G-CSF priming, clofarabine, and high dose cytarabine (GCLAC) for upfront treatment of acute myeloid leukemia, advanced myelodysplastic syndrome or advanced myeloproliferative neoplasm

Effect of Granulocyte Colony-Stimulating Factor on the Development of Spermatogenesis in the Adulthood of Juvenile AML Mice Model Treated with Cytarabine

Pediatric acute myeloid leukemia (AML) generally occurs de novo. The treatment of AML includes cytarabine (CYT) and other medications. The granulocyte-colony stimulating factor (GCSF) is used in the clinic in cases of neutropenia after chemotherapies. We show that the administration of GCSF in combination with CYT in AML-diagnosed mice (AML+CYT+GCSF) extended the survival of mice for additional 20 days. However, including GCSF in all treatment modalities does not affect the testis' weight or the histology of the seminiferous tubules (STs). We show that GCSF does not affect normal ST histology from AML-, CYT-, or (AML+CYT)-treated groups compared to the relevant treated group without GCSF 2, 4, and 5 weeks post-injection. However, when comparing the percentages of normal STs between the AML+CYT+GCSF-treated groups and those without GCSF, we observe an increase of 17%-42% in STs at 4 weeks and 5.5 weeks post-injection. Additionally, we show that the injection of GCSF into the normal, AML-alone, or CYT-alone groups, or in combination with AML, significantly decreases the percentage of STs with apoptotic cells compared to the relevant groups without GCSF and to the CT (untreated mice) only 2 weeks post-injection. We also show that injection of GCSF into the CT group increases the examined spermatogonial marker PLZF within 2 weeks post-injection. However, GCSF does not affect the count of meiotic cells (CREM) but decreases the post-meiotic cells (ACROSIN) within 4 weeks post-injection. Furthermore, GCSF not only extends the survival of the AML+CYT-treated group, but it also leads to the generation of sperm (1.2 ± 0.04 × 106/mL) at 5.5 weeks post-injection. In addition, we demonstrate that the injection of GCSF into the CT group increases the RNA expression level of IL-10 but not IL-6 compared to CT 2 weeks post-treatment. However, the injection of GCSF into the AML-treated group reverses the expression levels of both IL-10 and IL-6 to normal levels compared to CT 2 weeks post-injection. Thus, we suggest that the addition of GCSF to the regimen of AML after CYT may assist in the development of future therapeutic strategies to preserve male fertility in AML prepubertal patients.

[Treatment responses, outcomes, and prognostic factors associated with them in patients with secondary acute myeloid leukemia]

