Salvage therapy for acute myeloid leukemia with fludarabine, cytarabine, and idarubicin with or without gemtuzumab ozogamicin and with concurrent or sequential G-CSF

Effectiveness and safety of granulocyte colony-stimulating factor priming regimen for acute myeloid leukemia: A systematic review and meta-analysis of the Clinical Practice Guideline for the use of G-CSF 2022 from the Japan Society of Clinical Oncology

BACKGROUND

The outcomes of relapsed or refractory acute myeloid leukemia (AML) remain poor. Although the concomitant use of granulocyte colony-stimulating factor (G-CSF) and anti-chemotherapeutic agents has been investigated to improve the antileukemic effect on AML, its usefulness remains controversial. This study aimed to investigate the effects of G-CSF priming as a remission induction therapy or salvage chemotherapy.

METHODS

We performed a thorough literature search for studies related to the priming effect of G-CSF using PubMed, Ichushi-Web, and the Cochrane Library. A qualitative analysis of the pooled data was performed, and risk ratios (RRs) with confidence intervals (CIs) were calculated and summarized.

RESULTS

Two reviewers independently extracted and accessed the 278 records identified during the initial screening, and 62 full-text articles were assessed for eligibility in second screening. Eleven studies were included in the qualitative analysis and 10 in the meta-analysis. A systematic review revealed that priming with G-CSF did not correlate with an improvement in response rate and overall survival (OS). The result of the meta-analysis revealed the tendency for lower relapse rate in the G-CSF priming groups without inter-study heterogeneity [RR, 0.91 (95% CI 0.82-1.01), p = 0.08; I2 = 4%, p = 0.35]. In specific populations, including patients with intermediate cytogenetic risk and those receiving high-dose cytarabine, the G-CSF priming regimen prolonged OS.

CONCLUSIONS

G-CSF priming in combination with intensive remission induction treatment is not universally effective in patients with AML. Further studies are required to identify the patient cohort for which G-CSF priming is recommended.

Venetoclax: A Game Changer in the Treatment of Younger AML Patients?

The combination approach based on venetoclax (VEN) with azacytidine (AZA) has significantly improved outcomes for elderly patients with acute myeloid leukemia (AML). This innovative approach has led to higher rates of overall response, measurable residual disease (MRD)-negative remissions, and overall survival compared with AZA monotherapy. As a result, this combination has emerged as the gold-standard treatment for elderly or unfit patients with AML who are not eligible for intensive therapy. In younger, fit patients with AML, intensive induction and consolidation chemotherapy is commonly used as a first-line approach; however, relapse continues to be the main reason for treatment failure in approximately 30-40% of patients. Efforts to improve MRD-negative response rates and to facilitate the transition to allogeneic hematopoietic stem cell transplantation, particularly in high-risk AML, have inspired trials exploring the combination of intensive chemotherapy with targeted agents. VEN, a first-in-class anti-BCL2 agent, combined with intensive chemotherapy regimens has shown deep MRD-negative remissions, producing prolonged event-free survival and enhancing the transition to allogeneic transplant in first-complete-remission patients. These benefits support the incremental advantages of adding VEN to intensive chemotherapy approaches across ELN risk subcategories, and provides a robust benchmark to design future trials. In this review, we will discuss current studies assessing the efficacy of frontline regimens integrating VEN into intensive chemotherapy in younger patients with AML and specific molecularly defined subgroups.

The Role of Venetoclax in Relapsed/Refractory Acute Myeloid Leukemia: Past, Present, and Future Directions

Relapsed and/or refractory (R/R) acute myeloid leukemia (AML) is hallmarked by dramatic prognosis. Treatment remains challenging, with allogeneic hematopoietic stem cell transplantation (HSCT) as the only curative option. The BCL-2 inhibitor venetoclax (VEN) has proven to be a promising therapy for AML and is currently the standard of care in combination with hypomethylating agents (HMAs) for newly diagnosed AML patients ineligible for induction chemotherapy. Given its satisfactory safety profile, VEN-based combinations are increasingly being investigated as a part of the therapeutic strategy for R/R AML. The current paper aims to provide a comprehensive review of the main evidence regarding VEN in the setting of R/R AML, with a specific focus on combinational strategies, including HMAs and cytotoxic chemotherapy, as well as different clinical settings, especially in view of the crucial role of HSCT. A discussion of what is known about drug resistance mechanisms and future combinational strategies is also provided. Overall, VEN-based regimes (mainly VEN + HMA) have provided unprecedented salvage treatment opportunities in patients with R/R AML, with low extra-hematological toxicity. On the other hand, the issue of overcoming resistance is one of the most important fields to be addressed in upcoming clinical research.

Infectious complications of targeted drugs and biotherapies in acute leukemia. Clinical practice guidelines by the European Conference on Infections in Leukemia (ECIL), a joint venture of the European Group for Blood and Marrow Transplantation (EBMT), the European Organization for Research and Treatment of Cancer (EORTC), the International Immunocompromised Host Society (ICHS) and the European Leukemia Net (ELN)

The 9th web-based European Conference on Infections in Leukemia (ECIL-9), held September 16-17, 2021, reviewed the risk of infections and febrile neutropenia associated with more recently approved immunotherapeutic agents and molecular targeted drugs for the treatment of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Novel antibody based treatment approaches (inotuzumab ozogamicin, gemtuzumab ozogamicin, flotetuzumab), isocitrate dehydrogenases inhibitors (ivosidenib, enasidenib, olutasidenib), FLT3 kinase inhibitors (gilteritinib, midostaurin, quizartinib), a hedgehog inhibitor (glasdegib) as well as a BCL2 inhibitor (venetoclax) were reviewed with respect to their mode of action, their immunosuppressive potential, their current approval and the infectious complications and febrile neutropenia reported from clinical studies. Evidence-based recommendations for prevention and management of infectious complications and specific alerts regarding the potential for drug-drug interactions were developed and discussed in a plenary session with the panel of experts until consensus was reached. The set of recommendations was posted on the ECIL website for a month for comments from members of EBMT, EORTC, ICHS and ELN before final approval by the panelists. While a majority of these agents are not associated with a significantly increased risk when used as monotherapy, caution is required with combination therapy such as venetoclax plus hypomethylating agents, gemtuzumab ozogamicin plus cytotoxic drugs or midostaurin added to conventional AML chemotherapy.

