Venetoclax Research Articles

Outcomes with Molecularly Targeted Agents As Salvage Therapy Following Frontline HMA/Venetoclax in Adults with Acute Myeloid Leukemia: A Multi-Center Retrospective Analysis

Background: The combination of venetoclax (VEN) and a hypomethylating agent (HMA) has become the preferred first-line (1L) treatment for adults with acute myeloid leukemia (AML) who are unfit for intensive chemotherapy. Upon failure of VEN + HMA, outcomes are dismal, with a median overall survival (OS) of 2.4 months (Maiti et al., Haematologica, 2021). Molecularly targeted therapies represent a potential salvage strategy in patients (pts) harboring somatic alterations in FLT3, IDH1, or IDH2. This study describes outcomes for pts with FLT3- or IDH1/2-mutated AML who were treated with molecularly targeted therapy at the time of disease progression after VEN + HMA in the 1L setting. Methods: This is a multi-center retrospective cohort analysis of pts with FLT3- or IDH1/2-mutated AML diagnosed between January 2018 and December 2021. FLT3 and IDH1/2 mutation status were determined via clinically validated genetic assays performed on bone marrow or peripheral blood samples. For all cases, demographic and clinical information were collected and analyzed. Responses were adjudicated as per European Leukemia Network 2017 response criteria. Survival analyses were performed using the Kaplan-Meier method; survival curves were compared using a log-rank test. Each collaborating center's institutional review board approved this study. Results: Thirty individuals (9 female, 21 male) met inclusion criteria, with a median age of 74.5 years (inter-quartile range: 9.7 years) at the time of diagnosis. Nine pts carried mutations in FLT3 (7 internal tandem duplications [ITD], 2 tyrosine kinase domain mutations [TKD]) without co-occurring IDH1 or IDH2 mutations. Four pts carried IDH1 mutations alone and 11 carried IDH2 mutations alone. Five carried both a FLT3 mutation and an IDH2 mutation. One patient carried both an IDH1 and an IDH2 mutation. Eighteen of 30 pts received frontline azacitidine + VEN, with the remaining 12 pts receiving decitabine + VEN, for an average of 6.1 cycles. The overall response rate was 86% in response-evaluable pts (24/28); 75% (21/28) had either a complete response (CR) or a CR with incomplete hematologic recovery (CRi). Twenty-two pts were treated with a targeted inhibitor of either FLT3 or IDH1/2 upon disease relapse (Table 1); the remaining 8 pts switched to targeted therapy due to either poor performance status or persistent cytopenias without evidence of relapse. Six out of 9 pts with FLT3 mutations without concurrent IDH1 or IDH2 mutations received gilteritinib as salvage therapy following progression after VEN + HMA, while 3 received gilteritinib plus an HMA. Six pts with IDH2 mutations received IDH2-directed therapy upon relapse: 4/6 (67%) as monotherapy and 2/6 (33%) as enasidenib + HMA and enasidenib plus VEN + HMA, respectively. All 3 pts with IDH1 mutations were treated with IDH1 inhibitor monotherapy upon relapse. Overall, 15/22 (68%) pts received a targeted inhibitor as monotherapy and 7/22 (32%) received it in combination. Nineteen pts had response assessments following salvage therapy with targeted agents, with an ORR of 42% (8/19) and a median duration of response of 6.2 months (Table 1). The median overall survival (mOS) following progression on 1L VEN + HMA was 4.4 months for all 22 pts. However, mOS was 11.5 months in responders to targeted therapy vs 3.3 months in non-responders (p = 0.009; Figure 1). In addition, mOS for pts receiving targeted therapy in combination was 15.6 months vs 4.3 months for those treated with targeted therapy alone (p = 0.017). For the 9 pts with FLT3 mutations, mOS following relapse was 5.6 months compared to 4.2 months for those with IDH1 or IDH2 mutations. In all, 8/22 (36%) pts went on to receive further salvage therapy following targeted therapy. Conclusions: In this retrospective analysis, the use of targeted therapy as salvage treatment following frontline VEN + HMA was highly heterogeneous. In terms of mOS, targeted therapy compared favorably to historical data. Survival in responders to targeted therapy was superior to that of non-responders and pts treated with targeted therapy in combination with backbone therapies lived longer than those treated with targeted therapy alone. Further investigation is needed to determine the ideal sequencing and use of targeted therapies in this patient population. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase I/II Study of Combination of ASTX727, Gilteritinib and Venetoclax in Patients with Relapsed/Refractory FLT3 Mutated Acute Myeloid Leukemia (AML) and Frontline FLT3 Mutated AML Patients Unfit for Chemotherapy

Background:FLT3 gene mutations occur in approximately 30% of patients (pts) with AML and are associated with worse survival and higher relapse risk. Gilteritinib, a selective potent oral FLT3 tyrosine kinase inhibitor (FLT3i), improves survival in pts with relapsed FLT3 mutated AML. ASTX727 is an oral fixed-dose combination of decitabine (35 mg) and cedazuridine (a cytidine deaminase inhibitor; 100 mg) approved for treating pts with myelodysplastic syndrome (MDS). We are evaluating the safety and efficacy of the combination of ASTX727, gilteritinib, and venetoclax (VEN) in pts with relapsed or refractory FLT3-mutated AML and older/unfit pts unable to receive chemotherapy. Methods: In the phase I, pts with R/R FLT3-mutated AML or high-risk (HR) MDS or chronic myelomonocytic leukemia (CMML) are eligible. FLT3-ITD and/or FLT3-TKD mutations were allowed. In the phase II, the study will also enroll newly diagnosed pts with FLT3-mutated AML ineligible for induction therapy. Pts are required to have an ECOG performance status ≤3, total bilirubin ≤2.5 x upper limit of normal (ULN), ALT/AST ≤3 x ULN, and creatinine clearance ≥30 mL/min. Hydroxyurea or 1 dose of cytarabine up to 1000 mg was allowed in pts with proliferative disease to lower white blood count to ≤ 25 x 109/L before initiation of study therapy. In the phase 1, we evaluated two dose levels of gilteritinib (80 mg and 120 mg daily) continuously with fixed dosages of ASTX727 (35/100 mg daily on days 1-5) and VEN (400 mg daily, dose adjusted for concomitant azoles, for up to 28 days). Cycles are repeated every 28 days for up to 24 cycles, followed by indefinite therapy with gilteritinib as maintenance. During cycle 1, VEN was given at a dose of 100 mg on day 1, 200 mg on day 2, and 400 mg daily onwards. Bone marrow (BM) aspiration was performed on day 21, and VEN was held in pts with BM blasts <5% or aplasia. During cycles 2-24, VEN was given at 400 mg daily (dose adjusted for concomitant azoles) on days 1-21 but dose reductions depending on tolerance were permitted. Gilteritinib continued at the enrolled dose in cycles 2-24. Results: Between 11/2021 and 6/2022, 8 patients (7 AML and 1 HR-CMML) have been enrolled in the phase 1 portion of the trial (Table 1). Their median age was 57 years (range, 38-83). Median number of prior lines of therapy was 1 (range, 1-10). Four pts (50%) had a previous allogeneic hematopoietic stem cell transplant (HSCT), 6 pts (75%) had prior treatment with hypomethylating agent (HMA)+VEN, and 3 pts (27%) received prior FLT3i. None received prior gilteritinib. Cytogenetics was diploid in 4 pts, complex in 3 pts, and miscellaneous in 1 pt. The median FLT3-ITD allelic ratio (AR) was 0.4 (range, 0.11-10.60), with 50% having a high AR (≥0.5). All pts had a FLT3-ITD mutation and no pt had a FLT3-TKD mutation. NPM1 co-mutation was present in 4 pts (50%), followed by DNMT3A (37%) and IDH2 (37%). Six pts have been enrolled on dose level 1 (gilteritinib 80 mg) and 2 pt on dose level 2 (gilteritinib 120 mg). No DLTs have been observed in either dose level. Myelosuppression was frequent, requiring dose adjustment of ASTX727 and/or VEN in cycle 2 onward in 5 pts. Grade 3 non-hematologic adverse events included: sepsis (25%), bacteremia (25%), pneumonia (13%), and other infection (25%). No tumor lysis syndrome, differentiation syndrome, or QTc prolongation was observed. The 30-day and 60-day mortality rates were 0% and 13%, respectively. The overall response rate (ORR) was 87% with 4 (50%) pts achieving CR/CRi (1 CR, 3 CRi) and 3 (37%) pts achieving MLFS. One pt withdrew from the study in cycle 1 and was not evaluable for response. The ORR in pts with prior HMA+VEN was 83% (3 CRi, 2 MLFS). Five of 7 responders (71%) achieved the best response within 1 cycle and 2 (29%) within 2 cycles. Pts received a median of 2 cycles of therapy (range, 1-6). With a median follow-up of 6 months, median overall survival was not reached (range, 1.2-8+ months), and the estimated 6-month overall survival is 70%. One responding pt proceeded to HSCT. Two pts have died, 1 in CRi due to an unknown cause, and 1 due to disease progression and sepsis. Conclusion: The combination therapy with ASTX727, VEN, and gilteritinib appears to be effective and safe in R/R FLT3 mutated AML and HR-MDS. Myelosuppression was frequent but manageable. Continued accrual is anticipated to define the optimal triplet regimen in both R/R and newly diagnosed FLT3-mutated AML. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Efficacy of Hypomethylating Agents with Venetoclax in TP53mut AML