Objective: To evaluate treatment responses, outcomes, and prognostic factors in adults with secondary acute myeloid leukemia (sAML) . Methods: Between January 2008 and February 2021, date of consecutive cases of younger than 65 years of adults with sAML were assessed retrospectively. Clinical characteristics at diagnosis, treatment responses, recurrence, and survival were evaluated. Logistic regression and Cox proportional hazards model were employed to determine significant prognostic indicators for treatment response and survival. Results: 155 patients were recruited, including 38, 46, 57, 14 patients belonging to t-AML, and AML with unexplained cytopenia, post-MDS-AML, and post-MPN-AML, respectively. In the 152 evaluable patients, the rate of MLFS after the initial induction regimen was 47.4%, 57.9%, 54.3%, 40.0%, and 23.1% in the four groups (P=0.076) . The total rate of MLFS after the induction regimen was 63.8%, 73.3%, 69.6%, 58.2%, and 38.5% (P=0.084) , respectively. Multivariate analysis demonstrated that male gender (OR=0.4, 95% CI 0.2-0.9, P=0.038 and OR=0.3, 95% CI 0.1-0.8, P=0.015) , SWOG cytogenetic classification into unfavorable or intermediate (OR=0.1, 95% CI 0.1-0.6, P=0.014 and OR=0.1, 95% CI 0.1-0.3, P=0.004) and receiving low-intensity regimen as induction regimen (OR=0.1, 95% CI 0.1-0.3, P=0.003 and OR=0.1, 95%CI 0.1-0.2, P=0.001) were typical adverse factors impacting the first CR and the final CR; PLT<45 × 10(9)/L (OR=0.4, 95%CI 0.2-0.9, P=0.038) and LDH ≥258 U/L (OR=0.3, 95%CI 0.1-0.7, P=0.005) were independent factors for CR. Among the 94 patients with achieving MLFS, 46 cases had allogeneic hematopoietic stem cell transplantation. With a median follow-up period of 18.6 months, the probabilities of relapse-free survival (RFS) and overall survival (OS) at 3 years were 25.4% and 37.3% in patients with transplantation, and in patients with chemotherapy, the probabilities of RFS and OS at 3-year were 58.2% and 64.3%, respectively. At the time of achieving MLFS, multivariate analysis revealed that age ≥46 years (HR=3.4, 95%CI 1.6-7.2, P=0.002 and HR=2.5, 95%CI 1.1-6.0, P=0.037) , peripheral blasts ≥17.5% at diagnosis (HR=2.5, 95%CI 1.2-4.9, P=0.010 and HR=4.1, 95%CI 1.7-9.7, P=0.002) , monosomal karyotypes (HR=4.9, 95%CI 1.2-19.9, P=0.027 and HR=28.3, 95%CI 4.2-189.5, P=0.001) were typical adverse factors influencing RFS and OS. Furthermore, CR after induction chemotherapy (HR=0.4, 95%CI 0.2-0.8, P=0.015) and transplantation (HR=0.4, 95%CI 0.2-0.9, P=0.028) were substantially linked to longer RFS. Conclusion: Post-MDS-AML and post-MPN-AML had lower response rates and poorer prognoses than t-AML and AML with unexplained cytopenia. In adults with male gender, low platelet count, high LDH, and SWOG cytogenetic classification into unfavorable or intermediate at diagnosis, and receiving low-intensity regimen as the induction regimen predicted a low response rate. Age ≥46 years, a higher proportion of peripheral blasts and monosomal karyotype had a negative effect on the overall outcome. Transplantation and CR after induction chemotherapy were greatly linked to longer RFS.

Haploidentical Natural Killer Cell Therapy as an Adjunct to Stem Cell Transplantation for Treatment of Refractory Acute Myeloid Leukemia

Refractory acute myeloid leukemia (AML), defined as failure of two cycles of induction therapy at diagnosis or of one cycle at relapse, represents a subgroup with poor outcomes. Haploidentical natural killer cell (NK) therapy is a strategy that is being explored in refractory malignancies. Historically, at our center, patients with refractory AML have been treated with cytoreductive therapy (fludarabine + cytosine + granulocyte colony-stimulating factor ± idarubicin or mitoxantrone + etoposide) followed by 1-week rest and then reduced-intensity transplant with fludarabine + melphalan. We used the same backbone for this trial (CTRI/2019/02/017505) with the addition of CD56-positive cells from a family donor infused 1 day after the completion of chemotherapy. CD56-positive selection was done using a CliniMACS Prodigy system (Miltenyi Biotec, Bergisch Gladbach, Germany) followed by overnight incubation in autologous plasma with 2 micromolar arsenic trioxide and 500 U/mL of interleukin-2. From February 2019, 14 patients with a median age of 29 years (interquartile range [IQR]: 16.5-38.5) were enrolled in this trial. Six were females. Six had primary refractory AML while eight had relapsed refractory AML. The median CD56-cell dose infused was 46.16 × 106/kg (IQR: 25.06-70.36). One patient withdrew consent after NK cell infusion. Of the 13 patients who proceeded to transplant, five died of immediate post-transplant complications while two did not engraft but were in morphologic leukemia-free state (both subsequently died of infective complications after the second transplant). Of the remaining six patients who engrafted and survived beyond 1 month of the transplant, two developed disease relapse and died. The remaining four patients are alive and relapse free at the last follow-up (mean follow-up duration of surviving patients is 24 months). The 2-year estimated overall survival for the cohort was 28.6% ± 12.1% while the treatment-related mortality (TRM) with this approach was 38.5% ± 13.5%. Haploidentical NK cell therapy as an adjunct to transplant is safe and needs further exploration in patients with AML. For refractory AML, post-transplant NK infusion and strategies to reduce TRM while using pre-transplant NK infusion merit exploration.

