Successful treatment of relapsed AML after allogeneic stem cell transplantation with azacitidine

[Efficacy and safety of Venetoclax in the treatment of 25 patients with recurrent hematologic malignancies after an allogeneic hematopoietic stem cell transplantation]

Objegtive: To investigate the efficacy and safety of preemptive/salvage therapy with venetoclax (VEN) in patients with recurrence after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: Retrospective analysis the clinical data of 25 patients with minimal residual disease (MRD) positive or morphological recurrence after allo-HSCT treated with VEN in the hematological Hospital of Chinese Academy of Medical Sciences from 2021.2 to 2021.11, there were 15 MRD positive patients (preemptive treatment group) and 10 morphological recurrence patients (salvage treatment group) . The dose of VEN in both groups was 400 mg/d, which was reduced to 100 mg/d when combined with azole antifungal drugs. Results: ①In the preemptive group, there were 7 males and 8 females, with a median age of 32 (18-52) years; There were 13 cases of acute myeloid leukemia (AML) , 1 case of acute lymphoblastic leukemia (ALL) and 1 case of primary myelofibrosis (PMF) ; the median time from MRD positive to the application of VEN was 2.5 (0-12.5) months. The median course of treatment was 2 (1-4) . On the 7th day of the first course of treatment, the median concentration of VEN was 1945 (688-5383) μg/L. After one course of VEN treatment, MRD in 8 patients turned negative (major responses) , MRD in 4 patients decreased by 50% compared with that before treatment, 3 cases were ineffective, and the overall response rate (ORR) was 80% (12/15) . On the 7th day of treatment, 3 of the 9 patients with VEN blood concentration <1 000 μg/L or >3 000 μg/L turned negative for MRD (33.3%) , and 5 of the 6 patients with VEN blood concentration between 1000 and 3000 μg/L turned negative for MRD (83.3%) . Grade 3/4 neutropenia occurred in 5 patients (33%) and grade 3/4 thrombocytopenia occurred in 5 patients (33%) , there were no new cases of severe infection and death. ②In the salvage group, there were 7 males and 3 females, with a median age of 44 (28-59) years; there were 6 cases of AML, 2 cases of ALL, 1 case of atypical chronic myeloid leukemia (aCML) , 1 case of refractory hemopenia with multiline dysplasia (MDS-RCMD) ; the median time from relapse to application of VEN was 0 (0-1) months. The median treatment was 1 (1-2) course. The median concentration of VEN on the 7th day of the first course of treatment was 2 419 (1 200-6 155) μg/L. After one course of VEN treatment, 3 cases achieved complete remission (CR) (major responses) and 3 cases achieved partial remission (PR) , 4 cases were ineffective and the ORR was 60% (6/10) . On the 7th day of treatment, 1 of the 4 patients with VEN blood concentration >3 000 μg/L achieved CR (25%) , and 2 of the 6 patients with VEN blood concentration between 1 000 and 3 000 μg/L achieved CR (33.3%) . Grade 3/4 neutropenia and grade 3/4 thrombocytopenia occurred in 10 patients (100%) . One patient died of severe pulmonary infection. ③The median follow-up was 4.5 (1-8.5) months. The overall survival rate (OS) of the preemptive group and the salvage group were (70.2±12.7) % and (50.0± 15.8) %, respectively (χ(2)=1.873, P=0.171) . The OS of patients with and without primary response to one course of VEN were (90.9±8.7) % and (36.2±14.7) % respectively (χ(2)=6.843, P=0.009) . Three patients with TP53 mutation achieved the major responses after VEN treatment. Conclusion: Preemptive/salvage therapy with VEN after allo-HSCT in patients with hematological malignancies is effective and well tolerated, monitoring the concentration of VEN is expected to improve the curative effect. The prognosis of patients who fail to reach the major responses after one course of preemptive/salvage treatment with VEN is poor, so they need to switch to other treatment schemes as soon as possible.

Azacitidine and donor lymphocytes infusions in acute myeloid leukemia and myelodysplastic syndrome relapsed after allogeneic hematopoietic stem cell transplantation from alternative donors

Introduction

Azacitidine (AZA) either single-agent or with donor lymphocytes infusions (DLI) has been used as a salvage treatment for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) relapsing after allogeneic hematopoietic stem cell transplantation (HSCT). To date, the majority of data come from patients relapsed after HSCT from full-matched donors.

Methods

We report a multicenter, collaborative, retrospective analysis of 71 patients with hematologic (n = 40, 56%) and molecular relapse (n = 31, 44%) of myeloid neoplasms after HSCT from alternative donors (mismatched unrelated, n = 39, 55%; haploidentical, n = 29, 41%) consecutively treated at three European centers with AZA ± DLI.

