Venetoclax plus intensive chemotherapy with cladribine, idarubicin, and cytarabine in patients with newly diagnosed acute myeloid leukaemia or high-risk myelodysplastic syndrome: a cohort from a single-centre, single-arm, phase 2 trial

Intensive chemotherapy with dual induction and ALL-like consolidation for childhood acute myeloid leukemia: a respective report from multiple centers in China

Background

Pediatric acute myeloid leukemia (AML) has poor prognosis and high rate of relapse and mortality, and exploration of new treatment options is still critically needed.

Objectives

To summarize the outcome of our new treatment strategies for pediatric AML, which is characterized by dual induction and acute lymphoblastic leukemia (ALL) elements consolidation.

Design

Retrospective, single-arm study.

Methods

From July 2012 to December 2019, an intensive chemotherapy protocol was used for newly diagnosed children with AML, which contains dual induction, three courses of consolidations based on high-dose cytarabine, and two courses of consolidations composed of high-dose methotrexate, vincristine, asparaginase, and mercaptopurine (ALL-like elements). Blasts were monitored by bone marrow smears at intervals, and two lumbar punctures were performed during chemotherapy. We retrospectively analyzed the efficacy and safety of this study. The last follow-up was on 26 May 2023.

Results

A total of 70 pediatric AMLs were included. The median age at diagnosis was 6.7 (0.5-16.0) years. The median initial WBC count was 23.74 × 109/L, 11 of whom ⩾100 × 109/L. After dual induction, there were 62 cases of complete remission (CR), 5 cases of partial remission, and 3 cases of nonremission. The CR rate was 88.57%. The median follow-up time was 5.8 (0.2-9.4) years, the 5-year overall survival was 78.2% ± 5%, the event-free survival (EFS) was 71.2% ± 5.6%, and the cumulative recurrence rate was 27.75%. The 5-year EFS of patients with initial WBC < 100 × 109/L (n = 59) and ⩾100 × 109/L (n = 11) were 76.4% ± 5.7% and 45.5% ± 15% (p = 0.013), respectively. A total of 650 hospital infections occurred. The main causes of infection were respiratory tract infection (26.92%), septicemia (18.46%), stomatitis (11.85%), and skin and soft-tissue infection (10.46%).

Conclusion

This intensive treatment protocol with dual induction and ALL-like elements is effective and safe for childhood AML. Initial WBC ⩾ 100 × 109/L was the only independent risk factor in this cohort.

Trial registration

It is a retrospective study, and no registration on ClinicalTrials.gov.

AML treatment: conventional chemotherapy and emerging novel agents

Acute myeloid leukemia (AML) is driven by complex mutations and cytogenetic abnormalities with profound tumoral heterogeneity, making it challenging to treat. Ten years ago, the 5-year survival rate of patients with AML was only 29% with conventional chemotherapy and stem cell transplantation. All attempts to improve conventional therapy over the previous 40 years had failed. Now, new genomic, immunological, and molecular insights have led to a renaissance in AML therapy. Improvements to standard chemotherapy and a wave of new targeted therapies have been developed. However, how best to incorporate these advances into frontline therapy and sequence them in relapse is not firmly established. In this review, we highlight current treatments of AML, targeted agents, and pioneering attempts to synthesize these developments into a rational standard of care (SoC).

Myelodysplastic Neoplasms (MDS): The Current and Future Treatment Landscape

Myelodysplastic neoplasms (MDS) are a heterogenous clonal disorder of hemopoietic stem cells characterized by cytomorphologic dysplasia, ineffective hematopoiesis, peripheral cytopenias and risk of progression to acute myeloid leukemia (AML). Our understanding of this disease has continued to evolve over the last century. More recently, prognostication and treatment have been determined by cytogenetic and molecular data. Specific genetic abnormalities, such as deletion of the long arm of chromosome 5 (del(5q)), TP53 inactivation and SF3B1 mutation, are increasingly associated with disease phenotype and outcome, as reflected in the recently updated fifth edition of the World Health Organization Classification of Hematolymphoid Tumors (WHO5) and the International Consensus Classification 2022 (ICC 2022) classification systems. Treatment of lower-risk MDS is primarily symptom directed to ameliorate cytopenias. Higher-risk disease warrants disease-directed therapy at diagnosis; however, the only possible cure is an allogenic bone marrow transplant. Novel treatments aimed at rational molecular and cellular pathway targets have yielded a number of candidate drugs over recent years; however few new approvals have been granted. With ongoing research, we hope to increasingly offer our MDS patients tailored therapeutic approaches, ultimately decreasing morbidity and mortality.

Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

Advancements and Challenges in the Treatment of AML

The therapeutic arsenal for the management of AML has expanded significantly in recent years. Before 2017, newly diagnosed AML was treated with either standard cytarabine- and anthracycline-based induction chemotherapy (for all fit patients) or a single-agent hypomethylating agent (in unfit patients or those 75 years and older). While assessing patient fitness remains important, characterizing the disease biology has become critical to select the optimal initial therapy for each patient with more options available. FLT3 inhibitors, gemtuzumab ozogamicin, and CPX-351 have been shown to improve outcomes for specific subsets of patients. Venetoclax (VEN) with a hypomethylating agent (HMA) is the standard-of-care frontline regimen for most older patients, except perhaps for those with an IDH1 mutation where ivosidenib with azacitidine may also be considered. On the basis of the success seen with HMA/VEN in older patients, there is now increasing interest in incorporating VEN into frontline regimens in younger patients, with promising data from multiple early phase studies. This article focuses on recent updates and ongoing challenges in the management of AML, with a particular focus on the ongoing challenge of secondary AML and considerations regarding the selection of initial therapy in younger patients. An overview of common side effects and toxicities associated with targeted therapies is also presented here, along with recommended strategies to mitigate these risks.

Venetoclax in the treatment of acute myeloid leukemia: Beyond VIALE-A

Venetoclax and hypomethylating agent therapy in acute myeloid leukemia.

Comprehensive characterization of IFNγ signaling in acute myeloid leukemia reveals prognostic and therapeutic strategies

Interferon gamma (IFNγ) is a critical cytokine known for its diverse roles in immune regulation, inflammation, and tumor surveillance. However, while IFNγ levels were elevated in sera of most newly diagnosed acute myeloid leukemia (AML) patients, its complex interplay in AML remains insufficiently understood. We aim to characterize these complex interactions through comprehensive bulk and single-cell approaches in bone marrow of newly diagnosed AML patients. We identify monocytic AML as having a unique microenvironment characterized by IFNγ producing T and NK cells, high IFNγ signaling, and immunosuppressive features. IFNγ signaling score strongly correlates with venetoclax resistance in primary AML patient cells. Additionally, IFNγ treatment of primary AML patient cells increased venetoclax resistance. Lastly, a parsimonious 47-gene IFNγ score demonstrates robust prognostic value. In summary, our findings suggest that inhibiting IFNγ is a potential treatment strategy to overcoming venetoclax resistance and immune evasion in AML patients.

