Impact of intensity of conditioning therapy in patients aged 40–60 years with AML/myelodysplastic syndrome undergoing allogeneic transplantation

Secondary oral cancer following hematopoietic cell transplantation

The aim of this retrospective study was to determine the incidence and the clinical outcome of secondary oral cancer (SOC) and to assess potential risk factors in a large cohort of patients (n = 908), who received allogeneic hemopoietic cell transplantation (HCT) either for a malignant (n = 733) or nonmalignant hematologic disease (n = 175). The median follow-up of 438 transplant survivors was 17 years. Twelve patients developed SOC at a median of 13.5 years since HCT and at a median age of 47 years. The 35-year cumulative incidence function of SOC development was 3.47%. In univariate analysis, factors associated with increased incidence of SOC were reduced intensity conditioning and chronic graft-versus-host disease (cGvHD). On multivariate analysis, nonmalignant disease and duration of oral cGvHD ≥15 months were independent risk factors for SOC development. Nonmalignant disease recipients had 3.94× higher than expected rate of SOC (95% confidence interval, 1.50-10.39%, p = 0.0055). Recipients whose oral cGvHD persisted for more than ≥15 months had 58.6× higher than expected rate of SOC (95% confidence interval, 13.3-258.1%), p < 0.0001). This study demonstrates that oral cGvHD and a diagnosis of nonmalignant hematologic disease are strong risk factors in the SOC development.

Myeloablative Conditioning for Allogeneic Transplantation Results in Superior Disease-Free Survival for Acute Myelogenous Leukemia and Myelodysplastic Syndromes with Low/Intermediate but not High Disease Risk Index: A Center for International Blood and Marrow Transplant Research Study

Compared with reduced-intensity conditioning (RIC), myeloablative conditioning (MAC) is generally associated with lower relapse risk after allogeneic hematopoietic cell transplantation (HCT) for acute myelogenous leukemia (AML) and myelodysplastic syndromes (MDS). However, disease-specific risk factors in AML/MDS can further inform when MAC and RIC may yield differential outcomes. We analyzed HCT outcomes stratified by the Disease Risk Index (DRI) in 4387 adults (age 40 to 65 years) to identify the impact of conditioning intensity. In the low/intermediate-risk DRI cohort, RIC was associated with lower nonrelapse mortality (NRM) (hazard ratio [HR], .74; 95% confidence interval [CI], .62 to .88; P < .001) but significantly greater relapse risk (HR, 1.54; 95% CI, 1.35 to 1.76; P < .001) and thus inferior disease-free survival (DFS) (HR, 1.19; 95% CI, 1.07 to 1.33; P = .001). In the high/very high-risk DRI cohort, RIC was associated with marginally lower NRM (HR, .83; 95% CI, .68 to 1.00; P = .051) and significantly higher relapse risk (HR, 1.23; 95% CI, 1.08 to 1.41; P = .002), leading to similar DFS using either RIC or MAC. These data support MAC over RIC as the preferred conditioning intensity for patients with AML/MDS with low/intermediate-risk DRI, but with a similar benefit as RIC in high/very high-risk DRI. Novel MAC regimens with less toxicity could benefit all patients, but more potent antineoplastic approaches are needed for the high/very-high risk DRI group.

Increased overall and bacterial infections following myeloablative allogeneic HCT for patients with AML in CR1

