Treatment, risk factors, and outcome of adults with relapsed AML after reduced intensity conditioning for allogeneic stem cell transplantation

Haploidentical hematopoietic cell transplantation using in vitro T cell depleted grafts as salvage therapy in patients with disease relapse after prior allogeneic transplantation

Disease relapse after one or more allogeneic hematopoietic cell transplantations (HCT) represents a therapeutic challenge with all options bearing a significant morbidity and mortality. Haploidentical HCT may induce more pronounced anti-leukemic effects and was evaluated at our center in 25 consecutive patients with disease relapse after preceding HCT receiving haploidentical grafts after in vitro T cell depletion. Overall survival at 1 and 2 years was 32 and 14%, respectively. Of note, patients with complete remission (CR) before haploidentical HCT had a very favorable overall survival of 41.7% at 2 years. Cumulative incidence of non-relapse mortality was 36 and 40% at 1 and 2 years, respectively. With a cumulative incidence for relapse of 36 and 45.6% at 1 and 2 years, disease-free survival (DFS) was 28 and 14.4%, respectively. Here also, patients with CR before haploidentical HCT had a favorable DFS of 42% at 2 years. Only very limited acute (11 patients (44%) with a median grade 1) and chronic graft versus host disease (GvHD) (5 patients (11%), limited grade only) was observed. The main complications and causes of death comprised-besides relapse-infections and bleeding complications. Hence, haploidentical HCT can achieve long-term survival comparable to second transplantation with matched or mismatched donors for patients with otherwise deleterious prognosis and should be considered as a treatment option for patients experiencing disease relapse after previous allogeneic HCT.

Hypomethylating agents after allogeneic blood stem cell transplantation

Allogeneic blood stem cell transplantation (allo-SCT) is a potentially curative treatment for patients with myeloid malignancies such as acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), but relapse remains the major cause of treatment failure. So far, therapeutic options for patients with AML or MDS who relapse after allo-SCT generally consisted of palliative care, low-dose or intensive chemotherapy as well as cellular therapies such as donor lymphocyte infusions (DLI) and second transplantation in selected cases. Nevertheless, the prognosis of patients with myeloid malignancies relapsing after allo-SCT remains dismal therefore asking for novel treatment strategies. Considering their well-balanced profile of good efficacy and moderate toxicity in the non-transplant setting, the hypomethylating agents (HMA) azacitidine (Aza) and decitabine (DAC) have also been tested either alone or in combination with DLI in the post-transplant period. This review summarizes the current knowledge about the use of these two HMA as pre-emptive, salvage or consolidation therapy mostly retrieved from retrospective studies but also from a few prospective trials. Within this review, we also comment on some practical issues such as optimal dose and schedule, the choice of HMA candidates and the role of additional cellular interventions. Finally, we also give an overview on the assumed mode of actions, ongoing research, clinical studies and potential combination partners aiming to improve this treatment approach.

Sequential Intensified Conditioning Regimen Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Intermediate- or High-Risk Acute Myeloid Leukemia in Complete Remission: A Study from the Acute Leukemia Working Party of the European Group for Blood and Marrow Transplantation

Post-transplant relapse is the leading cause of treatment failure in acute myeloid leukemia (AML) patients after reduced-intensity conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT). To improve their outcome, we evaluated the outcome of a sequential intermediate-intensity conditioning regimen combining fludarabine, cytosine arabinoside, amsacrine, cyclophosphamide, and either total body irradiation or busulfan (FLAMSA) in patients with intermediate or high-risk AML in first or second complete remission (CR). A total of 265 patients (median age, 55 years; range, 19 to 76) with AML who underwent allo-HSCT using a FLAMSA regimen were included. At the time of transplant, 216 (81.5%) were in CR1 and 49 (18.5%) in CR2. Cytogenetic was intermediate in 114 (43%) and poor in 42 (15.8%) patients, whereas 109 patients (41.1%) had a secondary AML. With a median follow-up of 46 months (range, 1 to 145), the Kaplan-Meier estimate of overall and leukemia-free survival at 2 years were 56.1% (95% CI, 49.7% to 62.6%) and 52.8% (95% CI, 46.4% to 59.2%), respectively. At 2 years, the cumulative incidences of relapse and nonrelapse mortality were 22.8% (95% CI, 17.6% to 28.4%) and 24.0% (95% CI, 18.8% to 29.5%), respectively. In multivariate analysis, patient age and cytogenetics were the only parameters with a significant impact on overall survival. These data suggest that the FLAMSA sequential intermediate conditioning regimen provides an efficient disease control in intermediate- and high-risk AML patients, including those in CR2 and with secondary AML.