A phase 1/2 study of mini-hyper-CVD plus venetoclax in patients with relapsed/refractory acute lymphoblastic leukemia

ABSTRACT

Preclinical studies suggest that Bcl-2 inhibition with venetoclax has antileukemic activity in acute lymphoblastic leukemia (ALL) and may synergize with conventional chemotherapy. We designed a phase 1/2 clinical trial to evaluate the safety and efficacy of low-intensity chemotherapy in combination with venetoclax in adults with relapsed or refractory ALL. Patients received the mini-hyper-CVD regimen (dose-attenuated hyperfractionated cyclophosphamide, vincristine, and dexamethasone alternating with methotrexate and cytarabine) in combination with venetoclax (200 mg or 400 mg daily) on days 1 to 14 in cycle 1 and on days 1 to 7 in consolidation cycles. Twenty-two patients were treated. The median number of prior therapies was 2 (range, 1-6). Thirteen patients (59%) had undergone prior allogeneic stem cell transplant (allo-SCT), and 7 of 18 patients (39%) with B-cell ALL had previously received both inotuzumab ozogamicin and blinatumomab. The recommended phase 2 dose of venetoclax in the combination regimen was 400 mg daily. The composite complete remission (CR) and CR with incomplete hematologic recovery (CRi) rate was 57% (CR, 43%; CRi, 14%), and 45% of responders achieved measurable residual disease negativity by multiparameter flow cytometry. Four patients proceeded to allo-SCT. The median duration of response was 6.3 months. The median overall survival was 7.1 months, and the 1-year overall survival rate was 29%. The most common grade ≥3 nonhematologic adverse events were infection in 17 patients (77%) and febrile neutropenia in 4 patients (18%). Overall, the combination of mini-hyper-CVD plus venetoclax was active in heavily pretreated relapsed/refractory ALL. Further development of venetoclax-based combinations in ALL is warranted. This trial is registered at www.clinicaltrials.gov as #NCT03808610.

Biomarkers of Response to Venetoclax Therapy in Acute Myeloid Leukemia

Recent progress in the use of massive sequencing technologies has greatly enhanced our understanding of acute myeloid leukemia (AML) pathology. This knowledge has in turn driven the development of targeted therapies, such as venetoclax, a BCL-2 inhibitor approved for use in combination with azacitidine, decitabine, or low-dose cytarabine for the treatment of newly diagnosed adult patients with AML who are not eligible for intensive chemotherapy. However, a significant number of AML patients still face the challenge of disease relapse. In this review, we will explore biomarkers that may predict disease progression in patients receiving venetoclax-based therapy, considering both clinical factors and genetic changes. Despite the many advances, we conclude that the identification of molecular profiles for AML patients who will respond optimally to venetoclax therapy remains an unmet clinical need.

Venetoclax Combined with Intensive Chemotherapy: A New Hope for Refractory and/or Relapsed Acute Myeloid Leukemia?

Background. Primary resistance of acute myeloid leukemia (AML) to the conventional 3 + 7 intensive chemotherapy and relapses after first-line chemotherapy are two highly challenging clinical scenarios. In these cases, when allogeneic stem cell transplantation is feasible, patients are usually retreated with other chemotherapeutic regimens, as transplantation is still considered, nowadays, the only curative option. Methods. We discuss the mechanisms behind resistance to chemotherapy and offer a comprehensive review on current treatments of refractory/relapsed AML with a focus on novel approaches incorporating the BCL-2 inhibitor venetoclax. Results. Alas, complete remission rates after salvage chemotherapy remain relatively low, between 30 and 60% at best. More recently, the BCL-2 inhibitor venetoclax was combined either with hypomethylating agents or chemotherapy in refractory/relapsed patients. In particular, its combination with chemotherapy offered promising results by achieving higher rates of remission and bridging a substantial number of patients to transplantation. Conclusions. Venetoclax-based approaches might become, in the near future, the new standard of care for refractory/relapsed AML.

SOHO State of the Art Updates and Next Questions: Understanding and Overcoming Venetoclax Resistance in Hematologic Malignancies

The discovery of Venetoclax (VEN) has transformed the therapeutic landscape of acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL). However, the response is heterogeneous with 10% to 50% of newly diagnosed AML patients not responding to hypomethylating agent (HMA) and VEN. Furthermore, up to 40% of responding patients relapse shortly. This review discusses the mechanism of action of Venetoclax and the major mechanisms of inherent and acquired resistance to VEN. VEN is highly specific to BCL-2 binding, as such other antiapoptotic proteins in BCL-2 family induce resistance. These antiapoptotic proteins can also be upregulated via a number of compensatory cell signaling pathways including PI3K/AKT/mTOR, the MAPK/ERK pathway, and mutant FLT3-ITD. Mutations can occur in BCL-2 and BAX proteins, or they can be silenced by TP53 mutations and other epigenetic changes. Changes to mitochondrial structure and metabolism can induce resistance. Key metabolic regulators include OXPHOS and alternative amino acid metabolism. Finally microenvironmental factors can influence VEN responses. This paper evaluates subsets of AML by differentiation, histology, cytogenetics and molecular markers and their different responses to VEN; with spliceosome mutations, ASXL1, NPM1 and IDH1/2 being favorable while others such as FLT3, TP53 and BCL-2 mutations being less responsive. Currently intensive multiagent chemotherapy and Venetoclax combinations such as 7+3+VEN are favored in fit younger AML patients. However, with resistant patients' subsets targeted combination therapies are becoming an increasingly attractive option. We explore the incorporation of non-BCL-2 inhibitors, next-generation BCL-2 and multi-protein agents, other inhibitors most prominently FLT-3 inhibitors in addition to Venetoclax, and other novel approaches for resolving Venetoclax resistance.

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

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

SETD2 detection may reveal response to induction therapy and survival profile in acute myeloid leukemia patients

OBJECTIVE

SET domain containing protein 2 (SETD2) involves in the progression and development of chemotherapy resistance in acute myeloid leukemia (AML). Hence, this study aimed to investigate the relationship of SETD2 expression with disease risk, features, treatment response, and survival profile in AML.

METHODS

One-hundred and sixty primary AML patients were retrospectively analyzed. Their bone marrow (BM) samples before and after induction therapy were retrieved for SETD2 detection by RT-qPCR. Moreover, SETD2 expression in BM samples of 20 disease controls (DCs) were also determined.

RESULTS

SETD2 expression was downregulated in AML patients compared to DCs (P < 0.001). Higher SETD2 expression related to white blood cells ≤10 × 10⁹/L despite not reaching statistical significance (P = 0.062). One-hundred and nineteen (74.4%) AML patients achieved complete response (CR), while the remaining 41 (25.6%) did not achieve that. Furthermore, increased SETD2 expression was associated with CR achievement (P = 0.015). Survival analyses displayed that SETD2 high (vs. low) was related to prolonged event-free survival (EFS) (P = 0.001) and overall survival (OS) (P = 0.021). Moreover, increased SETD2 quartile was correlated with favorable EFS (P = 0.004) and OS (P = 0.042). After adjustment using multivariate Cox's regression analysis, higher SETD2 quartile was independently related to prolonged EFS [hazard ratio (HR): 0.766, P = 0.013] and OS (HR: 0.669, P = 0.013). It was also noticed that SETD2 expression was elevated during the induction therapy (P < 0.001).

CONCLUSION

Detection of SETD2 may assist in estimating treatment response and survival profile in AML patients.

Early Mortality as a Quality Indicator in Frontline and Salvage Acute Myeloid Leukemia

BACKGROUND

Early mortality is a historical measure of the quality of care incorporated into many quality measure algorithms that mostly account for patient comorbidities but do not incorporate disease characteristics and treatment status which independently increase early mortality. This is particularly significant in leukemia, especially in the refractory and salvage settings.

STUDY AIM

To define the independent adverse effect of leukemia salvage vs. frontline therapy on early mortality in acute myeloid leukemia (AML) after accounting for the pretreatment independent adverse effects associated with early mortality.