Results

Median time from HSCT to relapse was 9 months. Additional DLI were given to 33 patients (46%). After a median of four cycles, overall response rate (ORR) was 49% and complete response (CR) rate was 38%. CR lasted for a median of 17 months (range 5-89 months). Median follow-up in the entire cohort was 11 months (range 1-115 months). Event-free survival (EFS) and overall survival (OS) at 1 year were 26% and 53%, respectively. Treatment of molecular relapse granted higher CR rate (65% versus 15%; p = 0.0001), 1-year EFS (43% versus 13%; p = 0.006), and 1-year OS (79% versus 34%; p < 0.001) compared to hematologic relapses. Addition of DLI resulted in significantly higher responses and longer 1-year EFS and OS (Mantel-Byar test, p = 0.004 and p = 0.002, respectively). When applied to our cohort, the APSS-R score confirmed its ability to stratify patients into distinct prognostic groups with significantly different response rates (p = 0.0005) and survival (p < 0.0001). Treatment was well tolerated, with the incidence of late acute and chronic graft-versus-host disease of 27% and 18%, respectively.

Conclusion

AZA ± DLI proved feasible and effective in AML and MDS relapsing after HSCT from alternative donors. Despite modest efficacy among hematologic relapses, pre-emptive treatment with AZA ± DLI fared better in molecular relapse. Additional DLI contributed to improving efficacy and ensuring longer survival.

Hypomethylating Agent-Based Combination Therapies to Treat Post-Hematopoietic Stem Cell Transplant Relapse of Acute Myeloid Leukemia

Allogeneic stem cell transplantation still represents the best curative option for most patients with acute myeloid leukemia, but relapse is still dramatically high. Due to their immunologic activity and safety profile, hypomethylating agents (HMAs) represent an interesting backbone for combination therapies. This review reports mechanism of action, safety, and efficacy data on combination strategies based on HMAs in the setting of post-allogeneic stem cell transplant relapse. Several studies highlighted how HMAs and donor lymphocyte infusion (DLI) combination may be advantageous. The combination strategy of HMA with venetoclax, possibly in association with DLI, is showing excellent results in terms of response rate, including molecular responses. Lenalidomide, despite its well-known high rates of severe graft-versus-host disease in post-transplant settings, is showing an acceptable safety profile in association with HMAs with a competitive response rate. Regarding FLT3 internal tandem duplication (ITD) mutant AML, tyrosine kinase inhibitors and particularly sorafenib have promising results as monotherapy and in combination with HMAs. Conversely, combination strategies with gemtuzumab ozogamicin or immune checkpoint inhibitors did not show competitive response rates and seem to be currently less attractive strategies. Associations with histone deacetylase inhibitors and isocitrate dehydrogenase 1 and 2 (IDH1/2) inhibitors represent new possible strategies that need to be better investigated.

The Elephant in The Room: AML Relapse Post Allogeneic Hematopoietic Cell Transplantation

Relapsed acute myeloid leukemia (AML) following allogeneic hematopoietic cell transplantation (allo-HCT) is an unfavorable event associated with a poor prognosis, particularly for patients with early relapses. It usually arises from resistant leukemic blasts that escaped both preparative chemotherapy regimen and the graft-versus-leukemia (GVL) effect. Independent from the choice of salvage treatment, only minority of patients can achieve durable remissions. In recent years, better understanding of the disease relapse biology post allo-HCT allowed the application of newer strategies that could induce higher rates of remission, and potential longer survival. Those strategies aim at optimizing drugs that have a direct anti-leukemia activity by targeting different oncogenic mutations, metabolism pathways or surface antigens, and concurrently enhancing the immune microenvironment to promote GVL effect. This review discusses the current treatment landscape of AML relapse post allo-HCT.

Allogeneic hematopoietic cell transplantation with non-myeloablative conditioning for patients with hematologic malignancies: Improved outcomes over two decades

