Adverse-risk Acute Myeloid Leukemia Research Articles

Myelomonocytic/Monocytic Subtypes Are More Resistant to Venetoclax-Based Therapy in Acute Myeloid Leukemia Patients: A Monocentric, Real-Life Retrospective Study

Background： Venetoclax(VEN)-based regimens have seen broad adoption in newly diagnosed patients with acute myeloid leukemia (AML) who are not candidates for intensive induction chemotherapy. Nonetheless, a sizable proportion of AML patients do not respond. Finding biomarkers that can predict treatment results is crucial. FAB (French, American, British) classification system provides a well-described and clinically associated means to segregate AML patients by virtue of myeloid differentiation status. Whether FAB classification can be used as a predictor marker for VE-based therapy is controversial. In the Chinese population of patients with AML, we conducted this single center retrospective study to examine the predictive value of monocytic and myelomonocytic differentiation on the response to VEN-based treatment. Methods: The clinical features, treatment information, and clinical outcomes of AML patients who received at least one dose of VEN treatment at West China Hospital for more than seven days between January 1, 2019, and September 8, 2022 were retrospectively examined in this study. We classified the patients into two groups based on the FAB classification system: the primitive group (includes M0/M1/M2, abbreviated as PRI) and the myelomonocytic/monocytic group (includes M4/M5, abbreviated as M/M). AML response to VEN therapy was determined by the 2017 European Leukemia Net response criteria after one cycle of VEN treatment. The overall response rate (ORR) was defined as the combination of CR, CRi, PR. From the first day of VEN use until the patient dies or the end of follow-up, the overall survival (OS) time is calculated. Logistic regression and COX regression were used to examine the variables that influence ORR and survival. All statistical tests were two-sided, and p-values of 0.05 or lower were considered significant. All statistical analyses were performed using RStudio 4.2.2. Results: There were 267 patients in all, with 162 newly diagnosed (M/M n=69; PRI n=93) and 85 relapsed/refractory (M/M n=44; PRI n=41). The ORR for M/M is 63.77%, while that for PRI is 84.95% among newly diagnosed patients (p=0.018). The ORR for M/M is 40.91% and PRI is 68.29% among relapsed/refractory patients (p=0.0114, Figure1). In addition, we identified (i) FAB classification M/M subtypes, (ii) previously diagnosed MDS/MPN, (iii) IDH1/IDH2 mutations, (iv) relapsed/refractory event, (v) transfusion requirement, and (vi) TP53 mutation as significant factors predicting the response of all patients using univariate logistic regression analysis. M/M subtypes and MDS/MPN also trended toward independent predictors in the multivariate analysis. We identified (i) FAB Classification M/M subtype, (ii) adverse risk AMLs according to the 2022 ELN classification, (iii) CEBPA mutation, and (iv) TP53 mutation as significant factors predicting the risk of all patients using univariate COX regression analysis. M/M subtype and TP53 also trended toward independent predictors in the multivariate analysis (Table1). OS was significantly longer in the PRI than in the M/M(median OS: 621 days vs 266 days, hazard ratio 0.56, 95% CI: 0.39-0.80, p=0.0011). We compared the overall survival of various illness conditions; OS still was significantly longer in the PRI group than in the M/M group among newly diagnosed patients (median OS: newly diagnosed: 1124 days vs 295 days, HR: 0.47, 95% CI: 0.24-0.83, p=0.0017; refractory/relapsed: 204 days vs 266 days, HR 0.68: 95% CI: 0.45-1.97, p=0.72). Conclusion： Our research demonstrates that the response to VEN may differ depending on how advanced the AML is, with PRI patients being more sensitive and M/M patients being more resistant, particularly in newly diagnosed individuals. Previous research has discovered that AML cells with Monocyte/erythroid/Megakaryocyte differentiation are less sensitive to BCL-2 inhibition in vitro, indicating that the differentiation stage of AML may affect its sensitivity to BCL-2 family inhibitors. This is likely due to an increase in MCL1 family expression and a decrease in BCL2 family expression during cell differentiation. In conclusion, M/M subtype may be able to predict VENs resistance and the worse prognosis for patients treated with VEN-based regimens. Legends to figures Figure 1: Differences in ORR and NR (no response) between M/M and PRI in newly diagnosed and relapsed/refractory patients Table1: Regression analysis results

Clinical and Prognostic Implications of WT1 Mutations in De Novo and Relapsed Acute Myeloid Leukemia

Introduction Wilms Tumor 1 ( WT1) is integral to cell proliferation and survival and is mutated in up to 10-15% of patients (pts) with acute myeloid leukemia (AML). WT1 mutated ( WT1 m) AML frequently co-occurs with fms-like tyrosine kinase 3 ( FLT3) and nucleophosmin 1 ( NPM1) mutations, and is generally thought to impart poorer outcomes, however the impact of WT1 m remains incompletely understood. Methods We analyzed 307 pts with WT1 m AML, identified through next generation sequencing panels of recurrently mutated myeloid genes performed at two large academic cancer centers between 2015 - 2022. Of the 307 pts, 161 (52%) had WT1 m at AML diagnosis (ND) and 146 (48%) were identified at relapse (RR). Here we describe the baseline characteristics and outcomes in pts with WT1 m AML with emphasis on co-mutated FLT3 and NPM1. Results In pts with ND WT1 m AML, the median age was 59 years (range,22-87). Pts most commonly had intermediate (41%) or adverse (43%) risk disease by ELN 2022 criteria. 51% (n=82) had co-mutated FLT3 (ITD or TKD). Among pts with FLT3 mutated AML, 30% (37%) also had co-mutated NPM1. 10 (7%) pts had co-mutant NPM1 m without FLT3 m. Median OS in the ND cohort was 19.8 months. Variant allele frequency (VAF) ranges of WT1 m were 1-98 (median 27) and 1-97 (median 13) in the ND and RR cohorts respectively. OS was affected by mutational profile (table 1) with triple mutated NPM1/FLT3/WT1 exhibiting worse OS compared to others. 68% of ND pts received intensive chemotherapy (+/- venetoclax (VEN)) at time of diagnosis with mOS of 26.5 mos vs. 11.1 mos (p = <0.0001) for pts treated with lower intensity therapy (+/- VEN). Improved OS was observed in pts with ELN2022 favorable risk disease (mOS not reached (NR)) and in pts receiving an allogeneic hematopoietic stem cell transplant (SCT). Pts with ND AML and ELN2022 intermediate-risk disease who underwent SCT had significantly longer OS of 47.9 mos vs. 11.8 mos (p<0.0001, figure 1). In the ND cohort, pts had significantly improved OS if they underwent SCT after achievement of CR1 compared to SCT after first relapse, mOS NR vs. 38 months (p=0.00039), respectively. Notably, the median age of pts who received SCT was 50 (22-74) with 16% having secondary (s-AML) or therapy related (t-AML). Of those who did not undergo SCT median age was 63 (23-87) and had with 28% of pts with (s- or t-AML). Within the RR cohort, 44 (30%) pts acquired WT1 mutation post SCT. 56 (38%) were FLT3 m (25 pts with co-mutated NPM1) and 10 (7%) NPM1 m mutated (without FLT3 m). The mOS in the RR cohort (from time of WT1 m acquisition) was shorter in pts with co-mutated FLT3/WT1 without NPM1 (table 1). Pts who underwent SCT after WT1 macquisition had mOS of 25.7 mos (95% CI 23.8-38.7) compared to 18.3 mos (95% CI 13.2-21.2) (p=0.001) in those who did not undergo SCT. 28% of pts received intensive therapy (+/- VEN) as salvage after acquisition of WT1 mwithout difference in OS compared to those receiving low intensity therapy (66% with VEN). mOS (11.1 vs. 7.8 mos, p=0.12) . In pts ND AML and co-mutant NPM1/WT1, WT1 m was frequently (75%) subclonal to NPM1 m with a mOS NR. However, in pts who initially had NPM1 m disease and acquired a WT1 m at relapse, WT1 m was more clonally co-dominant with NPM1 mwith a mOS of 15.9 mos (p=0.11). Amongst both cohorts, there was no difference in survival based on sex. Conclusion WT1 mutations are enriched in intermediate and adverse risk AML, frequently acquired at relapse, and are associated with overall poor OS in the absence of SCT. Our data suggests that pts with WT1m AML benefit from high intensity induction regimens and SCT at CR1 should be considered in all WT1 m pts with ELN2022 intermediate or adverse risk disease. WT1 mutations should also be considered for inclusion into ELN risk stratification given poor overall survival without SCT.