PATIENTS AND METHODS

A total of 4151 patients with AML were analyzed, 2893 newly diagnosed and 1258 in salvage. Univariate and multivariate analyses (MVA) were conducted to determine the independent adverse effects associated with 8-week mortality.

RESULTS

The 8-week mortality was 13% in frontline therapy and 18% in salvage therapy. By MVA, older age; therapy-related AML; prior history of myelodysplastic syndrome; poorer performance status; high white blood cell count; lower platelet count; higher percent of peripheral blasts; lower albumin levels; higher bilirubin, creatinine, and lactate dehydrogenase levels; and adverse cytogenetic risk groups were independently associated with a higher 8-week mortality rate. Adding treatment status after accounting for the independent adverse variables still selected salvage status as significantly adverse for 8-week mortality (hazard ratio 1.954; P-value < .001).

CONCLUSIONS

Quality measure algorithms should incorporate a risk mortality index related to leukemia vs. other tumors and benign conditions and a risk mortality index related to the treatment status of leukemia (salvage vs. frontline therapy).

Venetoclax in adult acute myeloid leukemia

Venetoclax is a potent inhibitor that specifically targets B-cell lymphoma-2 (BCL-2), which has been demonstrated to be effective in preclinical studies utilizing acute myeloid leukemia (AML) cell lines and xenograft models. Significant antileukemic activity was also observed in clinical trials, both as a monotherapy and in combination with other drugs. This novel therapeutic approach has revolutionized the treatment prospects for AML patients with unfavorable prognoses and those who are unable to tolerate intensive chemotherapy. Nevertheless, further investigations are required to establish the optimal dosing, sequencing, and combinational strategies of venetoclax for AML treatments. Additionally, identifying biomarkers is crucial for predicting response and resistance to this targeted intervention. In this review, we provide an overview of venetoclax-based therapy for AML and explore potential avenues for future research.

Addition of venetoclax to myeloablative conditioning regimens for allogeneic hematopoietic stem cell transplantation in high-risk AML

BACKGROUND

Venetoclax monotherapy is an effective option for patients with acute myeloid leukemia (AML). Venetoclax has also been used in non-myeloablative conditioning allogeneic hematopoietic stem cell transplantation (allo-HSCT) for high-risk AML with a tolerable toxicity profile. However, the efficacy and safety of a venetoclax-containing myeloablative conditioning (MAC) allo-HSCT regimen for high-risk AML have not been evaluated.

OBJECTIVE

To evaluate the safety and efficacy of a MAC regimen containing venetoclax for high-risk AML.

STUDY DESIGN

From 25 February 2021 to 4 September 2022, a total of 31 patients with high-risk AML who underwent allo-HSCT and a MAC regimen with venetoclax were analyzed.

RESULTS

At the time of transplantation, 21 patients were in first complete remission (CR1), 4 were in a second complete remission (CR2), and 6 in non-remission (NR). Twenty-four patients (77.4%) were minimal residual disease (MRD)-positive before transplant. The FLT3-ITD gene mutation was present in 51.6% of patients. NUP98 rearrangement, MLL rearrangement or MLL-PTD and DEK::CAN fusion genes were found in 5 (16.1%), 7(22.6%) and 2 (6.5%) patients, respectively. Twenty-nine (93.6%) patients underwent haploidentical allo-HSCT. The median follow-up time was 278 days (range: 52-632 days). The 100-day cumulative incidence of grade 3 to 4 acute graft-versus-host disease (aGVHD) was 16.1% (95%CI, 7.2-36.0%). The 180-day cumulative incidence of moderate to severe chronic graft-versus-host disease (cGVHD) was 7.1% (95%CI, 1.9-26.9%). Cumulative incidence of 100-day cytomegalovirus (CMV) viraemia and 100-day Epstein-Barr virus (EBV) viraemia was 61.6% (95%CI, 46.5-81.4%) and 3.2% (95%CI, 0.4-22.2%), respectively. The 600-day overall survival (OS) and leukemia-free survival (LFS) were 80.9% (95%CI, 63.5-93.6%) and 81.3% (95%CI, 64.2-93.7%), respectively. The 600-day relapse incidence (RI) and non-relapse mortality (NRM) was 6.9% (95%CI, 1.8-26.3%) and 11.7% (95%CI, 3.9-35.0%).

CONCLUSION

Our study shows that the addition of venetoclax to a MAC allo-HSCT was feasible, safe and effective for high-risk AML patients.

Venetoclax abrogates the prognostic impact of splicing factor gene mutations in newly diagnosed acute myeloid leukemia

Mutations in splicing factor (SF) genes SRSF2, U2AF1, SF3B1, and ZRSR2 are now considered adverse risk in the European LeukemiaNet 2022 acute myeloid leukemia (AML) risk stratification. The prognostic impact of SF mutations in AML has been predominantly derived from younger patients treated with intensive (INT) therapy. We evaluated 994 patients with newly diagnosed AML, including 266 (27%) with a SFmut. Median age was 67 years overall, with patients with SFmut being older at 72 years. SRSF2 (n = 140, 53%) was the most common SFmut. In patients treated with INT, median relapse-free survival (RFS) (9.6 vs 21.4 months, P = .04) and overall survival (OS) (15.9 vs 26.7 months, P = .06) were shorter for patients with SFmut than without SFwt, however this significance abrogated when evaluating patients who received venetoclax with INT therapy (RFS 15.4 vs 20.3 months, P = .36; OS 19.6 vs 30.7 months, P = .98). In patients treated with LI, median RFS (9.3 vs 7.7 months, P = .35) and OS (12.3 vs 8.5 months, P = .14) were similar for patients with and without SFmut , and outcomes improved in all groups with venetoclax. On multivariate analysis, SFmut did not affect hazards of relapse and death for INT arm but reduced both these hazards in LI arm. In a large AML data set with >60% of patients receiving venetoclax with LI/INT therapy, SFmut had no independent negative prognostic impact. Newer prognostic models that consider LI therapy and use of venetoclax among other factors are warranted.

Targeting apoptosis dysregulation in myeloid malignancies - The promise of a therapeutic revolution

In recent years, the therapeutic landscape of myeloid malignancies has been completely revolutionized by the introduction of several new drugs, targeting molecular alterations or pathways crucial for leukemia cells survival. Particularly, many agents targeting apoptosis have been investigated in both pre-clinical and clinical studies. For instance, venetoclax, a pro-apoptotic agent active on BCL-2 signaling, has been successfully used in the treatment of acute myeloid leukemia (AML). The impressive results achieved in this context have made the apoptotic pathway an attractive target also in other myeloid neoplasms, translating the experience of AML. Therefore, several drugs are now under investigation either as single or in combination strategies, due to their synergistic efficacy and capacity to overcome resistance. In this paper, we will review the mechanisms of apoptosis and the specific drugs currently used and under investigation for the treatment of myeloid neoplasia, identifying critical research necessities for the upcoming years.