We have used a non-myeloablative conditioning regimen for allogeneic hematopoietic cell transplantation for the past twenty years. During that period, changes in clinical practice have been aimed at reducing morbidity and mortality from infections, organ toxicity, and graft-versus-host disease. We hypothesized that improvements in clinical practice led to better transplantation outcomes over time. From 1997-2017, 1,720 patients with hematologic malignancies received low-dose total body irradiation +/- fludarabine or clofarabine before transplantation from HLA-matched sibling or unrelated donors, followed by mycophenolate mofetil and a calcineurin inhibitor ± sirolimus. We compared outcomes in three cohorts by year of transplantation: 1997 +/- 2003 (n=562), 2004 +/- 2009 (n=594), and 2010 +/- 2017 (n=564). The proportion of patients ≥60 years old increased from 27% in 1997 +/- 2003 to 56% in 2010-2017, and with scores from the Hematopoietic Cell Transplantation Comborbidity Index of ≥3 increased from 25% in 1997 +/- 2003 to 45% in 2010 +/- 2017. Use of unrelated donors increased from 34% in 1997 +/- 2003 to 65% in 2010-2017. When outcomes from 2004 +/- 2009 and 2010-2017 were compared to 1997 +/- 2003, improvements were noted in overall survival (P=.0001 for 2004-2009 and P <.0001 for 2010-2017), profression-free survival (P=.002 for 2004-2009 and P <.0001 for 2010 +/- 2017), non-relapse mortality (P<.0001 for 2004 +/- 2009 and P <.0001 for 2010 +/- 2017), and in rates of grades 2 +/- 4 acute and chronic graft-vs.-host disease. For patients with hematologic malignancies who underwent transplantation with non-myeloablative conditioning, outcomes have improved during the past two decades. Trials reported are registered under ClinicalTrials.gov identifiers: NCT00003145, NCT00003196, NCT00003954, NCT00005799, NCT00005801, NCT00005803, NCT00006251, NCT00014235, NCT00027820, NCT00031655, NCT00036738, NCT00045435, NCT00052546, NCT00060424, NCT00075478, NCT00078858, NCT00089011, NCT00104858, NCT00105001, NCT00110058, NCT00397813, NCT00793572, NCT01231412, NCT01252667, NCT01527045.

Treatment of myeloid malignancies relapsing after allogeneic hematopoietic stem cell transplantation with venetoclax and hypomethylating agents-a retrospective multicenter analysis on behalf of the German Cooperative Transplant Study Group

Treatment of relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT) remains a great challenge. Aiming to evaluate the combination of venetoclax and hypomethylating agents (HMAClax) for the treatment of relapse of myeloid malignancies after alloHSCT, we retrospectively collected data from 32 patients treated at 11 German centers. Venetoclax was applied with azacitidine (n = 13) or decitabine (n = 19); 11 patients received DLI in addition. HMAClax was the first salvage therapy in 8 patients. The median number of cycles per patient was 2 (1–19). All but 1 patient had grade 3/4 neutropenia. Hospital admission for grade 3/4 infections was necessary in 23 patients (72%); 5 of these were fatal. In 30 evaluable patients, overall response rate (ORR) was 47% (14/30, 3 CR MRD^neg, 5 CR, 2 CRi, 1 MLFS, 3 PR). ORR was 86% in first salvage patients versus 35% in later salvage patients (p = 0.03). In 6 patients with molecular relapse (MR), ORR was 67% versus 42% in patients with hematological relapse (HR) (n = 24, p = n.s.). After a median follow-up of 8.4 months, 25 patients (78%) had died and 7 were alive. Estimated median overall survival was 3.7 months. Median survival of patients with HMAClax for first versus later salvage therapy was 5.7 and 3.4 months (p = n.s.) and for patients with MR (not reached) compared to HR (3.4 months, p = 0.024). This retrospective case series shows that venetoclax is utilized in various different combinations, schedules, and doses. Toxicity is substantial and patients who receive venetoclax/HMA combinations for MR or as first salvage therapy derive the greatest benefit.

Immune Escape after Hematopoietic Stem Cell Transplantation (HSCT): From Mechanisms to Novel Therapies

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. Recent advances in understanding its molecular basis have opened the way to new therapeutic strategies, including targeted therapies. However, despite an improvement in prognosis it has been documented in recent years (especially in younger patients) that allogenic hematopoietic stem cell transplantation (allo-HSCT) remains the only curative treatment in AML and the first therapeutic option for high-risk patients. After allo-HSCT, relapse is still a major complication, and is observed in about 50% of patients. Current evidence suggests that relapse is not due to clonal evolution, but instead to the ability of the AML cell population to escape immune control by a variety of mechanisms including the altered expression of HLA-molecules, production of anti-inflammatory cytokines, relevant metabolic changes and expression of immune checkpoint (ICP) inhibitors capable of “switching-off” the immune response against leukemic cells. Here, we review the main mechanisms of immune escape and identify potential strategies to overcome these mechanisms.

Donor lymphocyte infusion in myeloid disorders

A number of modalities including both pharmaceutical and cell-based treatments have long been tested and developed to prevent and treat relapses after allogeneic stem cell transplantation (allo-HSCT). The ability of donor T cells to recognize antigenic structures on leukemic cell surfaces and destroy them is a well-known fact. Based on this fact, the idea of using donor T cells to contribute to the development of adoptive immunotherapy has emerged. Donor lymphocytes are easy to obtain and donor lymphocyte infusions (DLI) have a simple rational while this treatment modality is an effective example of cellular therapy. The group of chronic myeloid leukemia patients who are more likely to benefit from DLI include: a) patients in the chronic phase of hematologic relapse and b) patients with molecular/cytogenetic relapse. DLI appear to be an appropriate treatment option to be used in combination with conventional chemotherapy or hypomethylating agents in the treatment of post-allo-HSCT relapse for acute myeloid leukemia and myelodysplastic syndrome, if:) the burden of tumor is low b) the relapse is at a molecular level rather than an overt hematologic relapse c) the patient has favorable cytogenetic characteristics d) time interval between transplantation and relapse is relatively longer (>5 months) e) response could be obtained after salvage therapies. In the event that minimal residual disease (MRD) or increasing mixed chimerism is detected, prompt administration of DLI for prophylactic purposes without waiting for a manifest relapse, was found to be effective in inducing a full donor chimerism and overcoming MRD and eventually preventing a manifest relapse.

