Augmenting NK cell-based immunotherapy by targeting mitochondrial apoptosis.

Interest in harnessing natural killer (NK) cells for cancer immunotherapy is rapidly growing. However, efficacy of NK cell-based immunotherapy remains limited in most trials. Strategies to augment the killing efficacy of NK cells are thus much needed. In the current study, we found that mitochondrial apoptosis (mtApoptosis) pathway is essential for efficient NK killing, especially at physiologically relevant effector-to-target ratios. Furthermore, NK cells can prime cancer cells for mtApoptosis and mitochondrial priming status affects cancer-cell susceptibility to NK-mediated killing. Interestingly, pre-activating NK cells confers on them resistance to BH3 mimetics. Combining BH3 mimetics with NK cells synergistically kills cancer cells in vitro and suppresses tumor growth in vivo. The ideal BH3 mimetic to use in such an approach can be predicted by BH3 profiling. We herein report a rational and precision strategy to augment NK-based immunotherapy, which may be adaptable to T cell-based immunotherapies as well.

Stressed to death: Mitochondrial stress responses connect respiration and apoptosis in cancer.

Mitochondrial energetics and respiration have emerged as important factors in how cancer cells respond to or evade apoptotic signals. The study of the functional connection between these two processes may provide insight into following questions old and new: how might we target respiration or downstream signaling pathways to amplify apoptotic stress in the context of cancer therapy? Why are respiration and apoptotic regulation housed in the same organelle? Here, we briefly review mitochondrial respiration and apoptosis and then focus on how the intersection of these two processes is regulated by cytoplasmic signaling pathways such as the integrated stress response.

Expanded profiling of WD repeat domain 5 inhibitors reveals actionable strategies for the treatment of hematologic malignancies.

WD40 Repeat Domain 5 (WDR5) is a highly conserved nuclear protein that recruits MYC oncoprotein transcription factors to chromatin to stimulate ribosomal protein gene expression. WDR5 is tethered to chromatin via an arginine-binding cavity known as the "WIN" site. Multiple pharmacological inhibitors of the WDR5-interaction site of WDR5 (WINi) have been described, including those with picomolar affinity and oral bioavailability in mice. Thus far, however, WINi have only been shown to be effective against a number of rare cancer types retaining wild-type p53. To explore the full potential of WINi for cancer therapy, we systematically profiled WINi across a panel of cancer cells, alone and in combination with other agents. We report that WINi are unexpectedly active against cells derived from both solid and blood-borne cancers, including those with mutant p53. Among hematologic malignancies, we find that WINi are effective as a single agent against leukemia and diffuse large B cell lymphoma xenograft models, and can be combined with the approved drug venetoclax to suppress disseminated acute myeloid leukemia in vivo. These studies reveal actionable strategies for the application of WINi to treat blood-borne cancers and forecast expanded utility of WINi against other cancer types.

Anti-CLL1 liposome loaded with miR-497-5p and venetoclax as a novel therapeutic strategy in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a lethal hematologic malignancy. Chemotherapy resistance results in a dismal survival rate of 1-2 years in older adults with AML. Therefore, novel therapies are urgently required. In this context, microRNA (miRNA)-based treatments remain an untapped strategy in AML. Using patient-derived specimens, we found increased inflammatory cytokines, including interleukin-6 (IL-6) in the serum of older adults with AML, and decreased miR-497-5p in CD34+ leukemic blasts. Target prediction revealed that miR-497-5p could directly target mitogen-activated protein kinase-1 (MAP2K1) mRNA to indirectly target cytokines and the JAK/STAT signaling pathway through the p38-MAPK signaling pathway, potentially inhibiting leukemic growth and overcoming chemoresistance from venetoclax. To improve miRNA delivery and minimize off-target effects, which represent key barriers to clinical translation, we developed liposomes for co-delivery of miR-497-5p and venetoclax. We decorated our liposomes with a peptide targeting CLL1, which is present on 92% of leukemia blasts while being absent in normal hematopoietic cells. This targeted approach demonstrated high efficacy in inhibiting AML growth in mice with minimal toxicity, as well as reduced exposure to chemoresistance. Our findings suggested that anti-CLL1-decorated, miR-497-5p, and venetoclax-loaded liposomes represent a promising novel miRNA-based therapeutic, which should be investigated further as a strategy to reduce venetoclax resistance in AML.

Reverse Phase Proteomic Array Profiling of Asparagine Synthetase Expression in Newly Diagnosed Acute Myeloid Leukemia.