Treatment of AML Relapse After Allo-HCT

With advances in allogeneic hematopoietic stem cell transplant (allo-HCT), disease relapse has replaced transplant-related mortality as the primary cause of treatment failure for patients with acute myeloid leukemia (AML). The efficacy of allo-HCT in AML is a consequence of a graft-versus-leukemia (GVL) effect that is mediated by T lymphocytes, and unique mechanisms of immune evasion underlying post-allo-HCT AML relapses have recently been characterized. Relapsed AML following allo-HCT presents a particularly vexing clinical challenge because transplant-related toxicities, such as graft-versus-host (GVHD) and infections, increase the risk of treatment-related morbidity and mortality. In general, the prognosis of relapsed AML following allo-HCT is poor with most patients failing to achieve a subsequent remission and 2-year survival consistently <15%. The two factors that have been found to predict a better prognosis are a longer duration of post-transplant remission prior to relapse and a lower disease burden at the time of relapse. When considered in combination with a patient's age; co-morbidities; and performance status, these factors can help to inform the appropriate therapy for the treatment of post-transplant relapse. This review discusses the options for the treatment of post-transplant AML relapse with a focus on the options to achieve a subsequent remission and consolidation with cellular immunotherapy, such as a second transplant or donor lymphocyte infusion (DLI). While intensive reinduction therapy and less intensive approaches with hypomethylating agents have long represented the two primary options for the initial treatment of post-transplant relapse, molecularly targeted therapies and immunotherapy are emerging as potential alternative options to achieve remission. Herein, we highlight response and survival outcomes achieved specifically in the post-transplant setting using each of these approaches and discuss how some therapies may overcome the immunologic mechanisms that have been implicated in post-transplant relapse. As long-term survival in post-transplant relapse necessarily involves consolidation with cellular immunotherapy, we present data on the efficacy and toxicity of both DLI and second allo-HCT including when such therapies are integrated with reinduction. Finally, we provide our general approach to the treatment of post-transplant relapse, integrating both novel therapies and our improved understanding of the mechanisms underlying post-transplant relapse.

Clinical Benefits and Safety of Gemtuzumab Ozogamicin in Treating Acute Myeloid Leukemia in Various Subgroups: An Updated Systematic Review, Meta-Analysis, and Network Meta-Analysis

Background

Previous trials demonstrated evidence involving the total effects of gemtuzumab ozogamicin (GO), an anti-CD33 humanized antibody, on treating acute myeloid leukemia (AML). In this updated systematic review, meta-analysis, and network meta-analysis (NMA), we aimed to comprehensively explore the clinical benefits and safety of GO in various subtypes of AML.

Methods

PubMed, Embase, Cochrane, and Chinese databases were filtered to search randomized controlled trials (RCTs) and retrospective cohort studies that compared clinical efficiency and toxicity of GO with non-GO groups in AML. Random-effects models were used to calculate pooled effect sizes and 95% confidence intervals (CIs). Relative risk (RR) was used for estimating complete remission (CR), early death, and toxicity. Hazard risk (HR) was accomplished to evaluate survival.

Results

Fifteen RCTs and 15 retrospective cohort studies were identified (GO: 4,768; Control: 6,466). GO tended to improve CR (RR 0.95, p = 0.084), followed by significantly improved survival (overall survival: HR 0.86, p = 0.003; event-free survival: HR 0.86, p = 0.015; relapse-free survival: HR 0.83, p = 0.001; cumulative incidence of relapse: HR 0.82, p < 0.001). GO benefits of CR and survival were evident in favorable- and intermediate-risk karyotypes (p ≤ 0.023). GO advantages were also associated with nucleophosmin 1 mutations (p ≤ 0.04), wild-type FMS-like tyrosine kinase 3 internal tandem duplication gene (p ≤ 0.03), age of <70 years (p < 0.05), de novo AML (p ≤ 0.017), and CD33(+) (p ≤ 0.021). Both adding GO into induction therapy (p ≤ 0.011) and a lower (<6 mg/m2) dose of GO (p ≤ 0.03) enhanced survival. Prognosis of combined regimens with GO was heterogeneous in both meta-analysis and NMA, with several binding strategies showing improved prognosis. Additionally, GO was related to increased risk of early death at a higher dose (≥6 mg/m2) (RR 2.01, p = 0.005), hepatic-related adverse effects (RR 1.29, p = 0.02), and a tendency of higher risk for hepatic veno-occlusive disease or sinusoidal obstruction syndrome (RR 1.56, p = 0.072).

Conclusions

These data indicated therapeutic benefits and safety of GO in AML, especially in some subtypes, for which further head-to-head RCTs are warranted.

Systematic Review Registration

[PROSPERO: https://www.crd.york.ac.uk/prospero/], identifier [CRD42020158540].

Venetoclax-based salvage therapy followed by Venetoclax and DLI maintenance vs. FLAG-Ida for relapsed or refractory acute myeloid leukemia after allogeneic stem cell transplantation

We retrospectively compared the outcomes of 20 patients receiving Venetoclax + low-dose Cytarabine + Actinomycin D (ACTIVE) with 29 patients receiving FLAG-Ida as salvage therapy for relapsed or refractory AML (R/R AML) after alloSCT. The groups were statistically balanced according to age, performance status, cytogenetics, and previous treatment. The overall response rate (CR + CRp + MLFS) of ACTIVE was 75% (15/20) in comparison to 66% (19/29) in the FLAG-Ida group (p = 0.542). The cumulative CR + CRp rate was significantly higher in the ACTIVE group compared to FLAG-Ida (70% (14/20) vs. 34% (10/29), respectively, p = 0.02). All three patients failing previous Venetoclax therapy and five out of seven patients with previous FLAG-Ida exposure achieved a CR/CRp after ACTIVE induction. ACTIVE patients survived longer compared to FLAG-Ida patients (13.1 vs. 5.1 months, respectively, p = 0.032). The treatment-related mortality was 0% in the ACTIVE group and 34% (10/29) in the FLAG-Ida patients (p = 0.003). The cumulative incidence of relapse did not differ between the two treatment groups. ACTIVE appears to have comparable antileukemic activity and lower toxicity compared to FLAG-Ida resulting in improved survival. Patients with Venetoclax or FLAG-Ida exposure responded to ACTIVE.