Identification of HLA‑A*1101‑restricted cytotoxic T lymphocyte epitopes derived from epidermal growth factor pathway substrate number 8

Epidermal growth factor receptor pathway substrate 8 (EPS8) is critical in the proliferation, progression and metastasis of solid and hematological types of cancer, and thus constitutes an ideal target for cancer immunotherapy. The present study aimed to identify human leukocyte antigen (HLA)‑A*1101‑restricted cytotoxic T lymphocyte (CTL) epitopes from EPS8 and characterize their immunotherapeutic efficacy in vitro. Two computer‑based algorithms were used to predict native EPS8 epitopes with potential high binding affinity to the HLA‑A*1101 molecule, which is the HLA‑A allele with the highest frequency in the Chinese population. The peptide‑induced cytokine production from the CTLs was examined using enzyme‑linked immunosorbent spot analysis. The cytotoxic effects on cancer cells by CTLs primed with the identified peptides were examined using flow cytometry. A total of five peptides, designated as P380, P70, P82, P30 and P529, presented with high affinity towards the HLA‑A*1101 molecule. In response to stimulation by these five peptides, enhanced secretion of interferon‑γ from the CTLs and increased cytolytic capabilities of the CTLs toward cancer cells were noted, with the most potent effects observed from the P380 peptide. Taken together, the present study identified five potential CTL epitopes from EPS8. Among these, P380 presented with the highest therapeutic efficacy in vitro. These peptides may benefit the development of EPS8‑based immunotherapy for the treatment of HLA‑A*1101‑positive hematological malignancies.

The role of second transplants for leukemia

Management of relapsed leukemia following allogeneic transplantation is challenging. Intensive chemotherapy, donor lymphocyte infusions (DLI), or second transplantation have some value, but most reported series describe only a limited number of patients surviving beyond 2 or 3 years following relapse. Additionally, understandable selection-bias of reports describing the outcomes of intensive management approaches for relapsed leukemia confound generalizability to a broader population. However numerous reports suggest that second allogeneic transplantation for relapsed leukemia following an initial transplant may produce extended disease control and survival for patients with favorable performance status, remission at the time of second transplant, and most importantly a long interval between initial transplant and relapse. Reduced intensity conditioning for second allografts may be preferable and little data exists to suggest that a new donor will improve disease control by inducing a stronger graft-versus-leukemia effect. Improved measures to prevent the first relapse, however, may protect more patients and produce a greater fraction enjoying extended leukemia-free survival.

Sequential regimen of clofarabine, cytosine arabinoside and reduced-intensity conditioned transplantation for primary refractory acute myeloid leukemia

The prognosis of patients with acute myeloid leukemia in whom primary treatment fails remains very poor. In order to improve such patients' outcome, we conducted a phase 2, prospective, multicenter trial to test the feasibility of a new sequential regimen, combining a short course of intensive chemotherapy and a reduced intensity-conditioning regimen, before allogeneic stem-cell transplantation. Twenty-four patients (median age, 47 years) with acute myeloid leukemia in primary treatment failure were included. Cytogenetic risk was poor in 15 patients (62%) and intermediate in nine (38%). The sequential regimen consisted of clofarabine (30 mg/m²/day) and cytosine arabinoside (1 g/m²/day) for 5 days, followed, after a 3-day rest, by reduced-intensity conditioning and allogeneic stem-cell transplantation combining cyclophosphamide (60 mg/kg), intravenous busulfan (3.2 mg/kg/day) for 2 days and anti-thymocyte globulin (2.5 mg/kg/day) for 2 days. Patients in complete remission at day +120 received prophylactic donor lymphocyte infusion. Eighteen patients (75%) achieved complete remission. With a median follow-up of 24.6 months, the Kaplan-Meier estimate of overall survival was 54% (95% CI: 33-71) at 1 year and 38% (95% CI: 18-46) at 2 years. The Kaplan-Meier estimate of leukemia-free survival was 46% (95% CI: 26-64) at 1 year and 29% (95% CI: 13-48) at 2 years. The cumulative incidence of non-relapse mortality was 8% (95% CI: 1-24) at 1 year and 12% (95% CI: 3-19) at 2 years. Results from this phase 2 prospective multicenter trial endorsed the safety and efficacy of a clofarabine-based sequential reduced-toxicity conditioning regimen, which warrants further investigation. This study was registered at www.clinicaltrials.gov, identifier number: NCT01188174.