Asparaginase-based therapy is a cornerstone in acute lymphoblastic leukemia (ALL) treatment, capitalizing on the methylation status of the asparagine synthetase (ASNS) gene, which renders ALL cells reliant on extracellular asparagine. Contrastingly, ASNS expression in acute myeloid leukemia (AML) has not been thoroughly investigated, despite studies suggesting that AML with chromosome 7/7q deletions might have reduced ASNS levels. Here, we leverage reverse phase protein arrays to measure ASNS expression in 810 AML patients and assess its impact on outcomes. We find that AML with inv(16) has the lowest overall ASNS expression. While AML with deletion 7/7q had ASNS levels slightly lower than those of AML without deletion 7/7q, this observation was not significant. Low ASNS expression correlated with improved overall survival (46 versus 54 weeks, respectively, p = 0.011), whereas higher ASNS levels were associated with better response to venetoclax-based therapy. Protein correlation analysis demonstrated association between ASNS and proteins involved in methylation and DNA repair. In conclusion, while ASNS expression was not lower in patients with deletion 7/7q as initially predicted, ASNS levels were highly variable across AML patients. Further studies are needed to assess whether patients with low ASNS expression are susceptible to asparaginase-based therapy due to their inability to augment compensatory ASNS expression upon asparagine depletion.

FLT3 and IRAK4 Inhibitor Emavusertib in Combination with BH3-Mimetics in the Treatment of Acute Myeloid Leukemia.

Targeting the FLT3 receptor and the IL-1R associated kinase 4 as well as the anti-apoptotic proteins MCL1 and BCL2 may be a promising novel approach in the treatment of acute myeloid leukemia (AML). The FLT3 and IRAK4 inhibitor emavusertib (CA4948), the MCL1 inhibitor S63845, the BCL2 inhibitor venetoclax, and the HSP90 inhibitor PU-H71 were assessed as single agents and in combination for their ability to induce apoptosis and cell death in leukemic cells in vitro. AML cells represented all major morphologic and molecular subtypes, including FLT3-ITD and NPM1 mutant AML cell lines and a variety of patient-derived AML cells. Emavusertib in combination with MCL1 inhibitor S63845 or BCL2 inhibitor venetoclax induced cell cycle arrest and apoptosis in MOLM-13 cells. In primary AML cells, the response to emavusertib was associated with the presence of the FLT3 gene mutation with an allelic ratio >0.5 and the presence of NPM1 gene mutations. S63845 was effective in all tested AML cell lines and primary AML samples. Blast cell percentage was positively associated with the response to CA4948, S63845, and venetoclax, with elevated susceptibility of primary AML with blast cell fraction >80%. Biomarkers of the response to venetoclax included the blast cell percentage and bone marrow infiltration rate, as well as the expression levels of CD11b, CD64, and CD117. Elevated susceptibility to CA4948 combination treatments with S63845 or PU-H71 was associated with FLT3-mutated AML and CD34 < 30%. The combination of CA4948 and BH3-mimetics may be effective in the treatment in FLT3-mutated AML with differential target specificity for MCL1 and BCL2 inhibitors. Moreover, the combination of CA4948 and PU-H71 may be a candidate combination treatment in FLT3-mutated AML.

Lower intensity therapy with cladribine/low dose cytarabine/venetoclax in older patients with acute myeloid leukemia compares favorably with intensive chemotherapy among patients undergoing allogeneic stem cell transplantation.

BACKGROUND: Allogeneic stem cell transplantation (SCT) remains the best consolidative modality in most patients with acute myeloid leukemia (AML). Along with factors directly pertaining to SCT, pretransplantation disease control, performance status, and prior treatment-related complications are important factors that affect posttransplantation survival outcomes. METHODS: The authors compared the survival outcomes of patients ≥60 years of age treated on the phase 2 clinical trial of venetoclax (Ven) added to cladribine (CLAD) and low dose cytarabine (LDAC) alternating with azacitidine (CLAD/LDAC/Ven arm) (NCT03586609) who underwent allogeneic SCT in first remission to a retrospective cohort of patients ≥60 years of age who underwent SCT after intensive chemotherapy. Intensive chemotherapy was defined as the use of cytarabine >1 g/m2 and anthracyclines during induction/consolidation. RESULTS: Thirty-five patients at median age of 68 years in the CLAD/LDAC/Ven arm were compared to 42 patients at a median age of 62 years in the intensive therapy arm. The 2-year relapse-free survival was superior with CLAD/LDAC/Ven versus intensive chemotherapy (88% vs. 65%; p = .03) whereas the 2-year overall survival (OS) was comparable (84% vs. 70%; p = .14). On a competing event analysis, the 2-year cumulative incidence of relapse (CIR) was significantly lower with CLAD/LDAC/Ven versus intensive chemotherapy (2.9% vs. 17.2%, Gray's p = .049) whereas nonrelapse mortality was comparable (16.2% vs. 17.1%; p = .486). CONCLUSION: In conclusion, treatment with CLAD/LDAC/Ven was associated with favorable outcomes in older patients who underwent subsequent allogeneic SCT. The OS was comparable to that with intensive chemotherapy followed by allogeneic SCT, but the CIR rate was significantly lower.