Presumably, reduced-intensity/nonmyeloablative conditioning (RIC/NMA) for allogeneic hematopoietic cell transplantation (alloHCT) results in reduced infections compared with myeloablative conditioning (MAC) regimens; however, published evidence is limited. In this Center for International Blood and Marrow Transplant Research study, 1755 patients (aged ≥40 years) with acute myeloid leukemia in first complete remission were evaluated for infections occurring within 100 days after T-cell replete alloHCT. Patients receiving RIC/NMA (n = 777) compared with those receiving MAC (n = 978) were older and underwent transplantation more recently; however, the groups were similar regarding Karnofsky performance score, HCT-comorbidity index, and cytogenetic risk. One or more infections occurred in 1045 (59.5%) patients (MAC, 595 [61%]; RIC/NMA, 450 [58%]; P = .21) by day 100. The median time to initial infection after MAC conditioning occurred earlier (MAC, 15 days [range, <1-99 days]; RIC/NMA, 21 days [range, <1-100 days]; P < .001). Patients receiving MAC were more likely to experience at least 1 bacterial infection by day 100 (MAC, 46% [95% confidence interval (CI), 43-49]; RIC/NMA, 37% [95% CI, 34-41]; P = .0004), whereas at least a single viral infection was more prevalent in the RIC/NMA cohort (MAC, 34% [95% CI, 31-37]; RIC/NMA, 39% [95% CI, 36-42]; P = .046). MAC remained a risk factor for bacterial infections in multivariable analysis (relative risk, 1.44; 95% CI, 1.23-1.67; P < .0001). Moreover, the rate of any infection per patient-days at risk in the first 100 days (infection density) after alloHCT was greater for the MAC cohort (1.21; 95% CI, 1.11-1.32; P < .0001). RIC/NMA was associated with reduced infections, especially bacterial infections, in the first 100 days after alloHCT.

T Cell Depletion as an Alternative Approach for Patients 55 Years or Older Undergoing Allogeneic Stem Cell Transplantation as Curative Therapy for Hematologic Malignancies

T cell-depleted (TCD) allogeneic hematopoietic stem cell transplantation (HSCT) is curative treatment for hematologic malignancies in adults, shown to reduce graft-versus-host disease (GVHD) without increased relapse. We retrospectively reviewed a single-center, 11-year experience of 214 patients aged ≥ 55 years to determine tolerability and efficacy in the older adult. Most patients (70%) had myeloid diseases, and most acute leukemias were in remission. Median age was 61 years, with related and unrelated donors ≥8/10 HLA matched. Hematopoietic cell transplantation-specific comorbidity index scores were intermediate and high for 84%. Conditioning regimens were all myeloablative. Grafts were peripheral blood stem cells (97%) containing CD3 dose ≤103-4/kg body weight, without pharmacologic GVHD prophylaxis. With median follow-up of 70 months among survivors, Kaplan-Meier estimates of overall and relapse-free survival were 44% and 41%, respectively (4 years). Cumulative incidence of nonrelapse mortality at day +100 was only 10%. Incidence of GVHD for acute (grades II to IV) was 9% at day +100 and for chronic was 7% at 2 and 4 years (8 extensive, 1 overlap). Median Karnofsky performance status for patients > 2 years post-transplant was 90%. As 1 of the largest reports for patients ≥2 aged ≥55 years receiving TCD HSCTs, it demonstrates curative therapy with minimal GVHD, similar to that observed in a younger population.

Myeloablative hematopoietic stem cell transplantation improves survival but is not curative in a pre-clinical model of myelodysplastic syndrome

Allogeneic hematopoietic stem cell transplantation (A-HSCT) remains the only curative option for patients with myelodysplastic syndrome (MDS). We used the NUP98-HOXD13 (NHD13) murine model for MDS to study HSCT in a pre-clinical setting. NHD13 recipients transplanted with syngeneic bone marrow (S-HSCT) following myeloablative irradiation showed disease remission, with normalization of peripheral blood parameters and marked decrease in circulating leukocytes derived from the MDS clone. Despite the disease remission and improved survival compared to non-transplanted NHD13 controls, all mice eventually relapsed, indicating persistence of a long-lived radio-resistant MDS clone. In an effort to induce a graft versus leukemia (GVL) effect, A-HSCT with donor bone marrow that was mismatched at minor histocompatibility loci was compared to S-HSCT. Although recipients in the A-HSCT showed a lower early relapse rate than in S-HSCT, all mice in both groups eventually relapsed and died by 54 weeks post-transplant. To obtain a more significant GVL effect, donor splenocytes containing reactive T-cells were transplanted with allogeneic bone marrow. Although the relapse rate was only 20% at post-transplantation week 38, suggesting a GVL effect, this was accompanied by a severe graft versus host disease (GVHD) Taken together, these findings indicate that a myeloablative dose of ionizing radiation is insufficient to eradicate the MDS initiating cell, and that transplantation of donor splenocytes leads to decreased relapse rates, at the cost of severe GVHD. We suggest that NHD13 mice represent a feasible pre-clinical model for the study of HSCT for MDS.