Current Advances and Future Strategies for BCL-2 Inhibitors: Potent Weapons against Cancers

Targeting the intrinsic apoptotic pathway regulated by B-cell lymphoma-2 (BCL-2) antiapoptotic proteins can overcome the evasion of apoptosis in cancer cells. BCL-2 inhibitors have evolved into an important means of treating cancers by inducing tumor cell apoptosis. As the most extensively investigated BCL-2 inhibitor, venetoclax is highly selective for BCL-2 and can effectively inhibit tumor survival. Its emergence and development have significantly influenced the therapeutic landscape of hematological malignancies, especially in chronic lymphocytic leukemia and acute myeloid leukemia, in which it has been clearly incorporated into the recommended treatment regimens. In addition, the considerable efficacy of venetoclax in combination with other agents has been demonstrated in relapsed and refractory multiple myeloma and certain lymphomas. Although venetoclax plays a prominent antitumor role in preclinical experiments and clinical trials, large individual differences in treatment outcomes have been characterized in real-world patient populations, and reduced drug sensitivity will lead to disease recurrence or progression. The therapeutic efficacy may vary widely in patients with different molecular characteristics, and key genetic mutations potentially result in differential sensitivities to venetoclax. The identification and validation of more novel biomarkers are required to accurately predict the effectiveness of BCL-2 inhibition therapy. Furthermore, we summarize the recent research progress relating to the use of BCL-2 inhibitors in solid tumor treatment and demonstrate that a wealth of preclinical models have shown promising results through combination therapies. The applications of venetoclax in solid tumors warrant further clinical investigation to define its prospects.

Safety and efficacy of FLAG-Ida-based therapy combined with venetoclax for the treatment for newly diagnosed and relapsed/refractory patients with AML - A systematic review

Venetoclax (VEN) in combination with intensive chemotherapy (IC) is increasingly used to treat patients with high-risk acute myeloid leukemia (AML). We conducted a systematic review to assess the safety and efficacy outcomes of FLAG-IDA in combination with VEN. The primary safety outcome was infection rate; the primary efficacy outcome was response to treatment (composite complete remission (CRc) and overall response rate (ORR). Risk of bias was assessed according to the ROBINS-I tool. Six studies including 221 patients with newly-diagnosed (ND AML (n = 120)) and R/R AML (n = 101) disease, were included in this systematic review. Pooling of results was not conducted due to major differences between studies. The reported rates of neutropenic fever, bacteremia, pneumonia and invasive fungal infections were at 44-55 %, 24-48 %, 12-30 % and 11-36 % of assessed patients, respectively. Time to ANC and platelet recovery ranged between 23 and 29 and 23-31 days, respectively. Early death rate was 8.7 % (14/160) patients: four patients at 30 days, additional ten in 60 days. CRc rates ranged between 53 % and 78 % for R/R AML. CRc for ND was reported by one study only (89 %). ORR were reported in 60-78 % of patients with R/R AML. Only one study reported an ORR for ND patients of 98 %. In our systematic review, FLAG-Ida plus VEN proved to be a potentially tolerable and effective regimen in ND and R/R AML patients. We suggest further evaluation and confirmation for the safety and efficacy of this new protocol in future RCTs.

Drug repurposing based on the similarity gene expression signatures to explore for potential indications of quercetin: a case study of multiple sclerosis

Quercetin (QR) is a natural flavonol compound widely distributed in the plant kingdom with extensive pharmacological effects. To find the potential clinical indications of QR, 156 differentially expressed genes (DEGs) regulated by QR were obtained from the Gene Expression Omnibus database, and new potential pharmacological effects and clinical indications of QR were repurposed by integrating compounds with similar gene perturbation signatures and associated-disease signatures to QR based on the Connectivity Map and Coexpedia platforms. The results suggested QR has mainly potential therapeutic effects on multiple sclerosis (MS), osteoarthritis, type 2 diabetes mellitus, and acute leukemia. Then, MS was selected for subsequent animal experiments as a representative potential indication, and it found that QR significantly delays the onset time of classical MS model animal mice and ameliorates the inflammatory infiltration and demyelination in the central nervous system. Combined with network pharmacology technology, the therapeutic mechanism of QR on MS was further demonstrated to be related to the inhibition of the expression of inflammatory cytokines (TNF-α, IL-6, IL-1β, IFN-γ, IL-17A, and IL-2) related to TNF-α/TNFR1 signaling pathway. In conclusion, this study expanded the clinical indications of QR and preliminarily confirmed the therapeutic effect and potential mechanism of QR on MS.

A Novel Type of Monocytic Leukemia Stem Cell Revealed by the Clinical Use of Venetoclax-Based Therapy

The BCL2 inhibitor venetoclax has recently emerged as an important component of acute myeloid leukemia (AML) therapy. Notably, use of this agent has revealed a previously unrecognized form of pathogenesis characterized by monocytic disease progression. We demonstrate that this form of disease arises from a fundamentally different type of leukemia stem cell (LSC), which we designate as monocytic LSC (m-LSC), that is developmentally and clinically distinct from the more well-described primitive LSC (p-LSC). The m-LSC is distinguished by a unique immunophenotype (CD34-, CD4+, CD11b-, CD14-, CD36-), unique transcriptional state, reliance on purine metabolism, and selective sensitivity to cladribine. Critically, in some instances, m-LSC and p-LSC subtypes can co-reside in the same patient with AML and simultaneously contribute to overall tumor biology. Thus, our findings demonstrate that LSC heterogeneity has direct clinical significance and highlight the need to distinguish and target m-LSCs as a means to improve clinical outcomes with venetoclax-based regimens.

SIGNIFICANCE

These studies identify and characterize a new type of human acute myeloid LSC that is responsible for monocytic disease progression in patients with AML treated with venetoclax-based regimens. Our studies describe the phenotype, molecular properties, and drug sensitivities of this unique LSC subclass. This article is featured in Selected Articles from This Issue, p. 1949.

Characteristics and clinical outcomes of patients with acute myeloid leukemia with inv(3)(q21q26.2) or t(3;3)(q21;q26.2)

Acute myeloid leukemia (AML) with inv(3)(q21q26.2)/t(3;3)(q21;q26.2) has a very poor prognosis. Determinants of clinical outcomes and optimal treatment remain uncertain. We retrospectively reviewed 108 cases of AML with inv(3)/t(3;3) and evaluated clinicopathological characteristics and clinical outcomes: 53 newly diagnosed (ND) AML and 55 relapsed/refractory (R/R) AML. Median age was 55 years. White blood cell (WBC) count ≥20x109/L and platelet count ≥140x109/L was observed in 25% and 32% of ND patients, respectively. Anomalies involving chromosome 7 were identified in 56% of patients. The most frequently mutated genes were SF3B1, PTPN11, NRAS, KRAS and ASXL1. In ND patients, the composite complete remission (CRc) rate was 46% overall; 46% with high-intensity treatments and 47% with lowintensity treatments. The 30-day mortality was 14% and 0%, with high- and low-intensity treatment, respectively. In R/R patients, the CRc rate was 14%. Venetoclax based-regimens were associated with a CRc rate of 33%. The 3-year overall survival (OS) was 8.8% and 7.1% in ND and R/R patients, respectively. The 3-year cumulative incidence of relapse was 81.7% overall. Older age, high WBC, high peripheral blast count, secondary AML and KRAS, ASXL1, DNMT3A mutations were associated with worse OS in univariable analyses. The 5-year OS rates were 44% and 6% with or without hematopoietic stem cell transplantation in CR1, respectively. AML with inv(3)/t(3;3) is associated with low CR rates, very high risk of relapse and dismal long-term survival. Intensive chemotherapy and hy pomethylating agents provide similar rates of remission and patients achieving CR benefit from hematopoietic stem cell transplantation in first CR.