Pre-transplantation minimal residual disease with cytogenetic and molecular diagnostic features improves risk stratification in acute myeloid leukemia

Our aim was to improve outcome prediction after allogeneic hematopoietic stem cell transplantation in acute myeloid leukemia by combining cytogenetic and molecular data at diagnosis with minimal residual disease assessment by multicolor flow-cytometry at transplantation. Patients with acute myeloid leukemia in first complete remission in whom minimal residual disease was assessed at transplantation were included and categorized according to the European LeukemiaNet classification. The primary outcome was 1-year relapse incidence after transplantation. Of 152 patients eligible, 48 had minimal residual disease at the time of their transplant. Minimal residual disease-positive patients were older, required more therapy to achieve first remission, were more likely to have incomplete recovery of blood counts and had more adverse risk features by cytogenetics. Relapse incidence at 1 year was higher in patients with minimal residual disease (32.6% versus 14.4%, P=0.002). Leukemia-free survival (43.6% versus 64%, P=0.007) and overall survival (48.8% versus 66.9%, P=0.008) rates were also inferior in patients with minimal residual disease. In multivariable analysis, minimal residual disease status at transplantation independently predicted 1-year relapse incidence, identifying a subgroup of intermediate-risk patients, according to the European LeukemiaNet classification, with a particularly poor outcome. Assessment of minimal residual disease at transplantation in combination with cytogenetic and molecular findings provides powerful independent prognostic information in acute myeloid leukemia, lending support to the incorporation of minimal residual disease detection to refine risk stratification and develop a more individualized approach during hematopoietic stem cell transplantation.

Comparison of Intensive Chemotherapy and Hypomethylating Agents before Allogeneic Stem Cell Transplantation for Advanced Myelodysplastic Syndromes: A Study of the Myelodysplastic Syndrome Subcommittee of the Chronic Malignancies Working Party of the European Society for Blood and Marrow Transplant Research

The European Society for Blood and Marrow Transplant Research data set was used to retrospectively analyze the outcomes of hypomethylating therapy (HMA) compared with those of conventional chemotherapy (CC) before hematopoietic stem cell transplantation (HSCT) in 209 patients with advanced myelodysplastic syndromes. Median follow-up was 22.1 months and the median age of the group was 57.6 years with 37% of the population older than > 60 years. The majority of patients (59%) received reduced-intensity conditioning and 34% and 27% had intermediate-2 and high international prognostic scoring system (IPSS) scores. At time of HSCT, 32% of patients did not achieve complete remission (CR) and 13% had primary refractory disease. On univariate analysis, outcomes at 3 years were not significantly different between HMA and CC for overall survival (OS), relapse-free survival (RFS), cumulative incidence of relapse (CIR), and nonrelapse mortality (NRM): OS (42% versus 35%), RFS (29% versus 31%), CIR (45% versus 40%), and NRM (26% versus 28%). Comparing characteristics of the groups, there were more patients < 55 years old, more patients in CR (68% versus 32%), and fewer patients with primary refractory disease in the CC group than in the HMA group (10% versus 19%, P < .001). Patients with primary refractory disease had worse outcomes than those in CR with regard to OS (hazard ratio [HR], 2.42; 95% confidence interval [CI], 1.41 to 4.13; P = .001), RFS (HR, 2.27; 95% CI, 1.37 to 3.76; P = .001), and NRM (HR, 2.49; 95% CI, 1.18 to 5.26; P = .016). In addition, an adverse effect of IPSS-R cytogenetic risk group was evident for RFS. In summary, outcomes after HSCT are similar for patients receiving HMA compared with those receiving CC, despite the higher proportion of patients with primary refractory disease in the HMA group.

Time to unrelated donor leukocyte infusion is longer, but incidence of GVHD and overall survival are similar for recipients of unrelated DLI compared to matched sibling DLI

Donor leukocyte infusion (DLI) is used to treat relapsed leukemia after allogeneic hematopoietic stem cell transplant (HCT). Data comparing outcomes after unrelated DLI (uDLI) to matched sibling DLI (msDLI) are scant. We performed a retrospective analysis to assess differences in time to administer uDLI versus msDLI, and impact on outcomes. Fifty three patients with relapsed acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or myelodysplastic syndrome (MDS) after allogeneic HCT received uDLI (n = 18) or msDLI (n = 35) from 2000 to 2011. Median time from relapse to uDLI request was 15 days (range 0-66). Median time from relapse to uDLI was 56 days versus 40 days for msDLI patients (p = 0.034). 35% of msDLI and 44% of uDLI patients developed acute GVHD (p = 0.50). There was no significant difference in Grade C/D GVHD among uDLI and msDLI (28% and 21%, p = 0.58) or median OS after DLI between uDLI and msDLI (95 versus 75 days, p = 0.76). For patients with relapsed acute leukemia and MDS after allogeneic HCT, time from relapse to uDLI was longer than to msDLI, but incidence of GVHD and overall survival were similar. Access to uDLI does not appear to be a barrier to DLI administration. Outcomes unfortunately remain poor regardless of donor source.

