Clinical experience with the BCL2-inhibitor venetoclax in combination therapy for relapsed and refractory acute myeloid leukemia and related myeloid malignancies

Blastic plasmacytoid dendritic cell neoplasm: Two case reports

BACKGROUND

Blastic plasmacytoid dendritic cell tumor (BPDCN) is a rare and highly invasive lymphohematopoietic tumor that originates from plasmacytoid dendritic cells. BPDCN has an extremely poor prognosis. Skin lesions are usually the first manifestation of BPDCN, although the tumor may also invade the bone marrow, lymph nodes, peripheral blood, and other parts of the body, leading to several other manifestations, requiring further differentiation through skin biopsy and immunohistochemistry.

CASE SUMMARY

In the present paper, the cases of 2 patients diagnosed with BPDCN are discussed. The immunohistochemistry analysis of these 2 patients revealed positivity for CD4, CD56, and CD123. Currently, no standard chemotherapy regimen is available for BPDCN. Therefore, intensive therapy for acute lymphoblastic leukemia was applied as the treatment method for these 2 cases.

CONCLUSION

Although allogeneic bone marrow transplantation could be further effective in prolonging the median survival the ultimate prognosis was unfavorable. Future treatment modalities tailored for elderly patients will help prolong survival.

Relapse and resistance in acute myeloid leukemia post venetoclax: improving second lines therapy and combinations

INTRODUCTION

The combined use of the BCL-2 inhibitor venetoclax with azacitidine now is the standard of care for patients with acute myeloid leukemia (AML) unfit for intensive chemotherapy with outcomes exceeding those achieved with hypomethylating agents alone. Venetoclax in combination with intensive chemotherapy is also increasingly used both as frontline as well as salvage therapy. However, resistance to and relapse after venetoclax-based therapies are of major concern and outcomes after treatment failure remain poor.

AREAS COVERED

A comprehensive search was performed using PubMed database (up to April 2024). Studies evaluating venetoclax-based combination treatments in AML and studies assessing markers of response and resistance to venetoclax were investigated. We summarize the status of venetoclax-based therapies in the frontline and relapsed/refractory setting with focus on the main mechanisms of resistance to BCL-2 inhibition. Further, strategies to overcome resistance including combinatorial regimens of hypomethylating agent (HMA) + venetoclax + inhibitors targeting actionable mutations like IDH1/2 or FLT3-ITD and the introduction of novel agents like menin-inhibitors are addressed.

EXPERT OPINION

Although venetoclax is reshaping the treatment of unfit and fit AML patients, prognosis of patients after HMA/VEN failure remains dismal and strategies to abrogate primary and secondary resistance are an unmet clinical need.

Outcomes by best response with hypomethylating agent plus venetoclax in adults with previously untreated acute myeloid leukemia

INTRODUCTION

We aimed to compare outcomes of patients with AML treated with frontline hypomethylating agent and venetoclax (HMA + Ven) who achieved complete remission (CR), complete remission with partial hematologic recovery (CRh), complete remission with incomplete hematologic recovery (CRi), or morphologic leukemia-free state (MLFS) as defined by ELN 2022.

METHODS

Patients with AML seen at Moffitt Cancer Center between 2018 and 2022 and treated with HMA + Ven were retrospectively evaluated.

RESULTS

About 120 patients achieved blast clearance with best response of CR in 52 (43.3%), CRh in 22 (18.3%), CRi in 31 (25.8%) and MLFS in 15 (12.5%) patients. Greater proportion of patients with MLFS had a prior myeloid malignancy (p = 0.003) and were treated with prior HMA (p < 0.001). Patients that achieved MLFS as their best response had inferior OS compared to the CR/CRh/CRi cohort (8 months vs. 27 months; p < 0.001). RFS was also worse for the MLFS cohort.

CONCLUSION

To the best of our knowledge, this is the largest study analyzing differences in outcomes of AML patients treated with HMA + Ven based on best response. We noted that prior myeloid malignancy and use of HMA led to more MLFS as best response compared to CR/CRi. The OS and RFS were inferior for MLFS cohort.

Homoharringtonine sensitized resistant acute myeloid leukemia cells to venetoclax-induced apoptosis

Venetoclax (VEN), a B-cell lymphoma 2 (BCL-2) selective inhibitor, is widely used for treating acute myeloid leukemia (AML) with promising results. However, the anti-leukemic effect of VEN in relapsed/refractory (R/R)- AML requires improvement. In this study, we observed that combining homoharringtonine (HHT) with VEN plus azacitidine resulted in a significantly higher response and better survival than VA alone in patients with R/R-AML. Basic research indicates that HHT combined with VEN has a highly synergistic effect against both resistant AML cells and primary cells with/without mesenchymal stem cell (MSC) co-culture in vivo, inhibiting proliferation and colony-forming capacity of AML cells associated with concomitant cell cycle arrest. Mechanistically, HHT sensitizes AML cells to VEN by downregulating the anti-apoptotic proteins MCL-1/BCL-xL, activating reactive oxygen species (ROS), leading to mitochondrial membrane potential loss, and attenuating fatty acid (FA) uptake. These findings adding HHT to VEN-based regimens may enhance outcomes in R/R-AML patients.

Cost-effectiveness of adding quizartinib to induction chemotherapy for patients with FLT3-mutant acute myeloid leukemia

The FLT3 inhibitor quizartinib has been shown to improve overall survival when added to intensive induction chemotherapy ("7 + 3") in patients 18-75 years old with newly diagnosed AML harboring a FLT3-ITD mutation. However, the health economic implications of this approval are unknown. We evaluated the cost-effectiveness of quizartinib using a partitioned survival analysis model. One-way and probabilistic sensitivity analyses were conducted. In the base case scenario, the addition of quizartinib to 7 + 3 resulted in incremental costs of $289,932 compared with 7 + 3 alone. With an incremental gain of 0.84 quality-adjusted life years (QALYs) with quizartinib + 7 + 3 induction vs. 7 + 3 alone, the incremental cost-effectiveness ratio for the addition of quizartinib to standard 7 + 3 was $344,039/QALY. Only an 87% reduction in the average wholesale price of quizartinib or omitting quizartinib continuation therapy after completion of consolidation therapy and allogeneic hematopoietic cell transplant would make quizartinib a cost-effective option.

Overcoming Tagraxofusp-Erzs Monotherapy Resistance in Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN) in a Real-World Clinical Setting

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and clinically aggressive hematologic malignancy with limited treatment options. Currently, standard treatment strategies include clinical trials; chemotherapy regimens such as hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (HCVAD); and tagraxofusp-erzs (TAG, previously SL-401) which is the first-in-class targeted therapy against CD123. TAG received Food and Drug Administration approval for frontline BPDCN treatment in December 2018 and has increasingly become an alternative to chemotherapy, offering potentially more effective and less toxic options. However, despite promising results, there are still patients who may be resistant to TAG monotherapy and/or who respond but eventually relapse. Herein, we discuss an important patient case of BPDCN treated with TAG and review BPDCN treatment strategies.

Combination of BCL-2 inhibitors and immunotherapy: a promising therapeutic strategy for hematological malignancies

The rapid development of high-throughput sequencing in recent years has facilitated great progress in the molecular-targeted therapy of hematological malignancies, including leukemia, lymphoma, and multiple myeloma. BCL-2 inhibitors are among the most important molecular-targeted agents. Immunotherapy for hematologic malignancy has rapidly increased in popularity in recent years and has been proven to improve the overall survival rate. However, few clinical studies have investigated combination therapy with BCL-2 inhibitors and immunotherapies, such as immune molecule-targeted drugs or immune cell adoptive therapy. In this review, we discuss the drug discovery process, current clinical application status, and resistance and tolerance issues associated with BCL-2 inhibitors. We emphasize their important role in regulating the immune system and propose that the combination of BCL-2 inhibitors with immunotherapy may be one of the most promising treatment methods for hematologic malignancies.