Building on Foundations: Venetoclax-Based Combinations in the Treatment of Acute Myeloid Leukemia

Frontline acute myeloid leukemia (AML) treatment is determined by a combination of patient and genetic factors. This includes patient fitness (i.e., comorbidities that increase the risk of treatment-related mortality) and genetic characteristics, including cytogenetic events and gene mutations. In older unfit patients, the standard of care treatment is typically venetoclax (VEN) combined with hypomethylating agents (HMA). Recently, several drugs have been developed targeting specific genomic subgroups of AML patients, enabling individualized therapy. This has resulted in investigations of doublet and triplet combinations incorporating VEN aimed at overcoming known resistance mechanisms and improving outcomes in older patients with AML. These combinations include isocitrate dehydrogenase-1/2 (IDH1/2) inhibitors (i.e., ivosidenib and enasidenib), fms-like tyrosine kinase 3 (FLT3) inhibitors (i.e., gilteritinib), anti-CD47 antibodies (i.e., magrolimab), mouse double minute-2 (MDM2) inhibitors, and p53 reactivators (i.e., eprenetapopt). This review summarizes ongoing trials aimed at overcoming known VEN resistance mechanisms and improving outcomes beyond that observed with HMA + VEN combinations in the treatment of AML.

BCL2 Inhibition: A New Paradigm for the Treatment of AML and Beyond

Altering the natural history of acute myeloid leukemia (AML) in unfit and older patients has proved a highly challenging hurdle, despite several decades of concerted clinical trial effort. The arrival of venetoclax (VEN) to the clinical stage represents the most important therapeutic advance to date for older patients with AML. In this review, we will explain how and why VEN works, summarize its remarkable pathway to regulatory approval, and highlight the key milestones that have been important for its successful development in AML. We also provide perspectives on some of the challenges associated with using VEN in the clinic, emerging knowledge regarding mechanisms of treatment failure, and current clinical research directions likely to shape how this drug and others in this new class of anticancer agents are used in the future.

Venetoclax plus cyclophosphamide and cytarabine as induction regimen for adult acute myeloid leukemia

Background

The efficacy of induction chemotherapy (IC) for acute myeloid leukemia (AML) has improved significantly with the application of targeting drugs. Our previous study showed that a 4-day IC regimen of cyclophosphamide (CTX) and Ara-C [CA (4 + 3)] achieved similar complete remission (CR) rate (80%) compared with the traditional 7-day regimen, and the survival rate appeared to be better.

Methods

In this pilot study, we further shortened the CA regimen to 3 days, added low-dose venetoclax (VEN, 200 mg/day) (VCA), and reported the efficacy and safety here.

Results

Twenty-five newly diagnosed adult AML patients were enrolled in this study and evaluated for the remission rate after one cycle of the VCA regimen. The CR/Cri was 92%, and all these patients had undetectable minimal residual disease (MRD^-). The estimated overall survival at 12 months was 79.3%. The median time for both platelet recovery and absolute neutrophil count recovery was 16 days, faster than that of traditional IC. Compared with the previous CA (4 + 3) regimen, a higher CR rate (92% vs. 80%, P < 0.01) and a deeper degree of remission (CR_MRD- rate, 92% vs. 45%, P < 0.01) were found in the VCA group.

Conclusions

This study showed that the 3-day CTX and Ara-C regimen is highly effective in newly diagnosed AML patients, and the addition of VEN to the CA regimen achieves higher and deeper one-course remission.

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.

Venetoclax combined with daunorubicin and cytarabine (2 + 6) as induction treatment in adults with newly diagnosed acute myeloid leukemia: a phase 2, multicenter, single-arm trial

BACKGROUND

Venetoclax (Ven) combined with intensive chemotherapy was proven effective in the management of acute myeloid leukemia (AML). However, the severe and prolonged myelosuppression remains a concern to worry about. To explore more appropriate combination regimens, we designed Ven combining daunorubicin and cytarabine (DA 2 + 6) regimen as induction therapy, aimed to evaluate the effectiveness and safety in adults de novo AML.

METHODS

A phase 2 clinical trial was performed in 10 Chinese hospitals to investigate Ven combined with daunorubicin and cytarabine (DA 2 + 6) in patients with AML. The primary endpoints were overall response rate (ORR), comprising of complete remission (CR), complete remission with incomplete blood cell count recovery (CRi), and partial response (PR). Secondary endpoints included measurable residual disease (MRD) of bone marrow assessed by flow cytometry, overall survival (OS), event-free survival (EFS), disease-free survival (DFS), and the safety of regimens. This study is a currently ongoing trial listed on the Chinese Clinical Trial Registry as ChiCTR2200061524.

RESULTS

Overall, 42 patients were enrolled from January 2022 to November 2022; 54.8% (23/42) were male, and the median age was 40 (range, 16-60) years. The ORR after one cycle of induction was 92.9% (95% confidence interval [CI], 91.6-94.1; 39/42) with a composite complete response rate (CR + CRi) 90.5% (95% CI, 89.3-91.6, CR 37/42, CRi 1/42). Moreover, 87.9% (29/33) of the CR patients with undetectable MRD (95% CI, 84.9-90.8). Grade 3 or worse adverse effects included neutropenia (100%), thrombocytopenia (100%), febrile neutropenia (90.5%), and one mortality. The median neutrophil and platelet recovery times were 13 (5-26) and 12 (8-26) days, respectively. Until Jan 30, 2023, the estimated 12-month OS, EFS, and DFS rates were 83.1% (95% CI, 78.8-87.4), 82.7% (95% CI, 79.4-86.1), and 92.0% (95% CI, 89.8-94.3), respectively.

CONCLUSION

Ven with DA (2 + 6) is a highly effective and safe induction therapy for adults with newly diagnosed AML. To the best of our knowledge, this induction therapy has the shortest myelosuppressive period but has similar efficacy to previous studies.

Venetoclax Combined with Azacitidine and Homoharringtonine in Relapsed/Refractory AML: A Multicenter, Phase 2 Trial

BACKGROUND

Relapsed or refractory acute myeloid leukemia (R/R AML) has a dismal prognosis. The aim of this study was to investigate the activity and tolerability of venetoclax combined with azacitidine plus homoharringtonine (VAH) regimen for R/R AML.

METHODS

This phase 2 trial was done at ten hospitals in China. Eligible patients were R/R AML (aged 18-65 years) with an Eastern Cooperative Oncology Group performance status of 0-2. Patients received venetoclax (100 mg on day 1, 200 mg on day 2, and 400 mg on days 3-14) and azacitidine (75 mg/m² on days 1-7) and homoharringtonine (1 mg/m² on days 1-7). The primary endpoint was composite complete remission rate [CRc, complete response (CR) plus complete response with incomplete blood count recovery (CRi)] after 2 cycles of treatment. The secondary endpoints include safety and survival.

RESULTS

Between May 27, 2020, and June 16, 2021, we enrolled 96 patients with R/R AML, including 37 primary refractory AML and 59 relapsed AML (16 relapsed after chemotherapy and 43 after allo-HSCT). The CRc rate was 70.8% (95% CI 60.8-79.2). In the patients with CRc, measurable residual disease (MRD)-negative was attained in 58.8% of CRc patients. Accordingly, overall response rate (ORR, CRc plus partial remission (PR)) was 78.1% (95% CI 68.6-85.4). At a median follow-up of 14.7 months (95% CI 6.6-22.8) for all patients, median overall survival (OS) was 22.1 months (95% CI 12.7-Not estimated), and event-free survival (EFS) was 14.3 months (95% CI 7.0-Not estimated). The 1-year OS was 61.5% (95% CI 51.0-70.4), and EFS was 51.0% (95% CI 40.7-60.5). The most common grade 3-4 adverse events were febrile neutropenia (37.4%), sepsis (11.4%), and pneumonia (21.9%).