Extramedullary disease at diagnosis of AML does not influence outcome of patients undergoing allogeneic hematopoietic cell transplant in CR1

OBJECTIVE

Extramedullary disease (EMD) at diagnosis of acute myeloid leukemia (AML) has been associated with increased risk of relapse and worse outcomes post-chemotherapy. This study sought to investigate the association of EMD with outcomes following allogeneic hematopoietic cell transplantation (allo-HCT).

METHODS

This single-center retrospective study investigated the impact of EMD at diagnosis on the outcome of patients transplanted for AML in first complete remission (CR1). The study included 303 consecutive patients with AML transplanted in CR1, median age 51 years (range 18-71).

RESULTS

EMD at diagnosis was documented in 39 patients (13%), either histologically (26 patients) or clinically/radiologically (13 patients). Among the 39 EMD patients, 16 had CNS disease, seven had gingival infiltration, and five had leukemia cutis. On univariate analysis, EMD had no significant impact on survival, with a 3-year OS of 55% (95% CI 38-69) compared to 48% for the non-EMD group (95% CI 42%-55%) (P=.84). Likewise, 3-year CIR was 18% vs 19% (P=.86) and 3-year NRM was 26% vs 33% (P=.83) for EMD vs non-EMD groups, respectively. Multivariate analysis confirmed these results.

CONCLUSIONS

We conclude that EMD at diagnosis of AML does not seem to influence outcomes following allo-HCT performed in CR1.

Long-Term Incidence of Secondary Malignancies after Allogeneic Hematopoietic Cell Transplantation: A Single-Center Experience

To review the emergence of secondary malignancies (SMs) in recipients of allogeneic hematopoietic cell transplantation (HCT), we documented the occurrence of SMs in 2415 allogeneic HCT recipients, ages 18 to 71, in a single center over 4 decades. SMs were seen in 209 patients, including 58 with nonmetastatic squamous cell (SCC) and basal cell carcinoma (BCC) of the skin. Cumulative incidence of SM was 6.3% at 10 years, 13.5% at 20 years, and 17.6% at 30 years post-HCT. Median age at diagnosis of SMs was 61 years (range, 21 to 85). By multivariable analysis, older age at HCT was the only independent prognostic factor for SM (HR, 1.39 for ages 41 to 55 and HR, 1.92 for age > 55 compared with age ≤ 40; P = .001). The rate of SM (excluding nonmetastatic SCC/BCC of skin) after HCT was 2.07 times higher (P = .01) compared with the general population. Overall survival (OS) after diagnosis of SM (excluding nonmetastatic SCC/BCC of skin) was 58% at 5 years and 50% at 10 years postdiagnosis. Eastern Cooperative Oncology Group (ECOG) score was the only independent predictor of OS on multivariable analysis, with over 2-fold increased risk of death for patients with an ECOG score of 1 and over 6-fold for ECOG scores of 2 to 4, compared with ECOG score 0 (P < .0001). Forty of 209 patients (19%) diagnosed with SMs subsequently developed another new malignancy. OS was 68% and 51% at 5 and 10 years, respectively. The survival of SM patients post-HCT is favorable, thus warranting diligent long-term cancer screening and standard of care treatment. ECOG status of these patients is a predominant prognostic factor.

Cyclophosphamide/fludarabine nonmyeloablative allotransplant for acute myeloid leukemia

We compared survival outcomes following myeloablative allotransplant (MAT) or cyclophosphamide/fludarabine (Cy/Flu) nonmyeloablative allotransplant (NMAT) for 165 patients with acute myelogenous leukemia (AML) in remission or without frank relapse. Patients who received NMAT were more likely to be older and have secondary AML and lower performance status. At a median follow-up of 61 months, median event-free survival and overall survival survival were not different between NMAT and MAT in univariate as well as multivariate analyses. Cy/Flu NMAT may provide similar disease control and survival when compared with MAT in patients with AML in remission or without frank relapse.