Venetoclax combined with azacitidine in blastic plasmacytoid dendritic cell neoplasm: a case report and comprehensive review on the current and future treatment

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is an extremely rare hematological malignancy with a highly aggressive behavior and median survival of <2 years. Especially, most BPDCN patients present with extensive and non-specific skin lesions, usually leading to misdiagnosis as a skin disease and delay therapy. As for treatment, most patients with BPDCN experience relapse shortly after treatment with the traditional regimens. The alleviation of skin symptoms reflects the effects of clinical treatments. Herein, we report a case of a 71-year-old man with intermittent and gradually expanding skin lesions over his chest, abdomen, and back for 1 year. On admission, physical examination revealed extensive skin lesions and multiple enlarged lymph nodes. Laboratory examinations showed pancytopenia and numerous malignant cells in the peripheral blood smear (60%), bone marrow aspirate smear (73.5%). Immunophenotyping using flow cytometry and immunohistochemistry presented large numbers of BPDCN cells in the bone marrow, cervical lymph nodes and dermal tissue. PET/CT revealed multiple enlarged lymph nodes and splenomegaly. Once the diagnosis was identified as BPDCN, the patient began treatment with the oral BCL2 inhibitor venetoclax and subcutaneously administered azacitidine. After the first course, skin lesions reduced markedly and complete remission was achieved in the bone marrow. Our study and current cumulative data according to reviewing systematically suggest that venetoclax combined with azacitidine is safe, effective, and applicable in the treatment of BPDCN, especially for elderly relapsed/refractory patients. This study, therefore, significantly contributes to the literature on the current and future treatment for BPDCN.

RSL3 enhances ROS-mediated cell apoptosis of myelodysplastic syndrome cells through MYB/Bcl-2 signaling pathway

Myelodysplastic syndromes (MDS) are clonal hematopoietic malignancies and seriously threaten people's health. Current therapies include bone marrow transplantation and several hypomethylating agents. However, many elderly patients cannot benefit from bone marrow transplantation and many patients develop drug resistance to hypomethylating agents, making it urgent to explore novel therapy. RSL3 can effectively induce ferroptosis in various tumors and combination of RSL3 and hypomethylating agents is promising to treat many tumors. However, its effect in MDS was unknown. In this study, we found that RSL3 inhibited MDS cell proliferation through inducing ROS-dependent apoptosis. RSL3 inhibited Bcl-2 expression and increased caspase 3 and PARP cleavage. RNA-seq analysis revealed that MYB may be a potential target of RSL3. Rescue experiments showed that overexpression of MYB can rescue MDS cell proliferation inhibition caused by RSL3. Cellular thermal shift assay showed that RSL3 binds to MYB to exert its function. Furthermore, RSL3 inhibited tumor growth and decreased MYB and Bcl-2 expression in vivo. More importantly, RSL3 decreased the viability of bone marrow mononuclear cells (BMMCs) isolated from MDS patients, and RSL3 had a synergistic effect with DAC in MDS cells. Our studies have uncovered RSL3 as a promising compound and MYB/Bcl-2 signaling pathway as a potential target for MDS treatment.

Continuously improving outcome over time after second allogeneic stem cell transplantation in relapsed acute myeloid leukemia: an EBMT registry analysis of 1540 patients

Second allogeneic stem cell transplantation (alloSCT2) is among the most effective treatments for acute myeloid leukemia (AML) relapse after first alloSCT (alloSCT1). Long-term EBMT registry data were used to provide large scale, up-to-date outcome results and to identify factors for improved outcome. Among 1540 recipients of alloSCT2, increasing age, better disease control and performance status before alloSCT2, more use of alternative donors and higher conditioning intensity represented important trends over time. Between the first (2000-2004) and last (2015-2019) period, two-year overall and leukemia-free survival (OS/LFS) increased considerably (OS: 22.5-35%, LFS: 14.5-24.5%). Cumulative relapse incidence (RI) decreased from 64% to 50.7%, whereas graft-versus-host disease and non-relapse mortality (NRM) remained unchanged. In multivariable analysis, later period of alloSCT2 was associated with improved OS/LFS (HR = 0.47/0.53) and reduced RI (HR = 0.44). Beyond, remission duration, disease stage and patient performance score were factors for OS, LFS, RI, and NRM. Myeloablative conditioning for alloSCT2 decreased RI without increasing NRM, leading to improved OS/LFS. Haploidentical or unrelated donors and older age were associated with higher NRM and inferior OS. In summary, outcome after alloSCT2 has continuously improved over the last two decades despite increasing patient age. The identified factors provide clues for the optimized implementation of alloSCT2.

Homoharringtonine enhances cytarabine-induced apoptosis in acute myeloid leukaemia by regulating the p38 MAPK/H2AX/Mcl-1 axis

Acute myeloid leukaemia (AML) is a fatal haematopoietic malignancy and is treated with the conventional combination of cytarabine (Ara-C) and daunorubicin (Dau). The survival rate of AML patients is lower due to the cardiotoxicity of daunorubicin. Clinically, homoharringtonine (HHT) plus Ara-C has been reported to be equally effective as Dau plus Ara-C in some types of AML patients with less toxic effects. We utilized the clinical use of homoharringtonine in combination with Ara-C to test its combination mechanism. We found that the insensitivity of AML cells to cytarabine-induced apoptosis is associated with increased Mcl-1 stability and p38 inactivation. HHT downregulates Mcl-1, phosphorylates H2AX and induces apoptosis by activating p38 MAPK. Inactivation of p38 through inhibitors and siRNA blocks apoptosis, H2AX phosphorylation and Mcl-1 reduction. HHT enhances Ara-C activation of the p38 MAPK signalling pathway, overcoming Ara-C tolerance to cell apoptosis by regulating the p38/H2AX/Mcl-1 axis. The optimal ratio of HHT to Ara-C for synergistic lethality in AML cells is 1:4 (M/M). HHT synergistically induces apoptosis in combination with Ara-C in vitro and prolongs the survival of xenografts. We provide a new mechanism for AML treatment by regulating the p38 MAPK/H2AX/Mcl-1 axis to improve cytarabine therapy.

Efficacy and safety of venetoclax plus hypomethylating agents in relapsed/refractory acute myeloid leukemia: a multicenter real-life experience

Venetoclax (VEN) has been shown to play a synergistic effect in combination with hypomethylating agents (HMAs) in the frontline treatment of acute myeloid leukemia (AML). However, the potential role of this therapy in the relapsed/refractory (R/R) AML setting, still needs to be further unveiled. The aim of the current study was to retrospectively outline the safety profile, response and survival outcomes of R/R AML patients treated with VEN in association with HMAs. Clinical, biological, and molecular data were collected from 57 patients with R/R AML treated with VEN combined with azacitidine or decitabine between 2018 and 2023. The median age of patients was 63 years, 38 (66.7%) received treatment for relapsed disease while 19 (33.3%) for refractory disease, 5 (8.7%) were treated for molecular relapse. A consistent proportion of the cohort was represented by patients with unfavorable prognostic factors such as complex karyotype (36.8%), secondary AML (29.8%), previous exposure to HMAs (38.6%), and relapse after allogeneic stem cell transplant (22.8%). A total of 14 patients achieved CR (24.6%), 3 (5.3%) CRi, 3 (5.3%) MLFS, and 3 (5.3%) PR, accounting for an ORR of 40.4%. The CR/CRi rate was higher in the group treated with azacitidine than in the group treated with decitabine (37.8% vs. 15%). The median OS was 8.2 months, reaching 20.1 months among responding patients. VEN-HMAs treatment allowed to bridge to allogeneic stem cell transplantation 11 (23.9%) of eligible patients, for which a median OS of 19.8 months was shown. On multivariate analysis, ECOG performance status ≥2, complex karyotype and not proceeding to allogeneic stem cell transplantation after therapy with VEN-HMAs were the factors independently associated with shorter OS. Patients treated with the azacitidine rather than the decitabine containing regimen generally displayed a trend toward superior outcomes. The major toxicities were prolonged neutropenia and infections. In conclusion, this study showed how VEN-HMAs could represent an effective salvage therapy in patients with R/R AML, even among some of those patients harboring dismal prognostic features, with a good toxicity profile. Further prospective studies are thus warranted.

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.