CONCLUSIONS

VAH is a promising and well-tolerated regimen in R/R AML, with high CRc and encouraging survival. Further randomized studies are needed to be explored. Trial registration clinicaltrials.gov identifier: NCT04424147.

Venetoclax Use in Paediatric Haemato-Oncology Centres in Poland: A 2022 Survey

Venetoclax, the best established BH3-mimetic, is a practice-changing proapoptotic drug in blood cancers in adults. In paediatrics the data are fewer but exciting results were recently presented in relapsed or refractory leukaemias demonstrating significant clinical activity. Importantly, the in-terventions could be potentially molecularly guided as vulnerabilities to BH3-mimetics were re-ported. Currently venetoclax is not incorporated into paediatric treatment schedules in Poland but it has been already used in patients that failed conventional therapy in Polish paediatric haemato-oncology departments. The aim of the study was to gather clinical data and correlates of all paediatric patients treated so far with venetoclax in Poland. We set out to gather this experience to help choose the right clinical context for the drug and stimulate further research. The questionnaire regarding the use of venetoclax was sent to all 18 Polish paediatric haemato-oncology centres. The data as available in November 2022 were gathered and analysed for the diagnoses, triggers for the intervention, treatment schedules, outcomes and molecular associations. We received response from 11 centres, 5 of which administered venetoclax to their patients. Clinical benefit, in most cases consistent with hematologic complete remission (CR), was reported in 5 patients out of ten, whereas 5 patient did not show clinical benefit from the intervention. Importantly, patients with CR included subtypes expected to show venetoclax vulnerability, such as poor-prognosis ALL with TCF::HLF fusion. We believe BH3-mimetics have clinical activity in children and should be available to pae-diatric haemato-oncology practitioners in well-selected applications.

Venetoclax: A New Partner in the Novel Treatment Era for Acute Myeloid Leukemia and Myelodysplastic Syndrome

BACKGROUND

Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS) are two closely related blood cancers that are more frequent in older adults. AML is the most common type of adult acute leukemia, and MDS is characterized by ineffective blood cell production and abnormalities in the bone marrow and blood. Both can be resistant to treatment, often due to dysfunction in the process of apoptosis, the body's natural mechanism for cell death. Venetoclax, an orally-administered medication that selectively targets the BCL-2 protein, has shown promise in enhancing treatment sensitivity in some hematological malignancies by reducing the apoptotic threshold. This review aims to evaluate the effectiveness of venetoclax in treating AML and MDS, as well as potential mechanisms of resistance to the medication.

METHODS

A literature search was conducted utilizing PUBMED to capture all relevant research articles on the use of venetoclax as a therapy for both diseases. The MeSH terms "acute myeloid leukemia", "myelodysplastic syndrome" and "venetoclax" were searched. Furthermore, Clinicaltrials.gov was accessed to ensure the inclusion of all ongoing clinical trials.

RESULTS

Although Venetoclax showed modest results as a single-agent therapy in AML, venetoclax-based combination therapies? mainly with hypomethylating agents or low-dose cytarabine? yielded significantly positive results. Preliminary results oN the use of venetoclax-based combination therapy with HMA, mainly azacitidine, in unfit high-risk MDS also yielded optimistic results. Identification of mutations for which various drugs have been approved has spurred active investigation of venetoclax in combination trials.

CONCLUSION

Venetoclax-based combination therapies have been shown to induce rapid responses and increase overall survival in AML patients unfit for intensive chemotherapy. These therapies are also yielding positive preliminary results in high-risk MDS patients in phase I trials. Resistance to venetoclax and drug-related toxicity are two main obstacles that need to be overcome to reap the full benefits of this therapy.

Targeting FLT3 Mutation in Acute Myeloid Leukemia: Current Strategies and Future Directions

FLT3 mutations are present in 30% of newly diagnosed patients with acute myeloid leukemia. Two broad categories of FLT3 mutations are ITD and TKD, with the former having substantial clinical significance. Patients with FLT3-ITD mutation present with a higher disease burden and have inferior overall survival, due to high relapse rates after achieving remission. The development of targeted therapies with FLT3 inhibitors over the past decade has substantially improved clinical outcomes. Currently, two FLT3 inhibitors are approved for use in patients with acute myeloid leukemia: midostaurin in the frontline setting, in combination with intensive chemotherapy; and gilteritinib as monotherapy in the relapsed refractory setting. The addition of FLT3 inhibitors to hypomethylating agents and venetoclax offers superior responses in several completed and ongoing studies, with encouraging preliminary data. However, responses to FLT3 inhibitors are of limited duration due to the emergence of resistance. A protective environment within the bone marrow makes eradication of FLT3^mut leukemic cells difficult, while prior exposure to FLT3 inhibitors leads to the development of alternative FLT3 mutations as well as activating mutations in downstream signaling, promoting resistance to currently available therapies. Multiple novel therapeutic strategies are under investigation, including BCL-2, menin, and MERTK inhibitors, as well as FLT3-directed BiTEs and CAR-T therapy.

Neue Therapieoptionen bei der Akuten Myeloischen Leukämie

BACKGROUND

While the "7+3" regimen of cytarabine + anthracycline has been the backbone of acute myeloid leukemia (AML) treatment for four decades, several novel drugs have been approved in the past five years. Despite these promising novel therapeutic options, treatment of AML remains challenging, given the biologically heterogenous character of the disease.

AIM

This review provides an update on novel treatment strategies for AML.

MATERIAL AND METHODS

This article is based on the current European LeukemiaNet (ELN) recommendations and the DGHO «Onkopedia» guideline on AML treatment.

RESULTS AND CONCLUSION

The treatment algorithm is based on patient-related and disease-specific factors, such as patient age and fitness as well as AML molecular profile. Younger patients considered fit for intensive chemotherapy receive 1-2 courses of induction therapy ("7+3" regimen, eg. cytarabine/daunorubicin, or CPX-351 for patients with myelodysplasia-related AML or therapy-related AML). For CD33+ patients or those with evidence of an FLT3 mutation "7+3" in combination with Gemtuzumab-Ozogamicin (GO) or Midostaurin is recommended, respectively. For consolidation, patients receive either high-dose chemotherapy (± GO/± Midostaurin) or undergo allogeneic hematopoietic cell transplantation (HCT), based on ELN risk stratification. In some cases, maintenance therapy with oral azacytidine or FLT3 inhibitor is indicated. Patients experiencing relapse should receive chemotherapy-based re-induction therapy or, in case of an FLT3 mutation, Gilteritinib and subsequently undergo allogeneic HCT. For older patients or those considered unfit for intensive therapy, azacytidine in combination with Venetoclax is a promising novel treatment strategy. Although not yet approved by the European Medical Agency (EMA), for patients with IDH1IDH1 or IDH2 mutations treatment with the IDH1 and IDH2 inhibitors Ivosidenib and Enasidenib should be considered.

Acute myeloid leukemia: 2023 update on diagnosis, risk-stratification, and management

DISEASE OVERVIEW

Acute myeloid leukemia (AML) is a frequently fatal bone marrow stem cell cancer characterized by unbridled proliferation of malignant marrow stem cells with associated infection, anemia, and bleeding. An improved understanding of pathophysiology, improvements in measurement technology and at least 10 recently approved therapies have led to revamping the diagnostic, prognostic, and therapeutic landscape of AML.