Comparison of reduced-intensity and myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in patients with acute myeloid leukemia and acute lymphoblastic leukemia: a meta-analysis

Currently, the indications to perform reduced-intensity conditioning allogeneic hematopoietic stem cell transplant (RIC-HCT) are based on data derived mainly from large registry and single-centre retrospective studies. Thus, at the present time, there is limited direct evidence supporting the current practice in selecting patients with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) for RIC versus myeloablative conditioning (MAC) transplants. To determine the relationship between dose intensity of conditioning regimen and survival outcomes after allografting in AML/ALL patients, we performed a meta-analysis of 23 clinical trials reported between 1990 and 2013 involving 15,258 adult patients that compare survival outcomes after RIC-HCT versus MAC-HCT. RIC-HCT resulted in comparable <2-year and 2-6 year overall survival (OS) rates post-transplantation even though the RIC-HCT recipients were older and had more active disease than MAC-HCT recipients. The 2-6 year progression-free survival (PFS), nonrelapse mortality, acute graft-versus-host disease (GvHD) and chronic GvHD rates were reduced after RIC-HCT, but relapse rate was increased. Similar outcomes were observed regardless of disease type and status at transplantation. Odds ratio for all outcomes remained comparable with or without performing separate analyses for the year of HCT and for retrospective versus prospective studies. Among RIC-HCT recipients, survival rates were superior if patients were in CR at transplantation. Significant inter-study heterogeneity for aGvHD data and publication bias for PFS data were observed. This meta-analysis showed no OS benefit of MAC-HCT over RIC-HCT across the entire cohort of patients suggesting that RIC-HCT could be an effective therapeutic option for AML/ALL patients who are ineligible for MAC-HCT and CR status is preferred before RIC-HCT.

Allogeneic hematopoietic cell transplantation for myelodysplastic syndromes: lingering uncertainties and emerging possibilities

The landscape of transplantation in myelodysplastic syndrome (MDS) has evolved rapidly in the last decade, driven mostly by advances in patient selection through better risk stratification, increasing age of allogeneic recipients, introduction of reduced-intensity conditioning regimens, increased availability of unrelated donors, new donor sources, and improvements in transplant technology and supportive care. Despite these advances, several issues, mostly centering on approaches to improve post-transplant survival while minimizing transplant-related mortality, continue to present significant challenges. Advances in understanding the molecular pathogenesis of MDS have made it feasible to construct clinically useful risk models that integrate prognostic genes with conventional risk parameters for better selection of patients likely to benefit from hematopoietic cell transplantation. Simultaneous research efforts in several areas, including comorbidity assessment, novel preparative regimens, optimal pretransplant cytoreductive strategy, and post-transplantation therapies, are expected to improve long-term disease-free survival and quality of life.

Benefit of allogeneic transplantation in patients age ≥ 60 years with acute myeloid leukemia is limited to those in first complete remission at time of transplant

We evaluated the impact of age and remission status on 242 consecutive patients who underwent allogeneic hematopoietic cell transplantation for acute myeloid leukemia (AML) in our program between 1999 and 2011. Median age of all patients was 48 years (range, 18 to 71). Based on age and remission status, patients were divided into 4 groups: first complete remission (CR1) age <60 years (n = 116), second complete remission (CR2) age <60 years (n = 78), CR1 age ≥60 years (n = 32), and CR2 age ≥60 years (n = 16). Donors were matched related (n = 155, 64%) or matched unrelated (n = 87, 36%). Median follow-up of survivors was 65 months (range, 12 to 145). In a univariate analysis, 3-year overall survival rates of the 4 groups were 57%, 43%, 39%, and 16% (P = .003), respectively. In a multivariable analysis, hazard ratios of nonrelapse mortality and survival were 2.08 (P = .06) and 1.52 (P = .23), respectively, in patients ≥60 years in CR2 compared with ≥ 60 years in CR1. Although a plateau in survival was observed for patients ≥60 years in CR1 similar to those <60 years in CR1 and CR2, no long-term survivors were seen in patients ≥60 years in CR2. Our data suggest disappointing outcomes in AML patients ≥60 years of age transplanted in CR2. Therefore, if a transplant is indicated, early referral is recommended in patients ≥60 years with AML.