DNA-hypomethylating agents as epigenetic therapy before and after allogeneic hematopoietic stem cell transplantation in myelodysplastic syndromes and juvenile myelomonocytic leukemia

Myelodysplastic syndrome (MDS) is a clonal bone marrow disorder, typically of older adults, which is characterized by ineffective hematopoiesis, peripheral blood cytopenias and risk of progression to acute myeloid leukemia. Juvenile myelomonocytic leukemia (JMML) is an aggressive myeloproliferative neoplasm occurring in young children. The common denominator of these malignant myeloid disorders is the limited benefit of conventional chemotherapy and a particular responsiveness to epigenetic therapy with the DNA-hypomethylating agents 5-azacytidine (azacitidine) or decitabine. However, hypomethylating therapy does not eradicate the malignant clone in MDS or JMML and allogeneic hematopoietic stem cell transplantation (HSCT) remains the only curative treatment option. An emerging concept with intriguing potential is the combination of hypomethylating therapy and HSCT. Possible advantages include disease control with good tolerability during donor search and HSCT preparation, improved antitumoral alloimmunity, and reduced risk of relapse even with non-myeloablative regimens. Herein we review the current role of pre- and post-transplant therapy with hypomethylating agents in MDS and JMML.

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.

5-Azacitidine Monotherapy Followed by Related Haploidentical Hematopoietic Stem Cell Transplantation Achieves Durable Remission in a Pediatric Patient With Acute Undifferentiated Leukemia Refractory to High-Dose Chemotherapy

Patients with acute leukemias of undifferentiated lineage (AUL) generally have guarded prognosis. Here, we describe the first reported pediatric patient with AUL refractory to high-dose chemotherapy who achieved clinical remission with ALL maintenance therapy and 5-azacitidine. His induction remission was followed by consolidation with reduced toxicity haploidentical hematopoietic stem cell transplant (HSCT). At 9 months post-HSCT, the patient is alive and in remission. This combination therapy of remission induction with ALL maintenance therapy and 5-azacitidine and consolidation with reduced toxicity haploidentical HSCT is novel and promising for patients who lack conventional donors and are not candidates for myeloablative therapy.

Mixed T Lymphocyte Chimerism after Allogeneic Hematopoietic Transplantation Is Predictive for Relapse of Acute Myeloid Leukemia and Myelodysplastic Syndromes

Chimerism testing after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) represents a promising tool for predicting disease relapse, although its precise role in this setting remains unclear. We investigated the predictive value of T lymphocyte chimerism analysis at 90 to 120 days after allo-HSCT in 378 patients with AML/MDS who underwent busulfan/fludarabine-based myeloablative preparative regimens. Of 265 (70%) patients with available T lymphocyte chimerism data, 43% of patients in first or second complete remission (CR1/CR2) at the time of transplantation had complete (100%) donor T lymphocytes at day +90 to +120 compared with 60% of patients in the non-CR1/CR2 cohort (P = .005). In CR1/CR2 patients, donor T lymphocyte chimerism ≤ 85% at day +90 to +120 was associated with a higher frequency of 3-year disease progression (29%; 95% confidence interval [CI], 18% to 46% versus 15%; 95% CI, 9% to 23%; hazard ratio [HR], 2.1; P = .04). However, in the more advanced, non-CR1/CR2 cohort, mixed T lymphocyte chimerism was not associated with relapse (37%; 95% CI, 20% to 66% versus 34%; 95% CI, 25% to 47%; HR, 1.3; P = .60). These findings demonstrate that early T lymphocyte chimerism testing at day +90 to +120 is a useful approach for predicting AML/MDS disease recurrence in patients in CR1/CR2 at the time of transplantation.

Treatment of relapse of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation

Disease relapse remains a major cause of mortality for patients with acute myeloid leukemia (AML) undergoing allogeneic hematopoietic stem cell transplantation (HSCT). Historically, patients who experience disease relapse after HSCT have a dismal prognosis with very few long-term survivors. There is no standard treatment for patients in this situation given the variability in patient characteristics, disease biology, complications such as graft-vs.-host disease (GVHD) and infections, donor availability, and patient choice. Here, we discuss the current options for treatment of relapsed AML after HSCT including conventional chemotherapy, novel agents, donor leukocyte infusion, second allogeneic HSCT, and emerging therapies.