Donor lymphocyte infusion after allogeneic stem cell transplantation

Allogeneic stem cell transplantation (allo-SCT) is considered the cornerstone in the treatment of several malignant and not malignant hematological diseases. However, relapse of hematological disease after allo-SCT is considered the most challenging point in the field. The risk can be reduced through optimal patients, donor and disease selection before allo-SCT, but harnessing donor immune system is an appealing way to treat or avoid disease relapse. Donor lymphocyte infusion (DLI) is a simple and effective therapy after allo-SCT. In this paper, the efficacy of DLI will be analyzed in different hematological diseases, focusing also on their therapeutic or pre-emptive use.

Individualizing treatment decisions for older adults with hematologic malignancies

Hematologic malignancies are a common cause of morbidity and mortality among older adults, who represent the majority of patients diagnosed with these diseases. Treatment options and disease outcomes have improved in recent years because of the development of novel treatment strategies and the design of elderly-specific clinical trials. Despite this, extrapolation of clinical trial data to patients routinely seen in practice is challenging because of the presence of multimorbidity and functional impairments. Individualized treatment decision making requires not only an understanding of underlying tumor biology but also careful estimation of an older patient's anticipated ability to withstand the stresses of therapy. This article will discuss approaches to standardizing patient assessment strategies and tailoring therapeutic decisions for older adults with hematologic malignancies with a focus on acute myeloid leukemia (AML), allogeneic bone marrow transplantation, multiple myeloma (MM), and chronic lymphocytic leukemia (CLL).

Clinical activity of azacitidine in patients who relapse after allogeneic stem cell transplantation for acute myeloid leukemia

Disease relapse is the most common cause of treatment failure after allogeneic stem cell transplantation for acute myeloid leukemia and myelodysplastic syndromes, yet treatment options for such patients remain extremely limited. Azacitidine is an important new therapy in high-risk myelodysplastic syndromes and acute myeloid leukemia but its role in patients who relapse post allograft has not been defined. We studied the tolerability and activity of azacitidine in 181 patients who relapsed after an allograft for acute myeloid leukemia (n=116) or myelodysplastic syndromes (n=65). Sixty-nine patients received additional donor lymphocyte infusions. Forty-six of 157 (25%) assessable patients responded to azacitidine therapy: 24 (15%) achieved a complete remission and 22 a partial remission. Response rates were higher in patients transplanted in complete remission (P=0.04) and those transplanted for myelodysplastic syndromes (P=0.023). In patients who achieved a complete remission, the 2-year overall survival was 48% versus 12% for the whole population. Overall survival was determined by time to relapse post transplant more than six months (P=0.001) and percentage of blasts in the bone marrow at time of relapse (P=0.01). The concurrent administration of donor lymphocyte infusion did not improve either response rates or overall survival in patients treated with azacitidine. An azacitidine relapse prognostic score was developed which predicted 2-year overall survival ranging from 3%-37% (P=0.00001). We conclude that azacitidine represents an important new therapy in selected patients with acute myeloid leukemia/myelodysplastic syndromes who relapse after allogeneic stem cell transplantation. Prospective studies to confirm optimal treatment options in this challenging patient population are required.

Hypomethylating Agents for Relapse after Allogeneic Hematopoietic Cell Transplantation in Myeloid Malignancies: A Case Series and Review of the Literature

BACKGROUND/AIMS

Relapse is a leading cause of mortality after allogeneic hematopoietic cell transplantation (HCT). Hypomethylating agents (HMAs) have immunomodulatory properties, including augmenting tumor antigen presentation that may enhance the graft-versus-leukemia effect. Moreover, inhibitory effects on T-cell activation and cytokine production may lead to a lower incidence of graft-versus-host disease (GVHD). Our aim was to describe outcomes in patients treated with HMAs for relapse after HCT.

METHODS

Subjects were retrospectively identified as patients with relapse or loss of donor chimerism after HCT for myeloid malignancies treated with HMAs at the University of Pittsburgh.

RESULTS

Thirteen patients were identified, with a median age of 57 years and a median time to relapse of 98 days. Nine of 12 (75%) evaluable patients had a complete remission (CR). Grade I-IV acute GVHD involving the liver occurred in 6 patients. Cases of acute liver GVHD were diagnosed clinically based on the elevation of liver function tests. The median survival was 14.3 months from the time of relapse.

CONCLUSION

HMAs for relapse after HCT can be effective in inducing a CR. This may be due to epigenetic changes and immunomodulatory effects that enhance the graft-versus-leukemia effect. There may be a risk of GVHD, and further exploration into pathophysiology and predisposing factors are warranted.