Toward a Measurable Residual Disease-Based Algorithm for Selection of Allogeneic Hematopoietic Stem Cell Transplant in Acute Myeloid Leukemia

Background: The diagnosis and management of acute myeloid leukemia (AML) have transformed in recent years with an improved understanding of leukemogenesis and improved methods of measurable residual disease (MRD) detection. Current treatment algorithms include consideration of allogeneic hematopoietic stem cell transplant (HCT) for intermediate and adverse-risk AML. MRD negativity is widely accepted as a predictive and prognostic marker for disease-free survival and overall survival. However, the clinical use of MRD status in consolidative HCT planning remains unclear. Methods: Two hundred thirty-three consecutive patients achieving complete remission (CR) as defined in ELN 2022 after receiving therapy at Massey Cancer Center were analyzed. MRD status was determined either by multiparameter flow cytometry, PCR-based sequencing, and/or next-generation sequencing. Patients were analyzed via retrospective chart review to obtain baseline characteristics, molecular and cytogenetic profiles, and survival data. Median overall survival (mOS) was calculated and compared using the Kaplan-Meier method. Continuous variables were compared using one-way ANOVA. Categorical variables were analyzed using Fisher's exact test. Results: In total,109 patients achieved MRD-negative CR and 124 patients achieved an MRD-positive CR. Of the MRD-negative patients, 42 went received HCT (39%). In the MRD-positive cohort, 44 underwent HCT (35%). Among the MRD negative group, those receiving HCT tended to be younger (52.1 y. [range: 24.8-71.7] vs 61. 8 y. (range: 27.1-82.9) p = 0.026) with fewer co-morbidities (Charlson comorbidity index [CCI] score: 3 [range: 2-9] vs 4 (range: 0-14), p = 0.322). We observed a similar trend in those who had MRD positivity at best response or at the time of transplant (age 55 y. [range: 24.5-72.2] vs 62 y. [range: 25.1-88], p = 0.142; CCI 4 [range: 2-7] vs 5 (range 2-11], p = 0.014). In the MRD-negative/no HCT group, 49.3% had ELN favorable-risk disease at initial AML diagnosis, 28.4% had intermediate risk, and 22.4% had adverse risk. In the MRD-negative/HCT group, 31% were favorable risk, 33.3% intermediate risk, and 35.7% were adverse risk. In the MRD-positive/HCT group, 46.3% favorable risk, 23.8% intermediate risk, and 29.5% were adverse risk. There were no significant differences in ELN risk between any group. MRD-positive patients who underwent HCT had a mOS of 25.7 m. vs 20.7 m. for no HCT (HR=0.68 [95% CI, 0.41-1.11], p = 0.125). The median OS was not reached for MRD-negative patients, regardless of receipt of HCT (HR=0.61 [95% CI, 0.30-1.23], p = 0.168). Patients undergoing HCT in MRD-negative CR had improved OS compared to those undergoing HCT with persistent MRD positivity (p = 0.006). Discussion: MRD positivity is a known predictor of relapse and decreased survival despite HCT. However, the use of MRD as a decision point predicting which patients will benefit from transplant a priori needs to be better understood. Our data suggest that MRD negativity has a more significant impact on overall prognosis than HCT status.Likewise, the negative impact of MRD positivity was not significantly abrogated by subsequent HCT. This highlights the need for refinement in HCT selection beyond ELN 2022 intermediate/adverse-risk patients, and new validated algorithms incorporating MRD status are warranted.

Current Results of Intensive Therapy in Younger Adults with Acute Myeloid Leukemia (AML): The Large Randomized French Backbone Intergroup (BIG)-1 Study on Behalf of the Filo, ALFA, and SFGM-TC Study Groups

Introduction. This multicenter study randomly explored various standard intensive chemotherapy (ICT) strategies in adults with AML, namely higher-dose idarubicin (IDA) vs high-dose daunorubicin (DNR) and intermediate-dose (IDAC) vs high-dose (HDAC) cytarabine. The study was planned large enough to allow patient subgroup analysis. Treatments. Eligible patients (pts) were randomized (R1) to receive an induction course with either DNR at 90 mg/m 2/d for 3 days or IDA at 9 mg/m 2/d for 5 days combined with cytarabine at 200 mg/m 2/d CIV for 7 days. Since 09/2018, FLT3-mutated AML pts may also receive midostaurin 100 mg/d d8-21. Then, all pts alive without contra-indication for further ICT were randomized (R2) to receive a first consolidation (C1, if in CR/CRp/CRi) or salvage (if induction failure) with either HDAC (3g/m 2/12h) or IDAC (1.5g/m 2/12h) cytarabine at day 1, 3 and 5. Pts in CR/CRp/CRi after C1/salvage received two additional HDAC/IDAC cycles (C2, C3), according to R2 arm. In intermediate (int) or adverse (adv) risk AML pts as defined in the protocol, allogeneic HSCT from sibling or 10/10 (or even 9/10 if adv-risk) matched donors was offered after C1 (adv-risk) or C2 (int-risk). Conditioning regimens were myeloablative (MAC; Bu-Cy ± ATG) if age<45y or reduced-intensity (RIC; Bu-Flu-ATG) if age≥ 45y or HCTCI> 2 in int-risk pts, and sequential FLAMSA/Bu-Cy-ATG in adv-risk pts. Fav-risk pts were also eligible for HSCT if late CR/CRp/CRi or suboptimal NPM1 MRD response. Alternative stem cells sources and conditioning regimens might also be offered to adv-risk pts. Patients & Methods. Pts aged 18-60y with de novo, post-MDS or therapy-related AML (CBF, APL, Ph+, and post-MPN excluded) were eligible if ECOG-PS ≤3, no active infection or neoplasia, no organ contra-indication, and a health insurance. Patient characteristics are shown in Table 1. Between 01/2015 and 05/2019, 1405 pts were enrolled and 1357 were evaluable. Among them, 1159 were randomized in R1 with the primary objective to increase 3-year OS from 45% in the DNR to 55% in the IDA arm. A total of 1221 pts were randomized in R2, including 198 pts after the end of the R1 inclusion period (they received DNR or IDA according to centers' preferences). Primary R2 objective was to show OS non-inferiority after IDAC vs HDAC in a per protocol (PP) set, defined as pts who received the planned HDAC/IDAC dose ± 20% during C1/salvage. The non-inferiority boundary was an upper limit of the hazard ratio [HR] CI below 1.25. Analysis of R1 and R2 effects was adjusted on ELN-2022 risk groups, the other randomization/treatment arms, and time-dependent HSCT in first remission. Median follow-up was 5.4 years. Results. Overall, 1148 (84.6%) pts achieved CR/CRp/CRi and 564 (41.6%) received HSCT in first remission ( Table 1). At 6 years, OS was estimated at 53.4% (95% CI, 50.6-56.2). In the R1 population, IDA did not prolong OS (adjusted HR, 1.04 [0.88-1.23]; p=0.67). This lack of effect was observed in the three ELN-2022 risk groups. During induction, IDA was associated with longer neutropenia and antibiotic administration durations, more RBC/platelet transfusions, more mucositis and fungal infections. Remission and induction death rates were similar in both arms. In the R2-PP set that excluded 39 R2 pts, OS was significantly non inferior in the IDAC as compared to the HDAC arm (adjusted p-value, 0.004) and this was observed in the three ELN-2022 groups ( Figure 1). During the first C1/salvage cycle, IDAC was associated with less CNS toxicity and less RBC/platelet transfusions. Only 2 pts died during this cycle. Neither responses, HSCT rates, relapse incidence, nor RFS were significantly impacted by R1 or R2. With respect to the OS endpoint, no interactions were found between induction anthracycline and R2. In pts in induction failure at R2, the salvage rate was 51.6% after HDAC vs 39.5% after IDAC (adjusted p-value, 0.081). As expected, time-dependent HSCT in first remission significantly prolonged RFS (adjusted HR, 0.41 [0.32-0.52]; p<0.0001) and OS from remission (adjusted HR, 0.65 [0.50-0.83]; p=0.001) in int/adv-risk AML pts. In these pts, no interaction was found between the effect of HSCT and the R2 arm (HDAC or IDAC). Conclusions. In younger adults with non-CBF AML, benefit/risk analysis favors high-dose DNR vs IDA for remission induction and confirms IDAC as the standard for consolidation. The high overall transplant rate may have contributed to the good results of this study.