Extramedullary relapse of acute leukemia after allogeneic hematopoietic stem cell transplantation: different characteristics between acute myelogenous leukemia and acute lymphoblastic leukemia

Extramedullary relapse (EMR) of acute leukemia (AL) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a contributor to post-transplantation mortality and remains poorly understood, especially the different characteristics of EMR in patients with acute myelogenous leukemia (AML) and those with acute lymphoblastic leukemia (ALL). To investigate the incidence, risk factors, and clinical outcomes of EMR for AML and ALL, we performed a retrospective analysis of 362 patients with AL who underwent allo-HSCT at the First affiliated Hospital of Soochow University between January 2001 and March 2012. Compared with patients with AML, those with ALL had a higher incidence of EMR (12.9% versus 4.6%; P = .009). The most common site of EMR was the central nervous system, especially in the ALL group. Multivariate analyses identified the leading risk factors for EMR in the patients with AML as advanced disease status at HSCT, hyperleukocytosis at diagnosis, history of extramedullary leukemia before HSCT, and a total body irradiation-based conditioning regimen, and the top risk factors for EMR in the patients with ALL as hyperleukocytosis at diagnosis, adverse cytogenetics, and transfusion of peripheral blood stem cells. The prognosis for EMR of AL is poor, and treatment options are very limited; however, the estimated 3-year overall survival (OS) was significantly lower in patients with AML compared with those with ALL (0 versus 18.5%; P = .000). The characteristics of post-allo-HSCT EMR differed between the patients with AML and those with ALL, possibly suggesting different pathogenetic mechanisms for EMR of AML and EMR of ALL after allo-HSCT; further investigation is needed.

Prolonged Survival of a Refractory Acute Myeloid Leukemia Patient after a Third Hematopoietic Stem Cell Transplantation with Umbilical Cord Blood following a Second Relapse

Although hematopoietic stem cell transplantation (HSCT) has been considered to be the only way for potential cure of relapsed acute myeloid leukemia (AML), there has been no report on a third HSCT in patients with multiple relapsed AML. Here, we report a case of 53-year-old female who received a successful third allogeneic HSCT after relapse of AML following a second allogeneic HSCT. She was treated with a toxicity reduced conditioning regimen and received direct intrabone cord blood transplantation (CBT) using a single unit of 5/6 HLA-matched cord blood as a graft source. Graft-versus-host disease prophylaxis was performed with a single agent of tacrolimus to increase graft-versus-leukemia effect. She is in remission for 8 months since the direct intrabone CBT. This report highlights not only the importance of individually adjusted approach but also the need for further investigation on the role of HSCT as a treatment modality in patients with refractory or multiple relapsed AML.

The role of hypomethylating agents in the treatment of elderly patients with AML

There is a major unmet medical need for treatment options in elderly patients with acute myeloid leukemia (AML) who are deemed ineligible for intensive treatment. The recent approval of decitabine in the European Union for the treatment of patients with AML≥ 65 years old highlights the potential for hypomethylating agents in this setting. Here, we review evidence to support the use of hypomethylating agents in elderly patients and emphasize the importance of tolerability and quality of life considerations. We focus on the rationale for the continued clinical development of the ribonucleoside analog azacitidine in this setting. We discuss potential differences in the activity of azacitidine and decitabine in different patient subgroups that could possibly be explained by important differences in mechanism of action. Finally, we assess practical challenges that will be faced when integrating hypomethylating agents into clinical practice, such as how to define ineligibility for intensive treatment.

Epigenetic therapy in allogeneic hematopoietic stem cell transplantation

DNA methylation and other epigenetic phenomena appear to be relevant in the pathogenesis of several malignant disorders. DNA methyltransferases add methyl groups to cytosine-phosphate-guanine (CpG) islandsleading to gene promoter silencing. The DNA methyltransferases inhibitors azacitidine and decitabine have anti-tumor activity against a broad range of malignancies, but have been investigated mostly in myelodysplastic syndrome. In addition, these agents have immunomodulatory effects that are under investigation in the allogeneic stem cell transplantation scenario. Both drugs have been used in the perioperative period of allogeneic transplantations with varying degrees of success. It has been hypothesized that low dose azacitidine may increase the graft-versus-leukemia effect and have a role in the maintenance of remission after allogeneic transplantation for myeloid leukemias. It is also intriguing that this favorable effect might occur while mitigating graft-versus-host disease. Here we present a review of the rapidly growing field of epigenetic manipulation using hypomethylating agents in allogeneic transplantation.