Reduced intensity conditioning allogeneic hematopoietic cell transplantation for adult acute myeloid leukemia in complete remission - a review from the Acute Leukemia Working Party of the EBMT

Acute myeloid leukemia is the most common indication for an allogeneic hematopoietic cell transplant. The introduction of reduced intensity conditioning has expanded the recipient pool for transplantation, which has importantly made transplant an option for the more commonly affected older age groups. Reduced intensity conditioning allogeneic transplantation is currently the standard of care for patients with intermediate or high-risk acute myeloid leukemia and is now most often employed in older patients and those with medical comorbidities. Despite being curative for a significant proportion of patients, post-transplant relapse remains a challenge in the reduced intensity conditioning setting. Herein we discuss the studies that demonstrate the feasibility of reduced intensity conditioning allogeneic transplants, compare the outcomes of reduced intensity conditioning versus chemotherapy and conventional myeloablative conditioning regimens, describe the optimal donor and stem cell source, and consider the impact of post-remission consolidation, comorbidities, center experience, and more intensive (reduced toxicity conditioning) regimens on outcomes. Additionally, we discuss the need for further prospective studies to optimize transplant outcomes.

Comparable outcomes between autologous and allogeneic transplant for adult acute myeloid leukemia in first CR

Although allogeneic hematopoietic stem cell transplantation from an HLA-matched sibling donor (MSD) is a potentially curative post-remission treatment for adults with acute myeloid leukemia (AML) in their first CR, transplant-related morbidity and mortality remains a major drawback. We retrospectively compared the outcomes of patients who underwent autologous peripheral blood stem cell transplantation (auto-PBSCT; n=375) with those who underwent allogeneic bone marrow transplantation (allo-BMT; n=521) and allo-PBSCT (n=380) from MSDs for adults with AML/CR1, in which propensity score models were used to adjust selection biases among patients, primary physicians and institutions to overcome ambiguity in the patients' background information. Both the multivariate analysis and propensity score models indicated that the leukemia-free survival rate of auto-PBSCT was not significantly different from that of allo-BMT (hazard ratio (HR), 1.23; 95% confidence interval (CI), 0.92 to 1.66; P=0.16) and allo-PBSCT (HR, 1.13; 95% CI, 0.85-1.51; P=0.40). The current results suggest that auto-PBSCT remains a promising alternative treatment for patients with AML/CR1 in the absence of an available MSD.

Multi-state analysis illustrates treatment success after stem cell transplantation for acute myeloid leukemia followed by donor lymphocyte infusion

In the field of hematopoietic stem cell transplantation, the common approach is to focus outcome analyses on time to relapse and death, without assessing the impact of post-transplant interventions. We investigated whether a multi-state model would give insight into the events after transplantation in a cohort of patients who were transplanted using a strategy including scheduled donor lymphocyte infusions. Seventy-eight consecutive patients who underwent myeloablative T-cell depleted allogeneic stem cell transplantation for acute myeloid leukemia or myelodysplastic syndrome were studied. We constructed a multi-state model to analyze the impact of donor lymphocyte infusion and graft-versus-host disease on the probabilities of relapse and non-relapse mortality over time. Based on this model we introduced a new measure for outcome after transplantation which we called 'treatment success': being alive without relapse and immunosuppression for graft-versus-host disease. All relevant clinical events were implemented into the multi-state model and were denoted treatment success or failure (either transient or permanent). Both relapse and non-relapse mortality were causes of failure of comparable magnitude. Whereas relapse was the dominant cause of failure from the transplantation state, its rate was reduced after graft-versus-host disease, and especially after donor lymphocyte infusion. The long-term probability of treatment success was approximately 40%. This probability was increased after donor lymphocyte infusion. Our multi-state model helps to interpret the impact of post-transplantation interventions and clinical events on failure and treatment success, thus extracting more information from observational data.

Risk factors for outcome in refractory acute myeloid leukemia patients treated with a combination of fludarabine, cytarabine, and amsacrine followed by a reduced-intensity conditioning and allogeneic stem cell transplantation

INTRODUCTION

Hematopoietic stem cell transplantation (HCT) is considered a standard treatment for high-risk acute myeloid leukemia (AML) in first or second complete remission (CR). Unfortunately, not all patients achieve complete remission prior to HCT. We sought to establish predictive factors for survival after HCT for refractory AML after FLAMSA-RIC.

PATIENTS AND METHODS

We analyzed the outcome of 44 consecutive patients aged between 21 and 65 years transplanted at the University Hospitals of Jena and Leipzig for refractory AML between 2006 and January 2013. Conditioning for HCT was performed with chemotherapy consisting of fludarabine, cytarabine, and amsacrine followed by total body irradiation or busulfan combined with cyclophosphamide. Antithymocyte globulin was given when transplanting from unrelated donors (FLAMSA-RIC).