Mega-Dose Decitabine Intensified Regimen Is More Effective at Eliminating Pre-HSCT Measurable Residual Disease Compared to the Bu/Cy Regimen: A Multicenter Prospective Phase II Study

Background: Acute myeloid leukemia (AML) patients with high-risk pre-HSCT measurable residual disease (MRD, KMT2A-r, etc.) have a high relapse rate (>50%) even after allogeneic hematopoietic stem cell transplantation(allo-HSCT). In 2018, we developed two multi-institutional, single-arm, prospective phase II trials, to investigate the efficacy and safety of a novel intensified conditioning with “Mega-Dose 400mg/m 2” decitabine following allo-HSCT for high-risk MRD AML (NCT03793517). Method： Inclusion: 1) Detectable pre-HSCT MRD detected by recurrent genetic abnormalities (KMT2A-r, DEK, etc.) in ELN adverse-risk AML; or high-level pre-HSCT MRD in all risk groups, defined as the reduction of recurrent genetic abnormalities ≤1 log compared to initial diagnosis (RUNX1:RUNX1T1, etc.); 2) Age≥18; no HSCT history, available donor; ECOG 0-2, HCT-CI 0-3. Uniform conditioning regimen: intravenous decitabine (200mg/m 2/day) on days-12, -11, intravenous cytarabine+ busulfan+ cyclophosphamide (Bu/Cy) on days -10 to -2 (Blood. 2015;125(25):3956-62). The primary endpoint was cumulative incidence of relapse (CIR). Competing risk analysis and time-dependent Cox model were constructed in R software 4.21. Contemporary MRD+ AML patients with the same recurrent genetic abnormalities following Bu/Cy regimen or relapsed/refractory AML patients following 400mg/m 2 decitabine regimen (NCT03799224) were enrolled as nest-control to compare the post-HSCT kinetics of recurrent genetic abnormalities. Results: Between Dec 2018-Feb 2023, twenty-one patients received allo-HSCT from HLA-matched siblings (n=2), and haploidentical donors (n=19), including 13 patients with KMT2A-r genes. Median follow-up was 19 (4.6-58) months after HSCT. The cumulative 30-day neutrophil (median 13 days) was 100.0% and 100-day platelet engraftment and 95.2% (median 21 days); all patients reached negative MRD by flow cytometry after HSCT. This conditioning regimen was well tolerated without irreversible grade III-IV toxicity peri-engraftment. Primary endpoint: 2-year CIR was 5.6% (95%CI: 0.3-23.3). Secondary endpoint: 2-year NRM was 4.8% (0.3-20.2); 2-year LFS was 89.6% (77-100); 2-year OS was 89.3% (76.2-100). The median fold reductions (log10) of leukemia burden with recurrent genetic abnormalities were 3.6 (range 1.3-5.1) one month after HSCT (Figure). Conclusion: Compared to Bu/Cy regimen, “Mega-Dose” decitabine (400mg/m2) is a novel conditioning regimen with improved efficacy to eradicate pre-HSCT MRD and reduce post-HSCT relapse.

Outcomes of venetoclax combined with homoharringtonine and cytarabine in fit adults patients with de novo adverse-risk acute myeloid leukaemia: A single-centre retrospective analysis.

Adverse-risk acute myeloid leukemia (AML) has a dismal prognosis. We aimed to investigate the activity and tolerability of venetoclax combined with homoharringtonine (HHT) plus cytarabine (VHA) regimen for de novo adverse-risk AML. Thirteen de novo AML patients with adverse-risk factors were treated with venetoclax (100 mg day 1, 200 mg day 2, 400 mg days 3-21), HHT (1 mg/m2 days 1-5) and cytarabine (100 mg/m2 days 1-5) (VHA regimen). Complete remission (CR) was achieved in 11/13 patient (84.6%), all of CR responders were measurable residual disease (MRD) negative detected by multi-parameter flow cytometry (MFC). Grade 3-4 neutropenia, anaemia, and thrombocytopenia occurred in most patients. Grade 3-4 non haematological adverse events (AEs) included febrile neutropenia (4/13, 30.8%). With a median follow-up of 10 months (range 4-19), median overall survival and event-free survival were not reached. VHA may be a promising and well-tolerated regimen in de novo adverse-risk AML.

POSTER: AML-530 Sequential Salvage Chemotherapy and Lintuzumab-Ac225 in Relapsed/Refractory AML Results in Deep Responses and Prolonged Survival in Adverse Risk Acute Myeloid Leukemia (AML) and in AML Patients that Received Prior Venetoclax Therapy

POSTER: AML-530 Sequential Salvage Chemotherapy and Lintuzumab-Ac225 in Relapsed/Refractory AML Results in Deep Responses and Prolonged Survival in Adverse Risk Acute Myeloid Leukemia (AML) and in AML Patients that Received Prior Venetoclax Therapy

AML-530 Sequential Salvage Chemotherapy and Lintuzumab-Ac225 in Relapsed/Refractory AML Results in Deep Responses and Prolonged Survival in Adverse Risk Acute Myeloid Leukemia (AML) and in AML Patients that Received Prior Venetoclax Therapy

AML-530 Sequential Salvage Chemotherapy and Lintuzumab-Ac225 in Relapsed/Refractory AML Results in Deep Responses and Prolonged Survival in Adverse Risk Acute Myeloid Leukemia (AML) and in AML Patients that Received Prior Venetoclax Therapy

Impact of Type of Induction Therapy on Outcomes in Older Adults with AML after Allogeneic Stem Cell Transplantation.