Ivosidenib significantly reduces triazole levels in patients with acute myeloid leukemia and myelodysplastic syndrome.

BACKGROUND: Ivosidenib is primarily metabolized by CYP3A4; however, it induces CYP450 isozymes, including CYP3A4 and CYP2C9, whereas it inhibits drug transporters, including P-glycoprotein. Patients with acute myeloid leukemia are at risk of invasive fungal infections, and therefore posaconazole and voriconazole are commonly used in this population. Voriconazole is a substrate of CYP2C9, CYP2C19, and CYP3A4; therefore, concomitant ivosidenib may result in decreased serum concentrations. Although posaconazole is a substrate of P-glycoprotein, it is metabolized primarily via UDP glucuronidation; thus, the impact of ivosidenib on posaconazole exposure is unknown. METHODS: Patients treated with ivosidenib and concomitant triazole with at least one serum trough level were included. Subtherapeutic levels were defined as posaconazole <700 ng/mL and voriconazole <1.0 µg/mL. The incidences of breakthrough invasive fungal infections and QTc prolongation were identified at least 5 days after initiation of ivosidenib with concomitant triazole. RESULTS: Seventy-eight serum triazole levels from 31 patients receiving ivosidenib-containing therapy and concomitant triazole were evaluated. Of the 78 concomitant levels, 47 (60%) were subtherapeutic (posaconazole: n = 20 of 43 [47%]; voriconazole: n = 27 of 35 [77%]). Compared to levels drawn while patients were off ivosidenib, median triazole serum levels during concomitant ivosidenib were significantly reduced. There was no apparent increase in incidence of grade 3 QTc prolongation with concomitant azole antifungal and ivosidenib 500 mg daily. CONCLUSIONS: This study demonstrated that concomitant ivosidenib significantly reduced posaconazole and voriconazole levels. Voriconazole should be avoided, empiric high-dose posaconazole (>300 mg/day) may be considered, and therapeutic drug monitoring is recommended in all patients receiving concomitant ivosidenib.

Venetoclax plus a hypomethylating agent versus cytarabine, aclarubicin, and granulocyte colony-stimulating factor chemotherapy as a first-line therapy for newly diagnosed acute myeloid leukemia: A propensity score-matched analysis.

BACKGROUND: Both venetoclax plus a hypomethylating agent (VEN/HMA) and cytarabine, aclarubicin, and granulocyte colony-stimulating factor (CAG) are low-intensity regimens for older patients with acute myeloid leukemia (AML) that show good efficacy and safety. It is unknown how VEN/HMA compares with the CAG regimen for the treatment of newly diagnosed AML. METHODS: The outcomes of patients with newly diagnosed AML treated with VEN/HMA were compared with those of patients treated with a CAG-based regimen. Propensity score matching between these two cohorts at a 1:1 ratio was performed according to age at diagnosis, sex, Eastern Cooperative Oncology Group performance status, state of fitness, and European LeukemiaNet (ELN) 2022 risk stratification to minimize bias. RESULTS: A total of 84 of 96 patients in the VEN/HMA cohort were matched with 84 of 147 patients in the CAG cohort. VEN/HMA resulted in a better response than the CAG-based regimens, as indicated by a higher composite complete remission (CRc) rate (82.1% vs. 60.7%; p = .002) and minimal residual disease negativity rate (88.2% vs. 68.2%; p = .009). In patients with an ELN adverse risk, VEN/HMA was associated with a higher CRc rate compared to CAG (80.5% vs. 58.3%; p = .006). VEN/HMA was associated with longer event-free survival (EFS) (median EFS, not reached vs. 4.5 months; p = .0004), whereas overall survival (OS) was comparable between the two cohorts (median OS, not reached vs. 18 months; p = .078). CONCLUSIONS: The VEN/HMA regimen may result in a better response than CAG-based treatment in older patients with newly diagnosed AML.

