Cladribine combined with high doses of arabinoside cytosine, mitoxantrone, and G-CSF (CLAG-M) is a highly effective salvage regimen in patients with refractory and relapsed acute myeloid leukemia of the poor risk: a final report of the Polish Adult Leukemia Group

A hybrid protocol CLAG-M, a possible player for the first-line therapy of patients with mixed phenotype acute leukemia. A Polish Adult Leukemia Group experience

Introduction

Mixed-phenotype acute leukemia (MPAL) is a rare disease with poor prognosis. So far, no standard approach has been established as the "know-how" of MPAL is based only on retrospective analyses performed on small groups of patients.

Materials and methods

In this study, a retrospective analysis of the outcomes of adult MPAL patients included in the PALG registry between 2005 and 2024 who received the CLAG-M hybrid protocol as induction or salvage therapy was performed.

Results

Sixteen of 98 MPAL patients received CLAG-M: eight as first-line and eight as salvage therapy. In the first line, two patients achieved partial response (PR), and six achieved complete remission (CR), of whom four successfully underwent allogeneic hematopoietic stem cell transplantation (alloHSCT). Two patients who did not undergo alloHSCT promptly relapsed. Within the whole group, the overall response rate (ORR) was 75% (n = 12/16). With the median follow-up of 13 months, six out of eight patients remain in CR, however, two of them died due to acute graft versus host disease. Out of eight patients who received CLAG-M in the second line, four patients (50%) obtained CR. AlloHSCT was conducted in seven cases, six of which were in CR. Only two patients remained in CR at the time of the last follow-up. Tolerance to treatment was good. The median times for severe neutropenia and thrombocytopenia were 22 days (range, 16-24) and 17 days (range, 12-24), respectively. Overall, grade 3-4 infections were observed in 12 cases, and all infections presented successful outcomes.

Conclusions

CLAG-M is an effective first-line salvage regimen for MPAL with an acceptable safety profile. Early achievement of CR with prompt alloHSCT allows for satisfactory disease control.

Decitabine as epigenetic priming with CLAG induce improved outcome of relapsed or refractory acute myeloid leukemia in children

BACKGROUND

Decitabine (DAC), a DNA methyltransferase inhibitor, has shown efficacy combined with chemotherapy for relapsed or refractory (R/R) acute myeloid leukemia (AML) in adults, but less is known about its efficacy in children. Accordingly, we conducted a study which involved a priming regimen consisting of DAC with cladribine, cytarabine, and granulocyte-stimulating factor (DAC-CLAG) and compared the efficacy and safety of this regimen with CLAG alone.

METHODS

A total of 39 R/R AML children who received the CLAG or DAC-CLAG regimen in Shanghai Children's Hospital were retrospectively enrolled in this non-randomized study. These regimens were studied sequentially over time. Twenty-two patients received CLAG from 2015, while 17 patients were administered epigenetic priming with DAC before CLAG from 2020. Patients were subsequently bridged to stem cell transplantation (SCT) or consolidation chemotherapy. Complete remission (CR) and adverse effects were analyzed by Fisher's exact test, and survival was analyzed by the Kaplan-Meier method.

RESULTS

DAC-CLAG conferred a numerically higher CR compared to CLAG (70.59% vs 63.64%; P = 0.740). High CR rates occurred in patients with good cytogenetics (P = 0.029) and prior induction without cladribine (P = 0.099). The 1-year event-free survival (EFS) was 64.71% ± 11.59% and 63.31% ± 10.35% in the DAC-CLAG and CLAG group (P = 0.595), and 1-year overall survival (OS) was 81.45% ± 9.72% and 77.01% ± 9.04%, respectively (P = 0.265). The 1-year OS and EFS after SCT were higher in the DAC-CLAG than in the CLAG cohort (100% vs 92.31% ± 7.39%, P = 0.072; 92.31% ± 7.39% vs 85.71% ± 9.35%, P = 0.158). Univariate analysis revealed that a good prognosis included good cytogenetics (P = 0.002), non-complex karyotype (P = 0.056), CR on reinduction (P < 0.0001), and bridging to SCT (P = 0.0007). Use of a hypomethylating agent (P = 0.049) and bridging to SCT (P = 0.011) were independent prognostic factors. Grade 3/4 hematologic toxicity and infection were the main adverse events.

CONCLUSIONS

DAC prior to the CLAG regimen improved remission in pediatric R/R AML, and was feasible and well tolerated. CLAG ± DAC as a salvage therapy prior to SCT induced improved survival.

Clofarabine Preconditioning followed by Allogeneic Transplant Using TBI and Post-Transplant Cyclophosphamide for Relapsed Refractory Leukemia

Acute myeloid leukemia patients with induction failure or relapsed refractory disease have minimal chance of achieving remission with subsequent treatments. Several trials have shown the feasibility of clofarabine-based conditioning in allogeneic stem cell transplants (allo-HSCT) for non-remission AML patients. Pre-transplant conditioning with clofarabine followed by reduced-intensity allo-HSCT has also demonstrated a potential benefit in those patients with human leukocyte antigen (HLA)-identical donors, but it is not commonly used in haploidentical and mismatched transplants. In this case report, we describe our experience of seven cases of non-remission AML who received clofarabine preconditioning followed by an allo-HSCT with PTCy. The 2-year overall survival and disease-free survival was 83.3% (95% confidence interval (CI): 27.3-97.9%) and 85.7% (95% CI: 33.4-97.9%). Median days of neutrophil and platelet recovery were 16 (range of 13-23) and 28 (range of 17-75), respectively. The cumulative incidence of grade II-IV acute graft-versus-host disease (GVHD) at day 100 and chronic GVHD at 1-year showed 28.6% (95% CI: 8-74.2%) and 28.6% (95% CI: 3-63.9%), respectively. The two-year relapse rate was 14.3% (95% CI: 2.14-66.6%). One-year GVHD-free relapse-free survival (GFRS) at 1-year was 71.4% (95% CI: 25.8-92%). Our patients showed successful outcomes with clofarabine preconditioning to reduce the leukemic burden at the pre-transplant period followed by PTCy to reduce GVHD resulting in lower relapsed rate and better GFRS in these patients.

Phase II study of cladribine, idarubicin, and ara-C (CLIA) with or without sorafenib as initial therapy for patients with acute myeloid leukemia

The addition of cladribine, or sorafenib to standard chemotherapy have each demonstrated improved survival in patients with newly-diagnosed acute myeloid leukemia (AML). We studied the combination of cladribine, idarubicin, and intermediate-dose cytarabine (CLIA) in patients ≤65 years of age with newly diagnosed AML, fit to receive intensive therapy. Cladribine (5 mg/m2) IV was administered on days (D)1-5, cytarabine (1 g/m2) on D1-5, and idarubicin (10 mg/m2) on D1-3. Sorafenib was added to the CLIA backbone for patients with FLT3-ITD mutated AML. 80 patients were enrolled: 65 with newly diagnosed AML and 15 with AML arising from previously treated MDS (ts-AML). The median age was 55 years (range, 21-65). CR + CRi was 83% (54/65) and 27% in the untreated and ts-AML cohorts, respectively; 74% and 75% of responding patients, respectively, had undetectable measurable residual disease (MRD). Among patients with FLT3-ITD mutated AML receiving CLIA+sorafenib, the CR + CRi rate was 95%, with 81% negative for MRD. With a median follow-up of 76 months, the 2- and 4-year OS of 57% and 50% compared to 20%, and 13% for ts-AML, respectively. Patients treated with CLIA+sorafenib had 2- and 5-year OS rates of 63% and 59%, respectively. The most common Grade ≥3 adverse events were infection/fever, elevated bilirubin, rash, and nausea. CLIA was safe and effective in young, fit patients with newly diagnosed AML with inferior outcomes among patients with ts-AML. The addition of sorafenib to CLIA in FLT3-ITD mutated AML resulted in high rates of durable remission and excellent long-term survival.