Although venetoclax-based lower-intensity regimens have greatly improved outcomes for older adults with acute myeloid leukemia (AML) who are unfit for intensive chemotherapy, the optimal induction for older patients with newly diagnosed AML who are suitable candidates for hematopoietic stem cell transplant (HSCT) is controversial. We retrospectively analyzed post-HSCT outcomes of 127 patients ≥60 years of age who received induction therapy at our institution with intensive chemotherapy (IC, n=44), lower-intensity therapy (LIT) without venetoclax (n=29) or LIT with venetoclax (n=54) and who underwent allogeneic HSCT in first remission. The 2-year relapse-free survival with LIT with venetoclax was 60%, versus 54% with IC and 41% with LIT without venetoclax, and 2-year overall survival for LIT with venetoclax was 72%, versus 58% with IC and 41% with LIT without venetoclax. The benefit to LIT with venetoclax induction was greatest in patients with adverse-risk AML (2-year OS 74%, 46%, and 29%, respectively). Induction with LIT, with or without venetoclax, was associated with the lowest rate of non-relapse mortality (NRM) (2-year NRM 17% versus 27% with IC; P=0.04). By multivariate analysis, type of induction therapy did not significantly impact any of the post-HSCT outcomes evaluated; hematopoietic cell transplantation-specific comorbidity index (HCT-CI) was the only factor that independently predicted for RFS and OS. LIT plus venetoclax followed by HSCT is feasible treatment strategy in older, fit, and HSCT-eligible patients with newly diagnosed AML and may be particularly beneficial in those with adverse-risk disease.

Effect of disease status prior to T-cell depleted allogeneic stem cell transplantation on relapse-free and overall survival in patients with adverse-risk acute myeloid leukemia (AML).

7049 Background: Patients (pts) with adverse risk AML experience poor long term disease control. Some of these pts can be rescued with allogeneic stem cell transplantation (SCT). Adverse risk was defined by high risk cytogenetic and molecular markers (2017 European Leukemia Network criteria) and by disease status prior to SCT. We investigated outcomes of pts receiving in vivo T-cell depleted allogeneic SCT (TCD-SCT) at our center. Methods: We retrospectively analyzed 200 adverse-risk AML pts who received TCD-SCT from 2002-19. Pts were categorized into groups: untreated first relapse at SCT, primary induction failure with active disease at SCT, resistant to first induction but achieving morphologic complete remission (CR) by SCT, and induction sensitive CR with high-risk disease by ELN criteria. Outcomes were evaluated by 1-year (yr) and 3-yr relapse-free survival (RFS), overall survival (OS), and non-relapse mortality (NRM), and compared with log-rank tests of significance. Results: Baseline pt characteristics included a median age of 54 years (IQR, 44-61) with 62 (31%) pts older than 60, and 81 (41%) with HCT-CI score 3 or greater. All pts underwent in vivo TCD with alemtuzumab or ATG; 153 (77%) received reduced-intensity conditioning; 142 (71%) had 8/8 or 7/8 matched donors. Fourteen (7%) pts developed grade III-IV acute graft versus host disease (GVHD), and 25 (13%) developed chronic GVHD. With a median follow up of 14.3 months, cumulative incidence of relapse was 59% and NRM was 27%. Outcomes are summarized in the table. There was a statistically significant difference between categorized groups by RFS (p<0.01) and OS (p<0.01). Conclusions: We conclude that among adverse-risk AML pts, those in CR at time of TCD-SCT have superior survival outcomes to those with active disease. For those in CR at TCD-SCT, prior resistance to frontline induction was associated with inferior survival, suggesting that AML biology, treatment sensitivity, and remission status are important factors for TCD-SCT outcomes. The inferior outcomes observed for those with primary refractory disease suggest that while TCD-SCT can be effective with acceptable NRM, more work is needed to identify which pts can benefit from future transplant strategies. Better post-SCT therapy is needed to prevent relapses. [Table: see text]

Treatment phase stratified outcomes of core binding factor acute myeloid leukemia.

e19055 Background: Mutations in core binding factor (CBF) are associated with a favorable prognosis in acute myeloid leukemia (AML). However, between 30-40% of patients with CBF-AML relapse, and relative outcomes with each subsequent line of therapy remain unclear. Additionally, the overall survival of CBF-AML compared to other favorable risk molecular aberrations — such as NPM1mut and CEBPA — is unknown in light of the addition of monoallelic CEBPA in ELN 2022. Therefore, the purpose of this study was to clarify the outcomes of CBF-AML relative to other favorable risk aberrations and to determine the relative overall survival associated with each subsequent relapse. Methods: We retrospectively analyzed 46 consecutive patients with CBF-AML treated from January 2013 to January 2022 at VCU Massey Cancer Center that underwent intensive chemotherapy (IC) with or without gemtuzumab ozogamicin. During the same study period, we analyzed a comparison cohort of 272 consecutive patients: 103 ELN 2017 intermediate-risk patients, 111 adverse-risk patients, eight patients with mono- or biallelic mutations in CEBPA, and 50 with ELN 2017 favorable-risk NPM1mut. All patients were treated with front-line IC. We analyzed survival by the Kaplan-Meier method and compared groups with the log-rank test. Results: We analyzed 46 patients with CBF-AML across 136 treatment phases. Patients with CBF-AML had superior overall survival compared to patients with NPM1mut (median overall survival not reached at a median follow-up time of 5.0 years versus 21.0 m., p = 0.028). There were no differences in survival between CBF-AML and AML with monoallelic or biallelic mutations in CEBPA at a median follow-up time of 3.7 years (not reached, p = 0.976). Expectedly, the overall survival for CBF-AML was superior to ELN 2017 intermediate (30.1 m., p = 0.011) and adverse (10.9 m., p < 0.0001) risk disease. Next, we analyzed survival trends in the relapsed or refractory setting for CBF-AML by lines of therapy, using ELN 2017 intermediate and adverse risk cohorts as a comparison. During the first relapse, CBF-AML was associated with a significantly superior overall survival compared to the adverse cohort (19.1 m. versus 10.0 m., p = 0.024) but not the intermediate cohort (14.5 m., p = 0.734). The absence of KITmut was not associated with improved survival compared to the ELN 2017 intermediate category at the first relapse ( p = 0.610). At the second relapse, the survival disparity disappeared between the CBF-AML and adverse risk groups (7.7 m. vs 4.0 m., p = 0.964). Conclusions: CBF-AML was associated with similar survival to mono- or biallelic mutations in CEBPA, and significantly prolonged overall survival compared to NPM1mut. Relative to a matched cohort of adverse-risk AML at the time of the first relapse, outcomes of relapsed CBF-AML remain favorable. The relative overall survival benefit of CBF-AML disappeared at the time of the second relapse.

Real-world outcomes of frontline venetoclax-based therapy in older adults with acute myeloid leukemia: an analysis utilizing EHR data

Venetoclax (VEN) in combination with hypomethylating agents (HMA) or low-dose cytarabine has become the standard of care for patients with acute myeloid leukemia (AML) who are ineligible to receive intensive induction chemotherapy. Clinical trials are performed in a controlled setting that can be difficult to emulate in the real world. We sought to investigate outcomes of patients treated with VEN-based therapy in the real world. Patients with an age of ≥65 years who received frontline VEN-based therapy were identified using the COTA database (n = 112). The majority of patients (91%) were treated in the community setting and had adverse-risk AML (63%). The real-world overall response rate (rwORR) was 55% with a median real-world overall survival (rwOS) of 13 months after VEN/HMA. The rwORR was lower and median rwOS was shorter than those reported in the VIALE-A trial, underscoring the importance of studying novel therapies using real-world data.

Comparison and validation of the 2022 European LeukemiaNet guidelines in acute myeloid leukemia.