Azacitidine and donor lymphocyte infusions as first salvage therapy for relapse of AML or MDS after allogeneic stem cell transplantation

The combination of azacitidine and donor lymphocyte infusions (DLI) as first salvage therapy for relapse after allogeneic transplantation (allo-HSCT) was studied in 30 patients with acute myeloid leukemia (AML; n=28) or myelodysplastic syndromes (MDS; n=2) within a prospective single-arm multicenter phase-II trial. Treatment schedule contained up to eight cycles azacitidine (100 mg/m(2)/day, days 1-5, every 28 days) followed by DLI (from 1-5 × 10(6) to 1-5 × 10(8) CD3(+)cells/kg) after every second azacitidine cycle. A median of three courses azacitidine (range 1-8) were administered, and 22 patients (73%) received DLI. Overall response rate was 30%, including seven complete remissions (CRs, 23%) and two partial remissions (7%). Five patients remain in CR for a median of 777 days (range 461-888). Patients with MDS or AML with myelodysplasia-related changes were more likely to respond (P=0.011), and a lower blast count (P=0.039) as well as high-risk cytogenetics (P=0.035) correlated with the likelihood to achieve CR. Incidence of acute and chronic graft-versus-host disease was 37% and 17%, respectively. Neutropenia and thrombocytopenia grade III/IV occurred during 65% and 63% of treatment cycles, while infections were the most common grade III/IV non-hematological toxicity. Azacitidine and DLI as salvage therapy is safe, induces long-term remissions and may become an alternative for patients with AML or MDS relapsing after allo-HSCT.

Acute myeloid leukemia: focus on novel therapeutic strategies

Acute myeloid leukemia (AML) is a heterogeneous disease with variable clinical outcomes. Cytogenetic analysis reveals which patients may have favorable risk disease, but 5-year survival in this category is only approximately 60%, with intermediate and poor risk groups faring far worse. Advances in our understanding of the biology of leukemia pathogenesis and prognosis have not been matched with clinical improvements. Unsatisfactory outcomes persist for the majority of patients with AML, particularly the elderly. Novel agents and treatment approaches are needed in the induction, post-remission and relapsed settings. The additions of clofarabine for relapsed or refractory disease and the hypomethylating agents represent recent advances. Clinical trials of FLT3 inhibitors have yielded disappointing results to date, with ongoing collaborations attempting to identify the optimal role for these agents. Potential leukemia stem cell targeted therapies and treatments in the setting of minimal residual disease are also under investigation. In this review, we will discuss recent advances in AML treatment and novel therapeutic strategies.

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.

Molecular genetics in acute myeloid leukemia

PURPOSE OF REVIEW

Acute myeloid leukemia (AML) is a highly heterogeneous disorder being composed of various genetically defined subtypes. In recent years, molecular research provided the basis for a more differentiated characterization of AML patients, for example, of the large subgroup with normal karyotypes. This review summarizes the current status of molecular diagnostics in AML and refers to the diagnostic techniques being most suitable for the individual markers.

RECENT FINDINGS

A molecular data set based on mutations of the NPM1, FLT3, and CEBPA genes and the MLL-PTD provides a prognostically relevant risk stratification that can support the decision pro or con an allogeneic hematopoietic stem cell transplantation in first remission. The panel of known molecular markers is continuously increasing, for example, considering the recently described TET2 and IDH1 mutations. The introduction of next generation sequencing will certainly catalyze the molecular characterization of AML. Monitoring of the minimal residual disease load with quantitative real-time PCR can be performed for NPM1 and MLL-PTD-mutated cases.

SUMMARY

Targeted therapy studies with FLT3 inhibitors for patients with FLT3-mutated AML as single agents or combined with chemotherapy illustrate the translation of the molecular techniques into clinical practice already being realized in distinct subgroups of AML.

Azacitidine for treatment of patients with myelodysplastic syndromes (MDS): practical recommendations of the German MDS Study Group

Myelodysplastic syndromes (MDS) are a group of common bone marrow disorders characterized by ineffective hematopoiesis, peripheral cytopenias, and a substantial risk of progression to acute myeloid leukemia (AML). For many years, the main treatment option for MDS was best supportive care which alleviates symptoms, but has no effect on the natural course of the disease. Recently, demethylating agents have become available as a promising new treatment for patients with MDS. In two randomized clinical trials, the demethylating agent azacitidine has demonstrated a reduced risk of transformation to AML, improvement of peripheral blood values, an improved quality of life, and a definite survival advantage compared to conventional care regimens for patients with International Prognostic Scoring System score of intermediate-2 or high-risk MDS. This review aims to provide practical recommendations for the use of azacitidine and the management of its side effects in patients with MDS, assuring safe administration and best efficacy of treatment.