Pretransplant bone marrow cellularity and blood count recovery are not associated with relapse or survival risk following allogeneic stem cell transplant for AML in CR

INTRODUCTION

Allogeneic hematopoietic cell transplantation (HCT) can be curative for acute myeloid leukemia (AML). Novel therapies may render patients' bone marrow hypocellularity and lead to prolonged post-therapy pancytopenia. Patients' bone marrow cellularity (BMC) at pretransplant assessment and post-treatment pancytopenia (classification CR-incomplete [CRi]) may manifest AML persistence.

METHODOLOGY

We retrospectively examined the impact of BMC and ELN response (ELNr) on a single-center cohort of 337 patients who underwent allogeneic HCT for AML in CR1.

RESULTS

Median follow-up was 33 months. Overall survival (OS) for the whole cohort was 55.8% at 2 years, while cumulative incidence of relapse (CIR) was 20.8%, and non-relapse mortality was 27.5%. OS and CIR were not significantly different between BMC groups; and neither was ELNr. ELNr CRi was associated with BMC aplastic and hypocellular marrow states (P < 2.6e-8). Multivariate analysis confirmed neither BMC nor attainment of ELNr CR vs CRi affected OS or relapse. Significant factors for survival included age at transplant, cytogenetic risk, development of acute Gr II-IV GvHD, and moderate-severe chronic GvHD, while cytogenetic risk and chronic GvHD affected relapse.

CONCLUSION

Neither ELNr status nor pretransplant BMC influenced relapse post-HCT or OS. Hypocellularity and CRi are not negative prognostic factors for post-HCT outcomes of AML.

Long non-coding RNA taurine-upregulated gene 1 correlates with unfavorable prognosis in patients with refractory or relapsed acute myeloid leukemia treated by purine analogue based chemotherapy regimens

OBJECTIVE

This study aimed to explore the correlation of long non-coding RNA taurine-upregulated gene 1 (lncRNA TUG1) expression with clinicopathological features and its predictive value for treatment response and survival profiles in refractory or relapsed acute myeloid leukemia (R/R AML) patients.

METHODS

Seventy three R/R AML patients who received cladribine combined with cytarabine and granulocyte colony-stimulating factor (G-CSF) (CLAG) or fludarabine combined with cytarabine and G-CSF (FLAG) based chemotherapy and 37 non-malignant controls were recruited. LncRNA TUG1 expression was detected in bone marrow sample obtained before treatment. Complete response (CR), partial response (PR), overall response rate (ORR) and overall survival (OS) were evaluated.

RESULTS

LncRNA TUG1 expression was upregulated in R/R AML patients compared to controls. It was also elevated in R/R AML patients with age ⩾ 60 years (vs. age < 60 years, P= 0.030) and in patients with secondary AML (vs. primary AML, P= 0.035). R/R AML patients with lncRNA TUG1 high expression achieved numerically lower CR (P= 0.053), decreased ORR (P= 0.028) and shorter OS (P< 0.001) than patients with lncRNA TUG1 low expression. Univariate logistic regression and COX's regression disclosed that lncRNA TUG1 high expression correlated with declined ORR, numerically decreased CR, and reduced OS. Furthermore, multivariate analyses verified that lncRNA TUG1 high expression was an independent predictive factor for decreased ORR and worse OS.

CONCLUSIONS

In conclusion, lncRNA TUG1 expression was elevated in R/R AML patients, and it might serve as a potential biomarker for poor prognosis in R/R AML patients treated with CLAG or FLAG based chemotherapy.

Comparison of efficacy of HCAG and FLAG re-induction chemotherapy in acute myeloid leukemia patients of low- and intermediate-risk groups

PURPOSE

The aim of the present study was to investigate the efficacy and adverse effects of HCAG and FLAG re-induction chemotherapy in acute myeloid leukemia (AML) patients of low- and intermediate-risk groups following induction failure.

METHODS

A total of 98 AML patients were enrolled. Among these subjects, 47 patients were treated with HCAG chemotherapy, while 51 patients were treated with FLAG chemotherapy.

RESULT

The complete remission (CR) and overall remission (OFF) were 24% and 38%, respectively in patients with HCAG induction chemotherapy, while the corresponding percentages were 28% and 42% in subject receiving FLAG chemotherapy. The median survival time of progress-free survival (PFS) was 29.8 (95% CI 23.749-35.851) months in the HCAG group and 30.8 (95% CI 21.728-39.872) months in the FLAG group (P = 0.620). A total of 42 patients in the HCAG group suffered from grade 4 hematological toxicity, while this adverse reaction was noted for all patients who were treated with FLAG chemotherapy (P = 0.023). A total of 19 cases indicated apparent nonhematological toxicity in the HCAG group, while only 40 (78.4%) were noted with these adverse reactions in the FLAG group (P = 0.000).

CONCLUSION

The HCAG regimen exhibited a similar effect compared with the FLAG regimen in low- and intermediate-risk groups, although the HCAG regimen significantly decreased the toxicity compared with that noted in the FLAG regimen group.

FLAG/FLAG-IDA regimen for children with relapsed/refractory acute leukemia in the era of targeted novel therapies

BACKGROUND

Outcomes of relapsed/refractory childhood acute leukemia remain poor. We analyzed the safety/efficacy of fludarabine, cytarabine, and granulocyte colony stimulating factor, with/without idarubicin (FLAG ± IDA) as salvage therapy compared with recent published results of novel therapies.

METHODS

This retrospective study included children aged 1 to 15 years with relapsed/refractory acute leukemia who received FLAG ± IDA salvage therapy from January 2000 to December 2014. Patients with infant leukemia, mixed lineage leukemia, Philadelphia-positive acute leukemia, or secondary leukemia were excluded.