Olanzapine within steroid-sparing antiemetic regimen to prevent chemotherapy-induced nausea and vomiting in patients with acute leukemia receiving multi-day intensive chemotherapy

INTRODUCTION

Olanzapine use for chemotherapy-induced nausea and vomiting (CINV) in hematological malignancies, for multi-day chemotherapy, and with a steroid-sparing antiemetic strategy is poorly understood. This study investigated if olanzapine is associated with improved prevention of CINV when added to a steroid-sparing antiemetic regimen in patients with acute leukemia receiving intensive, moderately emetogenic, multi-day chemotherapy.

METHODS

This was a single-center, retrospective cohort study in patients with acute leukemia. Patients who received olanzapine for CINV prevention were compared to those who did not. All patients received a 5-HT3 antagonist. Adult patients receiving moderately emetogenic, multi-day, intensive chemotherapy for acute leukemia were included. Patients were excluded if they received steroids greater than physiological doses during the study period. The primary endpoint was the complete response of CINV (no emesis or rescue antiemetic usage).

RESULTS

This study included 58 patients, 12 patients received olanzapine and 46 patients were in the control group. Baseline demographics were similar. In the study population, 89.7% had acute myeloid leukemia, median age was 54 (interquartile range 42-63) years, 34.5% were female, 27.6% had prior CINV. Complete response of CINV was similar between groups, 4 (33.3%) and 15 (32.6%) patients in the olanzapine and control groups, respectively. Safety events were similar between groups.

CONCLUSION

Patients with acute leukemia receiving multi-day intensive chemotherapy are at high risk for CINV. The limited data in this study suggests that olanzapine use within a steroid-sparing antiemetic regimen was well tolerated and associated with similar incidence and severity of CINV compared to the control group.

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 after intensive chemotherapy with CLAG-M versus 7+3 for AML and other high-grade myeloid neoplasms

Contemporary data on infections after intensive chemotherapy for acute myeloid leukemia (AML) are scarce. Cladribine, high-dose cytarabine, G-CSF, and dose-escalated mitoxantrone ("CLAG-M") may result in higher remission rates than standard-dose cytarabine plus anthracycline ("7 + 3") but may result in more infections. We compared moderate to severe infections occurring up to 90 days after the first induction cycle for AML or other high-grade myeloid neoplasms in patients receiving CLAG-M for newly diagnosed (n = 196) or relapsed/refractory disease (n = 131) or 7 + 3 for newly diagnosed disease (n = 115). For newly diagnosed disease, microbiologically documented infections were more frequent after CLAG-M compared to 7 + 3 (adjusted rate ratio, 1.65 [95% CI, 1.06-2.58]; P = 0.03), with a cumulative incidence of 27.8% and 16.5% by day 90, respectively. Patients receiving CLAG-M for relapsed/refractory disease had the highest cumulative incidence of 50.7%. Bacterial bloodstream infections were the most frequent followed by respiratory tract infections. Among 29 patients (7%) who died, infection was a primary or contributing cause of death in 59%. These data indicate that infections continue to cause substantial morbidity in patients treated for AML, especially those treated for relapsed/refractory disease, and are more common with newer, more myelosuppressive regimens such as CLAG-M. Improved strategies for infection prevention are needed.

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.

Phase II Trial of Pembrolizumab after High-Dose Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia

Immune suppression, exhaustion, and senescence are frequently seen throughout disease progression in acute myeloid leukemia (AML). We conducted a phase II study of high-dose cytarabine followed by pembrolizumab 200 mg i.v. on day 14 to examine whether PD-1 inhibition improves clinical responses in relapsed/refractory (R/R) AML. Overall responders could receive pembrolizumab maintenance up to 2 years. Among 37 patients enrolled, the overall response rate, composite complete remission (CRc) rate (primary endpoint), and median overall survival (OS) were 46%, 38%, and 11.1 months, respectively. Patients with refractory/early relapse and those receiving treatment as first salvage had encouraging outcomes (median OS, 13.2 and 11.3 months, respectively). Grade ≥3 immune-related adverse events were rare (14%) and self-limiting. Patients who achieved CRc had a higher frequency of progenitor exhausted CD8⁺ T cells expressing TCF-1 in the bone marrow prior to treatment. A multifaceted correlative approach of genomic, transcriptomic, and immunophenotypic profiling offers insights on molecular correlates of response and resistance to pembrolizumab.

Significance

Immune-checkpoint blockade with pembrolizumab was tolerable and feasible after high-dose cytarabine in R/R AML, with encouraging clinical activity, particularly in refractory AML and those receiving treatment as first salvage regimen. Further study of pembrolizumab and other immune-checkpoint blockade strategies after cytotoxic chemotherapy is warranted in AML.See related commentary by Wei et al., p. 551. This article is highlighted in the In This Issue feature, p. 549.

Efficacy and safety of cladribine addition to induction treatment of newly diagnosed acute myeloid leukemia: a systematic review and meta-analysis

OBJECTIVES

Compared with the 3 + 7 regimen, the cladribine-containing regimen has led to improvements in the rate of complete remission (CR) in the treatment of newly diagnosed acute myeloid leukemia (AML) patients. We conducted a systematic review and meta-analysis to investigate the overall efficacy and safety of cladribine-containing regimens in the induction treatment of newly diagnosed AML patients.

METHODS

Eligible studies were identified from the PubMed, EMBASE, and Cochrane Library databases. Efficacy was assessed by CR rate, disease-free survival (DFS), and overall survival (OS). Safety was evaluated based on the early death (ED) rate, days for neutrophils<0.5 × 10⁹/L, days for platelets<50 × 10⁹/L, and duration of hospital stay after treatment.

RESULTS

A total of 14 clinical trials were included in this meta-analysis, enrolling a total of 1058 newly diagnosed AML patients. The pooled estimate with a 95% confidence interval (CI) for CR was 64% (95% CI: 58-70%). Compared with the control group, the CR rate of the cladribine-containing regimen was higher (OR was 1.92 (95% CI: 1.55-2.38)). The combined ED rate was estimated to be 10% (95% CI: 5-14%). Compared with the control group, the ED rate of the cladribine-containing regimen was not increased (OR was 1.09 (95% CI: 0.78-1.53)).

CONCLUSION

This meta-analysis suggests that cladribine-containing regimens are likely to be effective and safe for induction treatment of newly diagnosed AML patients. However, large sample size and prospective controlled studies are needed to confirm our findings.