Emerging therapies for AML with myelodysplasia-related changes: slowly but surely moving the needle

Introduction: Patients with acute myeloid leukemia with myelodysplasia-related changes (AML-MRC) have historically poor outcomes with conventional chemotherapy regimens. Current treatment strategies focus on intensive induction therapy followed by allogeneic stem cell transplant or a less intensive approach with hypomethylating agents with or without venetoclax. CPX-351 is a liposomal formulation of cytarabine and daunorubicin that has been shown to significantly improve response rates and survival compared with 7 + 3 (continuous infusion cytarabine plus anthracyclines). Despite the approval of CPX-351 for AML-MRC, overall prognosis remains poor with an unmet need to develop novel therapeutic strategies for this patient population.Areas covered: This article reviews the data for existing therapeutic options for patients with AML-MRC and the emerging therapies undergoing clinical trial development for this patient population.Expert opinion: The development of CPX-351 as a more effective induction therapeutic backbone for patients with AML-MRC presents an opportunity to investigate novel combination regimens in order to further improve outcomes. Promising emerging therapeutic modalities include immunotherapeutic strategies, small-molecule inhibitors and targeted agents. Unfortunately, there have been few clinical trials focusing on patients with AML-MRC with reliance instead on subgroup analyses. Clinical trials focused specifically on this patient population are urgently needed.

Outpatient intensive induction chemotherapy for acute myeloid leukemia and high-risk myelodysplastic syndrome

To improve patient quality of life and reduce health care costs, many conditions formerly thought to require inpatient care are now treated in the outpatient setting. Outpatient induction chemotherapy for acute myeloid leukemia (AML) may confer similar benefits. This possibility prompted a pilot study to explore the safety and feasibility of intensive outpatient initial or salvage induction chemotherapy administration for adults with AML and high-risk myelodysplastic syndrome (MDS). Patients with no significant organ dysfunction and a treatment-related mortality (TRM) score corresponding to a day 28 mortality rate of <5% to 10% were eligible for study. Patients were treated as outpatients with daily evaluation by providers and only admitted to the hospital if mandated by complications. Twenty patients were consented, and 17 were treated. Eight patients received initial induction chemotherapy and 9 received salvage induction chemotherapy. Fourteen patients completed induction chemotherapy administration in the outpatient setting (82.4%; exact 95% confidence interval [CI], 55.8-95.3). Three patients were admitted during the course of chemotherapy administration, 2 for neutropenic fever and 1 for grade 3 mucositis. No patients died within 14 days of the initiation of induction chemotherapy (exact 95% CI, 0-22.9). Results of this pilot study suggest it is feasible to complete outpatient induction chemotherapy in select patients with AML and high-risk MDS. A team including nurses, social workers, medical providers, and pharmacists was key to the successful implementation of outpatient induction.

Secondary AML Emerging After Therapy with Hypomethylating Agents: Outcomes, Prognostic Factors, and Treatment Options

PURPOSE OF REVIEW

Secondary AML (s-AML) encompasses a distinct subgroup of AML with either therapy-related AML or AML arising from preexisting myeloid neoplasms. Despite recent advances in the treatment armamentarium of AML, outcomes remain poor in s-AML. The purpose of this review is to highlight distinct characteristics, prognostic factors, and treatment options for patients with s-AML. Further, we focus on a distinctly poor-risk subgroup of s-AML with previous exposure to hypomethylating agents (HMAs) and describe ongoing clinical trials in this patient population.

RECENT FINDINGS

CPX-351 (liposomal daunorubicin and cytarabine) is the first drug approved for s-AML and represents an advancement in the management of fit patients with this subtype of AML. Despite incremental improvement in remission rates and survival, long-term survival remains poor. Patients who have received prior HMAs for antecedent MDS rarely benefit from CPX-351 or other cytotoxic chemotherapy regimens. The approval of venetoclax in combination with azacitidine has led to a paradigm shift in the management of newly diagnosed older unfit AML patients; however, patients with s-AML and prior HMA therapy were excluded from the landmark randomized phase 3 study. Several early phase clinical trials with both low- and high-intensity therapies are ongoing for s-AML patients, though prior HMA exposure limits inclusion in many of these studies that include HMAs. Patients with s-AML previously treated with an HMA have dismal outcomes with standard therapeutic options and are under-represented in clinical trials. Trials investigating novel therapeutic options in this population are critically needed.