Venetoclax and hypomethylating agents in critically ill patients with newly diagnosed acute myeloid leukaemia

Venetoclax (VEN) in combination with hypomethylating agents (HMAs) is considered the standard of treatment for individuals with newly diagnosed acute myeloid leukaemia (AML) who are ineligible for intensive chemotherapy. We conducted a retrospective analysis that encompassed 16 critically ill patients newly diagnosed with AML who were admitted to the intensive care unit (ICU) and received the VEN and HMA regimen. Among them, 13 were primary AML, and three were MDS-transformed AML. The mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 18.9, and the mean sepsis-related organ failure assessment score (SOFA) was 6.2. The average length of the ICU stay was 27.3 days. The median duration of VEN administration was 16 days. After the first course of VEN + HMA, 12 cases (75%) achieved complete remission (CR) or CR with incomplete haematological recovery (CRi). Among the five patients harbouring TP53 mutations, the overall response rate (ORR) was 90%. All patients experienced grade 3-4 haematological adverse events (AEs). With a median follow-up of 9.5 months (range: 0.5-23), the overall survival (OS) rate was 43.75%. TP53-wild patients and CR state after the first course of VEN-HMA indicated better survival. The combination of VEN and HMA has demonstrated a significantly elevated therapeutic response rate in newly diagnosed AML patients with critical illness.

Investigations of the prognostic value of RUNX1 mutation in acute myeloid leukemia patients: Data from a real-world study

RUNX1 is one of the recurrent mutated genes in newly diagnosed acute myeloid leukemia (AML). Although historically recognized as a provisional distinct entity, the AML subtype with RUNX1 mutations (AML-RUNX1mut) was eliminated from the 2022 WHO classification system. To gain more insight into the characteristics of AML-RUNX1mut, we retrospectively analyzed 1065 newly diagnosed adult AML patients from the First Affiliated Hospital of Soochow University between January 2017 and December 2021. RUNX1 mutations were identified in 112 patients (10.5%). The presence of RUNX1 mutation (RUNX1mut) conferred a lower composite complete remission (CRc) rate (40.2% vs. 58.4%, P＜0.001), but no significant difference was observed in the 5-year overall survival (OS) rate (50.2% vs. 53.9%; HR=1.293; P=0.115) and event-free survival (EFS) rate (51.5% vs. 49.4%; HR=1.487, P=0.089), even within the same risk stratification. Multivariate analysis showed that RUNX1mut was not an independent prognostic factor for OS (HR=1.352, P=0.068) or EFS (HR=1.129, P=0.513). When patients were stratified according to induction regimen, RUNX1mut was an unfavorable factor for CRc both on univariate and multivariate analysis in patients receiving conventional chemotherapy, and higher risk stratification predicted worse OS. In those who received venetoclax plus hypomethylating agents, RUNX1mut was not predictive of CRc and comparable OS and EFS were seen between intermediate-risk and adverse-risk groups. The results of this study revealed that the impact of RUNX1mut is limited. Its prognostic value depended more on treatment and co-occurrent abnormalities. VEN-HMA may abrogate the prognostic impact of RUNX1, which merits a larger prospective cohort to illustrate.

Azacitidine-venetoclax versus azacitidine salvage treatment for primary induction failure or first relapsed acute myeloid leukaemia patients

OBJECTIVES

To compare the efficacy of venetoclax-azacitidine (VEN-AZA) with AZA in the real-life for patients with first relapsed or refractory acute myeloid leukaemia (R/R AML).

METHODS

We retrospectively analysed R/R AML patients treated with VEN-AZA at the Institut Paoli Calmettes between September 2020 and February 2022. We compared them to a historical cohort of patients treated with AZA between 2010 and 2021.

RESULTS

Thirty-five patients treated with VEN-AZA were compared with 140 patients treated with AZA. There were more favourable cytogenetics (25.7% vs. 8.6%; p = 0.01) and less FLT3-ITD mutated AML (8.8% vs. 25.5%; p = .049) in the VEN-AZA group. The overall 30-day mortality rate was 7.4% and the overall 90-day mortality was 20%, with no difference between the groups. The complete remission rate was 48.6% in the VEN-AZA group versus 15% (p < .0001). The composite complete response rate was 65.7% in the VEN-AZA group versus 23.6% (p < .0001). OS was 12.8 months in the VEN-AZA group versus 7.3 months (p = 0.059). Patients with primary refractory AML, poor-risk cytogenetics, prior hematopoietic stem-cell transplantation (HSCT) and FLT3-ITD mutated AML had lower response and survival rates.

CONCLUSION

VEN-AZA was associated with a better response rate and a longer survival than AZA monotherapy in AML patients who relapsed after or were refractory to intensive chemotherapy.

Venetoclax combined chemotherapy versus chemotherapy alone for acute myeloid leukemia: a systematic review and meta-analysis

Objective

To compare the efficacy and safety of venetoclax (VEN) in combination with chemotherapy (chemo) versus chemo alone in the treatment of acute myeloid leukemia (AML).

Method

To compare the efficacy and/or safety of VEN+chemo versus chemotherapy alone for AML, PubMed, Embase, Web of Science, and the Cochrane Library were used to searching up to June 2023. Comparisons included complete remission (CR), CR with incomplete hematologic recovery (CRi), morphologic leukemia-free state (MLFS), overall response rate (ORR), and adverse events (AEs).

Result

A total of 9 articles were included, including 3124 patients. The baseline characteristics between two patient groups were similar. The combined analysis showed that compared with the group receiving chemo alone, the VEN+chemo group exhibited higher rates of CR, CRi, MLFS and ORR. Additionally, the VEN+chemo group had longer event-free survival (EFS) and overall survival (OS) durations. The incidence rates of AEs and serious AEs (SAEs) were similar between the two groups, but the early 30-day mortality rate was lower in the VEN+chemo group than in the chemo alone group.

Conclusion

The VEN+chemo therapy demonstrates significant efficacy and safety profile in AML patients. However, more prospective studies are needed in the future to provide more accurate and robust evidence for treatment selection in patients.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023439288, identifier CRD42023439288.

Efficacy and safety of coadministration of venetoclax and anti-fungal agents under therapeutic drug monitor in unfit acute myeloid leukemia and high-risk myelodysplastic syndrome with neutropenia: a single-center retrospective study

Unfit acute myeloid leukemia and high-risk myelodysplastic syndrome patients with prolonged neutropenia demand coadministration of venetoclax and azoles. However, venetoclax dosing under drug-drug interaction with azoles remains controversial. Therapeutic drug monitoring (TDM) is expected to guide drug dosage adjustments. We retrospectively enrolled 17 patients under this coadministration and TDM. Venetoclax dosages were interfered when inappropriate drug concentrations appeared. The primary endpoints were objective response and adverse events. Venetoclax concentration outliers were more frequently evaluated before than after dose adjustment (Cmax 60.87% vs. 0.00%, p < .0001). MRD negativity rate was higher in patients staying within reference range than those having outliers (90.91% vs. 33.33%, p = .028). Objective response rate was 100%. Hematologic adverse events included neutropenia (93.3%), febrile neutropenia (53.3%), and thrombocytopenia (81.3%). Median time to neutropenia and thrombocytopenia recovery was 20 (14-32) and 16.5 (6-34) days, respectively. No invasive fungal and other life-threatening infections were observed.

Pivekimab sunirine (IMGN632), a novel CD123-targeting antibody-drug conjugate, in relapsed or refractory acute myeloid leukaemia: a phase 1/2 study

BACKGROUND

Pivekimab sunirine (IMGN632) is a first-in-class antibody-drug conjugate comprising a high-affinity CD123 antibody, cleavable linker, and novel indolinobenzodiazepine pseudodimer payload. CD123 is overexpressed in several haematological malignancies, including acute myeloid leukaemia. We present clinical data on pivekimab sunirine in relapsed or refractory acute myeloid leukaemia.