Risk stratification in acute myeloid leukemia (AML) remains principle in survival prognostication and treatment selection. The 2022 European LeukemiaNet (ELN) recommendations were recently published, with notable updates to risk group assignment. The complexity of risk stratification and comparative outcomes between the 2022 and 2017 ELN guidelines remains unknown. This comparative analysis evaluated outcomes between the 2017 and 2022 ELN criteria in patients enrolled within the multicenter Beat AML cohort. Five hundred thirteen patients were included. Most patients had 1 or 2 ELN risk-defining abnormalities. In patients with ≥2 ELN risk-defining mutations, 44% (n= 132) had mutations spanning multiple ELN risk categories. Compared with ELN 2017 criteria, the updated ELN 2022 guidelines changed the assigned risk group in 15% of patients, including 10%, 26%, and 6% of patients categorized as being at ELN 2017 favorable-, intermediate-, and adverse-risk, respectively. The median overall survival across ELN 2022 favorable-, intermediate-, and adverse-risk groups was not reached, 16.8, and 9.7 months, respectively. The ELN 2022 guidelines more accurately stratified survival between patients with intermediate- or adverse-risk AML treated with induction chemotherapy compared with ELN 2017 guidelines. The updated ELN 2022 guidelines better stratify survival between patients with intermediate- or adverse-risk AML treated with induction chemotherapy. The increased complexity of risk stratification with inclusion of additional cytogenetic and molecular aberrations necessitates clinical workflows simplifying risk stratification.

Multiparameter Flow Cytometry-Based Residual Disease Analysis Identifies Intermediate-Risk AML Patients Who May Benefit from Allogeneic Hematopoietic Stem Cell Transplantation

Background Allogeneic hematopoietic stem cell transplantation (alloSCT) is a curative therapeutic modality in acute myeloid leukemia (AML). While numerous studies have confirmed the benefit of alloSCT - improved overall survival (OS) and reduced cumulative incidence of relapse (CIR) - restricted mainly to the intermediate and high-risk groups, indications for alloSCT are becoming more restricted over time. Residual disease (RD) monitoring has been proven to be highly predictive of long-term AML outcomes and is now used commonly to guide ongoing therapy decisions. RD-based guidelines in AML propose the use of multiparameter flow cytometry-based RD (FRD) analyses in patients whose disease cannot be followed by molecular means (e.g. CBF AML, APL, NPM1-mutated AML). Methods We performed a retrospective review to evaluate the potential therapeutic benefit of alloSCT in AML patients who achieved first complete remission (CR1) and to further define this benefit based on the FRD status at remission. We performed a time-dependent analysis using the covariate of time-to-alloSCT as the primary endpoint of the study. The Mantel-Byar method was applied to compare time to event between the alloSCT and non-transplant groups, addressing time bias concerns that occur with alloSCT studies, according to the FRD status at the time of remission. Results The FRD assay has been part of our standard of care since 2015 with a sensitivity of 0.1%. The cohort analyzed included 435 patients treated between 2015 and 2018, of which 336 patients had FRD assessment at CR1. The patients were risk classified using the European Leukemia Network (ELN) 2017 classification which integrates cytogenetic and mutational analyses. The proportion of patients with positive FRD (RDpos) at the post-induction time-point was 35.1% (n=118). Negative residual disease (RDneg) status after induction occurred more frequently in de novo, favorable risk, and NPM1-mutated AMLs, than in the adverse risk or secondary AML groups. Overall, across all ELN 2017 groups, the impact of alloSCT was neutral for both OS and relapse free survival (RFS). A potential impact of alloSCT could be discerned, however, when patients were grouped by FRD status at CR assessment. Overall, in the RDpos group, alloSCT improved OS and RFS, while not benefitting the RDneg group. The impact of alloSCT was defined further by considering ELN 2017 risk groups, with an OS/RFS benefit observed in adverse risk patients (n=186; HR for OS 0.55 [0.31-0.99]; p=0.05); HR for RFS 0.57 [0.31-1.05], p=0.07), while an increased risk of death or of an RFS event was seen in favorable risk patients (n=151; HR for OS 4.3 [1.65-11.2], p=0.003; HR for RFS 2.29 [1.07-4.93], p=0.03). In the ELN 2017 intermediate risk patients (n=98), a survival benefit of alloSCT was not seen (HR for OS 1.05 [0.45-2.46], p=0.92; HR for RFS 0.86 [0.42-1.78], p=0.69), although alloSCT was associated with a lower CIR (HR 0.43 [0.20-0.90], p=0.03). However, when only RDpos patients were considered (n=27), trends towards benefit from alloSCT in OS (HR 0.52 [0.11-2.52], p=0.42), RFS (HR 0.38 [0.09-1.62], p=0.19), and CIR (HR 0.44 [0.07-2.72], p=0.38) were observed. In RDneg patients (n=53), alloSCT was associated only with a lower CIR (HR 0.18 [0.05-0.66], p=0.01). We then re-analyzed the data using the older UK-MRC risk classification of AML based exclusively on cytogenetics at diagnosis. This approach increased the patients in the intermediate group from 98 (ELN 2017) to 298 (UK-MRC). When using UK-MRC, an RFS benefit from alloSCT was observed for intermediate risk RDpos patients (n=211; HR 0.44 [0.20-0.96], p=0.04). Trends for benefit in OS (HR 0.45 [0.19-1.03], p=0.06) and CIR (HR 0.45 [0.20-1.04], p=0.06) were observed as well. In RDneg patients, however, an RFS/CIR benefit of alloSCT was not observed, while inferior OS was seen in the alloSCT group from increased non-relapse mortality. Conclusion Our data underscore the established benefit of alloSCT in adverse risk AML and suggest a potential benefit of this treatment modality in RDpos intermediate risk patients, thus confirming the utility of ongoing RD assessment in AML. Our results also indicate that ongoing sophistication in AML risk assignment, based on mutational profile at diagnosis, influences the potential benefit of alloSCT. Further studies are needed to better define the subgroup of RDpos intermediate risk patients who may benefit from alloSCT. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Venetoclax Plus Decitabine for Young Adults with Newly Diagnosed ELN Adverse-Risk Acute Myeloid Leukemia: Updated Results of a Phase 2 Trial