RESULTS

Estimated overall survival (OS) and event-free survival (EFS) at 3 years after a median follow-up of 34 (range 6-71) months were 15 and 12 %, respectively. Causes of death were relapse in 66 %, infection in 11 %, and graft-versus-host disease (GvHD) in 7 % of all patients. Twenty-five from 42 evaluable patients (60 %) achieved CR 4 weeks after HCT, while eight patients had partial remission (PR), and nine patients had stable disease (SD). Another six patients with PR and SD achieved CR (overall CR rate 74 %) from 4 weeks to day 90 after HCT following reduction in immunosuppression. The strongest favorable factors in univariate analysis for OS, EFS, and RI were ≥98 % total donor chimerism 2-4 weeks after HCT and <3 lines of pretreatment prior to HCT. In addition, better OS was detected in patients with <20 % bone marrow blasts alone (32 vs. 5 % at 3 years) and in combination with <3 lines of pretreatment (38 vs. 4 % at 3 years). Only a trend for better EFS and lower RI was observed in patients with limited chronic GvHD. In addition, a lower RI was seen in patients with <5 % blasts 4 weeks after HCT. Multivariate analysis revealed that ≥98 % donor chimerism 2-4 weeks after HCT for OS, EFS, and RI and <3 lines of pretreatment for OS and EFS are the strongest predictors for better outcome.

CONCLUSION

FLAMSA-RIC shows long-term survival in refractory AML patients. Factors for favorable outcome are <20 % bone marrow blasts prior to HCT, <3 lines of pretreatment and complete donor chimerism after HCT.

Outcome of patients with distinct molecular genotypes and cytogenetically normal AML after allogeneic transplantation

In AML with normal cytogenetics, age, response to induction, and FLT3-ITD allow for an estimate of outcome after allogeneic HSCT in CR1. Neither variation of classical transplant techniques nor development of chronic GVHD outweighs the negative impact of FLT3-ITD.

Control of relapsed or refractory acute myeloid leukemia by clofarabine in preparation for allogeneic stem cell transplant

Allogeneic stem cell transplant is indicated for patients with refractory or relapsed acute myeloid leukemia (AML). Since elimination of the leukemic load is thought to be a prerequisite for treatment success, we here investigate toxicity and anti-leukemic activity of a clofarabine-AraC salvage protocol preceding transplant. In this retrospective analysis, we observed induction of objective remissions in 86% of patients receiving clofarabine-AraC as compared to 83% with sequential high dose AraC/mitoxantrone (S-HAM) and 50% after mitoxantrone/topotecane/AraC (MTC) salvage strategies. In addition, clofarabine conferred anti-leukemic activity to some patients who failed initial MTC or S-HAM therapy. For overall and leukemia-free survival, we identified cytogenetically defined adverse risk markers but not response to therapy to be a strong predictor. In summary, the clofarabine-AraC salvage strategy combines pronounced anti-leukemic activity with an acceptable toxicity profile and allows the majority of patients with relapsed or refractory AML to proceed to allo-SCT, even in cytogenetically defined high risk situations.

Management of Myelodysplastic Syndrome Relapsing after Allogeneic Hematopoietic Stem Cell Transplantation: A Study by the French Society of Bone Marrow Transplantation and Cell Therapies

To find out prognostic factors and to investigate different therapeutic approaches, we report on 147 consecutive patients who relapsed after allogeneic hematopoietic stem cell transplantation (allo-HSCT) for myelodysplastic syndrome (MDS). Sixty-two patients underwent immunotherapy (IT group, second allo-HSCT or donor lymphocyte infusion), 39 received cytoreductive treatment alone (CRT group) and 46 were managed with palliative/supportive cares (PSC group). Two-year rates of overall survival (OS) were 32%, 6%, and 2% in the IT, CRT, and PSC groups, respectively (P < .001). In multivariate analysis, 4 factors adversely influenced 2-year rates of OS: history of acute graft-versus-host disease (hazard ratio [HR], 1.83; 95% confidence interval [CI], 1.26 to 2.67; P = .002), relapse within 6 months (HR, 2.69; 95% CI, .82 to 3.98; P < .001), progression to acute myeloid leukemia (HR, 2.59; 95% CI, 1.75 to 3.83; P < .001), and platelet count < 50 G/L at relapse (HR, 1.68; 95% CI, 1.15 to 2.44; P = .007). A prognostic score based on those factors discriminated 2 risk groups with median OSs of 13.2 versus 2.4 months, respectively (P < .001). When propensity score, prognostic score, and treatment strategy were included in Cox model, immunotherapy was found to be an independent factor that favorably impacts OS (HR, .40; 95% CI, .26 to .63; P < .001). In conclusion, immunotherapy should be considered when possible for MDS patients relapsing after allo-HSCT.