Clofarabine, cytarabine, and mitoxantrone in refractory/relapsed acute myeloid leukemia: High response rates and effective bridge to allogeneic hematopoietic stem cell transplantation

Clofarabine is active in refractory/relapsed acute myeloid leukemia (AML). In this phase 2 study, we treated 18‐ to 65‐year‐old AML patients refractory to first‐line 3 + 7 daunorubicin/cytarabine induction or relapsing after 3 + 7 induction and high‐dose cytarabine consolidation, with clofarabine (30 mg/m²/d, Days 1‐5), cytarabine (750 mg/m²/d, Days 1‐5), and mitoxantrone (12 mg/m²/d, Days 3‐5) (CLAM). Patients achieving remission received up to two consolidation cycles of 50% CLAM, with eligible cases bridged to allogeneic hematopoietic stem cell transplantation (allo‐HSCT). The mutational profile of a 69‐gene panel was evaluated. Twenty‐six men and 26 women at a median age of 46 (22‐65) years were treated. The overall response rate after the first cycle of CLAM was 90.4% (complete remission, CR: 69.2%; CR with incomplete hematologic recovery, CRi: 21.2%). Twenty‐two CR/CRi patients underwent allo‐HSCT. The 2‐year overall survival (OS), relapse‐free survival (RFS), and event‐free survival (EFS) were 65.8%, 45.7%, and 40.2%, respectively. Multivariate analyses showed that superior OS was associated with CR after CLAM (P = .005) and allo‐HSCT (P = .005), and superior RFS and EFS were associated with allo‐HSCT (P < .001). Remarkably, CR after CLAM and allo‐HSCT resulted in 2‐year OS of 84.3% and 90%, respectively. Karyotypic aberrations and genetic mutations did not influence responses or survivals. Grade 3/4 neutropenia/thrombocytopenia and grade 3 febrile neutropenia occurred in all cases. Other nonhematologic toxicities were mild and uncommon. There was no treatment‐related mortality and the performance of allo‐HSCT was not compromised. Clofarabine, cytarabine, and mitoxantrone was highly effective and safe in refractory/relapsed AML. This study was registered at ClinicalTrials.gov (NCT02686593).

Phase I/II study on cytarabine and idarubicin combined with escalating doses of clofarabine in newly diagnosed patients with acute myeloid leukaemia and high risk for induction failure (AMLSG 17-10 CIARA trial)

This open-label, multicentre phase I/II study determined the maximum tolerated dose (MTD), safety and efficacy of clofarabine administered with cytarabine and idarubicin in newly diagnosed acute myeloid leukaemia (AML) patients lacking favourable genetic aberrations. The MTD was 30 mg/m² clofarabine for patients below and above 60 years. The most frequently reported grade 3-4 non-haematological adverse events were infectious and gastrointestinal toxicities. Complete remission (CR)/CR with incomplete recovery rate was 67%. Allogeneic haematopoietic cell transplantation in first remission was feasible in a high proportion of younger AML patients and probably contributed to the favourable outcome compared to historical controls.

The leukemia strikes back: a review of pathogenesis and treatment of secondary AML

Secondary AML is associated with a disproportionately poor prognosis, consistently shown to exhibit inferior response rates, event-free survival, and overall survival in comparison with de novo AML. Secondary AML may arise from the evolution of an antecedent hematologic disorder, or it may arise as a complication of prior cytotoxic chemotherapy or radiation therapy in the case of therapy-related AML. Because of the high frequency of poor-risk cytogenetics and high-risk molecular features, such as alterations in TP53, leukemic clones are often inherently chemoresistant. Standard of care induction had long remained conventional 7 + 3 until its reformulation as CPX-351, recently FDA approved specifically for secondary AML. However, recent data also suggests relatively favorable outcomes with regimens based on high-dose cytarabine or hypomethylating agents. With several investigational agents being studied, the therapeutic landscape becomes even more complex, and the treatment approach involves patient-specific, disease-specific, and therapy-specific considerations.