Background: Patients with TP53mut AML or with del(17p) experience refractoriness to conventional intensive chemotherapy and dismal outcomes. Treatment with 10-day decitabine may be beneficial in these patients. The utility of augmenting a hypomethylating agent (HMA) backbone with the BCL-2 inhibitor, venetoclax (VEN), in these patients is under debate, as recent studies suggest TP53mut may also confer resistance to VEN. The aim of this study was to report response, survival, and toxicity of HMA with and without addition of VEN in matched cohorts of del(17p) and TP53mut AML. Patients & Methods: We analyzed 47 patients with TP53mut or del(17p) AML treated with HMA +/- VEN from January 2016 to December 2021 at VCU Massey Cancer Center. Baseline patient and disease characteristics including molecular and cytogenetic profiling, treatment regimens, responses, and survival data were obtained via retrospective chart review. Patients were considered evaluable for response if there was a bone marrow biopsy following a minimum of 28 days of treatment. The event for calculating the overall survival (OS) was the date of death. Patients were otherwise censored at the date of last contact. Results: Thirteen patients with TP53mut/del(17p) AML were treated with HMA + VEN in the first-line setting. The median age at diagnosis was 73 years, median ECOG score 2, and the median Charlson Comorbidity Index (CCI) score was 5. The composite response rate (CRR; CR + CRi) was 33.3% in those evaluable (1 CR, 3 CRi). The median OS was 9.4 months and no patients proceeded to allogeneic stem cell transplant (alloSCT). In the HMA monotherapy cohort, nine patients were treated with decitabine (33.3%) or azacitidine (66.6%) with TP53mut or del(17p). The median age was 73 years, median ECOG score 1, and median CCI score 7. No patients achieved a CR or CRi. The median OS was 8.2 months and no patients proceeded to alloSCT. There was no significant difference in survival with or without the addition of VEN in the first-line setting (p = 0.8735). There were 12 patients in the relapsed/refractory (R/R) cohort treated with HMA/VEN that did not previously receive this therapy upfront. The median age was 63 years, median ECOG score was 2, and the median CCI score was 4. The CRR was 40.0% in those evaluable (2 CRi, 2 CRi). The median OS was 4.6 months. In the relapsed/refractory HMA monotherapy cohort, 13 patients were identified. The median age was 59 years, the median ECOG score was 1, and the median CCI score was 4. The CRR was 20.0% (1 CR, 1 CRi) in those evaluable. The median OS was 5.9 months. Conclusions: While HMA + VEN in the first-line setting did translate to a higher CRR in TP53mut disease compared to HMA monotherapy, our data suggest no clear additional survival benefit with the addition of VEN. These patients continue to experience refractory disease, inability to proceed with alloHSCT, and poor survival even with augmentation of the HMA backbone by BCL-2 inhibition. These findings suggest cautious selection for VEN candidates and highlight the need for novel therapeutic interventions for TP53mut disease. Larger studies with propensity score-based techniques are needed to confirm these findings. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Combined Ibrutinib and Venetoclax for First-Line Treatment of Patients with Chronic Lymphocytic Leukemia (CLL): 4-Year Follow-up Data

Background: Ibrutinib (IBR) and venetoclax (VEN) combination is an effective therapy for patients (pts) with CLL. We previously reported results of the first-line cohort of a phase II trial of combined IBR and VEN for high-risk pts with CLL (Jain, NEJM 2019, JAMA Oncology 2021). Here we report updated data for 120 pts (80 pts in the original published cohort and 40 pts in an expansion cohort) with a median follow-up of 4 years. Methods: Pts with previously untreated CLL meeting IWCLL treatment criteria were enrolled. All pts had at least one high-risk feature: del(17p), mutated TP53, del(11q), unmutated IGHV, or age ≥65 years. Pts received IBR 420 mg daily for 3 cycles followed by addition of VEN (weekly dose-escalation to 400mg daily). Combined therapy was given for 24 cycles (28 days/cycle). Pts with bone marrow (BM) undetectable MRD (U-MRD) (flow cytometry; sensitivity 10-4) at 24 cycles of combined therapy discontinued both VEN and IBR; MRD+ pts continued IBR. A trial amendment allowed an additional 12 cycles of combined VEN and IBR for pts who remained BM MRD+ after Cycle 24. Response assessments included BM and CT studies (2008 IWCLL criteria). U-MRD was defined as <0.01%; low MRD+ 0.01% to <1%; high MRD+ ≥1%. Progression-free survival (PFS) was assessed as the time from the start of study drug to CLL progression, Richter transformation, or death from any cause. Blood MRD was monitored every 6 months after active therapy. Results: Between August 2016 and February 2019, a total of 120 pts were enrolled. Baseline characteristics are shown in Table 1. The median follow-up is 48.8 months. Six pts came off study during 1st 3 cycles of IBR monotherapy; 114 pts initiated VEN. After 12 cycles of the combination, 62/120 (52%) achieved BM U-MRD remission; 43/120 (36%) were BM MRD-positive (low MRD+, n=35; high MRD+, n=8). After 24 cycles of the combination, 77/120 (64%) achieved BM U-MRD remission; 24/120 (20%) were BM MRD+ (low MRD+, n=23; high MRD+, n=1). Overall, 86/120 (72%) achieved BM U-MRD as the best response. We evaluated baseline pt and disease characteristics (age, gender, IGHV mutation status, CLL FISH panel, complex karyotype, TP53 mutation, del(17p)/TP53 mutation) and rate of bone marrow U-MRD at 6 months, 12 months and at any time during the combined IBR+VEN treatment. At 6 months of combined therapy, presence of TP53 mutation was associated with a lower rate of bone marrow U-MRD (p=0.03); however, none of the aforementioned characteristics, including TP53 mutation were associated with marrow U-MRD responses at 12 months or with best MRD response at any time during the combined therapy. There was a trend towards lower U-MRD rate among pts with mutated IGHV vs. unmutated IGHV at 12 month (p=0.09) and as best response (p=0.09). The 4-year PFS is 94.5% (95% CI, 90.3%-98.9%) and 4-year OS is 96.6% (95% CI, 93.3%-99.9%). The 4-year PFS by TP53 aberrant status is shown in Figure 1. The 4-year PFS for pts with del(17p)/TP53 mutation (n=27) is 90.9% and for pts without del(17p)/TP53 mutation (n=93) is 95.5%. None of the aforementioned pt/disease characteristics were associated with PFS. Of the 77 pts who were BM U-MRD at the end of cycle 24 of the combination, 73 discontinued all therapy, 4 pts continued IBR per treating physician discretion. Among these 77 pts, with a median time of 23.9 months post Cycle 24, 11 pts had recurrence of blood MRD (defined as MRD ≥0.01% in 2 consecutive visits). Of the 11 pts with MRD recurrence, 10 are being monitored without any active therapy for CLL and without clinical disease progression; 1 pt had disease progression after 22 months of treatment-free interval and is currently receiving acalabrutinib. There were 24 pts who were BM MRD+ at the end of cycle 24 of the combination (low MRD+, n=23; high MRD+, n=1). The only pt with high-MRD+ at end of cycle 24 was noted to have Richter transformation at that time. The remaining 23 pts (all low MRD+ in BM, range 0.01-0.95%) continued IBR monotherapy. With a recent trial amendment, MRD+ pts after Cycle 24 could get 12 additional cycles of VEN; 18/23 pts have resumed VEN. 11/18 (61%) pts achieved U-MRD remission during the third year of combined therapy. Conclusions: We report long term follow-up of combined IBR and VEN in first-line CLL (n=120) with a 4-year PFS of 94.5%. MRD responses and PFS were independent of baseline pt/disease characteristics. Continuation of combined therapy among marrow MRD+ pts during the second and the third year led to achievement of U-MRD in a subset of pts. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Unmodified Dose of Azacitidine Plus Venetoclax Regimen without Drug Interactions during the First Cycle Leads to Similar Outcomes between Viale-a Clinical Trial and Real-Life in Acute Myeloid Leukemia

Introduction: We frequently observe differences between results obtained in clinical trials and real-life. Several reasons may account for these discrepancies: age and coexisting conditions (older patients with additional comorbidities are often excluded from clinical trials), drug interactions and change of schedule (dose-intensity) as compared to the one used in the clinical trials. Azacitidine (AZA) combined with venetoclax (VEN) became the standard of care for acute myeloid leukemia (AML) for patients deemed ineligible for intensive chemotherapy. Composite complete remission (cCR) was 66.4% with median overall survival at 14.7 months (DiNardo et al., NEJM 2020). Recent real-life studies reported less promising results showing cCR between 40-70% and median overall survival (OS) between 7-12 months (Winters et al. Blood 2019; Garciaz et al. EHA 2022; Lam et al. EHA 2022). We report in this study the results of a single center cohort of AML patients receiving an AZA + VEN induction cycle strictly similar to the one reported in the VIALE-A clinical trial without drug interaction. Methods: All patients were treated using VIALE-A guidelines. The first cycle consisted in AZA 75/mg/m² D1-7 + VEN 100mg D1, 200 mg D2, 400 mg D3-28. Treatment was delivered to inpatients, patients were discharged when complete remission was obtained with ANC recovery. All patients received antifungal prophylaxis by liposomal amphotericin B 3mg/kg 3 times a week during the first cycle without VEN dose reduction. For patients who achieved complete remission after cycle 1, the dose of VEN was reduced in case of grade 4 neutropenia and cycle 2 was delayed. For non-responders' patients, cycle 2 started straight after the end of cycle 1. Response was evaluated according to the 2017 European Leukemia Network (ELN) criteria. OS was calculated from the time of diagnosis of AML to the time of death or last known follow-up. Median OS was estimated using the Kaplan−Meier method, and differences between subgroups were assessed using the log-rank test. Results: Twenty-nine (n=29) de novo AML patients were enrolled in this study in University Hospital of Nice. The median age was 79 years [range, 59-90] , Sex ratio M/F was 12/17 and median ECOG was 1 [range,0-3]. ELN 2017 prognostic classification was intermediate in 17 (59%) and adverse in 12 (41%) of patients. The most frequent mutations were NPM1, TP53 and TET2 in 6 (21%), ASXL1 in 5 (17%), DNMT3A in 3 (10%) patients, Median number of AZA + VEN cycles was 2 [range, 1-15]. Each patients of this study (100%) received VEN 400mg/d D1-28 during the first cycle without drug interactions needing VEN dose reduction. Twenty four of the 29 patients (83%) of patients received liposomal amphotericin B prophylaxis during the first cycle. Seven of the 29 patients (24%) patients developed a possible or probable aspergillosis (5 possible, 2 probable). Median duration of neutropenia was 23 days [range,0-116]. Febrile neutropenia occurred in 27/29 (93%) of patients. The overall response rate was 83% including 66% of cCR. Response was obtained after one cycle for 21 patients and after two cycles for 3 patients. Day-30 mortality was 3% and day-60 mortality was 14%. Median OS was 18 months [10.3-25.7, CI 95%]. Conclusions: Our data revealed that a strict introduction of AZA + VEN and a special attention in the monitoring for elderly patients with AML, appears feasible in real-life and was associated to similar outcomes than those observed in the VIALE-A study. Liposomal amphotericin B prophylaxis was also feasible without any need of VEN dose reduction and led to improvements. These outcomes need to be confirmed in a larger cohort. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase I/II Study of Combination of Azacitidine, Venetoclax and Pevonedistat in Patients with Newly-Diagnosed Secondary Acute Myeloid Leukemia (AML) and Myelodysplastic Syndrome (MDS) with Hypomethylating Agent (HMA) Failure