Cladribine Combined with Low-Dose Cytarabine as Frontline Treatment for Unfit Elderly Acute Myeloid Leukemia Patients: Results from a Prospective Multicenter Study of Polish Adult Leukemia Group (PALG)

Simple Summary

Treatment of acute myeloid leukemia (AML) in elderly patients unfit for intensive chemotherapy (IC) is a challenge in clinical practice. Here we prospectively evaluated a novel low-intensity regimen consisting of low-dose cytarabine combined with cladribine (LD-AC+cladribine) for remission induction followed by LD-AC alone in the maintenance phase as the frontline treatment for elderly AML patients ineligible for IC. We included a cohort of 117 elderly patients in poor performance status or with significant comorbidities. High-risk or intermediate-risk cytogenetics were observed in almost 90% of patients. Treatment with LD-AC+cladribine led to the objective response rate of 54% and the median overall survival of 17.3 months in the responders group. The toxicity profile was predictable and infectious complications were the most common non-hematological adverse events. In conclusion, we found LD-AC+cladribine as a beneficial therapeutic option with an acceptable safety profile in the difficult-to-treat population of elderly AML patient ineligible for IC.

Abstract

Acute myeloid leukemia (AML) in older unfit patients is a therapeutic challenge for clinical hematologists. We evaluated the efficacy and safety of a novel low-intensity regimen consisting of low-dose cytarabine and cladribine (LD-AC+cladribine) in first-line treatment of elderly (≥60 years) AML patients not eligible for intensive chemotherapy (IC) who had either the Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2 or the hematopoietic cell transplantation comorbidity index (HCT-CI) score ≥3. The induction phase included two cycles of LD-AC+cladribine. Patients who achieved at least partial remission (PR) received maintenance treatment with LD-AC alone. Overall, 117 patients with a median age of 70 years were enrolled. Adverse cytogenetics, ECOG PS ≥2 and HCT-CI score ≥3 was observed in 43.5%, 60%, and 58% of patients, respectively. The response rate (≥PR) was 54% (complete remission [CR], 32%; CR with incomplete hematologic recovery [CRi], 5%). A median overall survival (OS) was 21 and 8.8 months in CR/CRi and PR group, respectively. Advanced age (≥75 years) and adverse cytogenetics had a negative impact on OS. The 56-day mortality rate was 20.5%. In conclusion, LD-AC+cladribine is a beneficial therapeutic option with a predictable safety profile in elderly AML patients not eligible for IC.

Long-term results of low-intensity chemotherapy with clofarabine or cladribine combined with low-dose cytarabine alternating with decitabine in older patients with newly diagnosed acute myeloid leukemia

The treatment of older patients with newly diagnosed acute myeloid leukemia (AML) using intensive chemotherapy is associated with treatment intolerance and poor survival. We evaluated two new lower-intensity regimens with clofarabine (n = 119) or cladribine (n = 129) combined with low-dose cytarabine (LDAC) alternating with decitabine. We reviewed response rates by subgroup and long term outcomes of 248 patients with newly diagnosed non core-binding-factor AML treated on two clinical trials investigating double nucleoside-analogue therapy (DNT) alternating with HMA from October, 2008 to April, 2018. Of 248 patients with a median age of 69 years (range, 49-85 years), 102 patients (41%) were ≥ 70 years, and 108 (44%) had adverse karyotype. Overall, 164 patients (66%) responded: 147 (59%) complete remission (CR) and 17 (7%) CR with incomplete count recovery (CRi). With a median follow up of 60 months, median relapse-free and overall survival (OS) were 10.8 and 12.5 months, respectively. The 2-year OS was 29%. Among patients with normal karyotype, the CR/CRi rate was 79% and the median OS 19.9 months. High response rates and OS were observed in patients with mutations in NPM1, FLT3, IDH2, and RUNX1. The 4- and 8-week mortality rates were 2% and 11%, respectively. The backbone of clofarabine or cladribine and LDAC alternating with decitabine was effective and safe for the treatment of older patients with newly diagnosed AML. Incorporating targeted therapies could extend the efficacy of this approach and provide more curative therapeutic options in this AML population.

Adoptive immunotherapy with CB following chemotherapy for patients with refractory myeloid malignancy: chimerism and response

We conducted a prospective evaluation of cord blood (CB)-derived adoptive cell therapy, after salvage chemotherapy, for patients with advanced myeloid malignancies and poor prognosis. Previously, we reported safety, feasibility, and preliminary efficacy of this approach. We present updated results in 31 patients who received intensive chemotherapy followed by CB infusion and identify predictors of response. To enhance the antileukemic effect, we selected CB units (CBU) with shared inherited paternal antigens and/or noninherited maternal antigens with the recipients. Twenty-eight patients with acute myeloid leukemia (AML), 2 with myelodysplastic syndrome, and 1 in chronic myeloid leukemia myeloid blast crisis were enrolled; 9 had relapsed after allogeneic transplant. Response was defined as <5% blasts in hypocellular bone marrow at 2 weeks after treatment. Thirteen patients (42%) responded; a rate higher than historical data with chemotherapy only. Twelve had CBU-derived chimerism detected; chimerism was a powerful predictor of response (P < .001). CBU lymphocyte content and a prior transplant were associated with chimerism (P < .01). Safety was acceptable: 3 patients developed mild cytokine release syndrome, 2 had grade 1 and 2 had grade 4 graft-versus-host disease. Seven responders and 6 nonresponders (after additional therapy) received subsequent transplant; 5 are alive (follow-up, 5-47 months). The most common cause of death for nonresponders was disease progression, whereas for responders it was infection. CB-derived adoptive cell therapy is feasible and efficacious for refractory AML. Banked CBU are readily available for treatment. Response depends on chimerism, highlighting the graft-versus-leukemia effect of CB cell therapy. This trial was registered at www.clinicaltrials.gov as #NCT02508324.

Reinduction chemotherapy regimen involved decitabine and cladribine improves the prognosis of patients with relapsed or refractory acute myeloid leukemia: A preliminary study

Relapsed/refractory acute myeloid leukemia (R/R-AML) is characterized by a high incidence, short survival and poor prognosis. Presently, no unified effective reinduction chemotherapy regimen has been developed. Therefore, the use of reinduction chemotherapy regimens before allogeneic hematopoietic stem cell transplantation (allo-HSCT) is controversial. Our study aims to analyze the prognostic factors of R/R-AML and to evaluate the efficacy of the regimen involved decitabine, cladribine, idarubicin or homoharringtonine, and cytarabine (DCIA/DCHA). Clinical and survival data of 112 R/R-AML patients were obtained. Among the 102 R/R-AML patients that were treated with conventional regimens, we found that poor prognosis was related to a greater proportion of bone marrow blasts (>70%) and not achieving complete remission (non-CR) after the first reinduction chemotherapy. Hematopoietic stem cell transplantation (of which 89.47% was allo-HSCT) following CR after the first reinduction chemotherapy often improves the prognosis. Of the 10 R/R-AML patients that were treated with the DCIA/DCHA regimen, nine patients achieved CR or complete response with incomplete hematopoietic recovery (CRi) after one course of chemotherapy. The median overall survival of the 10 patients was 10.14 (1.23-29.13) months. In conclusion, non-CR was associated with poor prognosis in R/R-AML. Therefore, intensive reinduction chemotherapy should be selected to achieve CR. This creates conditions for allo-HSCT and improves prognosis of R/R-AML patients. The DCIA/DCHA regimen showed good efficacy and tolerable adverse reactions in R/R-AML treatment. This combination may be used as a bridging regimen for allo-HSCT in R/R-AML.