Immunological effects of vaccines combined with granulocyte colony-stimulating factor on a murine WEHI-3 leukemia model

Granulocyte colony-stimulating factor (G-CSF) mobilizes regulatory T cells (Tregs) from bone marrow into the peripheral blood, by reducing the expression of stromal cell-derived factor-1α (SDF-1α). However, G-CSF has rarely been studied in acute myeloid leukemia (AML) immunotherapy. The present study performed a Transwell migration assay in vitro to determine the contribution of SDF-1α to the migration of leukemia cells, and the effects of G-CSF were evaluated. The effects of G-CSF on SDF-1α and Tregs in the AML microenvironment were examined, by employing a WEHI-3-grafted BALB/c mouse AML model (AML-M4). It is evident that G-CSF reversed immunosuppression of the AML microenvironment by reducing SDF-1α in bone marrow and elevating Tregs in the peripheral blood in in vivo studies. Furthermore, AML mice treated with vaccines combined with G-CSF achieved a longer survival time than those treated with vaccines without G-CSF, showing the efficiency of the regimen. The present study demonstrates the effects of G-CSF on the mobilization of leukemia cells and Tregs into the peripheral blood. In addition, immunotherapy with G-CSF priming represents a promising therapeutic strategy of targeting the immunosuppression.

Frontline treatment of acute myeloid leukemia in adults

Recent years have highlighted significant progress in understanding the underlying genetic and epigenetic signatures of acute myeloid leukemia(AML). Most importantly, novel chemotherapy and targeted strategies have led to improved outcomes in selected genetic subsets. AML is a remarkably heterogeneous disease, and individualized therapies for disease-specific characteristics (considering patients' age, cytogenetics, and mutations) could yield better outcomes. Compared with the historical 5-to 10-year survival rate of 10%, the survival of patients who undergo modern treatment approaches reaches up to 40-50%, and for specific subsets, the improvements are even more dramatic; for example, in acute promyelocytic leukemia, the use of all-trans retinoic acid and arsenic trioxide improved survival from 30 to 40% up to 80 to 90%. Similar progress has been documented in core-binding-factor-AML, with an increase in survival from 30% to 80% upon the use of high-dose cytarabine/fludarabine/granulocyte colony-stimulating factor combination regimens. AML treatment was also recently influenced by the discovery of the superiority of regimens with higher dose Ara-C and nucleoside analogues compared with the "7+3"regimen, with about a 20% improvement in overall survival. Despite these significant differences, most centers continue to use the "7+3" regimen, and greater awareness will improve the outcome. The discovery of targetable molecular abnormalities and recent studies of targeted therapies (gemtuzumab ozagomycin, FLT3 inhibitors, isocitrate dehydrogenase inhibitors, and epigenetic therapies), future use of checkpoint inhibitors and other immune therapies such as chimeric antigen receptor T-cells, and maintenance strategies based on the minimal residual disease evaluation represent novel, exciting clinical leads aimed to improve AML outcomes in the near future.

Association between early promoter-specific DNA methylation changes and outcome in older acute myeloid leukemia patients

Treatment options for older patients with acute myeloid leukemia (AML) range from supportive care alone to full-dose chemotherapy. Identifying factors that predict response to therapy may help increase efficacy and avoid toxicity. The phase II SWOG S0703 study investigated the use of hydroxyurea and azacitidine with gemtuzumab ozogamicin in the elderly AML population and found survival rates similar to those expected with standard AML regimens, with less toxicity. As part of this study, global DNA methylation along with promoter DNA methylation and expression analysis of six candidate genes (CDKN2A, CDKN2B, HIC1, RARB, CDH1 and APAF1) were determined before and during therapy to investigate whether very early changes are prognostic for clinical response. Global DNA methylation was not associated with a clinical response. Samples after 3 or 4 days of treatment with azacitidine showed significantly decreased CDKN2A promoter DNA methylation in patients achieving complete remission (CR) compared to those who did not. Samples from day 7 of treatment showed significantly decreased RARB, CDKN2B and CDH1 promoter DNA methylation in responders compared to nonresponders. Gene-specific DNA methylation analysis of peripheral blood samples may help early identification of those older AML patients most likely to benefit from demethylating agent therapy.