METHODS

This first-in-human, phase 1/2 dose-escalation and dose-expansion study enrolled participants aged 18 years or older at nine hospitals in France, Italy, Spain, and the USA with CD123+ haematological malignancies (Eastern Cooperative Oncology Group performance status of 0-1); participants reported here were in a cohort of participants with acute myeloid leukaemia who were refractory to or had relapsed on one or more previous treatments for acute myeloid leukaemia. The 3 + 3 dose-escalation phase evaluated two dosing schedules: schedule A (once every 3 weeks, on day 1 of a 3-week cycle) and fractionated schedule B (days 1, 4, and 8 of a 3-week cycle). The dose-expansion phase evaluated two cohorts: one cohort given 0·045 mg/kg of bodyweight (schedule A) and one cohort given 0·090 mg/kg of bodyweight (schedule A). The primary endpoints were the maximum tolerated dose and the recommended phase 2 dose. Antileukaemia activity (overall response and a composite complete remission assessment) was a secondary endpoint. The study is ongoing and registered with ClinicalTrials.gov, NCT03386513.

FINDINGS

Between Dec 29, 2017, and May 27, 2020, 91 participants were enrolled (schedule A, n=68; schedule B, n=23). 30 (44%) of schedule A participants were female and 38 (56%) were male; 60 (88%) were White, six (9%) were Black or African American, and two (3%) were other races. Pivekimab sunirine at doses of 0·015 mg/kg to 0·450 mg/kg in schedule A was administered in six escalating doses with no maximum tolerated dose defined; three dose-limiting toxicities were observed (reversible veno-occlusive disease; 0·180 mg/kg, n=1 and 0·450 mg/kg, n=1; and neutropenia; 0·300 mg/kg, n=1). Schedule B was not pursued further on the basis of comparative safety and antileukaemia findings with schedule A. The recommended phase 2 dose was selected as 0·045 mg/kg once every 3 weeks. At the recommended phase 2 dose (n=29), the most common grade 3 or worse treatment-related adverse events were febrile neutropenia (three [10%]), infusion-related reactions (two [7%]), and anaemia (two [7%]). Treatment-related serious adverse events occurring in 5% or more of participants treated at the recommended phase 2 dose were febrile neutropenia (two [7%]) and infusion-related reactions (two [7%]). Among 68 participants who received schedule A, one death (1%) was considered to be treatment-related (cause unknown; 0·300 mg/kg cohort). At the recommended phase 2 dose, the overall response rate was 21% (95% CI 8-40; six of 29) and the composite complete remission rate was 17% (95% CI 6-36; five of 29).

INTERPRETATION

Pivekimab sunirine showed single-agent activity across multiple doses, with a recommended phase 2 dose of 0·045 mg/kg once every 3 weeks. These findings led to a phase 1b/2 study of pivekimab sunirine plus azacitidine and venetoclax in patients with CD123-positive acute myeloid leukaemia.

FUNDING

ImmunoGen.

Low-dose venetoclax combined with azacitidine for blastic plasmacytoid dendritic cell neoplasm: a case report and literature review

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that is highly aggressive with a poor prognosis. There is no standard treatment for BPDCN. Although conventional chemotherapies are usually sensitive in the initial therapy, relapse and drug resistance are inevitable within a short duration. Targeted therapies have enlightened new prospects for the treatment of BPDCN, especially for those in a frail state and intolerable to standard chemotherapies or hematopoietic stem cell transplantation. Here, we report an 82-year-old man diagnosed with cutaneous-limited BPDCN. Considering the old age and limited involvement of the tumor, we reduced the dosage of venetoclax. His skin lesions subsided significantly after 1 cycle of azacytidine (100 mg d1-7) combined with reduced doses of venetoclax (200 mg d1-14). The reduction in the dose of venetoclax avoided severe myelosuppression while achieving satisfactory outcomes. The patient received 2 cycles of therapy with no skin lesions re-occurred for 7 months before relapsing.

Transcriptional and phenotypic heterogeneity underpinning venetoclax resistance in AML

The venetoclax BCL2 inhibitor in combination with hypomethylating agents represents a cornerstone of induction therapy for older AML patients, unfit for intensive chemotherapy. Like other targeted therapies, venetoclax-based therapies suffer from innate and acquired resistance. While several mechanisms of resistance have been identified, the heterogeneity of resistance mechanism across patient populations is poorly understood. Here we utilized integrative analysis of transcriptomic and ex-vivo drug response data in AML patients to identify four transcriptionally distinct VEN resistant clusters (VR_C1-4), with distinct phenotypic, genetic and drug response patterns. VR_C1 was characterized by enrichment for differentiated monocytic- and cDC-like blasts, transcriptional activation of PI3K-AKT-mTOR signaling axis, and energy metabolism pathways. They showed sensitivity to mTOR and CDK inhibition. VR_C2 was enriched for NRAS mutations and associated with distinctive transcriptional suppression of HOX expression. VR_C3 was characterized by enrichment for TP53 mutations and higher infiltration by cytotoxic T cells. This cluster showed transcriptional expression of erythroid markers, suggesting tumor cells mimicking erythroid differentiation, activation of JAK-STAT signaling, and sensitivity to JAK inhibition, which in a subset of cases synergized with venetoclax. VR_C4 shared transcriptional similarities with venetoclax-sensitive patients, with modest over-expression of interferon signaling. They were also characterized by high rates of DNMT3A mutations. Finally, we projected venetoclax-resistance states onto single cells profiled from a patient who relapsed under venetoclax therapy capturing multiple resistance states in the tumor and shifts in their abundance under venetoclax selection, suggesting that single tumors may consist of cells mimicking multiple VR_Cs contributing to intra-tumor heterogeneity. Taken together, our results provide a strategy to evaluate inter- and intra-tumor heterogeneity of venetoclax resistance mechanisms and provide insights into approaches to navigate further management of patients who failed therapy with BCL2 inhibitors.

Inhibition of NRF2 enhances the acute myeloid leukemia cell death induced by venetoclax via the ferroptosis pathway

Venetoclax, an inhibitor that selectively targets B cell lymphoma-2 (BCL-2) that has been approved for treating adult acute myeloid leukemia (AML) in combination with hypomethylating agents. However, its short duration of response and emergence of resistance are significant issues. In this study, we found that the sensitivity of AML cells to venetoclax was considerably enhanced by ML385, an inhibitor of the ferroptosis factor nuclear transcription factor erythroid 2-related factor 2 (NRF2). Using AML samples, we verified that NRF2 and its target gene ferritin heavy chain 1 (FTH1) were highly expressed in patients with AML and correlated with poor prognosis. Downregulation of NRF2 could inhibit FTH1 expression and significantly enhance the venetoclax-induced labile iron pool and lipid peroxidation. By contrast, NRF2 overexpression or administration of the reactive oxygen species inhibitor N-acetylcysteine and vitamin E could effectively suppress the anti-AML effects of ML385+venetoclax. Furthermore, the ferroptosis inducer erastin increased the anti-AML effects of venetoclax. Our study demonstrated that NRF2 inhibition could enhance the AML cell death induced by venetoclax via the ferroptosis pathway. Thus, the combination of ML385 with venetoclax may offer a favorable strategy for AML treatment.

Clinical and genetic characteristics predict outcomes of acute myeloid leukemia patients with FLT3 mutations receiving venetoclax-based therapy

BACKGROUND

Acute myeloid leukemia (AML) is a heterogeneous disease, and its heterogeneity is associated with treatment response. Despite the demonstrated success of venetoclax (VEN)-based therapy for AML, the effect of FLT3 mutations on the efficacy of the therapy is poorly understood. We aimed to compare the efficacy of VEN-based therapy between FLT3-mutated (FLT3mut ) and FLT3 wild-type (FLT3wt ) patients and identify the predictors of efficacy in FLT3mut patients.

METHODS

A total of 266 AML patients (127 newly diagnosed [ND] and 139 refractory/relapsed [R/R]) receiving VEN-based regimens were enrolled in this study. A retrospective analysis was performed, and the treatment responses and overall survival (OS) of FLT3mut and FLT3wt patients were compared. Logistic regression and Cox proportional hazards model were applied to examine the clinical and genetic predictors of outcomes.