Therapy with hypomethlyating agents/venetoclax in patients with newly diagnosed acute myeloid leukaemia requiring admission to the intensive care unit: Possible reduction in side effects with preserved efficacy.

Patients with newly diagnosed acute myeloid leukaemia and severe acute complications, such as respiratory failure or sepsis, suffer from a high mortality rate when induction chemotherapy is delivered in an ICU setting. The report by Liang et al. implies that less intensive therapy with hypomethylating agents/venetoclax results in a lower mortality and morbidity rate whereby preserving efficacy in this patient group. Commentary on: Liang et al. Venetoclax and hypomethylating agents in critically ill patients with newly diagnosed acute myeloid leukemia. Br J Haematol 2024;204:1219-1226.

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.

Cardiac events in newly diagnosed acute myeloid leukaemia during treatment with venetoclax + hypomethylating agents.

Among 301 newly diagnosed patients with acute myeloid leukaemia receiving venetoclax and a hypomethylating agent, 23 (7.6%) experienced major cardiac complications: 15 cardiomyopathy, 5 non-ST elevation myocardial infarction and/or 7 pericarditis/effusions. Four patients had more than one cardiac complication. Baseline characteristics included median age ± interquartile range; 73 ± 5 years; 87% males; 96% with cardiovascular risk factors; and 90% with preserved baseline ejection fraction. In multivariate analysis, males were more likely (p = 0.02) and DNMT3A-mutated cases less likely (p < 0.01) to be affected. Treatment-emergent cardiac events were associated with a trend towards lower composite remission rates (43% vs. 62%; p = 0.09) and shorter survival (median 7.7 vs. 13.2 months; p < 0.01). These observations were retrospectively retrieved and warrant further prospective examination.

Exploring the prognostic role of complex karyotype in chronic lymphocytic leukaemia patients treated with venetoclax-based regimens.

Although the unfavourable prognostic role of complex karyotype (CK) in chronic lymphocytic leukaemia (CLL) patients treated with chemoimmunotherapy has been clarified, its impact on the outcome of patients being treated with novel targeted agents, and especially with venetoclax-based regimens, remains to be resolved. In fact, only few studies, utilizing data derived from clinical trials (e.g. MURANO, CLL14, GAIA-CLL13), specifically focus on this topic while real-word evidence is missing. In our real-life retrospective study conducted on 61 patients with CLL and treated with venetoclax-based regimens in any therapeutic line, we documented a remarkable lower progression-free survival in patients harbouring both CK and high CK, while overall response rate (including complete remissions and partial remissions) and overall survival are not affected by CK in our population.

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.

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.

Clinical outcomes of hypomethylating agents and venetoclax in newly diagnosed unfit and relapsed/refractory paediatric, adolescent and young adult acute myeloid leukaemia patients.

Venetoclax (VEN) combined with hypomethylating agents (HMA) decitabine or azacitidine is used for adult acute myeloid leukaemia (AML), but its application in paediatric, adolescent and young adult (AYA) AML lacks prospective studies. We performed a retrospective chart review of paediatric and AYA AML patients treated with HMA + VEN at Cincinnati Children's Hospital Medical Centre. Twenty-seven patients received 30 HMA + VEN treatment courses for relapsed/refractory (R/R, n = 21) or newly diagnosed (n = 9) AML due to ineligibility for intensive chemotherapy. The R/R cohort had high-risk cytomolecular genetic alterations and prior extensive treatments, with 50% (n = 9) of relapse patients (n = 18) having undergone haematopoietic stem cell transplantation (HSCT). Venetoclax treatment using the 400 mg adult exposure-equivelant dosing (AED) had a median duration of 21 days (range 7-30 days). Grade 3-4 toxicities included neutropenia (90%), anaemia (64%), thrombocytopenia (64%) and febrile neutropenia (44%). The overall complete remission (CR)/CR with incomplete blood count recovery (CRi) rate was 73% (77% minimal residual disease [MRD] negativity <0.1%), with 60% undergoing HSCT. Among newly diagnosed patients (n = 9), 89% achieved CR/CRi (78% MRD negativity) and 78% proceeded to HSCT. The R/R cohort (n = 21) showed a 67% CR/CRi rate (71% MRD negativity), with 52% undergoing HSCT. These findings support the safety and efficacy of HMA + VEN in paediatric/AYA AML, indicating it as a viable option for patients unfit for intensive chemotherapy. Further studies are necessary to determine optimal venetoclax dosing, chemotherapy combinations and pharmacokinetics in this population.