RESULT

Fifty patients were identified: 25 with acute lymphoblastic leukemia and 25 with acute myeloid leukemia. The median age at initiation of FLAG ± IDA was seven years. Site of relapse was the bone marrow in 29, isolated central nervous system in 11, and combined in 10 patients. FLAG ± IDA was used after first relapse in 68% and after multiple relapses in 32%. Complete remission was achieved in 34 (68%) patients. No variables predictive of complete remission were identified. Grade 3 or greater toxicity was observed in 96% and 6% died from toxicity. Toxicities included hematologic toxicity (96%), infection (52%), and enterocolitis (28%). Twenty-four of 50 (48%) patients achieved a sustained complete remission and survived to bone marrow transplantation. The five-year overall survival was 23.9% ± 6.9%. Patients achieving second complete remission and patients proceeding to bone marrow transplantation following second complete remission demonstrated significantly improved overall survival (p = 0.001).

CONCLUSION

Despite a 68% complete remission rate using FLAG ± IDA, only 48% of patients survived to bone marrow transplantation. The regimen was associated with 96% toxicity and only one in four patients was alive at five years. This underscores the need to find more effective lower toxicity salvage regimens.

FLAG salvage therapy combined with idarubicin in relapsed/refractory acute myeloid leukemia

Acute myeloid leukemia (AML) is characterized by a high failure rate to achieve complete remission as well as high relapse rates that cause an emergent need for efficient and tolerable salvage therapies. The combination of FLAG with idarubicin (FLAG-Ida) is a widely used protocol. However, its efficacy has been analyzed in only a limited number of studies with majorly small patient cohorts. Here, we analyzed 132 patients with largely primary refractory or first-time relapsed AML treated according to the FLAG-Ida protocol. The overall complete remission rate (CR + CRi) was 56% with a median overall survival of 15 months (95% CI, 5.7-25.1). The median disease-free survival for CR/CRi-patients was not reached. The mortality rate on day 30 was 9% and increased on day 60 to 16%. Our results show in relapsed/refractory AML patients a high efficacy and compatibility for the FLAG-Ida regimen.

Re-induction chemotherapy using FLAG-mitoxantrone for adult patients with relapsed acute leukemia: a single-center experience from United Arab Emirates

We studied the outcome of 47 adult patients with relapsed acute leukaemia (AML = 25 and ALL = 22) treated with FLAG-mitoxantrone regimen. Median time to relapse was 10.7 months (range 1.9-27.7). Complete remission (CR2) was 60.1% which was significantly more frequent in ALL compared to AML (P = 0.049). WBC count < 100 × 10⁹/L at initial diagnosis and time to relapse > 1 year were significantly predictor for CR2 in AML (P = 0.005 for both). Induction death was significantly higher in ALL compared to AML (P = 0.039). Median follow-up was 4.0 months (0.9-119.8) for AML and 2.1 months (range 0.6-118.1) for ALL. Nine patients underwent allogeneic stem-cell transplantation (allo-SCT). Estimated overall survival (OS) at 12 and 18 months was 60.5 and 34.6%, respectively, for AML, and 39.9 and 29.9%, respectively, for ALL. For AML patients failure to achieve CR, WBC count at initial diagnosis > 5 × 10⁹/L and poor cytogenetic risk group was significant predictors of poor OS (P = 0.010, P = 0.025, and P = 0.015, respectively). For ALL patients failure to achieve of CR, WBC count at relapse < 5 × 10⁹/L (CR patients) and lack of any type of consolidation therapy were significant predictor of poor OS (P < 0.001, P = 0.008, P = 0.008, respectively).

Comparison of clinical remission and survival between CLAG and FLAG induction chemotherapy in patients with refractory or relapsed acute myeloid leukemia: a prospective cohort study

PURPOSE

To compare the clinical remission and survival between CLAG and FLAG induction chemotherapy in treating patients with refractory or relapsed acute myeloid leukemia (R/R AML).

METHODS

103 R/R AML patients were consecutively enrolled in this prospective cohort study. 55 patients were treated by CLAG induction chemotherapy as follows: 5 mg/m²/day cladribine (days 1-5); 2 g/m²/day cytarabine (days 1-5) and 300 μg/day filgrastim (days 0-5). While 48 patients were treated by FLAG: 30 mg/m²/day fludarabine (days 1-5), 2 g/m²/day cytarabine (days 1-5), and 300 μg/day filgrastim (days 0-5).

RESULTS

CLAG induction chemotherapy achieved 61.7% complete remission rate (CR) and 78.7% overall remission rate (ORR), which was similar with FLAG chemotherapy which realized 48.7% CR and 69.2% ORR. No difference of overall survival (OS) was discovered between two groups either. Age cytarabine 60 years, secondary disease, poor risk stratification and BM blast ≥ 42.7% and second or higher salvage therapy were independent factors for worse prognosis. Subgroups analysis revealed that in patients with second or higher salvage therapy, CLAG seemed to achieve a higher CR than FLAG. And in patients with relapsed disease, poor risk stratification or CR at first induction, CLAG seemed to realize a prolonged OS compared to FLAG.

CONCLUSION

CLAG was equally effective to FLAG induction chemotherapy in total R/R AML patients, while CLAG seemed to be a better option than FLAG in patients with relapsed disease, poor risk stratification, CR at first induction or second or higher salvage therapies.

Does High-Dose Cytarabine Cause More Fungal Infection in Patients With Acute Myeloid Leukemia Undergoing Consolidation Therapy: A Multicenter, Prospective, Observational Study in China

Invasive fungal infection (IFI) remains as a significant cause of morbidity and mortality in patients with acute myelogenous leukemia (AML). Here, we report the subgroup analysis of China Assessment of Antifungal Therapy in Haematological Disease (CAESAR) study to evaluate the risk of IFI in patients with AML in 1st remission receiving high-dose cytarabine (HiDAC) as consolidation. A total of 638 patients with AML in 1st complete remission were selected from the database. Among them, 130 patients received HiDAC alone with total dose of 2-3 g/m(2) × 6 while 508 patients received multiple-agent combination chemotherapy (multiagent chemo group). The patients' characteristics were generally not different but more patients in HiDAC group had peripherally inserted central catheter (61.5% vs 44.5%, P = 0.002). The median duration of neutropenia was 8.0 days in both HiDAC (2-20) and multiagent chemo group (2-28). Number of patients with prolonged neutropenia (>14 days) tended to be more in multiagent chemo group but not significant different (16.3% vs 8.8%, respectively). There was no significant difference between 2 groups in persistent neutropenic fever (40.8% vs 33.1%), antifungal treatment (11.5% vs 11.4%), and incidence of proven/probable IFI (4 probable in HiDAC vs 1 proven/4 probable in multiagent chemo, P = 0.35) or possible IFI. As to the clinical outcome in terms of duration of hospitalization and death in remission, there was a trend of shorter duration of hospitalization in HiDAC (19 days, 3-70) compare to multiagent chemo group (21 days, 1-367, P = 0.057) while no death documented in HiDAC group and only 2 patients died in the multiagent chemo group (0.4%). As to risk factors associated with IFI in all 638 patients, there was a trend of more IFI in patients with severe neutropenia (3.0%, P = 0.089) and previous history of IFI (3.85%, P = 0.086) while the antifungal prophylaxis was not associated significantly reduced IFI. Overall, our data support the perception that HiDAC alone as consolidation in first remission AML patients was well tolerated and not associated with increased hematological toxicity and IFI than conventional combination chemotherapy. Antifungal prophylaxis may not necessary except for patients with previous history of IFI.