Response and Toxicity to Cytarabine Therapy in Leukemia and Lymphoma: From Dose Puzzle to Pharmacogenomic Biomarkers

Simple Summary

In this review, the authors propose a crosswise examination of cytarabine-related issues ranging from the spectrum of clinical activity and severe toxicities, through updated cellular pharmacology and drug formulations, to the genetic variants associated with drug-induced phenotypes. Cytarabine (cytosine arabinoside; Ara-C) in multiagent chemotherapy regimens is often used for leukemia or lymphoma treatments, as well as neoplastic meningitis. Chemotherapy regimens can induce a suboptimal clinical outcome in a fraction of patients. The individual variability in clinical response to Leukemia & Lymphoma treatments among patients appears to be associated with intracellular accumulation of Ara-CTP due to genetic variants related to metabolic enzymes. The review provides exhaustive information on the effects of Ara-C-based therapies, the adverse drug reaction will also be provided including bone pain, ocular toxicity (corneal pain, keratoconjunctivitis, and blurred vision), maculopapular rash, and occasional chest pain. Evidence for predicting the response to cytarabine-based treatments will be highlighted, pointing at their significant impact on the routine management of blood cancers.

Abstract

Cytarabine is a pyrimidine nucleoside analog, commonly used in multiagent chemotherapy regimens for the treatment of leukemia and lymphoma, as well as for neoplastic meningitis. Ara-C-based chemotherapy regimens can induce a suboptimal clinical outcome in a fraction of patients. Several studies suggest that the individual variability in clinical response to Leukemia & Lymphoma treatments among patients, underlying either Ara-C mechanism resistance or toxicity, appears to be associated with the intracellular accumulation and retention of Ara-CTP due to genetic variants related to metabolic enzymes. Herein, we reported (a) the latest Pharmacogenomics biomarkers associated with the response to cytarabine and (b) the new drug formulations with optimized pharmacokinetics. The purpose of this review is to provide readers with detailed and comprehensive information on the effects of Ara-C-based therapies, from biological to clinical practice, maintaining high the interest of both researcher and clinical hematologist. This review could help clinicians in predicting the response to cytarabine-based treatments.

Improved outcome of children with relapsed/refractory acute myeloid leukemia by addition of cladribine to re-induction chemotherapy

Background

The preferred salvage treatment for children with relapsed/refractory acute myeloid leukemia (R/R‐AML) remains unclear. The combination of cladribine/Ara‐C/granulocyte‐colony stimulating factor and mitoxantrone (CLAG‐M) shown promising results in adult R/R‐AML. We aim to investigate the efficacy and safety of CLAG‐M versus mitoxantrone/etoposide/cytarabine (MEC) or idarubicin/etoposide/cytarabine (IEC) in R/R‐AML children.

Methods

Fifty‐five R/R‐AML children were analyzed. The overall response rate (ORR), overall survival (OS), and progression‐free survival (PFS) at 3‐year were documented. Karyotype or mutations status were summarized as different risk groups.

Results

The ORR was achieved in 80% (16/20) and 51% (18/35) of patients after one‐cycle of CLAG‐M and MEC/IEC treatment (p < 0.001). The CLAG‐M group's OS (66.8% ± 16.2% vs. 40.4% ± 10.9%, p = 0.019) and PFS (52.6% ± 13.7% vs. 34.9% ± 9.1%, p = 0.036) at 3‐year was significantly higher than the MEC/IEC group. In high‐risk patients, 33.3% experienced progression of disease (PD) and 22.2% dead in CLAG‐M group, while 50% experienced PD and 43.8% dead in MEC/IEC. When it comes to low‐risk group, none of them in CLAG‐M experienced PD or death, while up to 50% of patients received MEC/IEC suffered PD, and all of them died eventually. Similar results were also found in the intermediate‐risk group. Surprisingly, the presence of FLT3‐ITD was associated with poor outcome in both groups. The most common adverse events were hematologic toxicities, and the incidence was similar in both group.

Conclusions

CLAG‐M group demonstrated effective palliation along with acceptable toxicity in R/R‐AML patients. However, patients with FLT3‐ITD may benefit less from CLAG‐M, owing to higher PD rate and all‐cause mortality than other patients.

Successful treatment of two relapsed patients with t(11;19)(q23;p13) acute myeloid leukemia by CLAE chemotherapy sequential with allogeneic hematopoietic stem cell transplantation: Case reports

The prognosis of patients with relapsed/refractory acute myeloid leukemia (R/R AML) is poor, with a 3-year overall survival rate of 10%. Patients with translocation (t)(11;19)(q23;p13) have a higher risk of relapse and there is no optimal regimen for these patients. The present study treated two young patients with t(11;19)(q23;p13) AML, who relapsed after one or two cycles of consolidation, with a salvage treatment consisting of sequential cladribine, cytarabine and etoposide (CLAE) and allogeneic hematopoietic stem cell transplantation (allo-HSCT). Both neutrophil and platelet engraftments were achieved within 15 days, and no severe transplant-related complications and graft-versus-host diseases were observed. Following allo-HSCT, both patients achieved complete hematologic and cytogenetic remission. Decitabine was used for the prophylaxis of relapse. The two patients remained alive and disease-free for 100 days following allo-HSCT. The results presented here suggest that CLAE regimen sequential with allo-HSCT may be effective in treating patients with R/R AML, with t(11;19)(q23;p13). However, further studies and a larger sample size are required to validate the effectiveness of this treatment regimen.

CLAG-M chemotherapy followed by umbilical cord blood stem cell transplantation for primary refractory acute myeloid leukaemia in a child: A case report

BACKGROUND

The prognosis of paediatric primary refractory/relapsed acute myeloid leukaemia (R/R AML) remains poor. Intensive therapy is typically used as salvage treatment for those with R/R AML. No data are currently available about the use of the CLAG-M protocol as salvage therapy in paediatric patients with R/R AML.

CASE SUMMARY

An 8-year-old patient was diagnosed with acute myeloid leukaemia by bone marrow morphology and immunophenotype. The patient showed poor response to two cycles of induction therapy with 60% blast cells in the bone marrow after the second induction cycle. The patient achieved complete remission after being treated with the CLAG-M protocol as salvage therapy before undergoing umbilical cord blood stem cell transplantation. Morphological complete remission with haematological recovery has hitherto been maintained over 4 mo. Abnormal gene mutations detected at diagnosis were undetectable after haematopoietic stem cell transplantation.

CONCLUSION

Here we present a paediatric patient with primary refractory acute myeloid leukaemia who was successfully treated with the CLAG-M protocol. Given the positive results of the presented patient, large-scale clinical studies are required to assess the role of the CLAG-M protocol in the salvage treatment of refractory or relapsed AML in childhood.