Background: Pevonedistat (PEV) is an inhibitor of NEDD8-activating enzyme (NAE) which is critical for degradation of several cellular proteins essential for tumor growth and survival. The combination of azacitidine (AZA) and venetoclax (VEN) is approved for patients (pts) with newly diagnosed (ND) AML who are unsuitable for intensive chemotherapy, and clinical studies show preliminary efficacy with AZA+VEN in higher risk MDS pts. We evaluate the efficacy and safety of the combination of AZA, VEN, and PEV in ND secondary AML (s-AML) and in MDS after HMA failure. Methods: This phase 1/2 trial enrolled pts with ND s-AML, including therapy-related AML (t-AML), AML from prior MDS or chronic myelomonocytic leukemia (CMML) or myeloproliferative neoplasm (MPN), or AML with dysplasia in ≥50% cells in ≥2 myeloid lineages (MRC). A second arm enrolled pts with MDS or CMML that had progressed on prior HMA therapy. Pts had to have a performance status ≤2, total bilirubin ≤1.5 x upper limit of normal (ULN), ALT/AST ≤2.5 x ULN, and creatinine clearance ≥30 mL/min. Pts in AML arm may have received prior HMA for preceding hematologic malignancy. In both AML and MDS/CMML cohorts, pts received AZA 75 mg/m2 SC/IV on days 1-7 and PEV 20 mg/m2 IV on days 1, 3 and 5 on every 28 day-cycle. In AML cohort, VEN was given on days 1-28 in cycle 1 and days 1-21 on cycle 2+. In MDS/CMML cohort, VEN was given on days 3-14 in cycle 1 and days 1-14 on cycle 2+. In initial phase 1 portion of the study (AML cohort only), VEN at max dose 200 mg and 400 mg were explored. Results: Between 3/2019 and 8/2021, 32 pts with AML (10 t-AML, 22 AML from MDS/CMML/MPN, 4 MRC) and 8 pts with MDS/CMML post-HMA failure (6 with MDS, 2 with CMML) were treated (Table). In the AML cohort, the median age was 74 years, with 14 pts (44%) ≥75 years of age. Cytogenetics was adverse in 21 pts (66%), and adverse risk mutations, including TP53, RUNX1, and ASXL1 were present in 34%, 31%, and 22%, respectively. 17 pts (53%) had treated secondary AML (ts-AML; i.e. prior exposure to HMA or chemotherapy for preceding myeloid neoplasm). The overall response rate (ORR, defined as CR+CRi+MLFS) was 75%, with CR in 15 pts (47%), CRi in 6 pts (19%), and MLFS in 3 pts (9%). One pt achieved PR (3%). 78% of pts achieved best response after 1 cycle of therapy (range, 1-4 cycles to best response). Among 21 pts with CR/CRi, 10 pts (48%) achieved MRD negativity by flow cytometry. 14/21 pts (67%) with poor-risk cytogenetics responded, compared to 10/11 pts (91%) with non-poor cytogenetics. 9/11 pts (82%) with TP53-mutated AML responded. 11/17 pts (65%) with ts-AML responded, compared with 13/15 pts (87%) who did not have ts-AML. With median follow up of 20 months (mos) for the AML cohort, the median OS was 8.2 mos and median relapse-free survival (RFS) was 7.4 mos. 5 pts proceeded to transplant in first remission. The median OS for pts with adverse cytogenetics was 6.8 mos and was not reached in pts without adverse cytogenetics (1-year OS of 70%). The median OS for pts with TP53-mutated AML (n=11) was 8.1 mos, pts with inv(3) (n=4) was 3.8 mos, and pts without TP53 mutation or inv(3) (n=17) was 18 mos (Figure). In MDS/CMML HMA failure cohort, the median age was 73 years. Most pts had adverse cytogenetics (50%) and were high to very high-risk by IPSS-R (87%). Overall response rate (CR+marrow CR [mCR]+HI) was 75%, with CR in 3 pts (37%), mCR in 2 pts (25%), and HI in 1 pts (13%). With a median follow up of 11 mos, the median OS was 9.9 mos. Transformation to AML occurred in 1 pt (after 11 mos). No DLTs were observed in the phase 1 portion, and VEN 400 mg daily was the recommended phase 2 dose. Myelosuppression was similar to expectations with AZA+VEN alone. Grade 3/4 non-hematologic adverse events occurring in ≥10% pts were febrile neutropenia or other infection in 75%, hypophosphatemia in 22%, and hyperbilirubinemia in 10%. The 4-week and 8-week mortality rates were 9% and 25% in AML cohort and 0% and 13% in MDS/CMML cohort, respectively. Conclusion: AZA, VEN, and PEV combination is active and well-tolerated in both ND s-AML and MDS/CMML after HMA failure. This population was enriched with very poor risk features, including a majority of pts in the AML cohort with prior HMA or chemotherapy exposure for an antecedent myeloid malignancy and 1/3 of pts with a TP53 mutation. Response rates were high across disease subgroups, although duration of responses and survival were modest in pts with historically poor risk features, including those with adverse risk cytogenetics and TP53 mutations. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase II Study of the Combination of Decitabine, Venetoclax and Ponatinib in Patients with Chronic Myeloid Leukemia (CML) in Myeloid Blast Phase (MBP) or Philadelphia-Chromosome Positive (Ph+) Acute Myeloid Leukemia (AML)

Background: Advanced phases of CML and Ph+ AML are therapeutic challenges. Preclinical and early clinical data have shown that combining venetoclax (VEN) with a tyrosine kinase inhibitor (TKI) works synergistically in Ph+ myeloid leukemias (Leonard et. al., Sci Transl Med 2016 and Maiti et. al., Acta Haematologica 2020). We hypothesized that combining a potent TKI (ponatinib) with a hypomethylating agent plus VEN backbone might lead to high rates of response that could facilitate potentially curative allogeneic stem cell transplantation (SCT). Methods: This is a single-arm phase II study (NCT04188405) that enrolled patients (pts) ≥ 18 years (yrs) of age with newly diagnosed or relapsed/refractory advanced phase CML [CML in accelerated phase (CML-AP) or CML-MBP] or Ph+ AML. Pts were required to have an ECOG PS ≤ 3 and adequate liver and renal function. Pts with clinically significant cardiovascular comorbidities, including recent or active myocardial infarction, heart failure, clinically significant arrhythmias, cerebrovascular accident, venous thromboembolism or uncontrolled hypertension were excluded. Pts were treated with a combination of decitabine (DAC) (20 mg/m2/day) x 5 days, VEN (400 mg equivalent dose/day) x 21 days, and ponatinib (45mg/day) x 21 days in cycle 1 and then continuously in cycle 2+ (Fig. 1A). Ponatinib was reduced to 30mg/day for pts in CR/CRi and to 15 mg/day for pts in CMR. For C1 only, pts who had not received ponatinib prior to trial initiation had a lead-in phase of ponatinib monotherapy for 7 days before the initiation of DAC and VEN. Cycles were repeated every 28 days, as permitted by peripheral blood count recovery, and pts could receive a maximum of 24 cycles. Intrathecal prophylaxis with 4 doses of cytarabine was recommended. The primary objective was to determine the overall response rate of the regimen. Results: From July 2020 to May 2022, 12 pts were treated, 1 pt with de novo Ph+ AML and 11 pts with advanced phase CML (2 pts with CML-AP and 9 pts with CML-MBP). The median age of the pts was 45 yrs (range, 28-71 yrs). Three pts (25%) had received no prior therapy (1 each with Ph+ AML, CML-AP and CML-MBP). Nine pts (75%) had prior TKI exposure (including prior ponatinib exposure in 4 pts) and 3 pts (25%) had received prior chemotherapy. Eleven pts (92%) had the p210 transcript of BCR::ABL1. Eight pts (67%) had additional cytogenetic abnormalities, including 5 pts with complex karyotype and 2 pts with a MECOM rearrangement. 4 of 11 tested pts (36%) had an ABL1 kinase domain mutation detected at enrollment (T315I, Q252H, L384M and E255K in 1 pt each). The median number of cycles received was 2 (range, 1-7). Nine pts (75%) responded, including 1 with CR, 3 with CRi and 5 with MLFS as best response. The CR/CRi rate was 33%. Best response was achieved after cycle 1 in 7 of 9 responders. Both pts with CML-AP responded, and 2 of 3 pts without prior TKI exposure responded. One of the responders achieved an MMR. After a median follow-up of 9.1 months, the median overall survival (OS) is 9.5 months, and the estimated 9-month OS is 64%. The median relapse-free survival 5.1 months. Among the 9 responders, 3 pts are in continuous response without SCT, 1 pt proceeded to SCT and is still alive, 3 pts did not undergo SCT and relapsed (2 of whom had a complex karyotype), 1 pt died in MLFS, and 1 pt was lost to follow-up (Fig. 1B). The one pt who proceeded to SCT achieved MLFS as best response pre-SCT and remains in MRD-negative CR 22 months post-SCT. The toxicity profile of the regimen was similar to historical expectations with DAC plus VEN. One pt developed grade 3 mucositis, which was considered related to study therapy. No grade 4-5 related non-hematological adverse events were observed. Related grade 1-2 non-hematological adverse events included rash in 2 pts, and transaminitis, creatinine elevation and mucositis in 1 pt each. Of the 8 pts who received > 1 cycle of study therapy, 4 pts had delay (>1 week) in initiation of a subsequent treatment cycle due to cytopenias; for 2 of these pts the duration of VEN was reduced. The 60-day mortality rate was 0%. Two pts died on the study, one from leukemia and one from infection while in MLFS. Conclusion: The triplet combination of DAC, VEN and ponatinib was well-tolerated in pts with advanced Ph+ myeloid leukemias. In this poor-risk population, a marrow remission rate of 75% was achieved, although durations of remission were modest in the absence of consolidative SCT. This study continues to accrue pts. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Real-Life Experience of Use of Venetoclax in Patients with Relapsed/Refractory Acute Myeloid Leukemia. a Single Center Experience