RESULTS

With a median of two cycles of VEN-based therapy, for the ND AML cohort, the FLT3mut group had a comparable composite complete remission (CRc) rate with the FLT3wt group (79.3% vs. 61.2%, p = 0.072). For the R/R AML cohort, the FLT3mut group exhibited a lower CRc rate than the FLT3wt group. With a median follow-up of 8.6 months (95% confidence interval [CI], 8.0-10), the median OS observed in the FLT3mut and FLT3wt groups for both cohorts were close (14.0 vs. 19.9 months, p = 0.356; 10.0 vs. 11.9 months, p = 0.680). For the ND AML cohort, in FLT3mut patients, MRD-positive and RNA-splicing mutation predicted inferior survival (hazard ratio [HR], 10.3; 95% CI: 2.0-53.8; p = 0.006; HR 11.3; 95% CI: 1.2-109.3; p = 0.036, respectively). For the R/R AML cohort, in FLT3mut patients, adverse ELN risk was associated with an inferior response (odds ratio [OR], 0.2; 95% CI: 0.1-0.8; p = 0.025), whereas NPM1 co-mutation was associated with a superior response (57.1%; OR, 6.7; 95% CI: 1.5-30.1; p = 0.014). CR/CRi predicted a better survival (HR 0.2; 95% CI: 0.1-0.8; p = 0.029), while DNMT3A mutation predicted an inferior survival (HR, 4.6; 95% CI: 1.4-14.9; p = 0.011).

CONCLUSIONS

FLT3 mutations may influence response to VEN-based therapy in R/R AML patients but not in ND AML patients. Furthermore, clinical and genetic characteristics could predict outcomes of FLT3mut patients receiving VEN-based therapy.

Venetoclax plus hypomethylating agents in DDX41-mutated acute myeloid leukaemia and myelodysplastic syndrome: Mayo Clinic series on 12 patients

Venetoclax (VEN) is an FDA-approved selective inhibitor of B-cell leukaemia/lymphoma-2 (BCL-2), used for treating elderly or unfit acute myeloid leukaemia (AML) patients unable to undergo intensive chemotherapy. Combining VEN with hypomethylating agents (HMAs) has shown impressive response rates in high-risk myelodysplastic syndromes (MDS) and relapsed/refractory AML. However, the efficacy of VEN and HMAs in treating DDX41-mutated (mDDX41) MDS/AML patients remains uncertain. Despite the favourable prognostic nature of mDDX41 MDS/AML patients, there is a lack of clinical experience regarding their response to different treatment regimens, leading to an unknown optimal therapeutic approach.

GPRC5C drives branched-chain amino acid metabolism in leukemogenesis

Leukemia stem cells (LSCs) share numerous features with healthy hematopoietic stem cells (HSCs). G-protein coupled receptor family C group 5 member C (GPRC5C) is a regulator of HSC dormancy. However, GPRC5C functionality in acute myeloid leukemia (AML) is yet to be determined. Within patient AML cohorts, high GPRC5C levels correlated with poorer survival. Ectopic Gprc5c expression increased AML aggression through the activation of NF-κB, which resulted in an altered metabolic state with increased levels of intracellular branched-chain amino acids (BCAAs). This onco-metabolic profile was reversed upon loss of Gprc5c, which also abrogated the leukemia-initiating potential. Targeting the BCAA transporter SLC7A5 with JPH203 inhibited oxidative phosphorylation and elicited strong antileukemia effects, specifically in mouse and patient AML samples while sparing healthy bone marrow cells. This antileukemia effect was strengthened in the presence of venetoclax and azacitidine. Our results indicate that the GPRC5C-NF-κB-SLC7A5-BCAAs axis is a therapeutic target that can compromise leukemia stem cell function in AML.

Outcomes of adult patients with type 1 primary refractory acute myeloid leukemia: a single center experience

Adult patients with newly diagnosed de novo acute myeloid leukemia (AML), who had less than a 50% reduction in blast numbers and with > 15% residual blasts after first cycle of induction chemotherapy, defined as type 1 primary refractory (REF1), have grave prognosis. We retrospectively analyzed the data of 58 patients with REF1 who received salvage treatments with curative intension to evaluate the impact of salvage regimens with regard to response and overall survival (OS). Seventeen patients received intermediate- or high-dose cytarabine (ID/HD Ara-C) based intensive salvage chemotherapy, 36 patients received G-CSF primed less intensive chemotherapy and 5 patients received novel targeted drugs based low intensive therapy. The CR/CRi and MLFS rate was 6/17 and 2/17, 14/36 and 3/36, 3/5 and 0/5, respectively. The median OS for the whole cohort was 20.3 months. Median OS was comparable between the 3 arms. Overall, 42 patients underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT), 14 patients in the intensive arm, 24 patients in the less intensive arm and 4 patients in the low intensive arm. Median survival for allo-HSCT patients was significantly longer than for non-allo-HSCT patients (38.8 months vs. 2.1 months, p < 0.001). In multivariate analysis, achievement of CR/CRi after the salvage regimen were predictive of OS. We conclude that no significant difference in outcome among traditional salvage regimens in patients with REF1. G-CSF primed less intensive chemotherapy could serve as an alternative of ID/HD Ara-C based intensive chemotherapy and allo-HSCT is indispensable for long-term survival.

Venetoclax-based therapy in treatment-naïve and relapsed/refractory acute myeloid leukemia

Combining venetoclax with the hypomethylating agents azacitidine or decitabine has shown high complete response rates (60-70 %) in newly diagnosed (ND) acute myeloid leukemia (AML). However, studies addressing the efficacy of this approach in relapsed/refractory (R/R) AML remain limited. We conducted a retrospective analysis on patients treated with venetoclax-based therapy at a single institution. Objective response rates (ORR) and overall survival (OS) were assessed using logistic regression and Cox regression models, respectively. The total study population exhibited an ORR of 64 % with a complete remission at 34 %, complete remission with incomplete count recovery at 19%, and morphologic leukemia free state at 11 %. Patients with ND AML had a better ORR (71 %) compared to R/R AML (55 %), but the difference was not statistically significant. Median OS for the overall population was 14.4 months (range: 2-26 months). In the ND group, patients had a longer 6-month OS (82 % vs. 55 % in R/R AML), while both cohorts showed similar 12- and 24-month OS. Factors such as the hypomethylating agent chosen, adverse cytogenetics, TP53 mutations, prior hypomethylating agent use, and stem cell transplant status did not significantly affect ORR or OS. These findings support the effectiveness of venetoclax-based treatments in ND and R/R AML.

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.

Real-world results of venetoclax combined with hypomethylating agents in young adults with relapsed/refractory acute myeloid leukemia

OBJECTIVES

Young adults with acute myeloid leukemia (AML) often fail to achieve permanent complete remission (CR) and frequently relapse, indicating an urgent need to explore effective salvage therapies. Recent advances in AML treatment have been attributed to the combination of the B-cell lymphoma 2 (Bcl-2) inhibitor venetoclax (VEN) with hypomethylating agents (HMAs); however, the use of this combination in young adults with relapsed or refractory (R/R) AML has not been reported.

METHODS

We retrospectively examined 31 young patients with R/R AML treated with VEN plus an HMA. We evaluated the demographic data, cytogenetic characteristics, AML types, response rates, and transplantation-related data for the patients in our cohort.

RESULTS

The combination of VEN + HMA yielded a CR rate of 48.4%. The most prominent hematologic adverse event was neutropenia, which occurred in all patients, with 90.3% of cases being grade ≥3. Non-hematologic toxicities were relatively mild and infrequent, with an incidence of 45.2%. More than half of the patients with sustained CR had received an allogeneic hematopoietic stem cell transplantation (allo-HSCT), of whom two died of transplant-related complications.

CONCLUSION

Our results showed that the combination of VEN + HMA appeared to be a highly effective and well-tolerated salvage therapy option for young patients with R/R AML, enabling more young patients to proceed to potentially curative allo-HSCT. However, additional, well-designed studies with larger numbers of patients are required to confirm the advantages of VEN + HMA in this population.