Background: The young adults with newly diagnosed (ND) ELN adverse-risk acute myeloid leukemia (AML) fit for intensive chemotherapy (IC) have low complete remission (CR) rate and dismal outcomes compared with AML in favorable- and intermediate-risk categories. Venetoclax (VEN) combination with hypomethylating agents is a new standard of care for older and unfit AML patients (pts) and has been demonstrated to improve composite complete remission and overall survival (OS). We previously reported that VEN plus decitabine (DEC) as frontline treatment for young pts with ND ELN adverse-risk AML and demonstrated promising efficacy and safety at median follow-up of 2.7months in a phase 2 trial (Chen et al, ASH 2021). Here we present an updated analysis of efficacy and safety results in the ongoing study. Methods: This multicenter, single-arm, phase 2 trial (NCT04752527) enrolled young pts (aged between 18 and 59) with ND AML, who met the adverse risk group according to 2017 ELN risk stratification screened by fast next-generation sequencing (NGS), multiplex RT-PCR and fluorescence in situ hybridization (FISH) within 72 hours, and were eligible for standard induction chemotherapy. The study design was previously reported (Chen et al, ASH 2021). The primary outcome was composite complete remission (CRc: CR plus CR with incomplete blood count recovery [CRi] and morphologic leukemia free state [MLFS]). Secondary outcomes were OS, event-free survival (EFS) and safety. The data cut-off date was July 31, 2022. Results: Between February 12, 2021 and July 31, 2022, 286 patients aged between 18 and 59 with ND AML underwent screening. 78 pts were classified as ELN adverse-risk category by fast NGS (within 72 hours) together with multiplex RT-PCR and FISH and 42 pts were enrolled, comprising 26 males and 16 females. Median age was 39 years (range, 19-58) (Table 1). As of the cut-off date, 40 pts completed the first cycle of VEN+DEC and 37 pts completed two courses. In cycle 1, 31 (77.5% [95% CI, 61-89]) pts achieved CRc, 8 (20% [95% CI, 10-36]) pts had partial remission and 1 (2.5% [95% CI, 0-15]) had no response. 24 (77.4% [95% CI, 58-90]) of 31 pts achieving CRc had measurable residual disease (MRD) negativity assessed by multiparameter flow cytometry (MFC) with a sensitivity of 10-3-10-4(0.1%-0.01%). Pts with RUNX1 and FLT3-ITD mutations had higher CRc rates of 83.3% and 80%, respectively. Pts harboring TP53 and ASXL1 mutations achieved encouraging CRc rates of 62.5% and 75%, respectively. The CRc rates in pts with 11q23/KMT2A rearrangements and complex karyotype were 66.7% and 88.9%, respectively. The CRc and MRD negativity were achieved in 91.9% (34/37, 95% CI, 77-98) and 82.3% (28/34, 95% CI, 65-93) of the pts after the second course of treatment. 31 (73.8%) of 42 pts received allogeneic hematopoietic stem cell transplantation (HSCT), among them 26 patients achieved complete remission before HSCT, 3 received HSCT after morphologic relapse and 2 with salvaged HSCT. At median follow-up of 10.2 months (range, 0.8-17), the median OS and EFS were not reached (Figure1a, b). Estimated 12-months OS was 92.9% (95% CI, 79-98) and EFS was 71.4% (95% CI, 55-84). Among enrolled pts achieving CRc in cycle 1, median time to blood cell count recovery for absolute neutrophil count (ANC) ≥1000 cells per μL was 30 days (range, 16-NR), and for platelet count ≥50 000 platelets per μL was 20 days (range, 0-NR). Among 40 pts evaluable for safety analysis, the most common non-hematological adverse events were infections with grade 3 or worse neutropenia in 18 (45%) pts and febrile neutropenia in 11 (27.5%) pts. Notable serious adverse events were pneumonia in 5 (12.5%) pts and sepsis in 1 (2.5%). Mortality rates of 30-day and 60-day were 0%. Conclusions: VEN plus DEC was an effective, lower-intensity regimen that was well tolerated for young adults with ND ELN adverse-risk AML, producing high rates of CR and encouraging EFS and OS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Disruption of Intracellular Metal Homeostasis As a Vulnerability in SF3B1 Mutated AML

Acute Myeloid Leukemia (AML) is a heterogeneous disease in which outcome is highly dependent on cytogenetics and mutational profile. Adverse risk AML, recently defined and updated in the 2022 European LeukemiaNet (ELN) genetic risk classification, is associated with a poor overall survival. To identify novel therapeutic approaches for AML, we screened a library of 10,000 compounds across 56 genetically diverse primary AML specimens. We then looked for active compounds with increased activity towards adverse risk AML samples and with low cytotoxicity to normal hematopoietic cells. Among the hits identified, we were able to validate that S767 molecule is preferentially active on adverse risk AML samples. Additionally, we found a strong association between SF3B1 mutations and sensitivity to S767. To gain insights into S767 mechanism of action, we performed a CRISPR/Cas9 genome-wide functional screen, and identified multiples genes involved in mitochondrial processes both in synthetic rescue and synthetic lethal genes. In particular, knock-down of enzymes involved in heme biogenesis and iron-sulfur cluster biosynthesis appear to interfere with S767 cytotoxic activity. Given the central role of iron in these two synthetic pathways, and the structure of S767, we hypothesized that our molecule binds and disrupts intracellular iron homeostasis. Using UV-spectrometry analysis, we determined that S767 has metal affinity and binds to Fe2+, but also Cu2+ and Zn2+. We then quantified intracellular metal concentrations by ICP-MS (inductively coupled plasma mass spectrometry) and found that S767 exposure significantly decreases intracellular iron concentrations while increasing that of copper. Since metals are critical cellular cofactors involved in multiple enzymatic reactions, disruption of intracellular metal homeostasis can affect many processes. Mitochondrial respiratory chain is particularly sensitive to these perturbations as copper and iron-sulfur clusters are present in complexes I-IV of the electron transport chain and are essential for mitochondrial complexes function. By measuring oxygen consumption rate in leukemic cells exposed to S767, we found that the molecule indeed disrupts mitochondrial respiration. SF3B1 is a splicing factor recurrently mutated in myeloid malignancies including myelodysplastic syndromes (MDS) and AML. Heterozygous mutations typically affect SF3B1 splicing functions and induces consequently mis-splicing of target mRNAs, including the ABCB7 iron-sulfur cluster transporter. Analysis of the Leucegene transcriptomic data of primary AML specimens revealed mis-splicing and downregulation of ABCB7 in SF3B1 mutated patients. Strikingly, ABCB7 was one of the top synthetic lethal gene identified by chemogenomic CRISPR/Cas9 screen following exposure to S767 molecule. Given that ABCB7 exports iron-sulfur clusters out of the mitochondria to be assembled by cytosolic proteins and plays a role in iron homeostasis, we hypothesized that its aberrant expression in SF3B1 mutated AML participates to the high sensitivity of these leukemias to S767. We thus identified a novel molecule with selective activity in AML. Our data suggest that S767 is not a protein-targeting molecule but rather acts through the disruption of intracellular metal homeostasis, and ultimately affects mitochondrial respiration. Its mechanism of action highlighted a vulnerability in SF3B1 mutated AML which present a defect in ABCB7 expression. Importantly, SF3B1 mutations are now recognized in the 2022 ELN risk classification as an adverse prognostic marker if they are associated with intermediate or adverse risk AML, giving a unique opportunity to develop novel therapeutic approaches for this subgroup of patients with poor clinical outcome. In addition, SF3B1 mutations are found in 25% of MDS cases, which are associated with ring sideroblasts and accumulation of mitochondrial iron, and that could also benefit from such therapeutic approach.

ELN Risk Stratification Is Not Predictive of Outcomes for Treatment-Naïve Patients with Acute Myeloid Leukemia Treated with Venetoclax and Azacitidine