PD-1(hi)TIM-3(+) T cells associate with and predict leukemia relapse in AML patients post allogeneic stem cell transplantation

Prognosis of leukemia relapse post allogeneic stem cell transplantation (alloSCT) is poor and effective new treatments are urgently needed. T cells are pivotal in eradicating leukemia through a graft versus leukemia (GVL) effect and leukemia relapse is considered a failure of GVL. T-cell exhaustion is a state of T-cell dysfunction mediated by inhibitory molecules including programmed cell death protein 1 (PD-1) and T-cell immunoglobulin domain and mucin domain 3 (TIM-3). To evaluate whether T-cell exhaustion and inhibitory pathways are involved in leukemia relapse post alloSCT, we performed phenotypic and functional studies on T cells from peripheral blood of acute myeloid leukemia patients receiving alloSCT. Here we report that PD-1^hiTIM-3⁺ cells are strongly associated with leukemia relapse post transplantation. Consistent with exhaustion, PD-1^hiTIM-3⁺ T cells are functionally deficient manifested by reduced production of interleukin 2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). In addition, these cells demonstrate a phenotype consistent with exhausted antigen-experienced T cells by losing T_N and T_EMRA subsets. Importantly, increase of PD-1^hiTIM-3⁺ cells occurs before clinical diagnosis of leukemia relapse, suggesting their predictive value. Results of our study provide an early diagnostic approach and a therapeutic target for leukemia relapse post transplantation.

High Graft CD8 Cell Dose Predicts Improved Survival and Enables Better Donor Selection in Allogeneic Stem-Cell Transplantation With Reduced-Intensity Conditioning

PURPOSE

To characterize the impact of graft T-cell composition on outcomes of reduced-intensity conditioned (RIC) allogeneic hematopoietic stem-cell transplantation (alloHSCT) in adults with hematologic malignancies.

PATIENTS AND METHODS

We evaluated associations between graft T-cell doses and outcomes in 200 patients who underwent RIC alloHSCT with a peripheral blood stem-cell graft. We then studied 21 alloHSCT donors to identify predictors of optimal graft T-cell content.

RESULTS

Higher CD8 cell doses were associated with a lower risk for relapse (adjusted hazard ratio [aHR], 0.43; P = .009) and improved relapse-free survival (aHR, 0.50; P = .006) and overall survival (aHR, 0.57; P = .04) without a significant increase in graft-versus-host disease or nonrelapse mortality. A cutoff level of 0.72 × 10(8) CD8 cells per kilogram optimally segregated patients receiving CD8(hi) and CD8(lo) grafts with differing overall survival (P = .007). Donor age inversely correlated with graft CD8 dose. Consequently, older donors were unlikely to provide a CD8(hi) graft, whereas approximately half of younger donors provided CD8(hi) grafts. Compared with recipients of older sibling donor grafts (consistently containing CD8(lo) doses), survival was significantly better for recipients of younger unrelated donor grafts with CD8(hi) doses (P = .03), but not for recipients of younger unrelated donor CD8(lo) grafts (P = .28). In addition, graft CD8 content could be predicted by measuring the proportion of CD8 cells in a screening blood sample from stem-cell donors.

CONCLUSION

Higher graft CD8 dose, which was restricted to young donors, predicted better survival in patients undergoing RIC alloHSCT.

Haematopoietic stem cell transplantation for refractory Langerhans cell histiocytosis: outcome by intensity of conditioning

Patients with Langerhans cell histiocytosis (LCH) refractory to conventional chemotherapy have a poor outcome. There are currently two promising treatment strategies for high-risk patients: the first involves the combination of 2-chlorodeoxyadenosine and cytarabine; the other approach is allogeneic haematopoietic stem cell transplantation (HSCT). Here we evaluated 87 patients with high-risk LCH who were transplanted between 1990 and 2013. Prior to the year 2000, most patients underwent HSCT following myeloablative conditioning (MAC): only 5 of 20 patients (25%) survived with a high rate (55%) of transplant-related mortality (TRM). After the year 2000 an increasing number of patients underwent HSCT with reduced intensity conditioning (RIC): 49/67 (73%) patients survived, however, the improved survival was not overtly achieved by the introduction of RIC regimens with similar 3-year probability of survival after MAC (77%) and RIC transplantation (71%). There was no significant difference in TRM by conditioning regimen intensity but relapse rates were higher after RIC compared to MAC regimens (28% vs. 8%, P = 0·02), although most patients relapsing after RIC transplantation could be salvaged with further chemotherapy. HSCT may be a curative approach in 3 out of 4 patients with high risk LCH refractory to chemotherapy: the optimal choice of HSCT conditioning remains uncertain.

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.