Real-world comparative effectiveness of venetoclax-obinutuzumab versus Bruton tyrosine kinase inhibitors for frontline chronic lymphocytic leukaemia.

Real-world evidence comparing clinical outcomes between venetoclax and Bruton tyrosine kinase inhibitors (BTKis) in patients with frontline (1 L) chronic lymphocytic leukaemia (CLL) is lacking. We compared treatment effectiveness of 1 L venetoclax plus obinutuzumab (VenO) versus BTKi-based regimens. This retrospective observational study using Optum Clinformatics Data Mart® included adult patients with CLL (≥2 outpatient or ≥1 inpatient claim) who received VenO or BTKi-based regimens in 1 L (1/2019-9/2022). Baseline characteristics were balanced using stabilised inverse probability weighting. Outcomes included duration of therapy (DoT), persistence, time to next treatment or death (TTNT-D), and time off-treatment. Among 1506 eligible patients (VenO: 203; BTKi: 1303), the median follow-up duration was 12.6 (VenO) and 16.2 months (BTKi). Median DoT for VenO was 12.3 months; persistence remained higher in VenO versus BTKi through expected 1 L fixed treatment duration. Median TTNT-D was not reached for VenO; however, more VenO- versus BTKi-treated patients had not switched therapies/experienced death through Month 12 (87.1% vs. 75.3%). Among patients that discontinued, median time to discontinuation was 11.7 vs. 5.9 months for VenO versus BTKi and median time off-treatment was 11.3 vs. 4.3 months. In this real-world study, VenO was associated with better effectiveness outcomes than BTKi-based regimens in 1 L CLL.

Gilteritinib in combination with venetoclax, low-dose cytarabine and actinomycin D for relapsed or refractory FLT3-mutated acute myeloid leukaemia.

We have conducted a retrospective, single-centre analysis of 20 patients with relapsed or refractory FLT3-mutated acute myeloid leukaemia (FLT3m AML) who received a salvage quadruplet regimen consisting of gilteritinib, venetoclax, low-dose cytarabine and actinomycin D (G-ACTIVE). G-ACTIVE resulted in a 95% (19/20) overall response rate and 75% (15/20) complete remission and complete remission with an incomplete platelet recovery (CR + CRp) rate. Out of 13 transplant-eligible patients, 11 (86%) proceeded to an allogeneic stem cell transplantation. The median overall survival and relapse-free survival after G-ACTIVE were 32 and 12.9 months respectively. The Day 60 mortality rate was 15%.

Fungal infection frequency in newly diagnosed acute myeloid leukaemia patients treated with venetoclax plus azacitidine with or without antifungal prophylaxis.

Our observational study analysed fungal infection frequency within cohorts with versus without antifungal prophylaxis (AFP) among newly diagnosed first-line venetoclax and azacitidine (VEN + AZA)-treated acute myeloid leukaemias in Czech, Austrian and Slovak haematology centres. Among 186 patients, 85 (46%) received antifungal prophylaxis, while 101 (54%) received no prophylaxis. Fungal infections occurred in 1/85 patients with prophylaxis (1%) and 5/101 patients without prophylaxis (5%) (p = 0.222). No significant difference was recorded between cohorts with and without AFP in terms of death rate (p = 0.296) and overall survival (p = 0.844). In conclusion, most infections were not severe, developing during the first treatment-cycle and did not affect patients' overall outcome.

Monocentric experience of venetoclax-based regimen in paediatric refractory and relapsed AML/MDS.

BCL-2 inhibitor venetoclax demonstrates promising efficacy in paediatric relapsed/refractory acute myeloid leukaemia (r/r AML). This retrospective analysis evaluated 12 patients treated with venetoclax-based regimens under compassionate use for r/r myeloid malignancies. The overall response rate (ORR) was 41.6%, with complete response (CR) achieved in 33% of patients. Three patients successfully underwent allogeneic haematopoietic scell transplantation (HSCT) after venetoclax bridging therapy. Venetoclax demonstrated a favourable safety profile with manageable side effects. These findings suggest venetoclax's potential as a valuable therapeutic option for paediatric r/r AML, particularly for heavily pretreated patients. Further investigation in larger multicentre trials is warranted to refine treatment strategy.