Background: Venetoclax (Ven), a highly selective oral BCL-2 inhibitor, in combination with hypomethylating agents (HMAs) such as azacitidine (Aza), is approved for the treatment of patients (pts) with newly diagnosed acute myeloid leukemia (AML) who are ineligible for intensive chemotherapy (IC). An open-label, non-randomized phase 1b trial (NCT02203773) and the confirmatory VIALE-A phase 3 randomized trial (NCT02993523), both enrolling pts with intermediate and poor risk cytogenetics per NCCN Guidelines, demonstrated that the combination of Ven+Aza led to high rates of complete remission and longer overall survival (OS) than Aza alone (median OS of 14.7 months [mo] vs 9.6 mo), with similar safety profiles. In this exploratory post hoc analysis of the pooled treatment-naïve, IC ineligible pts treated with Ven+Aza in the phase 1b and phase 3 trials, patients were stratified according to the 2017 ELN risk classification system (which is based on data from patients receiving IC and utilizes cytogenetic and molecular determinants commonly associated with AML). We report clinical outcomes for these patients per ELN 2017 risk group, which will also be updated using the newly published ELN 2022 criteria. Methods: For the phase 1b trial, our analysis includes pts who were enrolled to evaluate safety and efficacy of Ven+Aza at a daily dose of 400 mg for VEN. For the phase 3 trial, pts were randomly assigned in a 2:1 ratio to the Ven+Aza group or placebo (Pbo)+Aza group. All pts received a standard dose of Aza (75 mg/m2 SC or IV on days 1-7 every 28-day cycle). Ven (400 mg) or Pbo was administered orally, once daily, in 28-day cycles. Pts with favorable risk cytogenetics such as t(8;21), inv(16), t(16;16) or t(15;17) as per the NCCN Guidelines Version 2 were excluded from the study. The pooled group of pts from the two trials having both site-reported cytogenetic data and bone marrow aspirate with centrally determined molecular data allowing for ELN genetic risk classification were included in this analysis. Pts were retrospectively classified per the ELN 2017 criteria as favorable-, intermediate-, or adverse-risk AML. Results: Inclusion of central molecular data allowed the reclassification of patients according to ELN 2017 recommendations (Figure 1). 63 of the 67 Ven 400mg + Aza pts enrolled in the phase 1b trial, and 329 of the 431 total pts enrolled in the VIALE-A trial were evaluable for inclusion in this analysis (279/353 in the pooled Ven+Aza group and 113/145 in the Pbo+Aza control group from the phase 3 study). In the Ven+Aza and Pbo+Aza groups, 46 (16.5%) and 20 (17.7%) pts had favorable-risk AML, 65 (23.3%) and 19 (16.8%) had intermediate-risk AML, and 168 (60.2%) and 74 (65.5%) had adverse-risk AML, respectively, by ELN. In favorable-risk AML pts, CR+CRi was achieved in 69.6% with VEN+AZA vs in 20% with Pbo+Aza; for intermediate-risk AML, CR+CRi was achieved in 75.4% vs 42.1%; for adverse-risk AML, CR+CRi was achieved in 61.3% vs 25.7%. Median OS was longer with Ven+Aza in all three risk categories when compared to Pbo+Aza: 21.09 vs. 12.96 mo, HR = 0.45 [95% CI: 0.24, 0.83] in the favorable-risk group; 23.26 vs. 13.14 mo, HR = 0.62 [95% CI: 0.35, 1.08] in the intermediate-risk group; 11.53 vs. 7.43 mo, HR = 0.59 [95% CI: 0.43, 0.82] in the adverse-risk group. The median OS was similar for favorable and intermediate risk groups who received Ven+Aza (21.09 mo and 23.26 mo, respectively; Figure 2). While the median OS of the Ven+Aza adverse risk group was lower (11.53 mo), two subgroups with distinct outcomes are apparent: adverse risk pts with a TP53 mutation (36.3% [61/168]) and adverse risk pts with a RUNX1 mutation (40.5% [68/168]) (one pt had both TP53 and RUNX1). The median OS for adverse risk pts with a RUNX1 mutation and TP53 WT was 22.9 mo while the median OS for adverse risk pts with a TP53 mutation and RUNX1 WT was 5.42 mo. Conclusions: ELN 2017 risk groups, based on younger patients who received IC regimens, are not prognostic in patients receiving Ven+Aza. This exploratory analysis suggests little OS distinction between favorable and intermediate risk groups. Furthermore, adverse risk ELN groups can be further refined to determine mutationally-defined cohorts with more favorable outcomes. A modified risk stratification system is needed for pts receiving newer therapies, such as Ven+Aza, that uses determinants that are prognostic for pts treated in the context of these regimens with distinct mechanisms of actions from IC. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Conditioning Regimen Intensity and Donor Choice Do Not Impact Outcomes of Patients (pts) with Acute Myeloid Leukemia (AML) after Allogeneic Hematopoietic Cell Transplantation (Allo-HCT) in First Complete Remission (CR1): An EBMT Analysis

Allo-HCT is a curative treatment for fit pts with intermediate and adverse risk AML who achieve CR1. The presence of minimal residual disease (MRD) before allo-HCT has been shown to increase risk of relapse and decrease survival. Here, we describe outcomes of pts with AML who received allo-HCT in CR1 and the impact of MRD before allo-HCT on outcomes. We identified 1032 pts with AML who received allo-HCT in CR1 between 2015 and 2020 from the EBMT registry. The median age was 53.6 (range, 18.1-82.5) years and 526 (51%) were male. Most (94%) pts had de novo AML. FLT3-ITD and NPM1 mutations were detected in 46% and 44% of pts, respectively and high-risk cytogenetics were present in 20%. >1 course of induction therapy was required by 18% of pts to achieve CR1 and 39% were MRD positive at time of allo-HCT. The median time from diagnosis to allo-HCT was 4.9 months. Of pts with FTL3-wild type (FLT3-wt) disease, 33% were MRD negative and 22% were MRD positive at time of allo-HCT. In pts with FTL3-ITD mutation, 29% were MRD negative and 17% were MRD positive at time of allo-HCT. Donor type was matched sibling donor (MSD) in 29% of pts (n=297), matched unrelated donor (MUD) in 47% (n=481), mismatched unrelated donor (MMUD 9/10) in 8% (n=88), or haploidentical donor (haplo) in 16% (n=166). HCT-specific comorbidity index (HCT-CI) was >3 in 22% of pts (n=190). Myeloablative conditioning (MAC) was administered to 45% of pts (n=470), while reduced intensity conditioning (RIC) was used in 55% (n=562). The most common conditioning regimen was fludarabine/busulfan in MSD (n=148, 50%), MUD (n=272, 57%) and MMUD (n=38, 43%) recipients, while thiotepa/fludarabine/busulfan was the most used in haplo-HCT (n=99, 60%). Total body irradiation (TBI) was given to only 8% of pts (n=84), mainly in haplo-HCT (n=29). Most (n=1002, 98%) pts received calcineurin inhibitors (CNI), tacrolimus or cyclosporine A, for graft-versus-host disease (GVHD) prophylaxis in addition to mycophenolate mofetil (43%) or methotrexate (38%). Post-transplant cyclophosphamide was used in 18% (n=191) of pts, with 71% (n=136) having received haplo-HCT, and anti-thymocyte globulin was given to 67% (n=689). The median follow-up was 24 months. At day 60, the cumulative incidence of neutrophil engraftment was 99%. The cumulative incidence of grade III-IV acute GVHD (aGVHD) was 9% at day 180. At 2 years, the cumulative incidence of extensive chronic GVHD (cGVHD) was 17%. At 2 years, relapse incidence (RI), NRM, overall survival (OS), leukemia-free survival (LFS), and GVHD-free, relapse-free survival (GRFS) were 26%, 13%, 69%, 61%, and 48%, respectively. The main cause of death was primary disease in 55% of pts (n=157). Other causes of NRM were infections in 16% (n=45), and GVHD in 17% (n=47). In the multivariate analysis, compared to MSD, the use of MUD increased NRM (hazard ratio (HR) 1.86, p=0.02), GRFS (HR 1.28, p=0.039), aGVHD (HR 2.17, p<0.0001), and cGVHD (HR 1.36, p=0.044). The use of MMUD was associated with worse OS (HR 1.6, p=0.042) and higher risk of aGVHD (HR 2.11, p=0.003). Haplo-HCT was associated with higher incidence of aGVHD (HR 1.69, p=0.021) but lower risk of cGHVD (HR 0.63, p=0.033). Older age, lower performance status (PS), requiring >1 induction to achieve CR1, and FLT3-MRD positivity before allo-HCT were associated with worse LFS. Factors associated with lower OS were MMUD 9/10, older age, poor PS, >1 induction to achieve CR1, adverse cytogenetics, and FLT3-MRD positivity before transplant. In vivo TCD was associated with improved GRFS and lower risk of acute and cGVHD without increase of relapse. The use of RIC compared with MAC did not affect relapse, NRM or any other outcome. In conclusion, in pts with AML transplanted in CR1, those requiring >1 induction or with persistent FLT3-MRD positivity at time of allo-HCT had lower OS. Strategies to improve induction therapy, possibly through the addition of targeted agents, aiming to improve CR rates and deepening responses could potentially improve OS after allo-HCT. The use of RIC was associated with similar outcomes compared to MAC. This finding is particularly important for older pts or those with high HCT-CI scores unlikely to tolerate MAC. Survival after MSD allo-HCT is comparable to MUD and haplo, a finding that is in accordance with previous results for haplo and MUD as valid alternative donors in the absence of MSD. The use of MMUD was associated with lower OS compared to MSD and should be used as a last resort donor in this setting.