TET2/IDH1/2/WT1 and NPM1 Mutations Influence the RUNX1 Expression Correlations in Acute Myeloid Leukemia

Background and objectives: Mutational analysis has led to a better understanding of acute myeloid leukemia (AML) biology and to an improvement in clinical management. Some of the most important mutations that affect AML biology are represented by mutations in genes related to methylation, more specifically: TET2, IDH1, IDH2 and WT1. Because it has been shown in numerous studies that mutations in these genes lead to similar expression profiles and phenotypes in AML, we decided to assess if mutations in any of those genes interact with other genes important for AML. Materials and Methods: We downloaded the clinical data, mutational profile and expression profile from the TCGA LAML dataset via cBioPortal. Data were analyzed using classical statistical methods and functional enrichment analysis software represented by STRING and GOrilla. Results: The first step we took was to assess the 196 AML cases that had a mutational profile available and observe the mutations that overlapped with TET2/IDH1/2/WT1 mutations. We observed that RUNX1 mutations significantly overlap with TET2/IDH1/2/WT1 mutations. Because of this, we decided to further investigate the role of RUNX1 mutations in modulating the level of RUNX1 mRNA and observed that RUNX1 mutant cases presented higher levels of RUNX1 mRNA. Because there were only 16 cases of RUNX1 mutant samples and that mutations in this gene determined a change in mRNA expression, we further observed the correlation between RUNX1 and other mRNAs in subgroups regarding the presence of hypermethylating mutations and NPM1. Here, we observed that both TET2/IDH1/2/WT1 and NPM1 mutations increase the number of genes negatively correlated with RUNX1 and that these genes were significantly linked to myeloid activation. Conclusions: In the current study, we have shown that NPM1 and TET2/IDH1/2/WT1 mutations increase the number of negative correlations of RUNX1 with other transcripts involved in myeloid differentiation.

Comparison of salvage chemotherapy regimens and prognostic significance of minimal residual disease in relapsed/refractory acute myeloid leukemia

We compared the outcomes of salvage chemotherapy in 146 patients with relapsed (57.5%) or refractory (42.5%) AML who received CLAG-M (51%), MEC (39%) or CLAG (10%). Minimal residual disease (MRD) was assessed by flow cytometry. Bivariate, Kaplan-Meier, and Cox regression analyses were conducted. Complete remission (CR) rate of 46% (CLAG-M 54% versus MEC/CLAG 40%, p = .045) was observed with MRD-negative CR of 33% (CLAG-M 39% versus MEC/CLAG 22%, p = .042). Median overall survival (OS) was 9.7 months; the longest OS occurred with CLAG-M (13.3, 95%CI 2.4-24.3) versus MEC (6.9, 95%CI 2.9-10.9) or CLAG (6.2, 95%CI 2.4-12.6) (p = .025). When adjusted for age, gender, relapsed/refractory AML, poor risk AML, MRD, chemotherapy and transplant, CLAG-M (HR 0.63, 95% CI 0.40-0.98, p = .042), MRD-negativity (HR 0.15, 95% CI 0.07-0.30, p < .001) and transplant (HR 0.22, 95% CI 0.13-0.39, p < .001) were associated with higher OS. Our findings confirm that CLAG-M is a reasonable salvage regimen for RR-AML followed by transplant.

Cladribine with Granulocyte Colony-Stimulating Factor, Cytarabine, and Aclarubicin Regimen in Refractory/Relapsed Acute Myeloid Leukemia: A Phase II Multicenter Study

Lessons Learned

Studies targeting cladribine in combination with granulocyte colony‐stimulating factor, low‐dose cytarabine, and aclarubicin (C‐CAG) regimen in relapsed and refractory acute myeloid leukemia (R/R AML) are limited.

The complete remission rate after two cycles of C‐CAG regimen was 67.6%, and 1‐year overall survival and disease‐free survival rates were 59.7% and 72.9%, respectively.

The C‐CAG regimen is significantly effective against R/R AML with a low hematological toxicity and thus serves as an alternative treatment for R/R AML.

Background

The optimal salvage chemotherapy regimen for relapsed and refractory acute myeloid leukemia (R/R AML) remains uncertain. Therefore, a phase II study was conducted for the prospective evaluation of the efficacy and safety of the purine analog cladribine in combination with granulocyte colony‐stimulating factor (G‐CSF), low‐dose cytarabine, and aclarubicin (C‐CAG) regimen for patients with R/R AML.

Methods

A total of 34 patients received C‐CAG regimen for salvage treatment as follows: cladribine 5 mg/m², days 1–5; G‐CSF 300 μg, days 0–9; aclarubicin 10 mg, days 3–6; cytarabine 10 mg/m² every 12 hours, subcutaneously, days 3–9; 4 weeks per cycle. Patients were allowed to withdraw from the study if complete remission (CR) was not achieved after two courses of chemotherapy. If conditions were right, the patients achieving CR were recommended to receive allogeneic hematopoietic stem cell transplantation. Otherwise, they were treated for a total of six cycles unless disease progression or unacceptable side effects were observed or they withdrew their consent.

Results

All patients received at least two cycles of C‐CAG regimen chemotherapy. After two cycles of C‐CAG, 23 patients (67.6%) achieved CR, and 5 patients had partial remission (14.7%). At a median follow‐up of 15 months (range, 3–38 months), the 1‐year overall survival (OS) and disease‐free survival (DFS) rates were 59.7% (95% confidence interval [CI], 42.6%–76.8%) and 72.9% (95% CI, 54.3%–91.5%), respectively. The most common adverse effect was myelosuppression. Nonhematological toxicities were mild, and no treatment‐related deaths occurred.

Conclusion

Preliminary data indicate that the C‐CAG regimen chemotherapy is significantly effective against R/R AML with a high remission rate and a low hematological toxicity. Thus, it may serve as an alternative treatment for R/R AML.

How I treat relapsed or refractory AML

Treatment of relapsed or refractory acute myeloid leukemia (AML) has presented challenges for hematologists for decades. Despite numerous clinical studies, outcomes are consistently disappointing with 5-year overall survival rates of ∼10%. Allogeneic hematopoietic cell transplantation at the time of second complete remission remains the only reliable option with curative potential. However, recent approval of several new agents has transformed treatment paradigms that had been in place for almost half a century in AML. This new therapeutic landscape provides the opportunity to revisit the approach to relapsed or refractory AML. Through illustrative cases, we describe our approach, which increasingly relies on specific disease biology. We focus on treatment outside of the context of clinical trials because such trials are not available in most parts of the world. Primarily, we consider age, fitness to tolerate intensive chemotherapy, remission duration, and presence of a targetable mutation to guide treatment. The coming years will inevitably bring new targets and agents that may prove most effective when combined with each other and/or chemotherapy. Future studies are needed to determine how best to implement this evolving armamentarium of treatment options, to elucidate mechanisms of resistance, and to continue the pursuit of novel drug discovery.

Administration sequence for multi-agent oncolytic regimens

Purpose

The existence of a multitude of oncolytics regimens containing two or more agents (combination) outlines the need to define their most adequate sequence of administration. However, limited resources are currently available to specify a particular sequence, presenting challenges potentially impacting on patient safety, and Pharmacy & Infusion Nursing workflows.

Methods

A comprehensive literature search was performed leading to the compilation of a document containing drug administration sequencing instructions for our Nursing, Pharmacy, and Oncology providers to follow. Regimens prioritized in our literature review represented regimens selected as part of our approved Clinical Pathways, regimens inquiries from Pharmacy or Nursing, as well as less frequently used regimens. We stratified the regimens by tumor type and arranged them alphabetically by indication.