How I treat refractory and early relapsed acute myeloid leukemia

Between 10% and 40% of newly diagnosed patients with acute myeloid leukemia (AML) do not achieve complete remission with intensive induction therapy and are therefore categorized as primary refractory or resistant. Few of these patients can be cured with conventional salvage therapy. They need to be evaluated regarding eligibility for allogeneic hematopoietic stem cell transplantation (HSCT) as this is currently the treatment with the highest probability of cure. To reduce the leukemia burden prior to transplantation, salvage chemotherapy regimens need to be employed. Whenever possible, refractory/relapsed patients should be enrolled in clinical trials as we do not have highly effective and standardized treatments for this situation. Novel therapies include tyrosine kinase inhibitors, small-molecule inhibitors (eg, for Polo-like kinase 1 and aminopeptidase), inhibitors of mutated isocitrate dehydrogenase (IDH) 1 and IDH2, antibody-based therapies, and cell-based therapies. Although the majority of these therapies are still under evaluation, they are likely to enter clinical practice rapidly as a bridge to transplant and/or in older, unfit patients who are not candidates for allogeneic HSCT. In this review, we describe our approach to refractory/early relapsed AML, and we discuss treatment options for patients with regard to different clinical conditions and molecular profiles.

Busulfan and fludarabine conditioning regimen given at hematological nadir of cytoreduction fludarabine, cytarabine, and idarubicin chemotherapy in patients with refractory acute myeloid leukemia undergoing allogeneic stem cell transplantation: a single arm pilot consort study

To improve the outcome of allogeneic stem cell transplantation in refractory acute myeloid leukemia (AML), we conducted a single-arm phase II clinical trial to evaluate the efficacy and feasibility of conditioning regimen following cytoreduction chemotherapy with 7-day interval. Adult patients with refractory AML were enrolled in the study and received fludarabine, cytarabine, and idarubicin (FLAG-IDA) as cytoreductive chemotherapy followed by busulfan and fludarabine (Flu-BU) conditioning regimen and transfusion of mobilized peripheral stem cells from human leukocyte antigen-matched sibling or unrelated donor. The primary endpoint of the study was 2-year leukemia-free survival (LFS) and secondary endpoints included complete-remission rate, 2-year overall survival (OS), nonrelapse mortality (NRM), and relapse rate. A total of 16 patients were enrolled with median age of 36 (16-60), which included 9 primary induction failure, 2 early relapse, and 5 with relapse/refractory disease. The median cycles of previous chemotherapy were 4 (3-10) with a median of 55% (1%-90%) blasts in bone marrow. Six patients received transplantation from matched sibling and 10 from matched unrelated donors. After transplantation, 15 patients achieved bone marrow remission (11 complete remissions [CRs] and 4 bone marrow remissions without platelet recovery) at day +28. A total of 8 patients remained alive in CR with median LFS of 29.5 months (9.5-40.5 months). Four patients relapsed and 3 of them died of disease and another 4 patients died because of transplantation-related toxicity. The 2-year NRM and relapse rates were 25.0% ± 10.8% and 33.4% ± 13.8%, respectively with 2-year OS at 53.5% ± 13.1% and LFS at 50.0% ± 12.5%. Based on the Simon 2-stage design, 5 out of first eligible 14 patients remained leukemia-free for more than 2 years after allogeneic hematopoietic stem cell transplantation; thus, the null hypothesis of the study will be rejected and the study protocol is accepted as being warranted for further study. Based on the above data, our phase II study demonstrated that the sequential FLAG-IDA cytoreduction chemotherapy followed by Flu-BU conditioning regimen given at the hematological nadir was feasible and has sufficient activity to warrant further investigation prospectively with a larger patient sample (clinicaltrials.gov identifier: NCT01496547).

Hematologic Recovery after Pretransplant Chemotherapy Does Not Influence Survival after Allogeneic Hematopoietic Cell Transplantation in Acute Myeloid Leukemia Patients

Pretransplant remission status in patients with acute myeloid leukemia (AML) is 1 of the most important factors determining their outcomes after allogeneic hematopoietic cell transplantation (allo-HCT). Most patients are in complete remission with full hematologic recovery (CR) before undergoing allo-HCT. However, some patients achieve CR without recovery of platelet count (CRp) or a morphologic leukemia-free state (MLFS), defined as meeting all CR criteria without recovery of both neutrophil and platelet counts. Currently, there is a paucity of data regarding transplant outcomes in AML patients achieving MLFS after chemotherapy. To address this question, we evaluated transplant outcomes in 270 AML patients who received 6/6 HLA-matched sibling or 10/10 HLA-matched unrelated donor transplantation at a single institution between 2006 and 2013. Of our 270 patients, 206 were in CR, 45 were in CRp, and 19 were in MLFS before allo-HCT. Patients in CR, CRp, or MLFS had similar 3-year overall survival rates (49%, 46%, and 47%, respectively; P = .88) and 3-year event-free survival rates (45%, 36%, and 40%, respectively; P = .53). However, the cumulative incidence of nonrelapse mortality was significantly higher in patients in MLFS compared with those in CR (58% versus 22%, P = .0004), whereas the cumulative incidence of relapse in patients in MLFS was significantly lower compared with those in CR (11% versus 36%, P = .03). Our results suggest that survival outcomes in AML patients are not influenced by degree of hematologic recovery before allo-HCT.