Comparison of conditioning regimens of various intensities for allogeneic hematopoietic SCT using HLA-identical sibling donors in AML and MDS with <10% BM blasts: a report from EBMT

In this multicenter retrospective study, the long-term outcomes of 878 adults with AML and refractory anemia with excess blasts (RAEB) with BM blasts <10% who underwent transplantation with an HLA-identical sibling donor between 1998 and 2004 were analyzed according to four regimens of conditioning intensity: reduced-intensity conditioning (RIC) (either intermediate RIC (IntermRIC) or non-myeloablative (NMA) RIC), and myeloablative conditioning (MC) in 718 patients (either conventional MC or hyperintense MC. In multivariate cox analysis, patients undergoing NMA transplantation had lower non-relapse mortality risk in the first 100 days after transplantation (P<0.01), but a higher risk beyond day +100 (P=0.02), as well as higher relapse incidence in the first 12 months (P<0.01), but the risk was similar in all groups beyond 12 months. The probabilities of PFS and OS up to 7 years were significantly lower only in the NMA subgroup (P0.01 for both). The 7-year OS was 53%, 29%, 56% and 51%, respectively. Our data suggest that prospective studies comparing RIC regimens (especially IntermRIC) with MC are appropriate in patients with AML and RAEB who are in a non-advanced disease status.

Allogeneic hematopoietic cell transplantation for acute myeloid leukemia in first complete remission: have the indications changed?

PURPOSE OF REVIEW

Many improvements in chemotherapy and supportive care, as well as greater understanding of immunology and procuring graft sources, have led to more acute myeloid leukemia patients proceeding to hematopoietic cell transplantation, now the most common indication for this procedure.

RECENT FINDINGS

As treatment-related mortality rates have been reduced, more practitioners and patients are amenable to use of this modality if the risk : benefit ratio appears justified. Clinical factors initially were used to identify patients at highest risk for relapse using conventional approaches, a strategy supplanted by one based on the genetic alterations of the leukemia cells. More recently, molecular factors are used to identify such candidates; the issue of which first remission acute myeloid leukemia patients receive hematopoietic cell transplantation is referred to as risk stratification.

SUMMARY

With significant improvements in donor : recipient matching and a more varied graft source, greater numbers of patients can proceed to alternative donor hematopoietic cell transplantation. Advancing age appears to be less of a barrier and outcomes are reasonable in patients with good performance status and few comorbidities. The most interesting aspect of the moving target of which patients to take to hematopoietic cell transplantation is to define those with favorable-risk disease and avoid the procedure, while using the armamentarium at hand to identify those at higher and highest risk for relapse as the group most likely to benefit. The field, however, still awaits the data that demonstrate improved outcome in these poor-risk patients using the hematopoietic cell transplantation approach.

Survival benefits from reduced-intensity conditioning in allogeneic stem cell transplantation for young lower-risk MDS patients without significant comorbidities

OBJECTIVE

The aim of this study was to determine the optimum conditioning intensity for allogeneic stem cell transplantation (SCT) in young (age ≤50), lower-risk (INT-1 by IPSS) Myelodysplastic syndrome (MDS) patients without significant comorbidities (hematopoietic cell transplantation-comorbidity index score ≤3).

METHODS

Transplant outcomes from 46 consecutive patients were retrospectively analyzed according to the conditioning intensity: reduced-intensity conditioning (RIC; n = 14), intensified RIC by adding low-dose total body irradiation (iRIC; n = 15), and myeloablative conditioning (MAC; n = 17).