INTRODUCTION: Venetoclax (VEN), a BCL-2 specific inhibitor, used in combination with azacitidine (AZA) in patients with newly-diagnosed acute myeloid leukemia (AML) who were ineligible for intensive chemotherapy treatment, has shown high response rate and overall survival compared with AZA monotherapy (Di Nardo et al. N Engl J Med 2020; 383:617-629). For patients failing frontline, VEN-based salvage therapy prognosis appears very poor, although a subgroup of patients might benefit. Moreover, recently, had been published the European LeukemiaNet 2022 recommendations and classification in AML (Döhner et al. Blood 2022). AIMS: We performed a retrospective study of patients with relapsed/refractory (R/R) AML receiving salvage treatment with VEN combinations in the Catalan Institute of Oncology (ICO) in order to determine the efficacy and safety of the combination. We also explored the probability of response according to the ELN 2022 risk classification by genetics. METHODS: We analyze 60 patients with R/R AML at 4 hospitals belonging to ICO in Spain, treated with VEN (400mg/24h or 600mg/24h; with recommended 3-day ramp-up to target dose) in combination with hypomethylating (HMA) agents (AZA 75mg/m2 7/28 days or Decitabine (DEC) 20mg/m2 5/28 days) or low-dose cytarabine (LDAC) (20mg/m2 10/28 days) from May 2019 until December 2021. Event was defined as death, refractoriness to treatment or progressive disease. RESULTS: Characteristics of our cohort are described in table 1. Thirty-seven (62%) patients had next-generation sequencing (NGS) panel study at diagnosis and/or at the time of R/R disease. 31 (52%) patients had high-risk AML according to ELN 2017 classification, and 38 of 46 (83%) patients had high-risk AML according to ELN 2022 classification. Six of 37 patients (15%) had TP53 mutation at a variant allele fraction (VAF) of at least 10%. Seven (19%) patients were reclassified as high-risk AML according to ELN 2022 classification. NGS panel study didn't show high risk mutations in 10 patients. According to ELN 2022 classification, 8, 11 and 8 patients, presented 1, 2 or ≥ 3 high risk gene mutations, respectively. Fourteen (23%) patients received VEN + DEC, 34 (57%) VEN + AZA, and 12 (20%) VEN + LDAC. The median number of cycles received was 3 (range 1-28), with a median of one cycle to achieve the best response (range: 1-4). Early mortality in the first 30 days was 15% (9 patients), 5 due to progression disease, 2 due to infection and 2 due to clinical worsening. Overall response rate after first cycle [Complete response (CR) + complete response without hematological recovery (CRi) and partial response (PR)] was 58%. Three patients were treated in a molecular relapse (MRD positive status), and all of them achieved molecular response. Six of 19 fit young patients (32%) achieved CR and received an allogeneic stem cell transplantation (alloSCT). The median event-free survival (EFS) and overall survival (OS) was 4.03 months and 7.63 months, respectively. No significant differences of EFS and OS were found according to ELN 2022 risk classification, mutational profile or TP53 status. Response to treatment after 3-4 cycles, discriminate two groups of patients with an OS of 17.26 months in those patients who achieved CR or PR vs 2.4 months in non-responders (p=0.000). Patients relapsed after alloSCT (7 patients) presented a poor outcome (median OS was 1.6 months). SUMMARY/CONCLUSIONS: Our study showed that real-world experience of treating patients with R/R AML with VEN + HMA or LDAC is feasible as salvage treatment in patients relapsed to HMA and as bridge therapy to alloSCT with a rapid response rate. No significant differences of response were found according to ELN 2022 risk classification. Rapid responses shown with the combination, allow us to identify those patients who may benefit from this approach. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

ALLG AMLM26 Phase 1B/2 Study Investigating Novel Therapies to Target Early Relapse and Clonal Evolution As Pre-Emptive Therapy in AML (INTERCEPT): A Multi-Arm, Precision-Based, Recursive, Platform Trial

Background Clinical trials investigating novel therapies in relapsed/refractory acute myeloid leukemia (AML) are challenged by rapid disease progression, severe cytopenias and a high frequency of infectious complications, limiting the capacity of such trials to determine efficacy and hematologic tolerance for new drugs and combinations. Guidelines for monitoring measurable residual disease (MRD) and defining MRD relapse have been established (Heuser, Blood 2021), with MRD relapse known to precede clinical relapse by 3-4 months (Ivey, NEJM 2016). A prospective pilot study utilizing low-dose cytarabine (LDAC) plus venetoclax (VEN) for patients with MRD relapse or oligoblastic relapse (5-15% marrow blasts) demonstrated a high response rate and durable outcomes (Tiong, ASH 2021). To extend this concept to include a broader range of targeted drug combinations directed against MRD relapse, we developed the Australasian Leukaemia and Lymphoma Group (ALLG) AMLM26 INTERCEPT study, a multi-domain, multi-arm, platform trial enabling proof-of-concept (POC) efficacy and tolerability to be obtained for multiple therapies in parallel in the setting of MRD relapse. Study Design and Methods Figure 1 summarizes the trial schema. The INTERCEPT trial (ANZCTR: ACTRN12621000439842), due activation in August 2022, is sponsored by the ALLG and conducted in partnership with the ALLG sites and the MD Anderson Cancer Center, U.S. The trial incorporates 2 phases, an MRD Monitoring Phase, and a Treatment Phase. Patients in first or second remission consent to a Master Protocol linked to a coordinated MRD monitoring framework to track FLT3-ITD, RUNX1::RUNX1T1, CBFB::MYH11, NPM1, KMT2A::X and aberrant myeloid immunophenotype. In patients in whom pre-leukemic clonal hematopoiesis is excluded by reduction of variant frequency in remission to <2.5%, IDH1 and IDH2 are also tracked. For molecular markers, MRD relapse is defined according to ELN recommendations (a log10 increase in serial MRD confirmed by repeat testing on concordant tissue). Flow cytometric detected disease for the INTERCEPT study is defined as an aberrant MRD phenotype ≥0.1% confirmed on repeat testing. MRD relapse is confirmed by a central laboratory and eligibility adjudicated by a blinded MRD reference committee. For the Treatment Phase, a clinical Trial Management Committee (TMC) will apply a pre-determined set of clinical decision rules to direct allocation of patients to the most applicable treatment "domain", based on review of prior therapy, baseline molecular profile and MRD relapse characteristics. For example, a patient with rising FLT3-ITD MRD meeting relapse criteria may be allocated to treatment with gilteritinib + VEN, rising IDH1 mutation to ivosidenib + VEN, rising KMT2A::X to SNDX-5613, rising NPM1 to LDAC + VEN or alternatively, to SNDX-5613. Where no specific targeted treatment is available, patients will be randomly allocated to non-targeted therapies, if more than one applicable arm exists, to arms including sabatolimab, sabatolimab + azacitidine, ASTX727 + VEN or LDAC + VEN. Future treatment options can be seamlessly incorporated in the INTERCEPT framework by amendment of the Master Protocol and addition of new Therapy-Specific Protocol Appendices (TSPAs). Each TSPA outlines specific eligibility criteria, dose schedules, study conduct and the statistical plan for each treatment arm. Patients may also be allocated to a morphologic relapse stratum, if MRD relapse was not captured by MRD surveillance. This will enable comparison of treatment tolerance and response at MRD vs morphologic relapse. If progression occurs with one treatment arm (including MRD relapse), the protocol allows the same patient to be transitioned to an alternative treatment arm if eligibility criteria are met. The primary objective is to determine if novel treatment options can produce an MRD response rate of ≥40% as determined by a Bayesian Proof of Concept design in each domain. The primary endpoint is MRD response (≥1 log10 reduction in molecular MRD or flow MRD<0.1%) within 100 days of the first dose of study drug. MRD responses will be determined centrally. Key secondary endpoints will be nadir MRD response, MRD clearance rate, median time to and duration of MRD response, relapse-free survival, overall survival and quality of life measures. Exploratory objectives will include analysis of drug resistance mechanisms and correlates of response. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Venetoclax (VEN) Plus Intensive Chemotherapy (IC) with FLAG-IDA in Patients (Pts) with Newly Diagnosed (ND) and Relapsed/Refractory (R/R) Acute Myeloid Leukemia (AML)

Background: Despite the high complete remission (CR) rates achieved with IC, relapse rates remain high underscoring the need for novel combination regimens capable of inducing deeper remissions via eradicating measurable residual disease (MRD). Recently, several studies have shown promising clinical activity of VEN when combined with different IC regimens in pts with ND AML with composite CR rates (CRc) above 90% and MRD-ve rates exceeding 80% (Wang 2022; Kadia 2021). FLAG-IDA + VEN has also shown significant clinical activity in pts with ND AML with a CRc rate of 89% and MRD-ve remission rate of 93% (DiNardo 2022). Methods: We conducted a single-center retrospective study to assess the clinical activity of FLAG-IDA + VEN in pts with AML. During induction, VEN was initially given for 14 days which was later on reduced to 7 days due to encouraging results by Kadia et al. Standard cytogenetic (CN) analysis was performed and molecular data was obtained using a 40-gene NGS platform. Responses were assessed using the modified International Working Group response criteria and included CR, CR with incomplete count recovery (CRi), morphologic leukemia-free state (MLFS), and partial remission (PR). Time-to-event analyses were estimated using the Kaplan-Meier method and compared using the log rank test. Results: From March 2020 to May 2022, 24 pts with AML (17 ND and 7 R/R) were treated using FLAG-IDA + VEN (Table 1). Median age was 48 years (range, 21-68) with male predominance (67%). Among the 17 pts with ND AML (8 de novo, 5 AML-MRC, 2 treated-secondary, 2 therapy-related), 3 had extramedullary disease (EMD). The most common ELN CN risk groups were complex (N=5), KMT2A-rearranged (N=4), other adverse (N=3), and diploid (N=3). Eight pts (47%) harbored a RAS mutation. Median time to initiation of therapy was 5 days (range, 2-14). Twelve pts (71%) [KMT2A-rearranged, N=4; complex CN, N=3; diploid, N=3; other adverse, N=1; other intermediate, N=1] achieved CR/CRi including 1 pt with EMD. Median time to ANC (≥ 500) and platelet (≥ 50,000) recovery were 29 days (range, 19- 42) and 25 days (range, 17- 42), respectively. Median number of consolidation cycles given were 1.5 (range, 1- 5). MRD status was available in 6 out of 12 pts and all 6 pts achieved MRD negativity using flow cytometry (<10-3). Median follow-up among ND AML pts was 4.3 months (mths) (range, 0.7- 13.2). Among the 12 responders: (1) 3 pts received allo-SCT [KMT2A-rearranged, N=2; (-7), N=1] after 7, 4, and 3 mths, respectively, and remain alive in CR 10+, 7.5+, and 3+ mths, respectively, after initiation of therapy, (2) 6 pts with ELN favorable (N=3), intermediate (N=2), and adverse (N=1) risk AML remain in CR/CRi for 6+, 4+, 1+, 3+, 2+, and 2+ mths, respectively, (3) 3 pts with ELN adverse risk AML (including 1 pt with de novo MLLr AML and EMD) achieved CR and relapsed after 0.7, 1.7, and 7.6 mths, respectively. One pt died due to progressive disease (PD) 4.7 mths after relapse and the remaining 2 pts are receiving salvage therapy and alive 4.3+ and 5.2+ mths after relapse, respectively. All nonresponders (N=5) had ELN adverse risk AML including 2 pts with EMD and 2 pts with treated secondary AML. All 5 nonresponders died due to PD including 3 pts who had no response to HMA+VEN based salvage therapy. Among the 7 pts with R/R AML, 6 were in salvage 1 and 1 pt received prior allo-SCT. Responses were observed in all pts: 4 CR, 1 CRi, 1 MLFS, and 1 PR. Median time to count recovery in R/R AML pts was 33 days (range, 24-78). Median follow-up in R/R AML pts was 6.2 mths (range, 1.5- 15.6). Of the 5 pts who achieved CR/CRi, 4 were bridged to allo-SCT and 1 pt died in CR after 3 cycles of consolidation due to sepsis. Of the 4 SCT recipients: (1) 2 pts relapsed 2 mths after allo-SCT and died 4 and 6.5 mths, respectively, after allo-SCT; (2) 2 pts (KMT2A-rearranged and NPM1mut) remain alive in CR for 8+ and 14+ mths, respectively. Two pts with complex CN achieved MLFS and PR after 1 cycle of therapy and died due to PD and fungal pneumonia after 5.3 and 1.5 mths of starting therapy, respectively. Median overall survival (OS) for pts with ND AML and R/R AML were 13.2 mths (95% CI: Not reached) and 6.2 mths (95% CI: 5-7), respectively (p=0.62; Figure 1). Among pts with ND AML, median OS was not reached among responders and was 2.6 mths in non-responders (p=0.002). Conclusion: FLAG-IDA + VEN is a feasible and active regimen in AML. Longer follow-up and larger multicenter studies are needed to confirm the efficacy of this regimen. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Mesenchymal Stromal Cells Protect Acute Myeloid Leukemia Cells from Venetoclax-Induced Apoptosis through Contact-Dependent Mechanisms