Survival of patients with acute myeloid leukemia relapsing after allogeneic hematopoietic cell transplantation: a center for international blood and marrow transplant research study

Acute myeloid leukemia (AML) relapse after allogeneic hematopoietic cell transplantation (alloHCT) remains a major therapeutic challenge. We studied outcomes of 1788 AML patients relapsing after alloHCT (1990 to 2010) during first or second complete remission (CR) to identify factors associated with longer postrelapse survival. Median time to post-HCT relapse was 7 months (range, 1 to 177). At relapse, 1231 patients (69%) received intensive therapy, including chemotherapy alone (n = 660), donor lymphocyte infusion (DLI) ± chemotherapy (n = 202), or second alloHCT ± chemotherapy ± DLI (n = 369), with subsequent CR rates of 29%. Median follow-up after relapse was 39 months (range, <1 to 193). Survival for all patients was 23% at 1 year after relapse; however, 3-year overall survival correlated with time from HCT to relapse (4% for relapse during the 1- to 6-month period, 12% during the 6-month to 2-year period, 26% during the 2- to 3-year period, and 38% for ≥3 years). In multivariable analysis, lower mortality was significantly associated with longer time from alloHCT to relapse (relative risk, .55 for 6 months to 2 years; relative risk, .39 for 2 to 3 years; and relative risk, .28 for ≥3 years; P < .0001) and a first HCT using reduced-intensity conditioning (relative risk, .77; 95% confidence interval [CI], .66 to .88; P = .0002). In contrast, inferior survival was associated with age >40 years (relative risk, 1.42; 95% CI, 1.24 to 1.64; P < .0001), active graft-versus-host disease at relapse (relative risk, 1.25; 95% CI, 1.13 to 1.39; P < .0001), adverse cytogenetics (relative risk, 1.37; 95% CI, 1.09 to 1.71; P = .0062), mismatched unrelated donor (relative risk, 1.61; 95% CI, 1.22 to 2.13; P = .0008), and use of cord blood for first HCT (relative risk, 1.23; 95% CI, 1.06 to 1.42; P = .0078). AML relapse after alloHCT predicted poor survival; however, patients who relapsed ≥6 months after their initial alloHCT had better survival and may benefit from intensive therapy, such as second alloHCT ± DLI.

[Current indications of allogeneic stem cell transplant in adults with acute myeloid leukemia]

Allogeneic stem cell transplantation (SCT) is an increasingly important therapeutic option for the treatment of adult patients with acute myeloid leukemia. Here we review the current indications of SCT in this disease. While patients with favorable cytogenetics should receive consolidation chemotherapy, patients with unfavorable karyotype are prime candidates for SCT or new approaches to SCT (which should be done in first complete remission). Patients with intermediate prognoses should also receive SCT in first complete remission. In the absence of a suitable matched related donor, most patients will be able to find an alternative donor to proceed to a potentially curative allogeneic transplantation. The use of reduced-intensity conditioning regimens before SCT has allowed patients in the sixth or seventh decades of life to be routinely transplanted. Despite major differences among transplant centers in the intensity and composition of the conditioning regimen and immunosuppression, choice of graft source, postgraft immune-modulation, and supportive care, there has been a dramatic improvement in terms of tolerance. Although it is presumed to be a curative strategy, major complications of SCT remain graft-versus-host disease, delayed immune recovery, multiple comorbidities, and relapse after transplant.

Clinical and pathologic analysis of extramedullary tumors after hematopoietic stem cell transplantation

Clinical and pathologic analyses of 41 extramedullary biopsy/resection specimens of extramedullary tumors (EMTs) after hematopoietic stem cell transplantation (HSCT) were performed. The 41 EMT specimens were from 28 patients, with 11 having more than 1 consecutive EMT in different anatomic locations at different times post-HSCT. The median age at EMT diagnosis was 45 years (range, 17-73 years), and the male/female ratio was 17:11. The most common initial diagnosis was acute myeloid leukemia (21), followed by chronic myeloid leukemia with myeloid blast phase (2), primary myelofibrosis with acute leukemic transformation (1), acute lymphoblastic leukemia (2), mixed lineage T/myeloid leukemia (1), and plasma cell myeloma (1). All initial presentations were limited to bone marrow-only disease. Twenty patients had abnormal chromosomal karyotypes, whereas 6 had normal cytogenetics with their original disease. All patients received standard chemotherapy followed by allogeneic (27) or autologous (1) HSCT. The EMTs occurred 2 to 177 months (median, 16.5 months) after HSCT and were diagnosed as solid mass lesions as follows: skin and soft tissue (10), central nervous system and paraspinal tissue (9), breast (7), gastrointestinal tract (4), lymph node (4), genitourinary system (4), and mediastinum (3). Interestingly, all but 3 patients had negative bone marrows at the time their EMT was diagnosed, indicating that most EMTs presented as sole lesion of relapsed disease. The overall outcome was dismal for patients with EMT, with 20 (71%) of 28 patients deceased at 1 to 26 months after EMT diagnosis, with a median overall survival of only 6.5 months.