leukemia effect which contributes to the cure of malignant diseases by allogeneic stem-cell transplantation.