Gemtuzumab ozogamicin in combination with intensive chemotherapy in relapsed or refractory acute myeloid leukemia

The prognosis of refractory/relapsed acute myeloid leukemia (AML) remains poor. The complete response (CR) rate after relapse is around 25%, with 11% of patients still alive after 5 years. The efficacy and toxicity of fractionated gemtuzumab ozogamicin (fGO; 3 mg/m2, days 1, 4, 7) in combination with intensive chemotherapy were retrospectively evaluated in patients with refractory/relapsed AML. Thirty-six patients (median age 54 years) were included. European LeukemiaNet classification was as follows: favorable (n=6), intermediate-I (n=13), intermediate-II (n=8), adverse (n=9). Median CR duration was 7.16 months (1.63-96.8). The overall response rate was 38.8%, with CR in eight patients (22.2%) and CR with incomplete platelet recovery (CRp) in six patients (16.7%). Two-year overall survival was 26% (95% confidence interval [CI]: 12-42) and 2-year relapse free-survival was 18.5% (95% CI: 6.6-35.0). Salvage therapy with fractionated GO in patients with very high-risk disease produced a 38.8% response rate and may be considered as a bridge therapy to transplant.

Prospective, multicenter, phase II study on reducing the dosage of idarubicin and FLAG for patients younger than 65 years with resistant acute myeloid leukemia: a comparison with a higher dosage trial

We previously assessed continuous infusion (CI) of fludarabine and cytarabine plus idarubicin (CI-FLAG1) for patients under 65 years of age with resistant acute myeloid leukemia. Induction chemotherapy consisted of idarubicin (IDA) plus fludarabine and cytarabine (ARAC) as a 24-hour CI. In response to induction, 31.6% of patients achieved complete remission (CR) and in 68.4% the treatment failed. We concluded that CI-FLAG1 carried a high risk of toxicity and reduced CI-FLAG doses were recommended. Therefore, we revised the protocol (CI-FLAG2) by reducing the dose of IDA and ARAC. In total, 38 and 68 patients were enrolled into CI-FLAG1 and CI-FLAG2, respectively. When comparing outcomes between CI-FLAG1 and CI-FLAG2, there were no differences in terms of the CR rate (p = 0.306) and the overall response rate (ORR; p = 0.206). The treatment failure patterns were different between CI-FLAG1 and CI-FLAG2. The median overall survival showed only a trend towards longer survival in CI-FLAG2 (p = 0.074). Among intermediate-risk patients, there were high response rates favoring CI-FLAG2 in terms of the CR rate (p = 0.108), the ORR (p = 0.031), and overall survival (p = 0.033). This represented a relatively improved response rate compared to our previous study. There was decreased aplasia with dose reductions at the expense of increased resistance. A reduced dose of CI-FLAG might be most beneficial for intermediate-risk groups.

The combination of fludarabine, cytarabine and etoposide is an active and well-tolerated regimen in relapsed/refractory acute myeloid leukemia

We retrospectively reviewed the outcome of 20 consecutive subjects with refractory/relapsed acute myeloid leukemia (AML; 9 refractory and 11 relapsed) treated at our institution with a fludarabine, cytarabine and etoposide (FCE) salvage regimen. Of 20 patients with refractory/relapsed AML, 15 (75%) achieved complete remission (CR)/CR with incomplete peripheral blood count recovery (CRi), including 14 CR and 1 CRi. The 4- and 8-week treatment-related mortality (TRM) for all patients during reinduction was 0 and 5%, respectively. Eight of 15 patients (53%) who successfully achieved CR were able to undergo allogeneic hematopoietic stem cell transplantation with a 0% non-relapse mortality rate. FCE is a new, well-tolerated, anthracycline-free regimen, which has a promising activity in relapsed/refractory AML and is associated with low TRM in this high-risk population.

Update on optimal management of acute myeloid leukemia

Acute myeloid leukemia (AML) represents a malignant accumulation of immature myeloid cells in the marrow, presenting with impaired hematopoiesis and its attendant complications, including bleeding, infection, and organ infiltration. Chromosomal abnormalities remain the most powerful predictors of AML prognosis and help to identify a subgroup with favorable prognosis. However, the majority of AML patients who are not in the favorable category succumb to the disease. Therefore, better efforts to identify those patients who may benefit from more aggressive and investigational therapeutic approaches are needed. Newer molecular markers aim at better characterizing the large group of intermediate-risk patients and to identify newer targets for therapy. A group that has seen little improvement over the years is the older AML group, usually defined as age ≥ 60. Efforts to develop less intensive but equally efficacious therapy for this vulnerable population are underway.

Sequential administration of methotrexate and asparaginase in relapsed or refractory pediatric acute myeloid leukemia

BACKGROUND

The efficacy of combination chemotherapy with methotrexate (MTX) and asparaginase is not well known in relapsed and refractory acute leukemia after contemporary therapy.

PROCEDURE

A retrospective study of pediatric patients with relapsed or refractory acute myeloid leukemia (AML) who received MTX and asparaginase as a salvage therapy at St. Jude Children Research Hospital was performed. MTX was given intravenously followed by a dose of asparaginase intramuscularly or intravenously 24 hours later. The chemotherapy cycle was repeated every 7-10 days. Response, survival, and toxicities were evaluated.

RESULTS

Fifteen patients, median age 10.5 years (range, 1.1-18.5 years), were treated. Median number of previous therapeutic regimens was three (range, 1-4). Six patients responded to treatment (three had morphologic complete remission with incomplete blood count recovery, two had partial remission, and one had stable disease for 16 months), and four are still alive. Three of six responders had monoblastic leukemia, and also developed tumor lysis syndrome. The 1- and 2-year overall survival rates are 35.6% and 17.8%, respectively. The most common adverse event was transient elevation of transaminases (nine patients). Two patients developed pancreatitis. Episodes of febrile neutropenia were rare (two patients), and most courses (75 out of 93 total courses) were given in an outpatient setting.

CONCLUSIONS

Combination chemotherapy with MTX and asparaginase appears to be an effective salvage therapy and well tolerated in patients with relapsed or refractory childhood AML, even in those heavily pretreated with contemporary frontline or salvage therapy.