DIAGNOSIS

One updated and one new classification system were published in 2022, both emphasizing the integration of molecular analysis into daily practice. Differences between the International Consensus Classification and major revisions from the previous 2016 WHO system provide both challenges and opportunities for care and clinical research.

RISK ASSESSMENT AND MONITORING

The European Leukemia Net 2022 risk classification integrates knowledge from novel molecular findings and recent trial results, as well as emphasizing dynamic risk based on serial measurable residual disease assessment. However, how to leverage our burgeoning ability to measure a small number of potentially malignant myeloid cells into therapeutic decision making is controversial.

RISK ADAPTED THERAPY

The diagnostic and therapeutic complexity plus the availability of newly approved agents requires a nuanced therapeutic algorithm which should integrate patient goals of care, comorbidities, and disease characteristics including the specific mutational profile of the patient's AML. The framework we suggest only represents the beginning of the discussion.

Preclinical evaluation of CD70-specific CAR T cells targeting acute myeloid leukemia

Backgrounds

Chimeric antigen receptor (CAR)-T cell therapy has achieved unprecedented success in treating hematopoietic malignancies. However, this cell therapy is hampered in treating acute myeloid leukemia (AML) due to lack of ideal cell surface targets that only express on AML blasts and leukemia stem cells (LSCs) but not on normal hematopoietic stem cells (HSCs).

Methods

We detected the CD70 expression on the surfaces of AML cell lines, primary AML cells, HSC, and peripheral blood cells and generated a second-generation CD70-specific CAR-T cells using a construct containing a humanized 41D12-based scFv and a 41BB-CD3ζ intracellular signaling domain. Cytotoxicity, cytokine release, and proliferation in antigen stimulation, CD107a assay, and CFSE assays were used to demonstrate the potent anti-leukemia activity in vitro. A Molm-13 xenograft mouse model was established to evaluate the anti-leukemic activity of CD70 CAR-T in vivo. CFU assay was explored to assess the safety of CD70 CAR-T on HSC.

Results

CD70 heterogeneously expressed on AML primary cells, including leukemia blasts, leukemic progenitor, and stem cells, but not expressed on normal HSCs and majority of blood cells. Anti-CD70 CAR-T cells exhibited potent cytotoxicity, cytokines production, and proliferation when incubated with CD70⁺ AML cell lines. It also displayed robust anti-leukemia activity and prolonged survival in Molm-13 xenograft mouse model. However, such CAR-T cell therapy did not completely eliminate leukemia in vivo.

Discussion

Our study reveals that anti-CD70 CAR-T cells are a new potential treatment for AML. However, such CAR-T cell therapy did not completely eliminate leukemia in vivo, suggesting that future studies aiming to generate innovative combinatorial CAR constructs or to increase CD70 expression density on leukemia cell surface to prolong the life-span of CAR-T cells in the circulation will be needed in order to optimize CAR-T cell responses for AML.

Moving toward individualized target-based therapies in acute myeloid leukemia

Acute myeloid leukemia (AML) is a heterogeneous disease at the genetic level. The field of AML therapy is increasingly shifting away from uniform approaches based solely on intensive chemotherapy (such as '7 + 3') toward personalized therapy. The treatment of AML can now be individualized based on patient characteristics and cytogenetic/molecular disease features. In this review, we provide a comprehensive updated summary of personalized, target-directed therapy in AML. We first discuss the selection of intensive versus low-intensity treatment approaches based on the patient's age and/or comorbidities. We follow with a detailed review of specific molecularly defined AML subtypes that benefit from the addition of targeted agents. In this context, we highlight the urgent need for novel therapies in tumor protein p53 (TP53)-mutated AML. We then propose approaches to optimize AML therapy in patients without directly actionable mutations. We conclude with a discussion on the emerging role of using measurable residual disease to modify therapy based on the quality of response.

The Cup Runneth Over: Treatment Strategies for Newly Diagnosed Acute Myeloid Leukemia

Since 2017, the number of agents for acute myeloid leukemia (AML) has rapidly expanded. Given the increased therapeutic options, better identification of high-risk subsets of AML and more refined approaches to patient fitness assessment, the decisions surrounding selection of intensive chemotherapy versus lower-intensity treatment have grown increasingly more nuanced. In this review, we present available data for both standard and investigational approaches in the initial treatment of AML using an intensive chemotherapy backbone or a lower-intensity approach. We summarize management strategies in newly diagnosed secondary AML, considerations around allogeneic stem-cell transplantation, and the role of maintenance therapy. Finally, we highlight important areas of future investigation and novel agents that may hold promise in combination with standard therapies.

Differential prognostic impact of RUNX1 mutations according to frontline therapy in patients with acute myeloid leukemia

RUNX1-mutated (mRUNX1) acute myeloid leukemia (AML) has historically been associated with poor outcomes in the setting of conventional chemotherapy. The prognostic impact of mRUNX1 AML is not well-established in the current era of lower-intensity treatment regimens incorporating venetoclax. We retrospectively analyzed 907 patients with newly diagnosed AML, including 137 patients with mRUNX1 AML, who underwent first-line therapy with intensive chemotherapy (IC), low-intensity therapy without venetoclax (LIT without VEN), or LIT with VEN. When stratified by RUNX1 status, there was no statistically significant difference in outcomes between mRUNX1 and wild-type (wtRUNX1) AML, regardless of therapy received. However, among patients who received LIT with VEN, there was a trend towards superior overall survival (OS) in those with mRUNX1 AML (median OS for mRUNX1 vs. wtRUNX1: 25.1 vs. 11.3 months; 2-year OS 54% vs. 33%; p = 0.12). In patients without another adverse-risk cyto-molecular feature, the presence of mRUNX1 conferred inferior OS in patients who received IC (p = 0.02) or LIT without VEN (p = 0.003) but not in those who received LIT with VEN (mRUNX1 vs. wtRUNX1: 25.1 vs. 30.0 months; 2-year OS 59% vs. 54%; p = 0.86). A multivariate analysis showed possible interaction between RUNX1 mutation status and treatment, suggesting a differential prognostic impact of RUNX1 mutations when patients received IC versus LIT with VEN. In summary, the prognostic impact of mRUNX1 AML may be treatment-dependent, and the presence of RUNX1 mutations may not impact clinical outcomes when venetoclax-based regimens are used.

Acute myeloid leukemia resistant to venetoclax-based therapy: What does the future hold?

Venetoclax is a highly selective B-cell lymphoma-2 (BCL-2) inhibitor, which, combined with a DNA hypomethylating agent or low dose cytarabine, results in high rates of initial responses in patients with acute myeloid leukemia (AML). However, the disease relapses in most patients. Mechanisms of resistance to venetoclax-based therapy include TP53 gene mutations or inactivation of p53 protein, activating kinase mutations such as FLT3 and RAS, and upregulation of other BCL-2 family apoptotic proteins. Current clinical trials are exploring strategies such as doublet or triplet regimens incorporating a p53 activator, an anti-CD47 antibody, or other novel agents that target genes and proteins responsible for resistance to venetoclax. Further studies should focus on identifying predictive biomarkers of response to venetoclax-based therapy and incorporating immunotherapeutic approaches such as checkpoint inhibitors, bispecific antibodies, antibody-drug conjugates, and CAR T-cell therapy to improve outcomes for patients with AML.