Glutathione promotes the synergistic effects of venetoclax and azacytidine against myelodysplastic syndrome‑refractory anemia by regulating the cell cycle

Azacitidine is a DNA methyltransferase inhibitor that has been used as a singular agent for the treatment of myelodysplastic syndrome-refractory anemia with excess blast-1 and -2 (MDS-RAEB I/II). However, recurrence and overall response rates following this treatment remain unsatisfactory. The combination of azacitidine and venetoclax has been used for the clinical treatment of a variety of hematological diseases due to the synergistic killing effect of the two drugs. Venetoclax is a BCL-2 inhibitor that can inhibit mitochondrial metabolism. In addition, azacitidine has been shown to reduce the levels of myeloid cell leukemia 1 (MCL-1) in acute myeloid leukemia cells. MCL-1 is an anti-apoptotic protein and a potential source of resistance to venetoclax. However, the mechanism underlying the effects of combined venetoclax and azacitidine treatment remains to be fully elucidated. In the present study, the molecular mechanism underlying the impact of venetoclax on the efficacy of azacitidine was investigated by examining its effects on cell cycle progression. SKM-1 cell lines were treated in vitro with 0-2 µM venetoclax and 0-4 µM azacytidine. After 24, 48 and 72 h of treatment, the impact of the drugs on the cell cycle was assessed by flow cytometry. Following drug treatment, changes in cellular glutamine metabolism pathways was analyzed using western blotting (ATF4, CHOP, ASCT2, IDH2 and RB), quantitative PCR (ASCT2 and IDH2), liquid chromatography-mass spectrometry (α-KG, succinate and glutathione) and ELISA (glutamine and glutaminase). Venetoclax was found to inhibit mitochondrial activity though the alanine-serine-cysteine transporter 2 (ASCT2) pathway, which decreased glutamine uptake. Furthermore, venetoclax partially antagonized the action of azacitidine through this ASCT2 pathway, which was reversed by glutathione (GSH) treatment. These results suggest that GSH treatment can potentiate the synergistic therapeutic effects of venetoclax and azacitidine combined treatment on a myelodysplastic syndrome-refractory anemia cell line at lower concentrations.

Impact of previous anthracycline therapy in patients with acute myeloid leukemia receiving venetoclax

Venetoclax (VEN) combination regimens are now recognized as effective against acute myeloid leukemia (AML). However, the prognosis of patients who do not attain a composite complete response (cCR) is extremely poor, and clinical determinants of response remain unknown. Medical records of 57 patients with AML treated with VEN combination regimens from April 2021 to March 2022 at six institutions were retrospectively analyzed. The primary endpoint was cCR, complete remission, or complete remission with incomplete hematologic recovery after one cycle of VEN combination regimen. Five patients had previously relapsed after allogeneic hematopoietic stem cell transplantation (allo-SCT). The treatment regimen was azacitidine-VEN in 48 patients (84%) and low-dose cytarabine-VEN in 9 patients (16%). Thirty patients (53%) achieved cCR after one cycle of a VEN regimen. In univariate analysis, the number of prior chemotherapy regimens, post-allo-SCT relapse, and cytogenetic risk category were associated with a decreased likelihood of achieving cCR. In multivariate analysis, second-line chemotherapy remained a significant predictor of response. Patients who received anthracycline immediately before the VEN regimen had a higher cCR rate than patients who did not receive anthracycline. In this study, prior chemotherapy/allo-SCT and cytogenetic risk were associated with VEN treatment outcomes.

Allogeneic hematopoietic cell transplantation for blastic plasmacytoid dendritic cell neoplasm: a CIBMTR analysis

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy with a poor prognosis and considered incurable with conventional chemotherapy. Small observational studies reported allogeneic hematopoietic cell transplantation (allo-HCT) offers durable remissions in patients with BPDCN. We report an analysis of patients with BPDCN who received an allo-HCT, using data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). We identified 164 patients with BPDCN from 78 centers who underwent allo-HCT between 2007 and 2018. The 5-year overall survival (OS), disease-free survival (DFS), relapse, and nonrelapse mortality (NRM) rates were 51.2% (95% confidence interval [CI], 42.5-59.8), 44.4% (95% CI, 36.2-52.8), 32.2% (95% CI, 24.7-40.3), and 23.3% (95% CI, 16.9-30.4), respectively. Disease relapse was the most common cause of death. On multivariate analyses, age of ≥60 years was predictive for inferior OS (hazard ratio [HR], 2.16; 95% CI, 1.35-3.46; P = .001), and higher NRM (HR, 2.19; 95% CI, 1.13-4.22; P = .02). Remission status at time of allo-HCT (CR2/primary induction failure/relapse vs CR1) was predictive of inferior OS (HR, 1.87; 95% CI, 1.14-3.06; P = .01) and DFS (HR, 1.75; 95% CI, 1.11-2.76; P = .02). Use of myeloablative conditioning with total body irradiation (MAC-TBI) was predictive of improved DFS and reduced relapse risk. Allo-HCT is effective in providing durable remissions and long-term survival in BPDCN. Younger age and allo-HCT in CR1 predicted for improved survival, whereas MAC-TBI predicted for less relapse and improved DFS. Novel strategies incorporating allo-HCT are needed to further improve outcomes.

Selinexor Synergistically Promotes the Antileukemia Activity of Venetoclax in Acute Myeloid Leukemia by Inhibiting Glycolytic Function and Downregulating the Expression of DNA Replication Genes

Introduction

The BCL-2 inhibitor venetoclax has been widely used in the treatment of acute myeloid leukemia (AML); however, AML patients treated with venetoclax gradually develop resistance. The exportin-1 (XPO1) inhibitor selinexor can synergistically promote the antileukemia activity of venetoclax, but the mechanism remains unclear.

Methods and Results

Annexin V/7-aminoactinomycin D assays were used to examine the effects of a combination of venetoclax and selinexor (VEN+SEL) on AML cell lines and primary AML cells. RNA sequencing and oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) determinations by a Seahorse XF analyzer were employed to investigate the molecular mechanism of the toxicity of the VEN+SEL combination to AML cells. The cytotoxicity of NK cell combined with VEN+SEL combination was assessed in vitro using flow cytometry. VEN+SEL enhanced the apoptosis of AML cells (KG-1A and THP-1) and primary AML samples in vitro. The ECAR and OCR results demonstrated that the VEN+SEL combination significantly inhibited glycolytic function. RNA sequencing of THP-1 cells demonstrated that DNA replication-related genes were downregulated after treatment with the VEN+SEL combination.

Conclusion

This study indicated that selinexor can synergistically enhance the antileukemia activity of venetoclax in AML cells in vitro by inhibiting glycolytic function and downregulating DNA replication-related genes. Based on our experimental data, combining selinexor with venetoclax is an appropriate advanced treatment option for AML patients.

Venetoclax combined with hypomethylating agents and the CAG regimen in relapsed/refractory AML: a single-center clinical trial

Objective

This study aimed to evaluate the efficacy and safety of venetoclax in combination with hypomethylating agents and CAG (VEN-DCAG) regimens in patients with relapsed/refractory acute myeloid leukemia (R/R AML).

Methods

The treatment response was analyzed by retrospective methods in R/R AML patients treated with the VEN-DCAG regimen at our institution. This included, but was not limited to, CR/CRi (complete remission/complete remission with incomplete hematologic recovery) rate, measurable residual disease (MRD) negative rate, and overall survival (OS).

Results

20 patients with R/R AML were recruited, with a median age of 40 years (10-70), 11 of whom were male (55%), and a median follow-up of 10.4 months (0.7-21.8). The overall response rate (ORR) after receiving 1 course of VEN-DCAG was 90% (18/20), with 17 (85%) CR/CRi (10 MRD-CR), 1 (5%) PR, and 2 (10%) NR. Subsequently, 12 patients (7 MRD-CR, 4 MRD+CR, 1 NR) were treated with the VEN-DCAG regimen, and 3 MRD+CR patients turned negative, and 13 patients finally achieved MRD-CR. Among them, 7 patients were in the relapse group, all achieving CR/CRi (6 MRD-CR), and 13 patients in the refractory group, with 10 CR/CRi (7 MRD-CR). The ORR for patients in the relapse and refractory groups was 100% (7/7) and 84.6% (11/13), respectively. Further, all patients experienced adverse events (AEs) of varying degrees of severity, with hematologic AEs primarily consisting of myelosuppression, while non-hematologic AEs were more common in the form of fever, gastrointestinal distress, and infections. 11 patients were followed up with bridging allogeneic hematopoietic stem cell transplantation (allo-HSCT) therapy. At the last follow-up, 11 patients (7 MRD-CR, 4 MRD+CR) who received allo-HSCT, 1 (MRD+CR) died, and 9 patients (6 MRD-CR, 1 PR, 2 NR) who did not receive allo-HSCT, 5 (2 MRD-CR, 1 PR, 2 NR) died as well.