Acute myeloid leukemia (AML) patients have a poor prognosis with standard treatments due to a high relapse rate. Recently, Venetoclax (VEN), the first B-cell lymphoma 2 (BCL-2) selective inhibitor to enter the clinic, has shown a breaking-through effect in combination with demethylating agents in older patients with treatment-naïve AML. However, resistance mechanisms were described, hampering the complete remission of VEN-treated patients. It has been proposed that the bone marrow microenvironment in general and Mesenchymal stromal cells (MSCs), in particular, favor a protective niche that sustains leukemic cell viability and plays a crucial role indetermining drug sensitivity in several hematological disorders, including AML. A previous study demonstrated that VEN, as well as other drugs commonly used in AML therapy, showed a reduced effect in the presence of an MSC-conditioned medium, suggesting that MSC-dependent release of inflammatory signals and other soluble factors could be involved in drug resistance. Our study aims to further investigate the mechanisms of MSC-mediated VEN resistance in AML. We found that primary AML cells isolated from patients at diagnosis and treated with VEN showed different apoptotic rates, indicating an AML cell-specific resistance/sensitivity to the drug. In co-culture experiments, primary MSCs, isolated from healthy donors or AML patients, protected VEN-sensitive AML cells from apoptosis, confirming the critical role of MSCs in drug resistance. To deeply investigate this issue, we performed co-culture experiments using the AML cell line MV4-11, which we demonstrated as sensitive to VEN in a dose-dependent manner. We found that MSCs significantly reduced MV4-11 apoptosis after VEN exposure. The addiction of transwells to the co-culture system abrogated the MSC-protective effect on VEN-induced apoptosis, suggesting the establishment in our setting of a complex interplay between AML cells and MSCs, not only mediated by soluble factors as already demonstrated but also involving direct cell-contact. Furthermore, when we cultured MV4-11 cells in direct contact with MSCs, we were able to distinguish, among leukemic cells, a cell population that remained floating in the supernatant and a cell population that kept adherent to MSCs and could be collected by trypsin detachment only. Interestingly, MSCs protected the adherent but not the floating cells from VEN-induced apoptosis, suggesting a central role of a close adhesion in the MSC-driven resistance to VEN. To gain insight into this mechanism, we sorted adherent vs. floating cells and analyzed and compared Gene Expression Profiling (GEP). Interestingly, the principal component analysis suggested that the floating cell GEP was more similar to the GEP of MV4-11 cells cultured without MSCs compared to adherent cell GEP. We found 159 differential expressed genes (DEGs) in adherent vs. floating MV4-11 cells (FC| ≥ 2 and P ≤ 0.05, according to Transcriptome Analysis Console software guidelines). Enrichment analysis revealed that DEGs were involved in cell adhesion migration and proliferation pathways. Among DEGs, we found that CD90/Thy-1, an adhesion molecule whose expression correlated with unfavorable karyotypes and shorter survival in AML, was significantly up-regulated in adherent MV4-11 cells. Flow cytometry analysis confirmed that the adherent compared to the floating MV4-11 cells, showed a higher expression of CD90 as well as CXCR4 as expected. Our study demonstrated that MSCs protect AML cells from VEN-induced apoptosis through a complex mechanism involving tight adhesion-mediated pathways. Further clarification of these interactions can shed light on putative targets to counteract MSC-mediated drug resistance to VEN treatment.

A Chemo-Free Bridge-to-Transplant Strategy with Venetoclax and Azacitidine for NPM1-Mutated Acute Myeloid Leukemia in Molecular Failure

Background: In patients (pts) with NPM1-mutated acute myeloid leukemia (AML) fit for intensive chemotherapy, the persistence, reoccurrence, or progression of NPM1mut transcript identifies poor chemotherapy responders that require allocation to allogeneic stem cell transplantation (alloSCT). Currently, there is no standard of care for pts in molecular failure and the proper bridging strategy to alloSCT still needs to be defined. The combination of Venetoclax (VEN) and Azacitidine (AZA) offers an alternative chemo-free strategy with favorable toxicity profile in NPM1mut AML, a molecular subset exquisitely sensitive to VEN. Aims: To characterize a series of NPM1mut AML pts in molecular failure who received VEN-AZA as bridge-to-transplant treatment strategy. Methods: We explored the off-label combination of Venetoclax (VEN) and Azacitidine (AZA) in 9 NPM1mut fit AML pts in molecular failure after intensive chemotherapy eligible for alloSCT, treated at 4 Italian Hematology Institutions. Disease was monitored on bone marrow (BM) with NPM1mut-specific qRT-PCR assay. The quantitative detection limit of the assays was 0.01%. Complete response with minimal residual disease negativity (CR-MRDneg) was defined as ratio NPM1mut/ABL x 100 transcript < 0.01 copies Results: Of the 9 pts analyzed 4 (44%) were female, median age at diagnosis was 56 years (range 41-66) and 58 years (range 43-68) at VEN-AZA therapy. Eight of the 9 pts had ELN2017 favorable-risk AML (2 pts with concomitant FLT3-ITDlow and 1 FLT3-TKD) and 1 pt had intermediate-risk AML (FLT3-ITDhigh). Pts received in median 4 (range 2-5) cycles of front line chemotherapy. Seven pts were treated for molecular relapse and 2 for molecular persistence/progression. All pts received full VEN dosage (400 mg/die or 100 mg/die if concomitant strong CYP3A4 inhibitor) and AZA 75 mg/m2/die s.c. in 5- or 7-day schedule. All pts but 1 performed VEN ramp-up. Pts received a median of 3 cycles (range 1-4). No AZA dose reduction occurred. Median VEN duration during cycle (C)1 was 25 days (range 14-28), 21 days (range 7-28) in C2, 24.5 days (range 7-28) in C3 and 25.5 days (range 19-28) in C4. VEN dosage reductions were due to hematological toxicity ≥ G3 in 60% of cases and in 40% for logistic reasons. The observed ≥ G3 toxicities were neutropenia in 4/9 (44%) pts, 1 thrombocytopenia and 1 febrile neutropenia, managed out-patient. No tumor lysis syndrome was observed. Best response to VEN-AZA was CR MRDneg (NPM1mut undetectable) in 7/9 (78%) pts, reached after a median of 2 cycles (range 1-4). Importantly, no pts relapsed ongoing therapy; 1 pt, notably the FLT3-ITDhigh pt, in CR MRDpos presented molecular progression after C3. Median time from VEN-AZA start to alloSCT was 4.3 months (range 1.7-8.1). At pre-transplant evaluation 6/9 (67%) pts were in CR MRDneg. Eight of 9 pts received myeloablative conditioning and 1 pt received reduced-intensity conditioning. With a median follow-up from alloSCT of 9.3 months (range 2.4-24.0) all patients are alive and 8/9 (89%) in CR MRDneg. Four pts presented NPM1mut reoccurrence after alloSCT: in 2 pts CsA tapering achieved molecular negativity, 1 pt underwent prophylactic therapy with sorafenib and 1pt is currently in CR MRDpos. In no pts FLT3 mutations were detected and, most importantly, no patients experienced morphological relapse. Conclusions: VEN-AZA demonstrated to be a safe and effective bridging regimen for NPM1mut AML pts in molecular failure, allowing to achieve deep responses in the majority of pts at the expense of low toxicity. These preliminary encouraging results will be explored in the GIMEMA AML2521 trial in the same patient subset (clinicaltrials.gov NCT04867928).

Updated Analyses: Safety and Efficacy of Gemtuzumab Ozogamicin and Venetoclax in Patients with Relapsed or Refractory CD33+ Acute Myeloid Leukemia: A Phase Ib/II Study

Background: Results of therapy for relapsed/refractory (R/R) AML patients (pts) remain poor, with few surviving >2 years. Refractoriness to treatment may be due to the resistance of quiescent leukemia stem cells (LSCs) to conventional chemotherapy. Gemtuzumab Ozogamicin (GO), a monoclonal antibody linked to the cytotoxin calicheamicin, targets CD33, an antigen with variable expression on LSC. However, decreased blast CD33 expression, p-glycoprotein upregulation and decreased mitochondrial apoptosis are recognized mechanism of resistance to GO (Linenberger et al Leukemia 2005; 19:176-82). GO-induced apoptosis requires Bax and Bak effectors and is opposed by the anti-apoptotic proteins BCL-2 and BCL-XL. Thus, Venetoclax (VEN), a BH3 mimetic with high affinity for BCL-2 should facilitate GO-mediated LSC apoptosis. In addition, LSC, due to their reliance on oxidative phosphorylation (Lagadinou, Cell Stem Cell 2013, 12:329-41) are also uniquely sensitive to BCL-2 inhibition. Thus, we hypothesized a potential synergy between these drugs in targeting LSC in R/R AML. Study design: Big Ten Cancer Research Consortium (BTCRC)-AML17-113 is a single arm, open-label, multi-center, dose-escalation phase Ib/II study of the combination of GO and escalating doses of VEN in R/R AML pts (18-75y), using a 3+3 design. Correlative studies include pre-treatment AML blast CD33 expression and BH3 profiling, minimal residual disease (MRD) measurements at post-therapy time points using digital drop PCR technology, and quality of life (QOL) assessments (EORTC QLQ-C30, FACT-Fatigue). Methods: The primary endpoint is to determine the maximum tolerated dose (MTD) of VEN with GO. Secondary endpoints include overall response rate (ORR), anti-leukemic activity, characterization of treatment emergent adverse events (TEAEs), and estimates of relapse free survival (RFS), event free survival (EFS), and overall survival (OS). Eligibility: ECOG 0-2, adequate organ function, CD33+ in ≥20% AML blasts, ≤2 lines of prior therapy, no prior use of GO, no history of veno-occlusive disease (VOD), no BMT within 2 months, no CNS disease or HIV. Induction: 3-day VEN ramp-up to the target dose of 200 (cohort #1), 400 (#2), or 600 (#3) mg daily x 28d, with GO 3mg/m2 infused d1, 4, and 7. Consolidation/Maintenance: If CR/CRi achieved, pts proceed to BMT if applicable. If no BMT, or if partial response (PR), pts are consolidated with VEN at the prescribed dose x 28d with GO 3mg/m2 given d1 and 4 (Cycle 2). If BMT not applicable, and in CR/CRi, VEN alone is then given as maintenance in cycles 3+ until disease progression or toxicity. Updated Analysis: Trial design was previously described by Arain, S et al. JCO 2020, 15:suppl. TPS7566. Cohort#3 is completing accrual with the last of 6 patients currently undergoing induction treatment. Enrollment n=12 pts. Barriers to accrual have been the COVID-19 pandemic and widespread use of VEN/HMA by referring community oncologists. The study has been amended to allow for prior use of VEN containing regimens. SAE: Respiratory failure gr 3 (n=1), febrile neutropenia (FN) gr 3/4 (n=3), Anemia/rectal pain gr 3/4 (n=1). TEAE:(%;max grade (gr)): thrombocytopenia and anemia (both 60%;gr 4); neutropenia (40%;gr 4); pruritus (30%;gr 3); FN (20%;gr 4), weight loss, diarrhea , headache, constipation (all 20%;gr 1-2). Outcomes: None of the 6 pts in cohorts #1 and #2 responded to treatment. One pt developed VOD gr 4, related to the use of total marrow irradiation conditioning regimen post-induction with GO/VEN. In cohort #3, 3 patients are in CR (one post-HSCT), 2 are undergoing induction and 1 has progressed. Conclusion: The updated analysis of this study reveals a well tolerated drug combination with low toxicities, demonstrating responses in cohort#3 (VEN 600 mg). We plan to expand accrual to this cohort adding 6-12 pts. This trial is registered at clinicaltrials.gov as NCT040768.

A Phase 1b Dose Escalation and Expansion Study of SNDX-5613, Azacitidine (AZA) and Venetoclax (VEN) in Newly Diagnosed, Patients ≥ 60 Years with Untreated NPM1-Mutated/ FLT3-Wild Type AML or KMT2A-Rearranged Acute Myeloid Leukemia (AML)

Background: SNDX-5613 is a potent, orally available, small molecule inhibitor of menin, which binds to MLL1, encoded by the KMT2A gene, and MLL1 fusion proteins. Menin expression leads to aberrant gene transcription through its activation of Homeobox-related genes, leading to maturation arrest and leukemogenesis in KMT2A-rearranged and NPM1-mutated leukemias. Inhibition of menin activity significantly blocks the transcriptional signature and subsequently the proliferative capacity of leukemia cells harboring NPM1 mutations or KMT2A rearrangements. SNDX-5613 and its analogs have demonstrated robust single-agent anti-proliferative activity in NPM1-mutated AML cells and AML patient-derived xenograft models. Currently, SNDX-5613 is being explored as a single agent in a phase 1/2 study in patients with NPM1-mutated or KMT2A-rearranged relapsed/refractory AML, mixed phenotypic acute leukemia and acute lymphoblastic leukemia. The primary objective of this study is to determine the safety and recommended dose of SNDX-5613 combined with AZA and VEN in untreated AML patients age ≥ 60 years who are not candidates for intensive chemotherapy. Study Design and Methods: This study is a sub-study of the BeatAML Master Trial (NCT03013998) in which untreated AML patients age ≥ 60 are assigned an investigational therapy based on cytogenetic and central genomic analysis. Patients must specifically harbor an identifiable NPM1 mutation without a concomitant FLT3 mutation or have a KMT2A rearrangement to be eligible. In this phase 1b study, the primary objective is to determine the safety and recommended dose using a standard 3+3 design based on dose-limiting toxicities with 3 dose levels (DL) of SNDX-5613 to be evaluated in combination with VEN/AZA and an anti-fungal (required during induction): 75mg (DL-1), 113mg (DL1), and 163mg (DL2). In continuation phase with anti-fungals not required, SNDX-5613 will be dosed at 113mg (DL-1), 163mg (DL1), or 226mg (DL2) with appropriate dose reductions added for both SNDX-5613 and VEN if continuing on anti-fungals. The secondary objectives are to assess the overall response rate, measurable residual disease (MRD) status, overall survival, transplant rate and duration of remission. During induction cycles, VEN (D1-28) and AZA (D1-7) are dosed per standard of care every cycle. SNDX-5613 is dosed continuously orally twice daily with dose levels listed above. In patients who achieve a morphologic remission (<5% blasts), SNDX-5613 will be held if absolute neutrophil count (ANC) is < 0.5x109/L and/or platelets (PLT) < 50x109/L. Patients can receive up to 3 induction cycles to achieve a composite complete remission (CRc: CR, CRi, CRh). Patients can receive continuation therapy with AZA, VEN and SNDX-5613 once they achieve CRc and after hematologic recovery. Following the determination of a safe and recommended dose in phase 1b, there will be a dose expansion cohort of 12-20 patients following the same schedule as described above (Figure 1) to further evaluate safety, tolerability and correlative biomarkers. Correlative objectives include assessment of SNDX-5613 pharmacokinetics and its correlation with response and toxicities. Additionally, the study will evaluate the impact of MRD, as measured by central flow cytometry and next-generation sequencing of NPM1 mutations. Additional evaluations and biomarkers of potential interest include menin- KMT2A-specific transcriptomic changes, myeloid differentiation/cell subset changes, mechanisms of resistance, and discovery of baseline features (methylation, mutations, etc.) that can impact outcomes. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Siremadlin in Combination with Venetoclax (VEN) Plus Azacitidine (AZA) in Adult Patients with Acute Myeloid Leukemia (AML) Who Are Ineligible for Intensive Chemotherapy: A Phase Ib/II Trial

Background: Patients with AML who are ineligible for intensive chemotherapy have limited treatment options. Adding VEN to standard-of-care hypomethylating agents (HMAs) improves remission rates and survival for these patients. However, relapse rates with VEN+HMA are high, and many patients do not achieve a complete remission (CR)/CR with incomplete hematological recovery (CRi), or do so and remain measurable residual disease-positive (DiNardo CD, N Engl J Med, 2020), which is associated with poor outcomes. Murine double minute 2 (MDM2) is a key negative regulator of tumor protein 53 (p53; encoded by the TP53 gene). Inhibition of the p53-MDM2 interaction upregulates the tumor suppressor effects of p53. Siremadlin (HDM201) is a selective inhibitor of the p53-MDM2 interaction. In combination with VEN, siremadlin had durable antitumor responses in p53-wild-type AML patient-derived xenograft models (Wang Y, Cancer Res, 2019). Siremadlin was tolerable and demonstrated preliminary single-agent antitumor activity in patients with relapsed/refractory AML in a first-in-human Phase I trial (Stein EM, Clin Cancer Res, 2021; NCT02143635). In combination with VEN, siremadlin also demonstrated promising preliminary antileukemic activity in a Phase Ib trial in patients with relapsed/refractory AML (Wei AH, ASH 2021; NCT03940352). Study design: This international, multicenter, Phase Ib/II, open-label, dose-confirmation, proof-of-concept trial will provide a dosing recommendation and assess the preliminary efficacy of siremadlin in combination with VEN+AZA in adults (≥18 years) with AML who are ineligible for intensive chemotherapy (NCT05155709). For this Phase Ib/II trial, patients must have an Eastern Cooperative Oncology Group performance status of 0-2 (if age ≥75 years) or 0-3 (if age ≥18-74 years) with at least 1 predefined comorbidity rendering the patient ineligible for intensive chemotherapy. Patients with TP53 mutations, chromosomal del17p, or prior MDM2-inhibitor or FLT3-inhibitor treatment are ineligible. Patients will be enrolled into 2 arms: (Arm 1) patients who have received 2-4 cycles of first-line VEN+AZA without achieving a best response of CR, CR with partial hematological recovery (CRh), CRi, or morphologic leukemia-free state, and (Arm 2) newly diagnosed patients with adverse genetic risk as defined in Figure 1. The trial has 2 parts: (Part 1) a safety run-in to assess the safety and confirm the recommended Phase II dose (RP2D) of siremadlin+VEN+AZA and (Part 2) an expansion phase to evaluate the preliminary efficacy of siremadlin in combination with VEN+AZA. Treatment will be administered in 28-day cycles until disease progression, relapse, or unacceptable toxicity. In Part 1, 3-6 patients per arm will receive the starting dose of siremadlin (20 mg; once-daily oral capsule) from Day 1 to Day 5 in each 28-day treatment cycle in combination with VEN+AZA. For Arm 1, VEN and AZA will be administered at doses determined prior to trial enrollment. For Arm 2, VEN will be administered once daily at 400 mg on each day of the cycle, following a 3-day ramp-up, and AZA will be administered intravenously or subcutaneously at 75 mg/m2 either on Days 1-7, or Days 1-5 and Days 8-9 (according to standard local clinical practice). If the starting dose of siremadlin is deemed safe, an additional ~6-9 patients will receive dose level +1 (30 mg) of siremadlin to determine the RP2D for Part 2. Approximately 26 patients will receive siremadlin at the RP2D in combination with VEN+AZA in Part 2. Two primary outcomes will be assessed: in Arms 1 and 2, the proportion of patients with dose-limiting toxicities reported during the first cycle (28 days); and in Arm 1 only, the proportion of patients at the expansion dose who achieve CR. Secondary outcomes include, in Arm 2 only, proportion of patients who achieve CR, and in Arms 1 and 2, duration of CR; proportion of patients who achieve CR, or CRh, or CRi; duration of CR/CRh and CR/CRi; overall survival; pharmacokinetics; proportion of CR-MRD negative overall and MRD negativity in patients achieving a CR, CR/CRh, and CR/CRi. Conclusions: This Phase Ib/II trial investigates siremadlin in combination with VEN+AZA in patients with AML who are ineligible for intensive chemotherapy and will aid in the understanding of the effectiveness of an MDM2 inhibitor with venetoclax combination in patients with AML. The trial is in progress and expected to enroll approximately 55 patients. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Incorporation of Nelarabine (NEL), Pegylated Asparaginase (PEG) and Venetoclax (VEN) in the Frontline Therapy of Adult Patients with T-Acute Lymphoblastic Leukemia/T-Lymphoblastic Lymphoma (T-ALL/LBL)

Background: NEL is effective for patients (pts) with relapsed T-ALL/LBL, but its incorporation into the front-line therapy has not been investigated extensively in the adult population. In children, the addition of NEL to the induction regimen has shown to improve disease-free survival (DFS) but not the overall survival (OS). VEN has shown preclinical and clinical activity in relapsed T-ALL/LBL. We investigated the addition of NEL and PEG to the hyper-CVAD (HCVAD) regimen in adult pts with T-ALL/LBL. Further on, we explored the safety and efficacy of adding VEN to this regimen. Methods: Pts with previously untreated or minimally pre-treated T-ALL/LBL were eligible if they had an ECOG PS ≤3, creatinine ≤ 2 mg/dL, total bilirubin ≤ 2 mg/dL and ALT/AST ≤ 4 x ULN. Pts received 8 cycles of HCVAD (cycles 1,3, 5, 7) alternating with high dose ara-C and methotrexate (MTX) (cycles 2, 4, 6, 8) at approximately 3-week intervals. Two cycles of NEL (650 mg/m2 daily x 5) were initially administered after cycle 8 (cohort 1). Later, after a protocol amendment, they were administered after cycle 4 and cycle 5 (cohort 2). Subsequently, the protocol was amended to add PEG (1500 IU/m2 capped at 3750 IU) on day 5 of the NEL cycles (cohort 3) and more recently, VEN 400 mg daily was added on the first 7 days of each of 8th cycle of therapy (cohort 4) and this was later modified to be given for 7 days during the induction cycle and reduced to 3 days per cycle post-induction only in pts with ETP-ALL or those with persistent MRD. All other pts did not receive VEN after cycle 1 (cohort 5). Pts with ETP-ALL were referred for allogeneic stem cell transplant in first complete remission (CR). After the completion of the intensive phase, pts in all cohorts received 30 cycles of maintenance therapy with monthly POMP and early intensification with NEL/PEG on cycles 6 and 7 and late intensification with MTX/PEG in cycle 18 and HCVAD on cycle 19. All pts received 8 intrathecal chemotherapy with MTX alternating with ara-C and mediastinal radiation was considered in pts with bulky mediastinal disease. Results: Between 8/2007 and 6/2022, 128 pts were enrolled in the 5 study cohorts sequentially (cohort 1= 30, 2= 49, 3=17, 4=16, 5=16) (Table). Seventy-seven pts had T-ALL, 50 T-LBL and 1 biphenotypic T/myeloid leukemia. Median age was 35 yrs. (range 18-78), 98 pts were male (77%) and 110 pts (86%) had PS 0-1. In pts with T-ALL, median bone marrow blast percentage was 83% (range, 20-97) Six pts (5%) had CNS disease at presentation. Cytogenetics were diploid in 82 pts (64%), abnormal in 36 (28%), and unavailable in 10 pts (8%). Pts were further characterized as early T-cell precursor (ETP; n=24), near ETP (ETP + CD5) (N=19), early-non-ETP (n=3), thymic (n=54), mature (n=12), not otherwise specified (NOS; n=16). Twenty-five pts had received 1-2 cycles of therapy prior to enrollment, with 18 having achieved CR. The 30-day mortality was 0%. One hundred and twelve pts (88%) had ≥ 1 grade 3/4 non-hematological treatment-emergent adverse events (TEAE) with the most frequent grade 3/4 TEAEs being neutropenic infections in 96 pts (75%) and elevated liver enzymes in 25 pts (20%). The overall response rate (CR/CRi/PR) was 98% with CR/CRp in 120/128 pts (94%), PR in 5 (4%), and no response in 3 (2%). The median number of cycles to response (including a negative PET scans) was 1 (range 1-10). CR/CRp rate in T-ALL was 91% and T-LBL was 98%. At a median follow-up of 50 months (1-174), 84 patients (66%) are alive with a 5-year PFS and OS of 60% and 61% (Figure 1) and 79 pts (62%) remain in CR. Conclusion: The addition of NEL/PEG cycles to the HCVAD regimen is feasible. The addition of VEN to each cycle is associated with significant myelosuppression. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Association of Hypometilating Agents (HMA) + Venetoclax (VEN) in the Treatment of Myeloproliferative Neoplasms in Blastic Phase (MPN-BP) and Acute Leukemias Evolved from Myelodysplastic Syndromes (AML-MDS) Already Treated with Azacytidine

Background Association of hypometilating agents (HMA) and venetoclax (VEN) is widely used in the treatment of elderly patients with de novo Acute Myeloid Leukemia (AML) not eligible for intensive chemotherapy, with improvement of survival. However, very few data are available about the use of this combined regimen in patients with Myeloproliferative Neoplasms evolved in blastic phase (MPN-BP) and in patients with AML secondary to Myelodysplastic Syndrome (AML-MDS) previously treated with HMA during the dysplastic phase. In both these settings the survival is dismal and at present no therapy seems to have a role. Methods Data of patients with MPN-BP and AML-MDS treated frontline with HMA+VEN in 20 hematological Italian Centers outside clinical trials were retrospectively collected and analysed. Patients treated with HMA + VEN as salvage therapy after induction failure/relapse were excluded. Composite overall response rate [ORR; complete remission (CR) + CR with incomplete hematologic recovery (iCR) + partial remission (PR) + hematological improvement (HI)], duration of response and overall survival (OS) were assessed. Results: A total of 64 patients (41 MPN-BP and 23 AML-MDS) treated between 11/2018 and 5/2022 were included. Baseline characteristics at evolution and starting treatment for the whole cohort and according to previous disease are reported in the Table 1. Median interval from initial MPN/MDS diagnosis to evolution was 31.5 months [interquartile range (IQR) 16.0 - 108.1] in the entire cohort [42.0 months (IQR 22.0 - 124.9) in MPN-BP and 18.8 months (IQR 10.9 - 39.8) in AML-MDS]. Patients were treated for a median of 2 courses (IQR 2-6): HMA were administered at standard dosage, VEN daily dose in the 1st cycle was 50 mg in 6 patients (9.4%), 100 mg in 27 patients (42.2%), 200 mg in 8 patients (12.5%) and 400 mg in 23 patients (35.9%), respectively. On the whole, 50/64 patients (78.1%) had at least one hematological toxicity of grade 3-4: in particular, severe neutropenia (PMN < 0.5 x 109/l) was reported in 46 patients (71.8%). Twenty-nine patients (45.3%) had at least one infective episode during the treatment: pulmonary infections were reported in 18 patients (28.1%). Response to treatment is shown in the Table 1: ORR was 60.0% (60.5% in MPN-BP and 59.1% in AML-MDS, respectively). Median response duration of the whole cohort was 5.3 months (95%CI 2.2-8.4), without significant differences in MPN-BP and AML-MDS patients [4.8 (95%CI 3.2 - 6.5) and 7.8 (95%CI 2.8 - 12.8) months, respectively (p=0.467)]. After a median follow-up of 6.1 months (IQR xx - xx) from the start of combined regimen, 37 patients (57.8%) died, 2 (3.1%) were lost to follow-up and 25 (39.1%) were alive. Median overall survival (OS) of the whole cohort was 7.2 months (95%CI 4.8-9.7), without differences between MPN-BP and AML-MDS groups [8.0 (95%CI 5.0 - 10.9) and 6.8 (95%CI 4.3 - 9.3) months, respectively (p=0.717, Figure 1)]. Patients with any type of response to the combination regimen had a significantly longer OS compared to patients with progressive/stable disease [11.6 (95%CI 8.2 - 14.9) and 5.4 (95%CI 2.8 - 7.9) months, respectively (p=0.006)]. Conclusions: Our real-life data confirm that HMA + VEN combination could have a role in these two very challenging subsets of secondary AML, with achievement of ORR > 50% in patients unfit for intensive approaches: however, this treatment is affected by severe hematological and infective toxicities and the response duration is short, leading to a persistently poor median OS. Larger cohorts of patients and a longer follow-up are needed to assess factors predictive of CR/iCR achievement, while the addition of other targeted therapies should be explored. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

A Phase I Study of Uproleselan Combined with Azacitidine and Venetoclax for the Treatment of Older or Unfit Patients with Treatment Naïve Acute Myeloid Leukemia

Introduction: VIALE-A established azacitidine (AZA) with venetoclax (VEN) as a standard of care for AML ineligible for induction chemotherapy (IC). Patients (Pts) who achieved a measurable residual disease (MRD) negative complete remission (CR) or CR with incomplete count recovery (CRi) by multiparameter flow cytometry (MFC) had improved outcomes; however, only 41% of CR/CRi responders achieved MRD negativity. Uproleselan (UPRO) is a novel E-selectin antagonist that disrupts cell survival pathways and improves chemotherapy responses in preclinical models, including in combination with AZA +/- VEN. A Phase I/II study of UPRO combining with IC in AML pts established a recommended Phase II dose (RP2D). UPRO was associated with higher CR/CRi and MRD negative (MRD-ve) rates, lower induction mortality, and less severe mucositis compared to historical controls. We are exploring the combination of UPRO with AZA/VEN to improve outcomes in pts with untreated AML ineligible for standard IC. Methods: This ongoing single center Phase I trial of frontline UPRO in combination with AZA/VEN in older or unfit AML pts (NCT04964505) consists of a dose optimization portion, using a modified 3+3 dose optimization design to confirm the RP2D UPRO dose level (800 mg IV q12h for 7 days), and a dose expansion cohort. We report results of the dose optimization portion and initial expansion phase subjects. Key eligibility criteria included age ≥18 years, AML diagnosis by WHO criteria, and eligibility for frontline AZA/VEN. Pts received UPRO 800 mg IV q12h and AZA 75 mg/m2 IV/SC q24h for 7 days, and VEN 400 mg PO daily for 28 days in 28-day cycles. Treatment continued until progression, intolerance, or patient decision to stop. Pts had a VEN ramp-up in cycle 1 including tumor lysis syndrome monitoring and prophylaxis. A bone marrow biopsy was done after every cycle until morphologic leukemia-free state or better response (MLFS+). UPRO was given for up to 6 cycles with dosing decreased to daily after achieving MLFS+. The primary objective was to determine safety and tolerability. Adverse events (AE) were monitored throughout treatment, and dose-limited toxicities (DLT) assessed in cycle 1. The secondary objective was to evaluate preliminary efficacy, notably MRD-ve CR/CRi rate, as measured by MFC. Results: As of June 26, 2022, 8 pts [75% female, median age 78 (range 70-81)] were enrolled in the dose optimization (n=6) and dose expansion (n=2) portions of the study. Four (50%) had de novo AML and four (50%) had secondary AML, including 3 (38%) with therapy-related AML. Six (75%) had ELN 2017 adverse risk disease; 3 (38%) had complex cytogenetics. The most common mutations identified were RUNX1 (n=4), BCOR (n=2) and TET2 (n=2), and one patient each had TP53, NPM1, FLT3-ITD, or IDH2 mutations. All pts completed cycle 1. Median time on study is currently 126 days (range 32-179). Pts received a median of 3 treatment cycles (range 1-6). No DLTs were observed. There were no deaths in the first 30 days from treatment initiation; there was one death from sepsis in the first 60 days. All pts had at least one treatment-emergent AE (TEAE). The most common TEAE regardless of grade and attribution included anemia (n=6), thrombocytopenia (n=6), anorexia (n=4), nausea (n=4), neutropenia (n=4), fatigue (n=3), hypocalcemia (n=3), and hyponatremia (n=3). All pts experienced at least one ≥grade 3 TEAE, with anemia (n=6), thrombocytopenia (n=6), neutropenia (n=4), and febrile neutropenia (n=2) most common. Four pts (50%) experienced nine total serious AEs (SAEs), including thrombocytopenia (n=2). There were two grade 5 events, sepsis and AML disease progression, both unrelated to UPRO. Two pts remain on study treatment, and six have discontinued study therapy [patient decision (n=4) and death (n=2)]. All pts with an MLFS+ had dose modifications and/or cycle delays. All 8 pts had a MLFS+ response. Five (63%) achieved CR and one CRi, for a total CR/CRi rate of 75%, and two achieved MLFS. Five CR/CRi responses occurred with cycle 1. Four of the CR/CRi responses were MFC MRD-ve, for an overall MRD-ve CR/CRi rate of 50% and 67% among the CR/CRi responders. Conclusions: Preliminary results from this Phase I study reveals a tolerable safety profile of UPRO with AZA/VEN in pts with untreated AML ineligible for IC. No DLTs were observed, and the most common Grade 3-4 AE and SAE were hematologic. The combination shows promising preliminary efficacy, including a 50% rate of MRD-ve CR/CRi.

A Phase Ib Study of the Safety and Efficacy of Venetoclax When Combined with Escalating Doses of Omacetaxine in Patients with Relapsed/Refractory Acute Myeloid Leukemia Failing Treatment with Venetoclax-Containing Regimens (VEN-OM)

Background: Venetoclax (VEN) combined with hypomethylating agents (HMA) are increasingly used as first line (1L) treatment in AML patients (pt) intolerant of intensive chemotherapy, due to the high complete remission (CR) rate (66.4%), tolerance of therapy and a median duration CR of 17.5 months. However, >60% of pts discontinued VEN/HMA (n=286) during the VIALE-A trial, mostly due to disease progression (DiNardo et al.N Engl J Med2020; 383:617-29). Outcomes for such pts receiving 2L and 3L therapies for relapsed/refractory (R/R) AML are poor and may be due to development of resistance to BCL-2 inhibition through mechanisms including the upregulation of the anti-apoptotic proteins BCL-XL or MCL1. In vitro studies demonstrate that VEN-resistant leukemia stem cells (LSC) are re-sensitized to BCL-2 inhibition when MCL-1 is also inhibited (Ramsey et al. Cancer Discov 2018; 8:1566-81). Novel MCL-1 inhibitors are thus in phase 1 clinical trials in R/R AML (e.g. NCT02675452), however there have been concerns for cardiotoxicity. Metabolic studies (Stevens et al. Nat Commun 2018: 9, 3694) indicate that the CD123+ malignant stem cell compartment of pts with high-grade MDS rely on upregulation of the protein synthesis machinery and mitochondrial oxidative phosphorylation (OxPhos). Omacetaxine (OM), a protein translation inhibitor both inhibits OxPhos and down-regulates (other) proteins with a short half-life such as MCL1. Treatment of a xenograft AML model with a combination of OM and VEN indicates in vivo synergistic effects in impairing mitochondrial respiration, ATP production, BCL-2 inhibition and MCL-1 downregulation (Fig 1A). We hypothesize this combination will prove effective in pts with R/R AML including those resistant to VEN-containing regimens. A similar drug combination is being studied by Dinardo et al. in R/R AML and MDS pts with RUNX1 mutations. Methods: VEN-OM is a single arm, open-label, phase Ib dose-escalation study in R/R AML pts (18-75y). The trial utilizes an innovative Bayesian Optimal Interval (BOIN) adaptive design (Yuan et al. Clin Cancer Res 2016)to determine the maximum tolerated dose (MTD), with a target dose-limiting toxicity (DLT) rate of 2%, and 4 pre-specified dose levels of OM, involving 24-30 pts. Major eligibility: ECOG 0-2, adequate organ function, R/R AML having progressed on ≥ 1L of therapy, which must have included a VEN-containing regimen. Exclusion criteria: Prior use of OM, peripheral blast count > 25 × 109/L, unresolved ≥ grade 2 clinically significant nonhematologic toxicities from prior anticancer therapy, unresolved ≥ grade 2 disseminated intravascular coagulation (DIC), other active malignancy within 1 year before study entry, or active infections. Induction Phase: Beginning with the first pt treated at the lowest dose of OM (0.625 mg/m2 q12h), OM dose escalation and de-escalation will involve comparison of the observed DLT rate at the current dose with a pair of fixed, pre-specified boundary rates. After a VEN ramp-up phase (days 1-3), the VEN dose is fixed at 400mg daily on days 4-28. OM doses are given days 1-7. OM dose will be escalated for each subsequent pt until the first DLT occurs, whereupon the current dose cohort is expanded to 3. In simulations of these conditions with a target DLT rate of 20%, the percentage correct selection of the MTD is between 60% with enrollment of 20 pts and 70% with 24 pts. Consolidation Phase: OM dose will be as per induction dose for days 1-7 of each cycle. VEN dose is 400mg days 1-21. Regimen comprises 3 cycles: Induction cycle x 1 and Consolidation cycles x 2 (Fig 1B). Primary endpoint is MTD of the combination of VEN and OM. Secondary endpoints include overall response rate after 3 cycles, characterization of adverse effects, and estimates of EFS and OS at 12 months. Exploratory objectives include measurement of validated markers of early renal injury including urine TIMP-2 x IGFBP7 and KIM-1 to identify pts susceptible to OM-induced nephrotoxicity and potential correlation with OM efficacy. Our previous experience with OM added to 7+3 ("AML-02", ASH 2022 abstract submitted) suggests that quantification of BM leukemia blast protein synthesis rates (Walker et al. Clin Cancer Res 2021, 27:819-30) and 'BH3 profiling' at presentation predicts outcomes, and these correlative studies will also be performed. The study recently opened, with the first patient completing induction without complications. Trial registered as (NCT04926285). Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Biomarkers of Clinical Resistance to Decitabine and Venetoclax Therapy Inferred By Transcriptome and Methylation Analyses

The combination of the selective BCL-2 inhibitor venetoclax (VEN) with the hypomethylating agent (HMA) decitabine (DEC) is highly effective in treating older ineligible for intensive chemotherapy AML patients. However, approximately 15-34% of newly diagnosed (ND) and 60% of relapsed/refractory (R/R) patients fail to achieve complete remission (CR) (DiNardo et al. New Engl J Med. 2020, DiNardo et al. Lancet Haematol. 2020). Factors that reduce efficacy remain to be elucidated. To dissect underlying mechanisms of HMA-VEN resistance, we performed RNA-seq utilizing primary samples from patients treated on a prospective clinical trial of 10-day DEC with VEN (NCT03404193). Previously, we reported that alterations of transcriptome signatures of energy-metabolism and cell migration/adhesion pathways were upregulated in primary resistant ND group, and immune-system-associated genes were downregulated in R/R group (Yamatani et al. ASH 2021). This study investigated transcriptomic and DNA methylation signatures associated with DEC10-VEN response or resistance in ND and R/R AML. Because DEC was reported to strongly induce interferon-stimulated genes (ISGs) through gene methylation modifications, we focused on 116 ISGs. An integrated analysis of DNA methylation status around the transcription start site (TSS) was performed using the Infinium methylated EPIC array (Illumina). Forty-four pre-treatment samples from 32 patients with AML from DEC-VEN clinical trial, ND patient group (CR/CRi 14; non-responder, NR 11) and R/R patient group (CR/CRi 6; NR 13), were analyzed. First, we performed the comparative analysis of NR vs CRs. In the ND group, NR cases showed significantly higher gene expression and lower TSS methylation of an urea cycle enzyme, ASS1 (Argininosuccinate Synthase 1) with RNA-seq Log2 fold-change (FC) 3.6 and methylation array Δβ (differential methylation β-value) -0.11, p < 0.05, and of an actin-based molecular motor, MYO1C (Myosin 1C), Log2FC 2.5, Δβ = -0.18, p< 0.05, than in CR cases. In the R/R group, gene expression levels of seven ISGs, including CCL3 (C-C motif chemokine 3), were significantly lower in NR than in CRs, with no difference in methylation status. Next, changes in gene expression levels and TSS methylation status after DEC-VEN treatment were investigated in non-responders in ND group (pre 19, post 12) and R/R group (pre 16, post 4). After DEC-VEN treatment, PPARG (Peroxisome Proliferator-Activated Receptor γ), a transcription factor that activates fatty acid metabolism and negatively regulates subsets of IFN-γ target genes, was significantly upregulated along with its TSS demethylation both in ND (Log2FC 4.9, Δβ = -0.14, p < 0.05), and R/R groups (Log2FC 3.7, Δβ = -0.06, p < 0.05). CDC42EP4, an effector protein of CDC42 involved in the organization of the actin cytoskeleton, was upregulated after the treatment in the R/R group (Log2FC 2.7, Δβ = -0.14, p < 0.05). Based on these findings, we validated transcriptional and methylation changes of ASS1, PPARG, MYO1C and CDC42EP4 by RT-qPCR and bisulfite pyrosequencing using HL60 and MV4-11 AML cell lines in which DEC (IC50, HL60, 249 nM; MV4-11, 2090 nM) and VEN (IC50, HL60, 18 nM; MV4-11, 64 nM) produced additive or synergistic combination effect. Cells were treated by DEC and/or VEN under BM-derived mesenchymal stem cells (MSCs) co-culture conditions to mimic the BM microenvironment. DEC upregulated gene expression levels with TSS demethylation of PPARG, MYO1C and CDC42EP4 both in HL60 and MV4-11, and of ASS1 only in HL-60. VEN treatment alone or in combination with DEC did not induce significant changes in the expression of these tested genes. Of note, PPARG expression was further upregulated under MSCs co-culture condition without TSS methylation status change in AML cells. DEC treatment induced no significant changes of PPARG in MSC. These findings suggest that not only TSS demethylation but also interaction with BM stromal cells may be involved in PPARG upregulation associated with energy production in AML cells. Taken together, DEC-VEN treatment stimulates two key factors, energy metabolism and interaction with the BM microenvironment, which may reduce therapeutic efficacy by increasing gene expression of PPARG,MYO1C,ASS1, and CDC42EP4 through TSS demethylation and/or interaction with BM stromal cells. Experimentally, the consequences of overexpression / knockdown of these genes will be further validated.