Older and new purine nucleoside analogs for patients with acute leukemias

Purine nucleoside analogs (PNAs) compose a class of cytotoxic drugs that have played an important role in the treatment of hematological neoplasms, especially lymphoid and myeloid malignancies. All PNA drugs have a chemical structure similar to adenosine or guanosine, and they have similar mechanisms of action. They have many intracellular targets: they act as antimetabolites, competing with natural nucleosides during DNA or RNA synthesis, and as inhibitors of key cell enzymes. In contrast to other antineoplastic drugs, PNAs act cytotoxically, both in the mitotic and quiescent cell cycle phases. In the last few years, three PNAs have been approved for the treatment of lymphoid malignancies and other hematological disorders: 2-chlorodeoxyadenosine (2-CdA), fludarabine and pentostatin. 2-CdA and fludarabine are also active in the treatment of acute myeloid leukemia (AML). These drugs, in combination with cytarabine and other agents, are commonly used as salvage regimens in relapsed or refractory AML. Moreover, the addition of 2-CdA to the standard induction regimen is associated with an increased rate of complete remission and improved survival of adult patients with AML. More recently three novel PNAs have been synthesized and introduced into clinical trials: clofarabine, nelarabine and forodesine. Clofarabine is the most promising PNA in current clinical trials in pediatric and adult patients with acute leukemias. Nelarabine is more cytotoxic in T-lineage than in B-lineage leukemias. Clofarabine and nelarabine have been approved for the treatment of refractory patients with acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma. Clofarabine is also an active drug in AML treatment when administered either alone or in combination regimens as front-line treatment and in relapsed or refractory patients. Unlike other PNA, forodesine is not incorporated into DNA but displays a highly selective purine nucleoside phosphorylase inhibitory action. Forodesine is undergoing clinical trials for the treatment of T-cell malignancies, including T-cell ALL. This article summarizes recent achievements in the mechanism of action, pharmacological properties and clinical activity and toxicity of PNAs, as well as their emerging role in lymphoid and myeloid acute leukemias.

Salvage therapy for relapsed or refractory acute myeloid leukemia

There are a significant number of patients diagnosed with acute leukemia who either fail to achieve remission or who relapse thereafter. Challenges in treating this patient population include accurately assessing prognosis of disease and whether remission can be achieved; assessing the ability of patients to tolerate aggressive salvage therapies; choosing a salvage therapy that is most likely to succeed; and identifying suitable patients for hematopoietic stem cell transplantation. Despite the development of a variety of new investigational therapies, relapsed or refractory acute myeloid Leukemia remains a difficult clinical problem. Clinicians will need to consider all currently available approaches, including cytotoxic chemotherapy, targeted agents, and allogeneic stem cell transplantation, to optimize outcomes.

The mortality and response rate after FLANG regimen in patients with refractory/relapsed acute leukemia

Background:

Oncologists today are greatly concerned about the treatment of relapsed/refractory acute leukemia. FLANG regimen, combination of novantron, cytarabine, fludarabine, and granulocyte-colony stimulating factor, has been used in treatment of refractory/relapsed acute leukemia since 1990s. The present study has evaluated mortality and response rate of this regimen.

Materials and Methods:

In this study, 25 patients with refractory/relapsed acute leukemia aged 15-55 years underwent FLANG regimen at Seyed-Al-Shohada Hospital, Isfahan, Iran during 2008-2009. One month later, bone marrow samples were taken to evaluate the responsiveness to treatment. Participants were followed for a year. The data was analyzed by student-t and chi-square tests, logistic, and Cox regression analysis, and Kaplan-Meier curves in SPSS₁₉.

Results:

Out of the 25 patients, 8 patients (32%) had acute lymphoblastic leukemia (5 refractory and 3 relapsed cases) and 17 subjects had acute myeloid leukemia (7 refractory and 10 relapsed cases). According to the bone marrow biopsies taken one month after FLANG regimen, 10 patients (40%) had responded to treatment. Five patients of the 10 responders underwent successful bone marrow transplantation (BMT). On the other hand, 13 patients (52%), who had not entered the CR period, died during the follow-up. Logistic regression analysis did not reveal any significant associations between disease type and responsiveness to treatment.

Conclusion:

This study indicated higher rates of unresponsiveness to treatment while its mortality rate was comparable with other studies. Overall, according to limitations for BMT (as the only chance for cure) in Iran, it seems that FLANG therapy is an acceptable choice for these patients.

What happened to anti-CD33 therapy for acute myeloid leukemia?

CD33, a 67-kDa glycoprotein expressed on the majority of myeloid leukemia cells as well as on normal myeloid and monocytic precursors, has been an attractive target for monoclonal antibody (mAb)-based therapy of acute myeloid leukemia (AML). Lintuzumab, an unconjugated, humanized anti-CD33 mAb, has modest single-agent activity against AML but failed to improve patient outcomes in two randomized trials when combined with conventional chemotherapy. Gemtuzumab ozogamicin, an anti-CD33 mAb conjugated to the antitumor antibiotic calicheamicin, improved survival in a subset of AML patients when combined with standard chemotherapy, but safety concerns led to US marketing withdrawal. The activity of these agents confirms that CD33 remains a viable therapeutic target for AML. Strategies to improve the results of mAb-based therapies for AML include antibody engineering to enhance effector function, use of alternative drugs and chemical linkers to develop safer and more effective drug conjugates, and radioimmunotherapeutic approaches.

Acute myeloid leukaemia: optimal management and recent developments

The current treatment of patients with acute myeloid leukaemia yields poor results, with expected cure rates in the order of 30-40% depending on the biological characteristics of the leukaemic clone. Therefore, new agents and schemas are intensively studied in order to improve patients' outcomes. This review summarizes some of these new paradigms, including new questions such as which anthracycline is most effective and at what dose. High doses of daunorubicin have shown better responses in young patients and are well tolerated in elderly patients. Monoclonal antibodies are promising agents in good risk patients. Drugs blocking signalling pathways could be used in combination with chemotherapy or in maintenance with promising results. Epigenetic therapies, particularly after stem cell transplantation, are also discussed. New drugs such as clofarabine and flavopiridol are reviewed and the results of their use discussed. It is clear that many new approaches are under study and hopefully will be able to improve on the outcomes of the commonly used '7+3' regimen of an anthracycline plus cytarabine with daunorubicin, which is clearly an ineffective therapy in the majority of patients.