Conclusion

The VEN-DCAG regimen may be an effective treatment option for R/R AML patients, with high ORR and MRD negative remission rates in both the relapsed and refractory groups. It is recommend that patients should be bridged to allo-HSCT as soon as possible after induction to CR by the VEN-DCAG regimen, which can lead to a significant long-term survival benefit.

Clinical trial registration

https://www.chictr.org.cn/, identifier ChiCTR2300075985.

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.

Novel Approaches to Treatment of Acute Myeloid Leukemia Relapse Post Allogeneic Stem Cell Transplantation

The management of patients with acute myeloid leukemia (AML) relapsed post allogeneic hematopoietic stem cell transplantation (HSCT) remains a clinical challenge. Intensive treatment approaches are limited by severe toxicities in the early post-transplantation period. Therefore, hypomethylating agents (HMAs) have become the standard therapeutic approach due to favorable tolerability. Moreover, HMAs serve as a backbone for additional anti-leukemic agents. Despite discordant results, the addition of donor lymphocytes infusions (DLI) generally granted improved outcomes with manageable GvHD incidence. The recent introduction of novel targeted drugs in AML gives the opportunity to add a third element to salvage regimens. Those patients harboring targetable mutations might benefit from IDH1/2 inhibitors Ivosidenib and Enasidenib as well as FLT3 inhibitors Sorafenib and Gilteritinib in combination with HMA and DLI. Conversely, patients lacking targetable mutations actually benefit from the addition of Venetoclax. A second HSCT remains a valid option, especially for fit patients and for those who achieve a complete disease response with salvage regimens. Overall, across studies, higher response rates and longer survival were observed in cases of pre-emptive intervention for molecular relapse. Future perspectives currently rely on the development of adoptive immunotherapeutic strategies mainly represented by CAR-T cells.

Mutated ZRSR2 and CUL3 accelerate clonal evolution and confer venetoclax resistance via RAS signaling pathway in blastic plasmacytoid dendritic cell neoplasm

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive subtype of myeloid malignancy characterized by skin, lymph node and central nervous system (CNS) involvement. Although various regimens are used, a standard therapeutic strategy for BPDCN has not been established. Recent studies revealed that BPDCN patients frequently have a mutation in ZRSR2, which is a minor spliceosome component. However, the association between the clinical features of BPDCN and ZRSR2 mutational status remains unknown. A 70-year-old man was referred to our hospital with skin rash and enlarged lymph nodes, as well as blasts in the peripheral blood. BPDCN was diagnosed based on the immunophenotype of the blasts derived from bone marrow. Whole exome sequencing revealed that BPDCN cells collected at diagnosis had mutations in ZRSR2, ZBTB33, CUL3, TET2 and NRAS. RNA sequencing analysis indicated that U12-type intron retention occurred in LZTR1, caused by ZRSR2 loss. After seven cycles of venetoclax combined with azacitidine therapy, BPDCN cells appeared in the peripheral blood and infiltrated the CNS. Two KRAS mutated clones appeared at BPDCN recurrence. These findings are important for understanding the pathogenesis of BPDCN, which will inform development of novel therapeutic strategies.

Outpatient initiation of venetoclax in patients with acute myeloid leukemia

INTRODUCTION

Venetoclax is a treatment option in patients with acute myeloid leukemia (AML) in both the front-line and relapsed/refractory settings. Initiation of therapy has been previously restricted to the inpatient setting at some institutions due to a risk of tumor lysis syndrome (TLS) and limitations in medication access efficiency given the high cost of therapy.

METHODS

We assessed the safety of initiating venetoclax in the outpatient setting through a single-arm, retrospective study of adult AML patients between April 1, 2019 and June 30, 2020.

RESULTS

Eighty-two patients started venetoclax during this time, with 47 (57%) patients initiated in the outpatient setting. Fifty-five percent of patients received venetoclax as first-line treatment for AML (n = 45) and 45% of patients received venetoclax for relapsed/refractory AML (n = 37). Successful initiation, defined as no hospitalizations secondary to TLS within seven days of therapy initiation, occurred in 98% of patients. The rate of TLS was 2.1% (n = 1) following venetoclax initiation. TLS symptoms were managed during hospitalization, requiring only one day of missed AML therapy. Median turnaround time for medication access was three days. Hospitalizations within seven days occurred in 17% of patients (n = 8), with the majority due to febrile neutropenia.

CONCLUSIONS

The results of our study provide further evidence for the safety and feasibility of initiating venetoclax in the outpatient setting with a pharmacist-led interdisciplinary protocol.

Blastic plasmacytoid dendritic cell neoplasm: a comprehensive review in pediatrics, adolescents, and young adults (AYA) and an update of novel therapies

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematologic malignancy that can involve the bone marrow, peripheral blood, skin, lymph nodes, and the central nervous system. Though more common in older adults, BPDCN has been reported across all age groups, including infants and children. The incidence of pediatric BPDCN is extremely low and little is known about the disease. Pediatric BPDCN is believed to be clinically less aggressive but often with more dissemination at presentation than adult cases. Unlike adults who almost always proceed to a hematopoietic stem cell transplantation in first complete remission if transplant-eligible, the majority of children can be cured with a high-risk acute lymphoblastic leukemia-like regimen. Hematopoietic stem cell transplantation is recommended for children with high-risk disease, the definition of which continues to evolve, or those in relapse and refractory settings where outcomes continue to be dismal. Novel agents used in other hematologic malignancies and CD123 targeted agents, including chimeric antigen receptor T-cells and monoclonal/bispecific antibodies, are being brought into research and practice. Our goal is to provide a comprehensive review of presentation, diagnosis, and treatment by review of pediatric cases reported for the last 20 years, and a review of novel targeted therapies and therapies under investigation for adult and pediatric patients.

Venetoclax Combined with Azacytidine Can Be a First-line Treatment Option for Elderly Blastic Plasmacytoid Dendritic Cell Neoplasm

An 84-year-old Japanese man was diagnosed with blastic plasmacytoid dendritic cell neoplasm (BPDCN). We administered combination therapy using venetoclax and azacytidine. We observed neutropenia (Grade 4), thrombocytopenia (Grade 2), and stomatitis (Grade 3). After six cycles of treatment, the BPDCN abnormal cells in the bone marrow specimen almost disappeared, and atypical cells were not detected in a skin biopsy. We propose venetoclax combined with azacytidine as a useful treatment approach in elderly patients, although clinicians should be mindful that therapeutic modifications may be essential to minimize and/or avoid adverse events.

Targeting metabolic vulnerabilities to overcome resistance to therapy in acute myeloid leukemia

Malignant hematopoietic cells gain metabolic plasticity, reorganize anabolic mechanisms to improve anabolic output and prevent oxidative damage, and bypass cell cycle checkpoints, eventually outcompeting normal hematopoietic cells. Current therapeutic strategies of acute myeloid leukemia (AML) are based on prognostic stratification that includes mutation profile as the closest surrogate to disease biology. Clinical efficacy of targeted therapies, e.g., agents targeting mutant FMS-like tyrosine kinase 3 (FLT3) and isocitrate dehydrogenase 1 or 2, are mostly limited to the presence of relevant mutations. Recent studies have not only demonstrated that specific mutations in AML create metabolic vulnerabilities but also highlighted the efficacy of targeting metabolic vulnerabilities in combination with inhibitors of these mutations. Therefore, delineating the functional relationships between genetic stratification, metabolic dependencies, and response to specific inhibitors of these vulnerabilities is crucial for identifying more effective therapeutic regimens, understanding resistance mechanisms, and identifying early response markers, ultimately improving the likelihood of cure. In addition, metabolic changes occurring in the tumor microenvironment have also been reported as therapeutic targets. The metabolic profiles of leukemia stem cells (LSCs) differ, and relapsed/refractory LSCs switch to alternative metabolic pathways, fueling oxidative phosphorylation (OXPHOS), rendering them therapeutically resistant. In this review, we discuss the role of cancer metabolic pathways that contribute to the metabolic plasticity of AML and confer resistance to standard therapy; we also highlight the latest promising developments in the field in translating these important findings to the clinic and discuss the tumor microenvironment that supports metabolic plasticity and interplay with AML cells.