Oral Antineoplastics in Acute Myeloid Leukemia: A Comprehensive Review

AML is a biologically and clinically heterogeneous disease that is associated with poor overall long-term survival. The expanding knowledge of genomic landscape in AML as well as advancements in molecular and chemical biology over the pathway in AML. After 40 years of stagnancy, the recent approval of numerous novel oral anti-leukemic agents for the treatment of AML has changed both the armamentarium of medications and treatment paradigms. These agents have unique clinical considerations in terms of administration, adverse effects, and monitoring parameters which may differ from clinician's historical expectations. Understanding the data, indication and clinical considerations for such novel oral anti-leukemic agents is paramount for clinicians caring patients with AML.

Phase II Study of Venetoclax Added to Cladribine Plus Low-Dose Cytarabine Alternating With 5-Azacitidine in Older Patients With Newly Diagnosed Acute Myeloid Leukemia

PURPOSE

The combination of venetoclax and 5-azacitidine (5-AZA) for older or unfit patients with acute myeloid leukemia (AML) improves remission rates and survival compared with 5-AZA alone. We hypothesized that the addition of venetoclax to cladribine (CLAD)/low-dose araC (low-dose cytarabine [LDAC]) alternating with 5-AZA backbone may further improve outcomes for older patients with newly diagnosed AML.

METHODS

This is a phase II study investigating the combination of venetoclax and CLAD/LDAC alternating with venetoclax and 5-AZA in older (≥ 60 years) or unfit patients with newly diagnosed AML. The primary objective was composite complete response (CR) rate (CR plus CR with incomplete blood count recovery); secondary end points were overall survival, disease-free survival (DFS), overall response rate, and toxicity.

RESULTS

A total of 60 patients were treated; median age was 68 years (range, 57-84 years). By European LeukemiaNet, 23%, 33%, and 43% were favorable, intermediate, and adverse risk, respectively. Fifty-six of 60 evaluable patients responded (composite CR: 93%) and 84% were negative for measurable residual disease. There was one death (2%) within 4 weeks. With a median follow-up of 22.1 months, the median overall survival and DFS have not yet been reached. The most frequent grade 3/4 nonhematologic adverse events were febrile neutropenia (n = 33) and pneumonia (n = 14). One patient developed grade 4 tumor lysis syndrome.

CONCLUSION

Venetoclax and CLAD/LDAC alternating with venetoclax and 5-AZA is an effective regimen among older or unfit patients with newly diagnosed AML. The rates of overall survival and DFS are encouraging. Further study of this non-anthracycline-containing backbone in younger patients, unfit for intensive chemotherapy, as well as comparisons to standard frontline therapies is warranted.

CD7-directed CAR T-cell therapy: a potential immunotherapy strategy for relapsed/refractory acute myeloid leukemia

Relapsed/refractory acute myeloid leukemia (AML) patients generally have a dismal prognosis and the treatment remains challenging. Due to the expression of CD7 on 30% AML and not on normal myeloid and erythroid cells, CD7 is an attractive target for immunotherapy of AML. CD7-targeted CAR T-cells had demonstrated encouraging efficacy in xenograft models of AML. We report here on the use of autologous CD7 CAR T-cells in the treatment of a relapsed/refractory AML patient with complex karyotype, TP53 deletion, FLT3-ITD mutation, and SKAP2-RUNX1 fusion gene. Before the CAR T-cell therapy, the patient achieved partial remission with IA regimen and attained complete remission after reinduction therapy (decitabine and venentoclax). Relapse occurred after consolidation (CLAG regimen). Then she failed CLIA regimen combined with venetoclax and exhibited resistance to FLT3 inhibitors. Bone marrow showed 20% blasts (CD7+ 95.6%). A total dose of 5 × 10⁶/kg CD7 CAR T-cells was administered after the decitabine +FC regimen. Seventeen days after CAR T-cells infusion, she achieved morphologic leukemia-free state. The patient developed grade 3 cytokine release syndrome. No severe organ toxicity or immune effector cell-associated neurotoxicity syndrome was observed. In summary, the autologous CD7 CAR T-cell therapy could be considered a potential approach for AML with CD7 expression (NCT04762485).

Trial registration Clinical Trials.gov, NCT04762485. Registered on February 21, 2021, prospectively registered

Venetoclax in combination with nucleoside analogs in acute myelogenous leukemia

PURPOSE OF REVIEW

Venetoclax in combination with nucleoside analogs such as hypomethylating agents (HMA) and low-dose cytarabine (LDAC) has led to unprecedented response and survival outcomes in patients with acute myeloid leukemia (AML). This has spurred the development of regimens combining venetoclax with other nucleoside analogs with distinct mechanisms of action. Here, we review older and newer nucleoside analogs, the rationale for their combination with venetoclax, and clinical evidence for the combination when available.

RECENT FINDINGS

Venetoclax with HMA prolonged survival in a phase 3 study. Additionally, biologic correlates of response and resistance to venetoclax with HMA have been identified. The addition of venetoclax to standard intensive regimens containing higher doses of cytarabine and purine nucleoside analogs are safe and induce very high rates of remission and measurable residual disease negativity (MRD) negativity in newly diagnosed and relapsed/refractory AML. Investigational nucleoside analogs aim to improve upon the safety, bioavailability, or efficacy of approved venetoclax combinations and are currently being evaluated in clinical studies.

SUMMARY

The development of venetoclax with HMA has transformed care for elderly adults with AML and opened the door for novel combinations of venetoclax with other nucleoside analogs. Further clinical studies are needed to see if these novel combinations further improve outcomes in AML particularly for patients with high-risk disease.

MRD in Venetoclax-Based Treatment for AML: Does it Really Matter?

The prognosis of newly diagnosed patients with acute myeloid leukemia is still unfavorable in the majority of cases within the intermediate and mainly adverse genetic risk group but also in a considerable fraction of favorable-risk patients, mainly due to recurrence of disease after complete remission achievement or, less frequently, primary refractoriness. Besides genetic classification at diagnosis, post-treatment prognostic factors include measurable residual disease evaluation in patients in complete remission and in most cases measurable residual disease (MRD) positivity predicts hematologic relapse potentially allowing early therapeutic intervention. Currently, the most commonly used methods for detection of minimal residual disease are multiparameter flow cytometry and quantitative PCR, applicable to around 90% and 50% of patients, respectively. In addition, in > 90% of acute myeloid leukemia (AML) patients, molecular aberrations can be identified by next-generation sequencing, a technology that is widely used in clinical practice for the initial mutational screening at the time of diagnosis but more often, for MRD detection because its flexibility allows almost every mutated gene to be used as an MRD marker. Threshold levels of residual disease and correlation with outcome have been thoroughly studied and established in younger patients treated with intensive induction and consolidation chemotherapy as well as after allogeneic transplantation. Yet, experience on MRD monitoring and interpretation in patients treated with low-intensity regimens, including new agents, is still limited. The updated armamentarium of anti-leukemic agents includes the BCL-2 inhibitor venetoclax, which demonstrated good tolerability, high response rates, and prolonged overall survival when combined with hypomethylating agents or low dose cytarabine in patients considered elderly/”unfit” to tolerate intensive regimens. Although remissions with negative minimal residual disease clearly translated into improved outcomes after intensive treatments, data supporting the same evidence in patients receiving low-intensity venetoclax-based treatments are not still consolidated. We here review and discuss more recent data on the minimal residual disease interpretation and role in AML patients treated with venetoclax-based combinations.