Gemtuzumab ozogamicin in non-acute promyelocytic acute myeloid leukemia

INTRODUCTION

Gemtuzumab ozogamicin (GO) has been used in relapsed, refractory and newly diagnosed acute myeloid leukemia (AML) as a single agent and in combination with intensive chemotherapy. Results of recent Phase III trials have led to its withdrawal in the USA although a beneficial effect of GO in genetically defined AML subgroups was evident.

AREAS COVERED

This review examines the use of GO as a single agent or in combination with intensive chemotherapy in non-acute promyelocytic AML. The literature search was based on publications on GO indexed in the PubMed electronic database and selected meeting abstracts. GO has shown moderate activity as a single agent but promising activity in combination with intensive chemotherapy in refractory or relapsed AML. Relapsed AML defined molecularly by mutant nucleophosmin-1 without concurrent fms-related tyrosine kinase 3 (FLT3) internal tandem duplication seems to benefit most from GO. In newly diagnosed AML two up-front randomized Phase III trials evaluating GO in induction therapy failed to demonstrate an improvement in response and survival. Again, genetically defined subgroups may benefit.

EXPERT OPINION

Future challenges of personalized therapy in AML will be to integrate the signals from current subgroup analyses underlining the role of GO in genetically defined AML entities.

Clofarabine and high-dose cytosine arabinoside in the treatment of refractory or relapsed acute myeloid leukaemia

Clofarabine (40 mg/m²/day × 5) and high-dose cytosine arabinoside (Ara-C, 1–2 g/m²/day × 5) were used in 10 men and 11 women, at a median age of 45 (22–62) years, with refractory (N = 4) and relapsed (N = 17) acute myeloid leukaemia, after a median of 3 (2–5) prior regimens. Grade 4 myelosuppression was observed in all cases, with two patients dying of bacterial sepsis. Nine patients achieved a complete remission. Disease status, number of prior therapies, and cytogenetic aberrations were not associated with the outcome. However, remission was only achieved with Ara-C at 2 g/m²/day and not 1 g/m²/day (9/15 versus 0/4, P = 0.03).

Improved outcome of patients with low- and intermediate-risk cytogenetics acute myeloid leukemia (AML) in first relapse with gemtuzumab and cytarabine versus cytarabine: results of a retrospective comparative study

BACKGROUND

Acute myeloid leukemia (AML) in first relapse is associated with a poor outcome even when treated with intermediate- to high-dose cytarabine (IHDAraC). Gemtuzumab ozogamycin (GO) used as a single agent has clinical activity in relapsed and refractory AML. Various combination regimens of GO have been developed, but few data are available regarding their efficacy compared with IHDAraC-based regimens.

METHODS

The authors performed a retrospective analysis of response and survival in 90 AML patients in first relapse treated with either IHDAraC (n = 56) or IHDAraC + GO (n = 34). Patient characteristics of the two groups were comparable.

RESULTS

Median follow-up was 37 months. Compared with IHDAraC, IHDAraC + GO induction was associated with a better response rate (68% vs 45%, P = .04), a better overall survival (median, 35 months vs 6 months, P = .001), and a better event-free survival (24 months vs 6 months, P = .002). This effect was limited to patients with low-risk and intermediate-risk cytogenetics. In multivariate analysis, age, cytogenetic risk, first complete remission duration, and the use of IHDAraC + GO were independently associated with better results.

CONCLUSIONS

This study showed that the addition of GO to IHDAraC is associated with a better efficacy for patients in first relapse of AML with low- or intermediate-risk cytogenetics. Prospective controlled studies of GO in this population are warranted. Patients with high-risk cytogenetics should be offered investigational new drugs.

Day 15 bone marrow driven double induction in young adult patients with acute myeloid leukemia: feasibility, toxicity, and therapeutic results

The strategy named double induction (DI) in acute myeloid leukemia (AML) consists of two courses of chemotherapy irrespective of the degree of cytoreduction in the bone marrow (BM) after the first course, unless severe complications prohibit its application. We describe treatment results from a series of 33 patients in whom DI was adopted only after demonstration of persistence of more than 10% blast cells at day 15 (D15) examination of BM. All patients received as induction idarubicin, cytarabine, and etoposide. As second induction, we administered the combination of fludarabine, intermediate dose cytarabine, and Granulocyte colony stimulating factor (G-CSF). The median blast count at D15 was 30 (15-90). Overall, 30 of 33 patients were judged as eligible to receive DI, reasons for exclusion being in all cases active infection in the context of severe pancytopenia. Nineteen patients (63%) had unfavorable karyotype and 11 (37%) normal karyotype; seven of these had Fms-like tyrosine kinase gene internal tandem duplication (FLT3/ITD) mutation. Overall, complete remission (CR) was achieved in 20/30 patients (67%), while eight patients (27%) were refractory and two died of infectious complications. All refractory patients had unfavorable cytogenetics. All patients achieving CR were programmed to receive allogeneic stem cell transplantation (allo-SCT), which was actually performed in 11 patients. Our study suggest that D15 driven DI represents a feasible and effective therapeutic strategy in young adult AML patients, improving therapeutic results and not compromising feasibility of allo-SCT. When compared with conventional DI, it offers the potential to avoid unnecessary toxicity in a consistent proportion of patients.

High dose cytarabine plus gemtuzumab ozogamicin for patients with relapsed or refractory acute myeloid leukemia: Cancer and Leukemia Group B study 19902

Gemtuzumab ozogamicin (GO), an anti-CD33 immunoconjugate, was combined with high dose cytarabine (HiDAC; cytarabine 3g/m(2) over 3h daily for 5 days) for adults with relapsed or refractory AML. HiDAC plus GO 9mg/m(2) on day 7 and 4.5mg/m(2) on day 14 was not tolerated, but HiDAC followed by GO 9mg/m(2) on day 7 was safe: 12/37 (32%) patients with relapsed AML achieved complete remission. Median overall survival was 8.9 months. No grade 4 hepatic veno-occlusive disease was observed. This regimen merits further study, both in this setting and as a remission consolidation therapy.