The DNA demethylating agent 5-aza-2'-deoxycytidine induces expression of NY-ESO-1 and other cancer/testis antigens in myeloid leukemia cells

Azanucleoside DNA-hypomethylating agents have remarkable clinical activity in myelodysplastic syndromes and acute myeloid leukemia (AML), particularly at low, non-cytotoxic doses favoring hypomethylation over cytotoxicity. Cancer/testis antigens (CTAs) encoding immunogenic proteins are not expressed in almost all normal tissues and many tumor types, but are consistently derepressed by epigenetically active agents in various cancer cell lines. Since the expression of CTA genes is usually very low or absent in myeloid leukemias, we treated various AML cell lines with 5-aza-2'-deoxycytidine (DAC) and quantified mRNA expression of the CTAs NY-ESO-1, MAGEA1, MAGEA3 and MAGEB2. Consistent time- and dose-dependent reactivation of all 4 CTA genes was observed, with maximum mRNA levels 72-144h after treatment start. As determined by RNA microarray analyses, numerous other CTA genes (all located on the X-chromosome) were also derepressed in a time-dependent fashion by DAC. NY-ESO-1 derepression was confirmed at the protein level. By Elispot and chromium release assays we showed that the de novo expressed NY-ESO-1 protein was naturally processed and presented in a time- and dose-dependent fashion up to 8 days after the start of DAC treatment, and converted the cell lines susceptible to antigen-specific recognition by CD8+ T-cell clones. In conclusion, NY-ESO-1 and numerous other CTAs localized on the X-chromosome are readily and transiently derepressed in AML cell lines treated with DAC. The susceptibility of DAC-treated AML cell lines to antigen-specific T-cell recognition has clear implications for future clinical trials combining DAC and specific immunotherapy in AML.

Review of azacitidine trials in Intermediate-2-and High-risk myelodysplastic syndromes

The efficacy of azacitidine, a cytosine nucleoside analog, has been demonstrated in two large phase III trials in myelodysplastic syndromes (MDS) patients, primarily in higher-risk patients. In the Cancer and Leukemia Group B (CALGB) study (lower-and higher-risk MDS patients; n = 191) azacitidine significantly prolonged median time-to-progression to acute myeloid leukemia or death (21 vs 13 months for supportive care; p = 0.007). The AZA-001 trial (Intermediate-2-and High-risk MDS patients; n = 358) showed azacitidine significantly prolonged median overall survival compared with conventional care regimens (24.5 vs 15.0 months; p = 0.0001). These results establish azacitidine as a reference first-line treatment in patients with Intermediate-2-and High-risk MDS who are not immediate candidates for allogeneic stem cell transplantation.

Monitoring of donor chimerism in sorted CD34+ peripheral blood cells allows the sensitive detection of imminent relapse after allogeneic stem cell transplantation

Analysis of donor chimerism is an important diagnostic tool to assess the risk of relapse after allogeneic stem cell transplantation, especially in patients lacking a specific marker suitable for monitoring of minimal residual disease. We prospectively investigated the predictive value of donor chimerism analyses in sorted CD34(+) peripheral blood cells in 90 patients with acute leukemia and myelodysplastic syndrome. The cumulative incidence of relapse after four years was significantly increased in cases with decreasing or incomplete CD34(+) donor chimerism (57% vs. 18%, p=0.0001). Multivariate analysis confirmed decreasing CD34(+) donor chimerism as an independent predictor of relapse and inferior survival. The interval between a decrease of CD34(+) chimerism of less than 80% and hematologic relapse was 61 days (range 0-567). Monitoring of CD34(+) donor chimerism in the peripheral blood allows prediction of imminent relapse after allogeneic stem cell transplantation even when a disease-specific marker is lacking.

Management of relapse after allo-SCT for AML and the role of second transplantation

Relapse after allo-SCT for AML carries very poor prognosis. Second allo-SCT, although curative, is not an appropriate treatment option for a large number of relapsing patients (only 2-20% patients receive a second allo-SCT), and efforts to increase the number of patients who may benefit from a second allo-SCT are ongoing. In addition, understanding the varied biological processes that are operative in disease relapse has encouraged the development of novel therapies, and could be beneficial to patients who are currently managed conservatively with supportive care for relapsed disease. Incorporating novel combinations of drugs with immunomodulation, although theoretically attractive, should be tested in the setting of clinical trials. In this review, we discuss the currently available approaches for relapsed AML after allo-SCT.