Efficacy and safety of venetoclax combined with hypomethylating agents for relapse of acute myeloid leukemia and myelodysplastic syndrome post allogeneic hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Currently, there is no standard treatment for managing relapse in patients with acute myeloid leukemia and myelodysplastic syndrome (AML/MDS) after allogeneic hematopoietic cell transplantation. Venetoclax-based therapies have been increasingly used for treating post-transplantation relapse of AML. The aim of this systematic review and meta-analysis was to evaluate the efficacy and adverse events of Venetoclax combined with hypomethylating agents (HMAs) for AML/MDS relapse post-transplantation.

METHODS

We searched PubMed, Web of Science, Excerpta Medica Database, Cochrane Library, and Clinical. gov for eligible studies from the inception to February 2022. The Methodological Index for Non-Randomized Studies was used to evaluate the quality of the included literatures. The inverse variance method calculated the pooled proportion and 95% confidence interval (CI).

RESULTS

This meta-analysis included 10 studies involving a total of 243 patients. The pooled complete response and complete response with incomplete blood count recovery rate of Venetoclax combined with HMAs for post-transplantation relapse in AML/MDS was 32% (95% CI, 26-39%, I2 = 0%), with an overall response rate of 48% (95% CI, 39-56%, I2 = 37%). The 6-month survival rate was 42% (95% CI, 29-55%, I2 = 62%) and the 1-year survival rate was 23% (95% CI, 11-38%, I2 = 78%).

CONCLUSION

This study demonstrated a moderate benefit of Venetoclax in combination with HMAs for patients with relapsed AML/MDS post-transplantation (including those who have received prior HMAs therapy), and may become one of treatment options in the future. Large-scale prospective studies are needed to confirm the potential benefit from venetoclax combined with HMAs.

15-days duration of venetoclax combined with azacitidine in the treatment of relapsed/refractory high-risk myelodysplastic syndromes: A retrospective single-center study

The treatment of patients with refractory and/or relapsed (R/R) high-risk myelodysplastic syndrome (HR-MDS) remains a daunting clinical challenge. Venetoclax is a selective BCL-2 inhibitor, which combined with hypomethylating agents (HMAs), increased responses and prolonged survival in unfit and previously untreated acute myeloid leukemia. We performed a retrospective study of patients with R/R HR-MDS receiving combination azacytidine (AZA) plus 15-days duration of venetoclax (VEN-15d) in order to determine their efficacy and toxicity in this context. We showed that the overall response rate was 57.2% (20/35) and the median over survival was 14 months in R/R MDS. The most common treatment-emergent adverse events were peripheral blood cytopenias and infectious complications. Our retrospective study showed that the real-world experience of treating R/R MDS with AZA plus VEN-15d highlights an encouraging response rate with myelosuppression being the major toxicity. Of note, VEN-15d with AZA may salvage patients failing to respond optimally to HMAs and reduce the disease-burden for subsequent allogeneic stem cell transplantation in our analysis. These data of combination AZA plus VEN-15d in R/R MDS warrant further prospective evaluation in clinical trials.

Efficacy and safety of FDA-approved IDH inhibitors in the treatment of IDH mutated acute myeloid leukemia: a systematic review and meta-analysis

OBJECTIVE

To systematically evaluate the efficacy and safety of FDA-approved isocitrate dehydrogenase (IDH) inhibitors in the treatment of IDH-mutated acute myeloid leukemia (AML).

METHODS

We used R software to conduct a meta-analysis of prospective clinical trials of IDH inhibitors in the treatment of IDH-mutated AML published in PubMed, Embase, Clinical Trials, Cochrane Library and Web of Science from inception to November 15th, 2022.

RESULTS

A total of 1109 IDH-mutated AML patients from 10 articles (11 cohorts) were included in our meta-analysis. The CR rate, ORR rate, 2-year survival (OS) rate and 2-year event-free survival (EFS) rate of newly diagnosed IDH-mutated AML (715 patients) were 47%, 65%, 45% and 29%, respectively. The CR rate, ORR rate, 2-year OS rate, median OS and median EFS of relapsed or refractory (R/R) IDH-mutated AML (394 patients) were 21%, 40%, 15%, 8.21 months and 4.73 months, respectively. Gastrointestinal adverse events were the most frequently occurring all-grade adverse events and hematologic adverse events were the most frequently occurring ≥ grade 3 adverse events.

CONCLUSION

IDH inhibitor is a promising treatment for R/R AML patients with IDH mutations. For patients with newly diagnosed IDH-mutated AML, IDH inhibitors may not be optimal therapeutic agents due to low CR rates. The safety of IDH inhibitors is controllable, but physicians should always pay attention to and manage the differentiation syndrome adverse events caused by IDH inhibitors. The above conclusions need more large samples and high-quality RCTs in the future to verify.

Venetoclax monotherapy as front-line therapy for blastic plasmacytoid dendritic cell neoplasm

Venetoclax is an approved treatment for relapsed/refractory Blastic Plasmacytoid Dendritic Cell Neoplasm (BPDCN). We report a unique case of venetoclax monotherapy used for front-line induction and as a bridge to allogeneic hematopoietic stem cell transplantation (HCT). Venetoclax therapy resulted in rapid complete resolution of skin lesions, however, treatment interruption due to neutropenia led to brisk cancer recurrence. Fortunately, the patient responded to re-challenge and was able to undergo HCT. Venetoclax is active in the first-line treatment setting for BPDCN, however its effect on blood counts and durability of response should be further studied.

Venetoclax in combination with chemotherapy as treatment for pediatric advanced hematologic malignancies

BACKGROUND

Venetoclax is frequently used as salvage treatment in pediatric, adolescent, and young adult (AYA) patients with advanced hematologic malignancies. However, more data are needed from real-world studies to guide the safe and appropriate use of venetoclax in this population.

PROCEDURE

We retrospectively reviewed the medical records of all patients diagnosed with hematologic malignancies less than 30 years of age treated with venetoclax outside of clinical trials at the University of California San Francisco Benioff Children's Hospitals from 2016 to 2022.

RESULTS

We identified 13 patients (acute myeloid leukemia, n = 8; B-acute lymphoblastic leukemia, n = 3; myelodysplastic syndrome, n = 2) aged 4 months to 27 years. A median of 3 prior lines of therapy weregiven (range 0-5). All patients received venetoclax in combination with either a hypomethylating agent or conventional chemotherapy. Three (23%) patients achieved complete remission (CR); two (15%) achieved partial remission (PR); 3 (23%) had stable disease (SD), and five (42%) had progressive disease. Median survival and time to progression from venetoclax initiation was 9 months (range 2.5-52 months) and 3 months (range 2 weeks to 7.5 months), respectively. Six patients (46%) developed grade 3 or higher infections while receiving venetoclax, including bacteremia due to atypical organisms, invasive pulmonary infections with Aspergillus, cytomegalovirus (CMV) viremia, skin infections, and encephalitis with bacterial brain abscesses.

CONCLUSIONS

Venetoclax in combination with hypomethylating agents or cytotoxic chemotherapy was effective in a subset of pediatric/AYA patients with advanced hematologic malignancies, but multiple severe infections were observed, particularly among patients who received venetoclax in combination with chemotherapy. Prospective studies will be required to determine the optimal dose and duration of venetoclax in this population.