RESULTS

After a median follow-up of 73.7 months, RIC had a better 4-yr overall survival (OS) (92.9%) compared with the iRIC (64.2%) or MAC (70.6%). Multivariate analysis showed that RIC was associated with improved OS compared with the MAC [relative risk (RR) of 0.08, P = 0.022] because of a lower transplant-related mortality (TRM) (RR, 0.08, P = 0.035). iRIC failed to show survival benefits over the MAC (RR of 0.77, P = 0.689) because of similarly high TRM (RR of 0.41, P = 0.480). Cumulative incidence of acute and chronic graft-versus-host disease (GVHD) after RIC was higher, but GVHD-specific survival was significantly better (RIC 100% vs. iRIC 45.7% vs. MAC, P = 0.018). Relapse rate was not different among the three groups, but in the RIC group, azacitidine was available and useful for inducing remission in two patients.

CONCLUSION

This study shows that RIC improved OS by directly lowering TRM and indirectly giving an additional chance for relapsed MDS in the era of hypomethylating treatment. RIC-SCT should be considered for relative healthy lower-risk MDS patients.

Hematopoietic stem cell transplantation for myelodysplastic syndrome: a review

Allogeneic hematopoietic stem cell transplantation (HSCT) continues to be the only curative option for myelodysplastic syndrome (MDS). Since the majority of the patients with this disease are often older and frail, treatment-related mortality and morbidity remain major obstacles to be overcome. Reduced-intensity conditioning and continued lines of investigation in the field of allogeneic transplantation are expected to ultimately improve the overall therapeutic approach to MDS. In this review we summarize current recommendations and controversies surrounding HSCT for MDS, as well as the use of novel therapeutics in the peri-transplant period.

Reduced-intensity allografting in patients with therapy-related myeloid neoplasms and active primary malignancies

Therapy-related myeloid neoplasms (t-MNs) are severe long-term consequences of cytotoxic treatments for a primary, often, malignant disorder. So far, the majority of patients eligible for transplantation have undergone myeloablative allo haematopoietic SCT (HSCT) as a potentially curative treatment, but it has been associated with high transplantation-related mortality (TRM) rates. In this retrospective study, we analysed the outcome of patients with t-MNs undergoing HSCT with reduced-intensity conditioning (RIC). Of 55 patients, seen at a single centre over a 10-year period, 17 underwent RIC HSCT with related or unrelated donors. The estimated overall survival was 53% at 1 year and 47% at 3 years, and disease-free survival was 47% at 1 year. At 1 year, the cumulative incidence of relapse and TRM were 24% and 30%, respectively. Of five patients with active primary neoplasms who underwent transplantation, two are alive beyond 1 year and show CR of both t-MNs and the primary malignancy. These data indicate that RIC HSCT is an encouraging approach for patients with t-MNs. The issue of primary malignancies not being in remission at the time of transplantation should be explored in further studies.

Allogeneic hematopoietic cell transplantation for adults with acute myeloid leukemia: myths, controversies, and unknowns

Progress in the last decade has improved the understanding of leukemia biology. Molecular markers in combinations with cytogenetics have improved the risk stratification of acute myeloid leukemia (AML) and informed decision-making. In parallel, several important advances in the transplant field, such as better supportive care, improved transplant technology, increased availability of alternative donors, and reduced-intensity conditioning have improved the safety as well as access of allogeneic hematopoietic cell transplantation (HCT) for a larger number of patients. In this review, the positioning of HCT in the management of patients with AML is evaluated in view of changing risk/benefit ratios associated with both conventional treatments and transplantation, and some of the controversies are addressed in light of emerging data. Increasing data demonstrate outcomes of alternative donor transplantation approaching HLA-identical sibling donors in high-risk AML supporting the inclusion of alternative donors in trials of prospective studies evaluating post remission strategies for high-risk AML. The use of reduced-intensity conditioning has expanded the eligibility of HCT to older patients with AML, and outcome data are encouraging. Continued study of HCT versus alternative therapies is required to optimize patients' outcomes in AML.