Efficacy of a 3-day, low-dose treatment with 5-azacytidine followed by donor lymphocyte infusions in older patients with acute myeloid leukemia or chronic myelomonocytic leukemia relapsed after allografting

We have piloted a low-dose schedule of 5-azacytidine followed by donor lymphocyte infusions (DLIs) in patients with relapse of AML or chronic myelomonocytic leukemia (CMMoL) after allografting. Of the 26 patients (median age 62 years, range 28-75) with relapsed AML (n=24) or CMMoL (n=2), 11 (42%) had poor-risk cytogenetics. Twenty-three patients had received fludarabine-based reduced-toxicity conditioning regimens, and three had received conventional myeloablative conditioning. Patients received 5-azacytidine s.c., at a total daily dose of 100 mg, on days 1-3, to be followed by DLI on day 10, with the next course of treatment to be started on day 22. A total of 60 courses of 5-azacytidine were administered, with a median of 2 courses (range: 1-10). In 44 courses, 5-azacytidine was followed by DLI, and thus 19/26 (73%) patients received at least one course of this combined treatment. Clinically relevant neutropenic infections not associated with progressive disease developed in four patients, one of them succumbing to sepsis. Only two patients developed de novo acute GvHD after the combination of 5-azacytidine and DLI. Overall, 66% of the patients benefited from this treatment, with continued CRs achieved in 4 (16%) patients, lasting a median of 525 days (range: 450+ to 820+), and a 50% rate of temporary disease control with stable mixed chimerism (median duration 72 days). The median survival from the start of 5-azacytidine treatment was 136 days (range: 23 to 873+), with an estimated 2-year survival probability of 16%. In conclusion, this non-intensive outpatient regimen of 5-azacytidine followed by DLI is feasible, with a very low aGVHD rate. Objective responses, including continuous complete donor chimerism, occurred also in patients with poor-risk cytogenetics.

Non-intensive treatment with low-dose 5-aza-2'-deoxycytidine (DAC) prior to allogeneic blood SCT of older MDS/AML patients

Novel, non-intensive treatment options in older MDS/AML patients planned for allografting, with the goal of down-staging the underlying disease and bridging time to transplantation, are presently being developed. 5-azacytidine and decitabine (DAC) are of particular interest, as they can be given repetitively, with very limited non-hematologic toxicity and result in responses both in MDS and AML even at low doses. We describe 15 consecutive patients (median age 69 years, range 60-75 years) with MDS (n=10) or AML (n=5) who all received first-line treatment with DAC and subsequent allografting (from sibling donor in four patients, unrelated donor in 11) after reduced-intensity conditioning with the FBM regimen. Successful engraftment was attained in 14/15 patients, all of whom achieved a CR, with a median duration of 5 months (range 1+ to 51+). Six of these 14 patients are alive (4 with complete donor chimerism), 8 have died either from relapse (n=4) or treatment-related complications while in CR (n=4). We conclude that allografting after low-dose DAC and subsequent conditioning with FBM is feasible, with no unexpected toxicities and appears as a valid alternative to standard chemotherapy ('InDACtion instead of induction') in elderly patients with MDS/AML.

Emerging treatment strategies for acute myeloid leukemia (AML) in the elderly

Acute myeloid leukemia (AML) is more prevalent in older adults, with an incidence in the United States of 17.6 per 100,000 for those 65 years of age, compared with an incidence of 1.8 per 100,000 for those <65 years of age. While there have been improvements in survival during the last decade for younger patients, prognosis in elderly patients is still poor; approximately 50% achieve complete responses, but many of them relapse. With increasing age, more patients are suboptimal candidates for standard induction chemotherapy due to poor performance status, pre-existing myelodysplasia, unfavorable cytogenetics, treatment-related AML, multidrug resistance protein expression, and CD34 positivity, which are often characteristic of this patient population. In addition, the presence of comorbid conditions make many treatment options less tolerable for elderly patients. Several investigators have described subgroups showing no benefit after intensive treatment approaches in recent years. However, several novel agents have been developed to treat elderly AML patients. These include new chemotherapeutic agents, such as nucleoside analogs, as well as targeted therapies like farnesyltransferase inhibitors, tyrosine kinase inhibitors, epigenetic drugs, and antibodies. On the other hand new insights into the biology of the disease lead to a better understanding of its heterogeneity. Thus, with a variety of novel substances at hand it is increasingly important to introduce a risk-adapted approach for the optimal management of patients. This review will identify subgroups not likely to benefit from intensive chemotherapy and highlight the efficacy and tolerability of new agents in the treatment of AML.

Advance in hepatic stem cells and liver injury

The liver diseases remain major causes of death all over the world. Although orthotopic liver transplantation is an effective treatment for end-stage liver diseases. However, shortage of healthy livers for transplantation worldwide have urgently limited the use of liver transplantation for acute and chronic liver diseases. Stem cells play an important role in the concert of liver regeneration. Hepatic stem cells have been shown experimentally to participate in liver proliferation. Furthermore, it has been postulated that hepatic stem cells are able to transdifferentiate into both hepatocytes and bole duct cells. These data indicate a possible role and therapeutic potential of hepatic stem cells in liver diseases. In this paper, we reviewed the application of stem cells in liver diseases.