Results

A table was compiled containing all the supporting literature for the recommended drug administration sequences. If, in certain instances, no literature support was identified outlining rationale such as enhanced management of adverse effects, a specific institutional decision was made by our enterprise Medical Oncology Committee with recommendations from Pharmacy experts. The primary guiding principles for outlining our recommendations were the following: administration of vesicant agents first; administration of biologic agents first; administration of taxanes prior to platinum agents; and duration of infusion (shorter infusions prioritized).

Conclusion

This guideline is not exhaustive. The compilation provided here is intended to be utilized as guidance for oncolytics administration sequence. We will continue to review and incorporate treatment sequencing recommendations for additional regimens.

Re-induction with modified CLAG regimen in relapsed or refractory acute myeloid leukemia in children bridging to allogeneic hematopoietic stem cell transplantation

BACKGROUND

The prognosis for relapsed or refractory acute myeloid leukemia (RR-AML) in children is poor, and the preferred salvage chemotherapy is unclear. One regimen is cladribine, cytarabine, and granulocyte-colony stimulating factor (CLAG), but little is known about its efficacy and safety in children with RR-AML.

METHODS

We enrolled RR-AML patients aged 0-18 years who received modified CLAG regimen for re-induction between July 1, 2015 and April 1, 2018, or conventional induction between August 1, 2011 and April 1, 2018. Patients were followed up to March 31, 2019. Patients underwent allogeneic stem cell transplantation (allo-SCT) or chemotherapy after the induction of complete remission (CR). The CR rate, survival, and side effects were analyzed.

RESULTS

The CR rate for induction was 66.7% after one cycle and 75.0% after two cycles of the CLAG regimen in 12 children. The nine children who received conventional chemotherapy had a CR rate of 22.2% after one cycle and 33.3% after two cycles (P = 0.087 vs. CLAG). The 3-year event-free survival (EFS) of the CLAG group and the conventional treatment group were 44.4 ± 15.7% and 22.2 ± 13.8% (P = 0.112). The 3-year overall survival of the two groups were 59.5 ± 16.2% and 22.2% ± 13.8% (P = 0.057). The 3-year EFS for allo-SCT and chemotherapy after CLAG regimen was 66.7 ± 19.2% and 25.0 ± 21.7% (P = 0.015). A single case of chemotherapy-related death was recorded.

CONCLUSION

Our data suggest a promising CR rate using CLAG salvage treatment in childhood RR-AML. Allo-SCT after CR may improve the long-term outcome in these patients.

Long-term follow-up of Cladribine, high-dose Cytarabine, and Idarubicin as salvage treatment for relapsed acute myeloid leukemia and literature review

PURPOSE

Outcome for relapsed acute myeloid leukemia (AML) is poor. Cladribine has activity in AML, and an enhancing effect on other cytostatic drugs thus may help overcome resistance. Here, we present the final analysis of our phase II trial evaluating safety and efficacy of cladribine, cytarabine, and idarubicin (CAI) in relapsed AML.

METHODS

Patients with relapsed AML after at least 6 months remission received two courses of CAI. After 9 patients, prolonged neutropenia prompted protocol change (omission of idarubicin in 2nd course and dose-reduction of cytarabine). Primary endpoints were remission rate and safety.

RESULTS

Twenty patients received treatment, fourteen one, and six two courses CAI/CA. After first course, complete remission (CR/CRi) was achieved in 60%. Most frequent toxicity was infection. Median OS was 8.8 months in all patients and 21.1 months in those with CR. Nine patients (48%) proceeded to allogeneic stem cell transplantation (allo-SCT), four of those are still alive and in CR, accounting for a 5-year survival rate of 55% of transplanted patients.

CONCLUSION

Cladribine, cytarabine, and idarubicin in relapsed AML is feasible and induces good response rates. As expected, infections are the most important complication. However, combined with allo-SCT, long-term survival can be achieved in a substantial number of patients.

Progress in acute myeloid leukaemia: small molecular inhibitors with small benefits

The use of small molecule inhibitors in acute myeloid leukaemia (AML) has become ubiquitous with the US Food and Drug Administration approval of multiple agents between 2017 and 2018. Despite the promise, some of these indications are based on early efficacy data (phase I/II), and single-arm studies, and have not been tested in randomised trials. Furthermore, there are important limitations in the evidence that exists in randomised trials. This perspective aims to summarise the data that formed the basis for approval of gilteritinib, glasdegib, ivosidenib, enasidenib and venetoclax. It also aims to shed a light on some of the limitations in the evidence. Clinicians should exercise caution when using drugs that largely have yet to show an improvement in survival over the standard of care in AML.

Comparison of High-Dose Cytarabine, Mitoxantrone, and Pegaspargase (HAM-pegA) to High-Dose Cytarabine, Mitoxantrone, Cladribine, and Filgrastim (CLAG-M) as First-Line Salvage Cytotoxic Chemotherapy for Relapsed/Refractory Acute Myeloid Leukemia

Currently, no standard of care exists for the treatment of relapsed or refractory acute myeloid leukemia (AML). We present our institutional experience with using either CLAG-M or HAM-pegA, a novel regimen that includes pegaspargase. This is a retrospective comparison of 34 patients receiving CLAG-M and 10 receiving HAM-pegA as first salvage cytotoxic chemotherapy in the relapsed or refractory setting. Composite complete response rates were 47.1% for CLAG-M and 90% for HAM-pegA (p = 0.027). Event-free survival was significantly different in favor of HAM-pegA (p = 0.045), though overall survival was similar between groups. There were no significant differences in toxicities experienced by patients treated with the two regimens, including adverse events of special interest related to pegaspargase (venous thromboembolism, hemorrhage, hepatotoxicity, pancreatitis, and hypersensitivity reactions). HAM-pegA is a novel regimen for relapsed or refractory AML that resulted in improved response rates and similar toxicities compared to CLAG-M.

The role of cladribine in acute myeloid leukemia: an old drug up to new tricks

Despite advances in understanding the pathogenesis of acute myeloid leukemia (AML), the standard therapy remained nearly unchanged for several decades. There have been many efforts to improve the response and survival by either increasing the cytarabine (ARA-C) dose or adding a third agent to the standard chemotherapy regimen. Several studies have evaluated the addition of cladribine (CdA) to standard induction, exploiting its property to potentiate ARA-C uptake. Response rates for combination regimens including CdA in relapsed/refractory (R/R) adults are approximately 50% and approximately 70% in de novo AML. Recently, a low intensity combination of CdA and ARA-C alternating with decitabine has shown promising results in older patients with AML. In this review, we will discuss the role of CdA in the treatment of AML, summarizing the recent clinical data regarding its incorporation into the induction therapy for adult AML.

Early induction intensification with cladribine, cytarabine, and mitoxantrone (CLAM) in AML patients treated with the DAC induction regimen: a prospective, non-randomized, phase II study of the Polish Adult Leukemia Group (PALG)

We present the results of a prospective, non-randomized phase 2 trial in which 253 AML patients (pts) under 60 years old received DAC (Daunorubicin + AraC + Cladribine) as first induction followed by CLAM (Cladribine + AraC + Mitoxantrone) as early second induction on day 16 based on bone marrow (BM) blasts on day 14 (D14). The CR/CRi rate after a single course of DAC was 83% for pts with D14 BM blasts less than 10%. Forty-six pts had >10% BM blasts on D14, of whom 35 received CLAM with rates of CR/CRi 60% and early death (ED) 23%. The remaining 11 pts were not fit to receive CLAM, with rates of CR/CRi 28%, PR 18%, and ED 18%. Median OS was 7.2 versus 7.5 months, respectively. The overall CR/CRi rate was 77% after the first induction, with final CR/CRi rate 80% after DAC reinduction for pts who achieved PR with initial DAC course. CLAM used as early second induction might improve CR/CRi rates for younger AML pts with poor early response to DAC induction, but may be associated with higher mortality.

Etoposide Combined with FLAG Salvage Therapy Is Effective in Multiple Relapsed/Refractory Acute Myeloid leukemia

Managing acute myeloid leukemia (AML) is often hampered by repeated failure to achieve complete remission as well as recurrent relapse that causes an emergent need for alternative salvage therapies. The efficacy of most salvage therapies is based on anthracycline combinations. In highly pretreated patients who are not eligible for anthracycline-based protocols therapeutic alternatives are limited. For this particular group we evaluated the efficacy and safety of fludarabine, cytarabine, granulocyte colony-stimulating factor (FLAG) in combination with etoposide (FLAG-Eto) in 36 patients. The complete remission rate (CR) was 25.7% with a median overall survival of 6 months (95% CI 4.5-7.7). The median disease-free survival for CR/CRi/MLFS (CR/CR with incomplete he-matological recovery/morphologic leukemia-free state) patients was 8 months (95% CI 0.6-15.5). The mortality rate on day 30 was 8% and increased on day 60 to 17%. Our results show meaningful anti-leukemic activity of the FLAG-Eto regimen with a moderate toxicity profile in heavily pretreated relapsed/refractory AML patients enabling consolidating allogeneic stem cell transplantation.

Antibody Therapies for Acute Myeloid Leukemia: Unconjugated, Toxin-Conjugated, Radio-Conjugated and Multivalent Formats

In recent decades, therapy for acute myeloid leukemia (AML) has remained relatively unchanged, with chemotherapy regimens primarily consisting of an induction regimen based on a daunorubicin and cytarabine backbone, followed by consolidation chemotherapy. Patients who are relapsed or refractory can be treated with allogeneic hematopoietic stem-cell transplantation with modest benefits to event-free and overall survival. Other modalities of immunotherapy include antibody therapies, which hold considerable promise and can be categorized into unconjugated classical antibodies, multivalent recombinant antibodies (bi-, tri- and quad-specific), toxin-conjugated antibodies and radio-conjugated antibodies. While unconjugated antibodies can facilitate Natural Killer (NK) cell antibody-dependent cell-mediated cytotoxicity (ADCC), bi- and tri-specific antibodies can engage either NK cells or T-cells to redirect cytotoxicity against AML targets in a highly efficient manner, similarly to classic ADCC. Finally, toxin-conjugated and radio-conjugated antibodies can increase the potency of antibody therapies. Several AML tumour-associated antigens are at the forefront of targeted therapy development, which include CD33, CD123, CD13, CLL-1 and CD38 and which may be present on both AML blasts and leukemic stem cells. This review focused on antibody therapies for AML, including pre-clinical studies of these agents and those that are either entering or have been tested in early phase clinical trials. Antibodies for checkpoint inhibition and microenvironment targeting in AML were excluded from this review.

Modified cladribine, cytarabine, and G-CSF as a salvage regimen in patients with relapsed/refractory acute myeloid leukemia: a bridge to myeloablative allogeneic hematopoietic stem cell transplantation

Patients with primary refractory or early relapsed acute myeloid leukemia (AML) have a dismal prognosis, and the treatment options for these patients are limited. The present study retrospectively examined the efficacy and toxicities of the combination of cladribine 5 mg/m² per day and intermediate-dose cytarabine 1 g/m² per day for 5 days and granulocyte colony-stimulating factor (G-CSF) as a salvage treatment in 36 patients with relapsed/refractory AML. Among these, 32 patients had de novo AML, and the remaining 4 patients had secondary AML. The median age for the study cohort was 45.8 years. According to the European LeukemiaNet prognostic index, 5 patients had favorable risk, 18 had intermediate risk, and 11 had poor risk. The complete remission was achieved in 58% of the patients with tolerable toxicities. Fifteen patients underwent stem cell transplantation later. Patients who underwent allogeneic hematopoietic stem cell transplantation had a significantly improved 1-year overall survival compared with those who did not (73% vs. 29%, P < 0.001). The results suggested that, as a salvage regimen, modified cladribine, cytarabine, and G-CSF were effective and well tolerated for patients with relapsed/refractory AML, especially for patients who underwent subsequent stem cell transplantation.

Efficacy and toxicity of cladribine for the treatment of refractory acute myeloid leukemia: a meta-analysis

Purpose: To investigate the overall efficacy and toxicity of cladribine and cladribine-based chemotherapy in the treatment of patients with refractory acute myeloid leukemia (AML) based on meta-analysis.

Methods: PubMed, EMBASE database, and the Cochrane Library were searched for relevant studies. Eligible studies were clinical trials of refractory AML assigned to cladribine with data on efficacy including complete remission (CR) rate, overall response rate (ORR) and overall survival. Toxicity was evaluated based on the early death rate and the incidence of grade 3 and 4 adverse events (AEs).

Results: A total of 10 clinical trials including 422 refractory AML patients were analyzed. The overall CR rate was 42.2% (95% CI: 31.0–54.3%). And the ORR of seven trials including 235 patients was 49.7% (95% CI: 33.5–66.0%). The overall early death rate of 260 patients enrolled in five trials was 6.8% (95% CI: 4.3–10.6%). Thrombocytopenia, anemia, neutropenia, and infection were the most common grade 3 and 4 AEs.

Conclusion: Cladribine is effective for refractory AML, and its efficacy can be increased with the combination of cladribine, cytarabine, and granulocyte-colony stimulating factor regimen.

Detection of Novel t(12;17)(p12;p13) in Relapsed Refractory Acute Myeloid Leukemia by Anchored Multiplex PCR(AMP)-based Next-Generation Sequencing

Although several technologies can be used to detect gene fusions, anchored multiplex PCR next-generation sequencing (AMP-NGS) offers the advantage of novel fusion detection and the ability to multiplex multitudinous genes. We applied AMP-NGS technology in the evaluation of a 56-year-old gentleman with myelodysplastic syndrome transformed acute myeloid leukemia (AML). Patient was initially diagnosed with low-risk myelodysplastic syndrome-refractory cytopenias and multilineage dysplasia (MDS-RCMD), progressed to AML after failing hypomethylating agent therapy. At progression patients had normal cytogenetics but NGS profiling showed ETV6 c.416_417del CT frame shift and U2AF1 S34F mutations. Patient attains brief remission of 2 months after induction chemotherapy and then he was refractory to 2 salvage chemotherapy regimens. Reassessment after failing second salvage, identified t(12;17)(p13;p13)[20] by karyotype. It was postulated that the 12p13 locus might represent a new rearrangement of ETV6. AMP-NGS confirmed involvement of the ETV6 with discovery of a novel fusion partner, HIC1. The detection of the novel fusion partners was supported by the breakpoints originally observed by karyotype. This discovery of ETV6-HIC1 gene fusion by AMP-NGS technology provided new insight into a leukemogenic pathway in AML. Future use of this technology can serve as an adjunct tool in workup of patients with AML and can also help in formulating therapeutic strategies.

Analysis of Efficacy and Prognostic Factors of CLAG Treatment in Chinese Patients with Refractory or Relapsed Acute Myeloid Leukemia

BACKGROUND/AIMS

The aim of this work was to investigate the efficacy and predictive factors of CLAG treatment in refractory or relapsed (R/R) acute myeloid leukemia (AML) patients.

METHODS

Sixty-seven R/R AML patients were enrolled in this prospective cohort study and treated by a CLAG regimen: 5 mg/m2/day cladribine (days 1-5), 2 g/m2/day cytarabine (days 1-5), and 300 μg/day filgrastim (days 0-5). The median follow-up duration was 10 months.

RESULTS

A total of 57 out of 67 patients were evaluable for remission after CLAG therapy, of whom 57.9% achieved a complete remission (CR) and the overall remission rate was 77.2%. The median overall survival (OS) was 10.0 months, with a 1-year OS of 40.3 ± 6.0% and 3-year OS of 16.7 ± 5.7%. CR at first induction after the initial diagnosis was associated with a favorable CR. Age above 60 years, high risk stratification, second or higher salvage therapy, and bone marrow (BM) blasts ≥42.1% were correlated with an unfavorable CR. Secondary disease, age ≥60 years, high risk stratification, and second or higher salvage therapy were associated with worse OS. Patients developed thrombocytopenia (41, 61%), febrile neutropenia (37, 55%), leukopenia (33, 49%), neutropenia (18, 27%), and anemia (9, 13%).

CONCLUSION

CLAG was effective and well tolerated for R/R AML. BM blasts ≥42.1%, age ≥60 years, high risk stratification, and second or higher salvage therapy were independent factors for a poor prognosis.

Outcomes of fludarabine, high dose cytarabine and granulocyte-colony stimulating factor (FLAG) as re-induction for residual acute myeloid leukemia on day 14 bone marrow

BACKGROUND

Patients with acute myeloid leukemia (AML) treated with intensive chemotherapy may require re-induction based on the evaluation of day 14 bone marrow biopsy.

METHODS

A retrospective chart review was performed to evaluate adult patients with AML who received re-induction with fludarabine, high dose cytarabine and granulocyte colony stimulating factor (FLAG) regimen for residual disease (≥ 5% blasts by morphology) on day 14 bone marrow examination between September 2012 and July 2017 at our institution.

RESULTS

We identified 27 patients who received FLAG therapy for treatment of residual disease on day 14 marrow examination following initial induction. The median age at diagnosis was 61 years and the majority of patients had poor risk AML. The overall response rate was 78% and 15 patients proceeded to allogeneic hematopoietic stem cell transplantation.

CONCLUSION

The regimen was well tolerated and is a viable re-induction option for patients with residual disease on a day 14 bone marrow.

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.

Initial Report of a Phase I Study of LY2510924, Idarubicin, and Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia

Background: The CXCR4/SDF-1α axis plays a vital role in the retention of stem cells within the bone marrow and downstream activation of cell survival signaling pathways. LY2510924, a second generation CXCR4, showed significant anti-leukemia activity in a murine AML model.

Methods: We conducted a phase I study to determine the safety and toxicity of LY2510924, idarubicin and cytarabine (IA) combination therapy in relapsed/refractory (R/R) AML. Eligible patients were 18–70 years of age receiving up to salvage 3 therapy. A peripheral blood absolute blast count of < 20,000/μL was required for inclusion. LY2510924 was administered daily for 7 days followed by IA from day 8. Two dose escalation levels (10 and 20 mg) were evaluated, with a plan to enroll up to 12 patients in the phase I portion.

Results: The median age of the enrolled patients (n = 11) was 55 years (range, 19–70). Median number of prior therapies was 1 (1–3). Six and five patients were treated at dose-levels “0” (10 mg) and “1” (20 mg), respectively. Only one patient experiencing a dose limiting toxicity (grade 3 rash and myelosuppression). Three and one complete responses were observed at dose-levels “0” and “1,” respectively; the overall response rate (ORR) was 36% (4 of 11 patients). A ≥ 50% decrease in CXCR4 mean fluorescence intensity was observed in 4 of 9 patients by flow cytometry, indicating incomplete suppression of CXCR4-receptor occupancy.

Conclusions: The combination of LY2510924 with IA is safe in R/R AML. Dose-escalation to a 30 mg LY2510924 dose is planned to achieve complete blockade of CXCR4 receptor occupancy, followed by expansion phase at the recommended phase 2 dose-level.

Management of primary refractory acute myeloid leukemia in the era of targeted therapies

Primary refractory acute myeloid leukemia (AML), or primary induction failure, represents a continued challenge in clinical management. This review presents an overview of primary refractory disease and a discussion of risk factors for induction failure, including current evidence regarding the impact of karyotype and molecular mutation status on responsiveness to chemotherapy. We review the evidence for various treatment options for refractory AML including salvage chemotherapy regimens, allogeneic hematopoietic stem cell transplantation, targeted agents, and non-intensive therapies such as hypomethylating agents. A therapeutic approach to this patient population is presented, and several new and emerging therapies are reviewed.

Sequential treatment combining cladribine-based re-induction, myeloablative allogeneic HSCT, and prophylactic donor lymphocyte infusion: a promising treatment for refractory acute myeloid leukemia

We describe the first multicenter prospective study to assess the efficacy, safety, and immune reconstitution of a novel sequential transplant approach in 24 patients with primary induction failure/relapsed acute myeloid leukemia (AML). The sequential regimen consisted of cladribine 5 mg/m²/day and cytarabine 2 g/m²/day for 5 days and mitoxantrone 7 mg/m²/day for 3 days, followed by myeloablative allogeneic hematopoietic stem cell transplantation (allo-HSCT) using intravenous busulfan (3.2 mg/kg/day) for 4 days and cyclophosphamide (60 mg/kg/day) for 2 days. Patients in CR without acute graft-versus-host disease at day + 90 received prophylactic donor lymphocyte infusion (pDLI). At the time of transplantation, a marrow blast infiltration > 20% or any level of circulating blasts was found in 62.5% of patients. The cumulative incidence of relapse at 2 years was 29.8%. Overall survival (OS) was 74.5% at 1 year and 56.5% at 2 years. Leukemia-free survival (LFS) at 1 and 2 years was 62.5 and 50.5%, respectively. Multivariate analysis demonstrated that haploidentical related donor, pDLI, and experiencing chronic graft-versus-host disease (cGVHD) were protective from relapse. Total T cells and T cell subsets in peripheral blood recovered at 3 months post-HSCT. The expressions of immune checkpoints (cytotoxic T lymphocyte antigen 4 and programmed death 1) were extremely low in T cells over the first 1 year post-transplantation.