Current Approaches in the Treatment of Relapsed and Refractory Acute Myeloid Leukemia

The limited sensitivity of the historical treatment response criteria for acute myeloid leukemia (AML) has resulted in a different paradigm for treatment compared with most other cancers presenting with widely disseminated disease. Initial cytotoxic induction chemotherapy is often able to reduce tumor burden to a level sufficient to meet the current criteria for "complete" remission. Nevertheless, most AML patients ultimately die from their disease, most commonly as clinically evident relapsed AML. Despite a variety of available salvage therapy options, prognosis in patients with relapsed or refractory AML is generally poor. In this review, we outline the commonly utilized salvage cytotoxic therapy interventions and then highlight novel investigational efforts currently in clinical trials using both pathway-targeted agents and immunotherapy based approaches. We conclude that there is no current standard of care for adult relapsed or refractory AML other than offering referral to an appropriate clinical trial.

Report of a phase II study of clofarabine and cytarabine in de novo and relapsed and refractory AML patients and in selected elderly patients at high risk for anthracycline toxicity

PURPOSE

To determine the efficacy and safety of clofarabine and cytarabine (Ara-C) in adult patients with relapsed or refractory acute myeloid leukemia (AML) and in elderly patients with untreated AML and heart disease.

PATIENTS AND METHODS

Patients with relapsed/refractory AML and older patients for whom there was a concern over toxicity from additional anthracyclines received 5 days of clofarabine, 40 mg/m(2) per day i.v. over 1 hour, followed 4 hours later by Ara-C, 1,000 mg/m(2) per day i.v. over 2 hours.

RESULTS

Thirty patients were enrolled. The median age was 67 years (range, 38-82 years) and 18 (60%) had received at least one prior therapy. Eleven (37%) patients had a history of cardiovascular disease and were considered to be at high risk for anthracycline toxicity. High-risk cytogenetic abnormalities were present in 14 (47%) patients. The overall response rate (complete remission [CR] plus partial remission) was 53%, including a CR in 14 patients (47%). Responses were observed in all cytogenetic risk groups and in patients who had received up to five prior therapies. The median disease-free survival interval was 9.5 months. The 30-day mortality rate was 20% (de novo AML, 8%; relapsed/refractory AML, 28%). Of the 14 patients achieving a CR, half were able to proceed to curative hematopoietic stem cell transplantation.

CONCLUSIONS

Clofarabine in combination with Ara-C is effective in both untreated and previously treated patients with AML. In addition, it represents a useful remission induction strategy to serve as a bridge to transplantation in older patients with AML.

Novel agents and regimens for acute myeloid leukemia: 2009 ASH annual meeting highlights

Prognostic markers, such as NPM1, Flt3-ITD, and cytogenetic abnormalities have made it possible to formulate aggressive treatment plans for unfavorable acute myeloid leukemia (AML). However, the long-term survival of AML with unfavorable factors remains unsatisfactory. The latest data indicate that the standard dose of daunorubicin (DNR) at 45 mg/m2 is inferior to high dose 90 mg/m2 for induction therapy. The rates of complete remission and overall survival are significantly better in the high dose induction regimen. New regimens exploring the new liposomal encapsulation of Ara-C and DNR as well as addition of gemtuzumab ozogamicin monoclonal antibody have been studied. New agents, including the nucleoside analogues (clofarabine, sapacitabine, elacytarabine), FLT3 inhibitor (sorafenib), farnesyl-transferase inhibitor (tipifarnib), histone deacetylase inhibitor (vorinostat), lenalidomide, as well as DNA methyltransferase inhibitors (decitabine, azacitidine), were recently reported for AML treatment in the 2009 ASH annual meeting. This review also summarizes the updates of the clinical trials on novel agents including voreloxin, AS1413, behenoylara-C, ARRY520, ribavirin, AZD1152, AZD6244, and terameprocol (EM-1421) from the 2009 ASH annual meeting.