Sequential Therapy Vs. Salvage Chemotherapy for Patients with AML Refractory to First Induction Regimen- a Bi-Institutional Retrospective Cohort Analysis

Background: Induction-refractory acute myeloid leukemia (AML) occurs in approximately 30% of AML patients and is mostly associated with inferior outcome. A sequential approach offers shorter time to allogeneic hematopoietic cell transplantation (HCT), reduces salvage-associated toxicities while providing significant anti-leukemic activity. We hypothesized that early intervention with a sequential approach based on the original FLAMSA regimen salvage these patients more effectively as compared with a standard salvage therapy. Methods: We retrospectively compared results between 2 tertiary centers in Israel that apply different therapeutic modalities for first-induction failure: The first (TASMC -"cases" group), employs a transplant-based sequential approach for patients with first-induction-refractory AML, while the second center (RMC - "controls" group), applies mostly conventional salvage regimens. All consecutive patients ≥18 years who were treated in both centers between 2013 and 2021 and given either high-intensity induction chemotherapy or low-intensity venetoclax (VEN)-based regimens were included. Refractory to first induction was defined as either blasts >10% on day 30 marrow after 7+3 regimen, or after 2-3 cycles of a VEN-based regimen. We compared baseline characteristics between the 2 groups and used time-to-event analyses to calculate non-relapse mortality (NRM) and overall survival (OS) with day of allocation (either sequential therapy or non-sequential approach) defined as day 0. Controls who underwent HCT were not censored at transplant. Cox regression analysis was used to identify predictors for survival. This trial was approved by both Institutional Ethic Committees. Results: Between 01/2013 and 12/2021 we identified 91 patients that fulfilled the eligibility criteria (cases, n=55; controls, n=36). Characteristics of cases and controls were similar, except for higher % of patients with metabolic syndrome in the control group, Table. Mean days from diagnosis to HCT in the cases group was 69±25 with longer mean time in patients who were given VEN-based compared to high-intensity induction chemotherapy (94±23 vs. 62±21 days, respectively, p<.001). All patients advanced to transplantation. Median days to neutrophils and platelets engraftment were 10 (range, 7-16) and 16 (range, 9-35), respectively. Incidences of grade 2-4 and 3-4 acute GVHD were 55% (95%CI 47%-63%) and 15% (95%CI 47%-63%), respectively, and incidences of overall and moderate-severe chronic GVHD at 3 years were 64% (95%CI 44%-84%) and 37% (95%CI 25%-49%), respectively. In the controls group, patients were given high-dose cytarabine-based salvage regimens (n=21, 58%), novel targeted therapies (n=5, 14%), HCT (n=4, 11%), VEN-based regimen (n=3, 8%), and palliation (n=2, 6%). Of those patients who were given chemotherapy/other targeted therapies (n=30), 11 (37%) responded and of them, 9 (82%) proceeded to HCT. Five additional patients underwent HCT in active disease. Thus, overall, 18 patients (50%) in the controls group underwent HCT. Percentage of complete remission was higher in the cases group (measured at 1 month after HCT) vs. controls group (measured at any time after allocation) (87% vs. 39%, p<.001). 1-year NRM was higher in the cases group compared to controls group, however this did not reach statistical significance (37% (95%CI 32%-42%) vs. 20% (95%CI 14%-26%), p=0.126). Median OS was similar in patients given intensive induction chemotherapy between the cases and controls groups (8.3 (95%CI 2.74-14.4) months vs. 7.1 (95%CI 2.15-11.4) months, p=0.66), although in patients with adverse ELN risk, OS within the intensive group was better (8.2 (95%5.1-11/7) months vs. 2.4 (95%CI 0-4.8) months, p=0.027). Importantly, OS was better in cases refractory to VEN-based induction regimens compared to controls (22 (95%CI n/a) months vs. 7.8 (95%CI 0-15.9) months, p<.001). Cox regression analysis identified adverse ELN risk group and lower performance status as predictors for mortality (HR=2.5, p=0.02 and p=0.008, respectively). Conclusions: sequential therapy in refractory to induction therapy AML may benefit patients with poor salvage options such as those with adverse risk AML and those with refractory disease to VEN-based induction regimens. Better salvage regimens and improved transplantation techniques may improve both strategies to enhance patients’ outcomes. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Healthcare Disparities Among African Americans Are Pervasive in the Treatment of AML

Background: There has been tremendous focus on reducing the impact of healthcare disparities in the treatment of cancer. We have previously demonstrated that healthcare disparities exist in patients undergoing treatment for acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). The purpose of this study was to present outcomes for African American and White patients stratified by disease risk (ELN 2017 cytogenetic and molecular classification) to illustrate healthcare disparities with respect to the biological characteristics of disease. Patients & Methods: We analyzed 214 patients that underwent treatment for AML from January 2016 to December 2021 at VCU Massey Cancer Center. Patients with intermediate and adverse-risk AML were analyzed, whereas those with favorable risk were excluded due to low sample size precluding meaningful statistical analysis. Within both categories, patients were sub-stratified by self-reported race. Baseline demographics were obtained, including age, performance status, and medical insurance type, as well as disease characteristics, including molecular profiling, cytogenetic risk, doses of induction regimens, response, and survival. 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 with censoring at the date of last contact. Results: The intermediate-risk category consisted of 92 patients, 31 (33.7%) African American and 61 (66.3%) White. The median ages for African Americans and Whites were 59 and 63 years, respectively, and the median ECOG was 1 while the median Charlson Comorbidity Index (CCI) score was 4 in both cohorts. A total of 67.7% of African Americans had private insurance or Medicare compared to 93.3% of Whites (p = 0.004).At the time of the post-induction marrow, the composite response rate (CRR; CR + CRi) was 23.1% and 24.4% for African Americans and Whites, respectively. The median OS was 15.7 months for African Americans and 25.8 months for Whites (p = 0.274). Rates of death within 30 and 60 days of induction were increased by 12.9% overall in African Americans but did not reach statistical significance (p = 0.406; p = 0.211). Whites were significantly more like to receive SCT than African Americans (34.4% versus 19.4%, p = 0.002). The adverse category consisted of 122 patients, 34 (27.9%) African Americans and 88 (72.1%) Whites. The median ages of African Americans and Whites were 63 and 67 years, respectively, and the median ECOG and CCI scores were similar between cohorts at 1 and 5, respectively. Significantly fewer African Americans had private insurance or Medicare (73.5%) compared to 89.7% in the White cohort (p = 0.043). The CRR was 32.1% for African Americans and 27.9% for Whites and the median OS was 7.3 months versus 11.8 months for the respective cohorts (p = 0.397). The combined rates of death within 60 days of induction were 12.5% for African Americans and 16.1% for Whites. Progression to SCT numerically favored the White cohort at 24.1% compared to 20.6% in African Americans. Conclusions: African American and White patients with AML appear to have similar baseline disease characteristics and performance status, although self-identified White patients were significantly more likely to have private insurance or Medicare. Despite similar response rates among those with intermediate-risk AML, African Americans are numerically more likely to experience death within 60 days of induction compared to Whites, although these findings did not reach statistical significance. Whites are also significantly more likely to receive SCT for intermediate-risk disease. The median OS numerically favors Whites in both intermediate and adverse risk cohorts. These findings suggest that structural healthcare disparities, including access to insurance and SCT, are pervasive in the treatment of AML, resulting in African Americans experiencing increased rates of death and reduced survival. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal