ELN Risk Research Articles

Prognostic Impact of Monoallelic Versus Biallelic TP53 Alterations in Intensively-Treated Adults AML Patients: A Retrospective Study from the ALFA Group

Introduction:TP53 is a key tumor suppressor gene involved in apoptotic pathways, metabolism functions, preservation of genomic balance and DNA repairs. TP53 locus is subject to mutations, deletions and copy-neural loss of heterozygosity. TP53 mutations are associated with a reduced overall survival and are assigned to the ELN 2017 adverse-risk group. Recent studies have suggested a worse prognostic impact of biallelic TP53 alterations compared to monoallelic TP53 mutations in myelodysplastic syndromes (Bernard et al, Nat. Medicine, 2020). Whether TP53 allelic state impairs the prognostic in intensively-treated acute myeloid leukemia (AML) patients and may refine the treatment strategy has not been addressed. Here, we analysed TP53 alterations in newly diagnosed AML patients (pts) from 3 prospective Acute Leukemia French Association (ALFA) trials. Methods: A total of 983 adult AML pts enrolled in ALFA-0701 (NCT00927498), ALFA-0702 (NCT00932412) and ALFA-1200 (NCT01966497) trials were retrospectively screened for TP53 alterations by high throughput sequencing and conventional cytogenetics. Pts displaying at least two TP53 mutations or one TP53 mutation associated with either TP53 locus deletion or TP53 locus copy-neutral loss of heterozygosity (CN-LOH) were assigned as biallelic TP53 alteration patients. TP53 locus CN-LOH were approximated based on variant allele frequencies and copy number analysis. Survival was analysed with multivariate Cox models stratified on the trial. Results: Eighty-three patients had TP53 mutations (8%; ALFA-0701: n=21, ALFA-0702: n=28; ALFA-1200: n=34), including 14 pts with monoallelic and 69 pts with biallelic TP53 alterations respectively. Median age of TP53 mutated patients was 62 years (IQR: 57-68). Leukocytes counts and bone marrow blast counts at diagnosis were lower in TP53 mutated patients (3.0 G/L vs. 8.7 G/L, p<0.0001; 40% vs. 58%, p=0.002, respectively). Median variant allele frequency of TP53 mutations was 43% (IQR: 21-69). As compared to TP53 wildtype AML, TP53 mutated pts more often harbored complex karyotype (n=69 (86%) vs n=51 (6%), p<0.0001) and monosomal karyotype (n=65 (81%) vs n=32 (4%), p<0.0001). The median number of additional mutations was 2 (IQR: 0-3). TP53 mutations were associated with mutations in signalling genes (NF1, NRAS, PTPN11, KRAS, FLT3, KIT and JAK2) in 33 pts (40%). Overall, 43 TP53 mutated AML patients (52%) achieved complete remission (CR)/complete remission without platelet recovery (CRp) after one or two courses of induction whereas 684 TP53-wt patients (76%) were in CR/CRp at that time (p<0.0001). TP53 mutations were associated with a significantly reduced OS and DFS in multivariate analysis including age and WBC count (2-year OS, 11% vs 56%, HR: 3.48, 95% CI: 2.71-4.47, p<0.0001; 2-year DFS, 12% vs 50%, HR: 2.97, 95% CI: 2.12-4.16, p<0.0001, respectively). Among TP53 mutated AML, biallelic TP53 alterations were associated with worse OS compared to monoallelic TP53 alterations (2-year OS, 4% vs 43%, HR: 4.13, 95% CI: 1.87-9.13, p=0.0004 in multivariate analysis accounting for age and WBC count). Interestingly, outcome of the 2017 ELN risk stratification intermediate group was not different to that of monoallelic TP53 pts (2-year OS, 43% for monoallelic TP53 pts vs 53%, HR: 1.07, 95% CI: 0.55-2.07, p=0.84). In pts with biallelic TP53 alterations, presence of signalling mutations was associated with a worse survival in a multivariate analysis accounting for age and WBC (HR: 1.82, 95% CI: 1.06-3.11, p=0.03). Conclusion: Allelic status refines the prognostic value of TP53 mutations in AML. While monoallelic TP53 alterations display similar outcome to that of the ELN 2017 intermediate risk group, biallelic TP53 alterations dramatically impair patient outcome. Patients with biallelic TP53 alterations may be good candidates for new first-line treatment strategies. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Data-Driven Molecular Hallmarks of Acute Myeloid Leukemia: Biological, Prognostic and Therapeutic Implications

The cancer hallmark concept defines the biological processes that contribute to cancer development and progression. While the hallmarks represent an important theoretical framework, they reflect generic properties of all cancer types and hence most hallmarks are not measurable nor applicable to guiding diagnosis or therapy. Here, we carried out deep multi-omic profiling (DNA panel sequencing, , transcriptome, DNA methylation and proteome) and functional testing of responses to 525 drugs in 118 primary acute myeloid leukemia (AML). In addition, 47 primary AML patients were used as an independent validation cohort, including measurements by single-cell assays. Using unsupervised multi-omic dimensionality reduction, we defined 11 independent axes of biological variability that we considered here to reflect the data-driven hallmarks (DDHM) of AML. We defined the molecular features that contributed most to each hallmark, hence forming an understanding of the biological nature and pathways of each DDHM We hypothesized that the 11 DDHMs define biologically and clinically important features of AML applicable to diagnostics, therapy and precision medicine. For example, each patient had a unique composition of the DDHMs that reflected the AML biology of that patient case. Each DDHM was associated with distinct AML biology, including NPM1 mutation, transcriptional deregulation, stem cell properties, cell cycle, stromal signals, HOX signaling, and stress response. The DDHMs captured both biology that is already well known in AML, but with multi-omic resolution, and highlighted also novel, previously poorly understood, properties of AML. Each DDHM included a ranked list of drugs that explained the biology reflected in the hallmarks. For instance, the DDHM2 that defined sensitivity to Bcl-2 (Venetoclax) and MEK inhibitors highlighted myeloid cell differentiation patterns. Moreover, DDHM8 was strongly associated with patient prognosis, a higher response to hypomethylating agents and complete remission,. Combining this prognostic DDHM8 with hallmark DDHM1 that explained the omics of the NPM1 mutation landscape, captured the ELN risk classification and other prognostic cell surface markers. This revealed that several previously independently defined biomarkers of prognosis converge in the multi-omic paradigms defined by our DDHMs. In summary, we have defined through multi-omics and functional analysis a set of eleven data-driven hallmarks of AML. These capture some of the most important known prognostic and therapeutic biomarkers in AML but also highlight opportunities for novel biomarker discovery and drug repurposing. This approach provides a new quantitative and measurable framework to understand the biological heterogeneity of AML and exploit it for diagnosis, prognosis and precision therapy.

Splicing Gene Mutations Do Not Affect Outcomes in Newly Diagnosed Patients with Acute Myeloid Leukemia

Background: Recent studies have shown that splicing factor (SF) gene mutations in AML implicate a negative prognostic significance associated with secondary AML and are now included as adverse in the 2022 ELN guidelines (Dohner et.al., Blood 2022). However, the contribution of these mutations to the prognosis of patients (pts) with AML, relative to their age, prior history of myeloid disorders, cytogenetics (CTG), concurrent mutations and frontline (FL) therapy requires further characterization. Methods: We retrospectively analyzed all pts with newly diagnosed (ND) AML treated at our center over the last 5 years (yrs) and compared outcomes for patients with and without SF mutations (Smut= SF3B1, SRSF2, U2AF1 and ZRSR2). FL therapy was classified as intensive (INT) and low intensity (L-I), with/without venetoclax (VEN). Relapse free survival (RFS) was calculated from the time of response to relapse or death and overall survival (OS) was calculated from the time of therapy initiation to death; both were censored at last follow up (F/U) Results: From January 2017 to April 2022, 994 ND pts with AML were reviewed; 266 (27%) had Smut in ≥ 1 of the SF genes while the rest were wild type (SWT). The most common Smut was SRSF2 (53%). Only 3% pts had >1 Smut (Table 1). The median age of Smut group was 72 yrs compared to 65 yrs in the SWT group, and significantly more pts in the former had secondary/therapy related AML (s/t AML) (51% vs 41%). The Smut group had less complex karyotype (CK), non CK adverse risk CTG and did not include any pts with core-binding factor (CBF) leukemias. Fewer pts in the Smut had a pathogenic TP53mut but had higher frequencies of RUNX1 and ASXL1 mutations. Overall, 71% Smut pts were classified as ELN 2017 adverse risk compared to 54% SWT pts (p<0.0001). 20% pts in the Smut group vs. 44% SWT pts received INT therapy (p<0.0001). Of the Smut pts who received L-I therapy, 62% received a hypomethylating agent (HMA) and 66% received a VEN- based combination, frequencies similar to the SWT group. At a median F/U of 26 months (mos), the median RFS and OS was 9.6 vs. 12.4 and 13.1 vs 13.3 mos for the Smut and SWT groups respectively. Given the significant age heterogeneity between the 2 groups we analyzed by young (<60 yrs) and older (≥60 yrs) pts with non-CBF AML and compared survival outcomes (Fig.1). Both Smut and SWT pts had similar RFS and OS in their respective age groups. In a small subgroup of older pts with de novo AML with CK treated with L-I regimens, the RFS and OS were especially dismal for those with Smut (RFS= 1.5 vs 5.7 mos, p=0.14 and OS= 2.6 vs 9.3 mos, p=0.003). For other subgroups (stratified based on ELN risk stratification, de novo or s/t AML, CK, TP53mut) outcomes of Smut and SWT were similar in both young and older pt groups treated with INT or L-I therapies. Smut pts who received VEN in the L-I arm had better RFS and OS, especially if they had denovo AML (RFS= 19 vs 5.5 mos and OS 25 vs 4 mos). On univariate (UV) analysis using age, CTG [adverse risk (AR) /intermediate risk (IR)], therapy arm (INT/L-I), Smut/SWT status and concurrent mutations (TP53, ASXL1, RAS, RUNX1, NPM1, FLT3-ITD) as covariates for overall response (OR= CR/CRi/MLFS): lower age, IR-CTG, TP53wt, RASwt ,FLT3mut, NPM1mut and use of INT therapy were favorable while all the factors other than FLT3mut , age and therapy arm remained significant on the multivariate (MV) model. Within the Smut cohort, the presence of SF3B1mut alone negatively affected the odds of OR (0.65, 95%CI=0.3-0.98) on UV but not on MV analysis. Cox regression analysis demonstrated adverse risk CTG, TP53mut and s/t AML had higher hazards of relapse, while the above factors along with the presence of RASmut increased the hazards of death. On stratifying by specific Smut, no individual mutation impacted OS. Cox regression analysis of the above covariates affecting RFS and OS in Smut pts who received L-I therapy showed VEN based combinations significantly reduced the hazards for relapse (0.5, 95% CI=0.3-0.8) and death (0.5, 95%CI=0.3-0.7). Overall, the presence of Smut did not affect response rates to therapy, RFS or OS in both young and older pts treated with L-I (majority VEN based) or intensive therapy. Conclusion: Smut are more common in elderly pts with AML and in s/t AML. Smut does not necessarily affect response rates and survival outcomes compared to SWT pts when controlled for these covariates, and with current therapeutic options including HMA + VEN based regimens. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Outcomes with Venetoclax Dose De-Escalation and Variable Cycle Intervals: A Real-World AML Survival Analysis

The treatment paradigm for acute myeloid leukemia (AML) includes regimens each specified for a target population. Unfit patients (pts) and those of older age are often limited in their treatments considering the toxicity profile associated with traditional induction regimens. Venetoclax (Ven), a potent BCL-2 inhibitor, is frequently administered for older adults who are deemed ineligible for more intensive chemotherapies. However, its clinical use remains a challenge due to its severe myelosuppressive effects. Despite the generally accepted clinical practice of delaying the next cycle or reducing the total Ven dosage per cycle, there is minimal data evaluating the effectiveness and resource needs under these circumstances. The objective of our analysis was to review the clinical course and identify survival rates in our pts undergoing treatment with Ven for AML. We retrospectively reviewed the clinical and molecular data of newly diagnosed and relapsing/refractory AML pts admitted to North Shore University Hospital for induction treatment with a hypomethylating agent (HMA) plus Ven from Nov 2019 to May 2022. Pts were categorized into subgroups based on their median number of days on Ven per cycle excluding induction cycle (≤ 14 days, 21 days, 28 days) as well as the median number of interval days between cycles (< 35 days or ≥ 35 days). Pts who did not complete 2 cycles were excluded from subgroup analyses. Median progression-free survival (mPFS) was defined as the time from Ven initiation to disease progression or death from any cause. PFS was analyzed with the Kaplan-Meier (KM) method and log rank testing. One-way analysis of variance and t-test was used to compare clinical interventions in each subgroup. A total of 53 pts underwent induction therapy with Ven + HMA: 79.2% frontline and 20.1% relapsed/refractory. The median age was 76 years-old (range 60-91). Of these 53 pts, 62.2% (n=33) were de novo, 24.5% (n=13) had AML with myelodysplastic related changes and 13.2% had therapy related AML (n=7). Utilizing the 2022 ELN risk categories (Dohner et al, Blood 2022), < 1% (n=3) were favorable risk while 33.9% (n=18) were intermediate risk and 60.3% (n=32) were adverse risk. All prognostic indicators were evenly dispersed among the subgroups. 33.9% of pts (n=18) died within their induction treatment admission. The mPFS was not reached in the subgroup of pts receiving ≤ 14 days of Ven/cycle while it was 10.8 months in pts receiving 21 days of Ven/cycle and 11.9 months for pts receiving 28 days of Ven/cycle. Although there was no significant difference between KM estimates when comparing number of days on Ven/cycle, there was a trend favoring ≤14 days of Ven/cycle. Patients who had ≥ 35 days interval between cycles had a mPFS of 11.9 months versus 8.5 months in pts who had < 35 days intervals. However, their KM estimates were not significantly different (p > 0.05). Pts included in subgroup analysis, received an average of 6.7 cycles and required an average of 2.6 hospital admissions while on a Ven regimen. Pts received an average of 4.8 pRBC units and 6.1 platelet units per cycle. Although there was a trend favoring reduction in Ven dosing (≤ 14 day subgroup), there was no significant difference in number of cycles, number of hospital admissions and transfusion requirements between each subgroup analysis (p > 0.05). This retrospective analysis demonstrates no difference in Ven outcomes with dose de-escalation and increased interval time between cycles in pts requiring such adjustments. The mPFS of each subgroup analyses was also similar compared to the mPFS (14.7 months) reported in the phase 3 clinical trial leading to its FDA approval (DiNardo et al, NEJM 2020; NCT02993523). Interestingly, the subgroup with a median dosing of ≤ 14 days of Ven/cycle had yet to reach a mPFS at 18 months. Also, the review of our patients’ clinical courses progress demonstrated a trend in decreased transfusion requirements and hospitalizations with lower Ven dosing although not statistically significant. Our analysis suggests that further larger retrospective and prospective enquiries are needed to evaluate the potential benefit of Ven dose de-escalation not only in terms of PFS and treatment related complications, but also for quality of life. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Utilization of Antifungal Prophylaxis and Treatment for Newly Diagnosed AML Patients Treated with Venetoclax Based Regimens in Routine Clinical Practice - a Prospective Analysis from the Revive Study

Background: Venetoclax (VEN)-based low intensity combinations are approved for the treatment of patients (pts) with acute myeloid leukemia (AML) ineligible for intensive chemotherapy. These combinations can be associated with prolonged cytopenias in particular neutropenia. Invasive fungal infections (IFIs) remain a major cause of morbidity and mortality in pts with AML but their incidence and impact on pts treated with VEN-based low intensity approach are uncertain. In the current study we assess real-world patterns of IFI's and antifungal treatments among newly-diagnosed (ND) AML patients treated with VEN-based low intensity therapies. Methods: The REVIVE study is a prospective, real-life, observational study that assesses patterns of pt. selection, efficacy and toxicity. ND pts with AML were enrolled at the time of VEN-based therapy initiation from 12 medical centers in Israel. Demographic, clinical and pt.-related baseline characteristics were documented. Antifungal medication selection for prophylaxis or therapy use and the incidence of IFIs were documented. The impact of prophylactic antifungal use on the incidence of IFIs and on leukemia related outcomes were assessed. Results: Between August 12, 2019, and April 15, 2022(data cut) ,189 AML pts were enrolled to receive VEN based therapy. Overall, the incidence of possible IFIs was relatively low and was observed in 17 patients (9% of patients). 23 pts (12.1%) were reported to have received prophylactic antifungal treatment, whereas 166 pts (87.8%) did not receive. Baseline characteristics of these two groups are shown in Table 1. Of note, pts. receiving antifungal prophylaxis were more likely to be treated as outpatients. A trend towards treatment in a tertiary center and unfavorable ELN risk was observed in pts. receiving antifungal prophylaxis vs. pts not receiving prophylaxis. All other characteristics seemed equally balanced between both groups. Antifungal prophylaxis included fluconazole (18 pts), voriconazole (6 pts) and posaconzole (1 pt). Of note, 2 patients received two different prophylactic treatments. The incidence of IFIs was not reduced in pts receiving antifungal prophylaxis. Of the 23 patients who received antifungal prophylaxis, 4 were considered to have an IFI (17.4%) compared with 13 in the non-prophylactic group (7.8%). Antifungal treatment in pts with an IFI included fluconazole (10pts) voriconazole (5 pts) posaconazole (1 pt) amphotericin B (1 pt) and anidulafungin (1pt). Of note, 3 patients received two different antifungal treatments. No difference in 30-day mortality was observed between the two groups:1 pt in the prophylaxis group died compared with 8 pts in the no-prophylaxis group (4.3% vs 4.8% respectively, p=0.92). Prophylactic antifungal treatment did not affect the rate of adverse events (AEs) leading to treatment discontinuation: 4 pts in the prophylaxis group and 31 pts in the no prophylaxis group discontinued VEN based treatment due to adverse events (17.4% vs 18.7%, p=0.88). The efficacy of VEN based treatment for AML was similar between pts who received or did not receive antifungal prophylaxis. Composite complete remission (CRc) rates were 60.9% in the antifungal prophylaxis group vs 54.2% in pts with no antifungal prophylaxis (p=0.54). A Kaplan-Meier analysis for overall survival (OS) showed no difference between the prophylaxis and no prophylaxis groups (p=0.505). 1year OS rates were: 50.6% (CI 28-73.3) and 39.4% (CI 30.5-48.3) for prophylaxis and no prophylaxis groups respectively. Median follow up in the prophylaxis group was 237 days (CI 56-878) compared with 173 days (CI 19-850) in the no-prophylaxis group. Conclusion: In this prospective 'real world' observational study, a low rate of IFIs were noted despite low utilization rates of antifungal prophylaxis, mostly with non-mold active azoles. Moreover, administration of antifungal prophylaxis was not associated with a reduced incidence of IFIs. Reassuringly, use of antifungal azoles as prophylactic treatment, which requires VEN dose adjustments, did not affect CRc and OS rates. Similarly, azole based prophylaxis did not affect for the rate of treatment discontinuation due to AEs or early mortality. This study does not support the routine use of antifungal prophylaxis and suggests that such treatment is safe if deemed necessary. Additional insights on antifungal treatment patterns and strategies are pending. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Gemtuzumab Ozogamicin for Cytoreduction in Hyperleukocytosis

Background Hyperleukocytosis can occur in acute leukemia at diagnosis or relapse, and leukostasis is more common in Acute Myeloid Leukemia (AML) than lymphoid leukemias due to larger blasts and increased adhesiveness. Patients presenting with hyperleukocytosis have early mortality rates of 20% during induction therapy and require prompt cytoreductive treatment (Oberoi et al. Leuk Res. 2014). The optimal cytoreductive technique is controversial with options including hydroxyurea, intensive chemotherapy, or leukapheresis. Due to the rarity of leukostasis and need for emergent treatment, randomized trials have not been performed. We previously investigated leukapheresis for this indication and found a 46.9% mortality by day 30 at our institution in patients with newly diagnosed AML (Hambley et al. Blood 2019). Subsequently, we have elected to use gemtuzumab ozogamicin (GO), an antibody-drug conjugate directed against CD33 approved for the treatment of adults with CD33+ AML, to manage hyperleukocytosis and leukostasis. We evaluated outcomes of patients receiving GO for this indication. Methods Demographic, clinical, laboratory, and outcome data were collected for AML patients treated with GO for cytoreduction at Johns Hopkins Hospital with a peak white blood cell (WBC) count greater than 50K/mm3. Demographic data consisted of age, sex, disease status (de novo presentation versus relapsed disease), ECOG performance status, APACHE II score, and Charlson Comorbidity Index (CCI) score. Clinical data incorporated CD33 status, karyotype, gene mutations, ELN risk stratification, and central nervous system (CNS) involvement. Laboratory data included peak WBC count, WBC count 72 hours after receiving GO, and laboratory markers of tumor lysis syndrome and disseminated intravascular coagulation within 72 hours of GO. Both toxicities pre-treatment and within 72 hours after treatment with GO were graded based on the Common Terminology Criteria for Adverse Events (CTCAE). The main outcomes recorded were response to induction and overall survival (OS). Results Demographics, clinical data, and toxicities are summarized in Table 1. Twenty-three patients received GO for cytoreduction from 2019 through 2021. Fifteen patients presented with newly diagnosed AML while 8 presented with relapsed disease. The blasts for all patients expressed CD33 with expression ranging from variable in 6 (26.1%), positive in 7 (30.4%), and bright in 10 (43.5%). For newly diagnosed patients, the ELN disease risk classification was favorable in 4 (26.7%), intermediate in 5 (33.3%), and adverse in 5 (33.3%). A significant portion (8/23) of patients had CNS involvement. Prior to treatment with GO, 15/23 (65.2%) patients had grade 3-4 hypoxia with 2 patients requiring intubation, 8/23 (34.8%) had evidence of myocardial damage, and 9/23 (39.1%) had acute kidney injury with 3 patients requiring dialysis. Most patients (18/23) received a single dose of 4.5mg GO. Patients also received hydroxyurea in 18/23 (78.3%) cases, receiving a median total dosage of 8 grams (range of 0-52g). Patients treated with GO had a median 96.9% reduction in WBC count 72 hours after treatment with a range of 0-99.7% (See Figure 1). The main grade 3-4 toxicities after GO included hypoxia and increased creatinine, which were often present prior to GO. Rasburicase was used for elevated uric acid in 13/23 (56.5%) cases. In the newly diagnosed cohort, 8/15 (53.3%) patients achieved a complete remission (CR) after induction with a 30-day OS of 86.7% and 1-year OS of 55%. Not surprisingly, the outcomes for the relapsed cohort were inferior with 2/8 (25.0%) achieving a CR, a 30-day OS of 75.0%, and a 1-year OS of 15%. Conclusions Gemtuzumab ozogamicin treatment effectively lowers WBC count in AML patients presenting with hyperleukocytosis and leukostasis, and 30-day mortality was lower than our experience with leukapheresis. Overall, GO was well-tolerated and provides another option for cytoreduction in patients with AML presenting with WBC counts greater than 50K/mm3. 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

IMBALANCED ACTIVATING AND INHIBITORY RECEPTORS ON CD56DIM NATURAL KILLER CELLS PREDICTS POOR OUTCOMES IN ACUTE MYELOID LEUKEMIA

Even with advances in understanding the physiopathology of Acute Myeloid Leukemia (AML), most patients still relapse leading to poor long-term prognosis and cure rates. Natural Killer (NK) cells are regulated by opposing signals from receptors that activate and inhibit effector function and are known to mediate anti-leukemic immunosurveillance in AML, but the mechanisms by which they control hematopoietic neoplasms remain unclear. We hypothesize that functionally impaired NK cells can predict poor outcomes in AML. We analyzed the expression of DNAM-1 and NKG2D (activating) and NKG2A and KIR2DL1 (inhibitory) receptors on CD56 + , CD56 bright CD16 - and CD56 dim CD16 + NK subsets, by flow cytometry, in 100 de novo AML bone marrow (BM), followed up from 02/2016 to 06/2022, 17 healthy BM (HBM) and 6 BM from remission after induction chemotherapy (AML-CR). Correlations with ELN2017 risk, complete remission (CR), relapse (R), measurable residual disease (MRD), overall survival (OS), and relapse-free survival (RFS) were verified. Co-culture of AML-exposed NK cells and K562 cell line was used to assay for killing and degranulation. Proteomics and genomics were accessed by CITE-seq single-cell sequencing. All NK cell subsets were decreased in AML (p < .01). AML CD56+ NK cells showed decreased NKG2D (p <.01) and increased NKG2A (p = .04) and KIR2DL1 (p < .01), recovering to near healthy values in AML-CR. NKG2D and DNAM-1 activating receptors were decreased (p < .01), while inhibitory NKG2A (p = .02) and KIR2DL1 (p < .01) were increased in CD56 dim NK (Most cytotoxic subset). Both activating receptors within CD56 dim NK were decreased in ELN2017 adverse risk (NKG2D, p =.05; DNAM-1, p < .01), in relapse (p < .01), and in MRD+ patients after remission induction. Inhibitory receptors were increased in adverse risk (p < .01), relapse (NKG2A, p < .01; KIRDL1, p < .05), and MRD+ (NKG2A, p = .03) patients. Degranulation (p < .01) and target cell death (5:1, p = .01; 10:1, p = .002) were decreased in AML. Patients with lower frequency of CD56 dim NK expressing low NKG2D and DNAM-1 showed less degranulation and target cell death (p = .03), whereas in those with higher inhibitory receptors lower degranulation (NKG2A, p = .06) and cytotoxicity (KIR2DL1, p = .005) was found. Both OS and RFS were decreased in patients with lower CD56 dim NK (OS, p = .04; RFS, p = .03) and patients with lower expression of NKG2D (OS, p = .03; RFS, p = .008) and DNAM-1 (OS, p = .02; RFS, p = .11). Our single cell preliminary analysis showed that NK cells from AML display a distinct pro-inflammatory gene signature compared to HBM, which is strongly correlated to its impaired function. Our data points that CD56 dim NK shows an exhaustion phenotype with high expression of inhibitory and low expression of activating receptors. This imbalance leads to impaired cytotoxicity, compromised anti-leukemic activity, and can predict worst response to treatment, relapse, and MRD positivity, and so, can be considered an adverse risk prognostic factor associated with lower survival rates. On top of that, identifying a pro-inflammatory gene signature on AML NK cells can lead to the identification of pathways that prevent their activation and functionality, making it possible to intervene and prevent the onset of the disease. Closing these gaps in the knowledge of NK-mediated immune evasion in leukemia is of significant interest for targeting the leukemic microenvironment by NK cell-mediated immunotherapy.

AML-251 Overall Survival (OS) With Intensive Chemotherapy (IC) vs Non-IC in Patients With Newly Diagnosed (ND) AML from the Connect® Myeloid Disease Registry Ineligible for Randomized Clinical Trials (RCT)

Patients with acute myeloid leukemia (AML) in RCTs may not reflect the population seen in clinical practice due to strict eligibility criteria. To evaluate outcomes in clinical practice with IC vs venetoclax-containing regimens based on the VIALE-A trial eligibility criteria in patients with AML from the Connect® Myeloid Disease Registry (NCT01688011). Patients were stratified into 3 groups: 1) eligible: met all VIALE-A inclusion criteria; 2) unfit: ineligible for VIALE-A; 3) fit: ineligible for a venetoclax-based regimen in VIALE-A (would have qualified for IC). Baseline characteristics were summarized by group. Induction regimens included IC or venetoclax-based therapies. OS was estimated by Kaplan-Meier method. Hazard ratios (HR) for induction regimens were estimated using Cox models adjusted for age, ELN risk, ECOG, frailty score, and comorbidity index. Of 734 patients (Dec 2021), 61% were male; 84% were white; median age 71 years. Only 26% of patients (n=192) were eligible for VIALE-A; 45% (n=327) and 29% (n=215) were ineligible due to unfitness and overall fitness, respectively. The main reason for VIALE-A ineligibility was high overall comorbidity grade (n=265 [36%]). At baseline, fit patients intended to undergo transplant more often than unfit patients. Median OS (mOS) for eligible, unfit, and fit patients was 14, 10, and 22 months, respectively (HR [95%CI], eligible vs unfit, 1.02 [0.83-1.25], P-value, NS; eligible vs fit, 1.77 [1.38-2.25], P<0.0001; unfit vs fit, 1.74 [1.40-2.16], P<0.0001). Unfit patients receiving IC had significantly longer mOS (14 vs 6 months, respectively; HR, 0.51 [95%CI, 0.27-0.98]; P=0.042) and were more likely to receive a transplant (16% [n=17] vs 1% [n=1], respectively) vs those receiving venetoclax-based regimens. Eligible patients receiving IC (n=31) tended to have shorter mOS (13 months) vs patients receiving venetoclax-based therapies (n=27; 23 months; HR, 1.45 [95%CI, 0.66-3.17]; P-value, NS). Most patients with ND AML in the Connect® Myeloid Disease Registry would have been ineligible for VIALE-A due to being too fit or unfit. Among patients ineligible for an RCT due to unfitness, there was an association with increased OS in patients receiving IC vs those receiving venetoclax-based therapies.

AML-348 A Phase Ib/II Study of Ivosidenib With Venetoclax +/- Azacitidine in IDH1-Mutated Hematologic Malignancies

IDH1-mutated (IDH1+) myeloid malignancies depend on the anti-apoptotic protein BCL-2 for survival. Combining the IDH1 inhibitor ivosidenib (IVO) with the BCL-2 inhibitor venetoclax (VEN) may improve outcomes. We report the completed P1b portion of a P1b/II study investigating IVO (500 mg PO daily D15-continuous) with VEN (D1-14), with or without azacitidine (AZA; 75 mg/m2 D1-7) every 28 days. Primary P1b objectives included safety, tolerability, and IWG-defined overall response (ORR: CR+CRi+CRh+PR+MLFS). A dose-escalation/-de-escalation study evaluating cohorts of 6 patients enrolled within 4 dose levels: DL1 (IVO+VEN 400 mg), DL2 (IVO+VEN 800 mg), DL3 (IVO+VEN 400 mg+AZA), DL4 (IVO+VEN 800 mg+AZA). Eligible patients were ≥ age 18 with IDH1+ MDS, newly diagnosed (ND) or relapsed/refractory (R/R) AML. Thirty-one patients enrolled with a median follow-up of 26 months. The median age was 67 years (range: 44-84), 71% had AML (ND: N=14, R/R: N=8), and 29% had MDS. ELN risk was intermediate or adverse in 19% and 55%, respectively (N=17). The ORR was 94% (DL1: 67%, DL2-DL4: 100%); composite CR (CRc: CR+CRi+CRh) was 87% (DL1: 67%, DL2: 100%, DL3: 85%, DL4: 100%). Of the AML patients, 60% attained measurable residual disease-negative CRc by multiparameter flow cytometry. IDH1+ mutation clearance by digital droplet PCR (sensitivity: 0.1%-0.25%) occurred in 64% of patients following cycle 5. Grade 3-5 adverse events (AEs) in ≥ 10% of patients included febrile neutropenia (29%) and pneumonia (23%). AEs of special interest (AESI) included grade 3 tumor lysis syndrome in 2 (dose-limiting toxicity in 1), and differentiation syndrome in 4 (G2: N=2, G3: N=2) patients. All AESIs were transient and reversible. Median EFS and OS were 36 and 42 months, respectively, and 24-month OS was 71% (95% CI: 55-91; ND-AML: 67%, R/R-AML: 50%, MDS: 100%). MRD-negative CRc improved OS (median NR vs. 8 months, P: 0.002) in ND- and R/R-AML. Based on efficacy and toxicity, DL3 (IVO+VEN400+AZA) was the recommended phase 2 dose. IVO+VEN±AZA is an effective treatment for IDH1+ myeloid malignancies with an expected toxicity profile and notable activity across disease groups. Single-cell sequencing and CyTOF correlatives will also be presented.

There’s no place like home: Home time among older adults with AML by therapy intensity.

376 Background: Older adults with acute myeloid leukemia (AML) have identified home time (HT) as a critical outcome influencing their treatment selection. However, few studies have characterized HT in this disease setting. Methods: We conducted a retrospective, observational study of adults age ≥60 diagnosed with AML from 2015 to 2020 at University of North Carolina Health. First-line therapy was classified by intensity: low (hypomethylating agent [HMA]), intermediate (HMA+Venetoclax), and high (anthracycline-based). The primary outcome was cumulative HT days from time of diagnosis. A day was defined as HT if an individual was not hospitalized and did not utilize emergency department services or ambulatory oncology clinics. Secondary outcomes were proportion of days at home (PDH) and overall survival (OS). Covariates included demographics and disease risk by ELN 2017 criteria. HT was evaluated via summary statistics with comparisons among treatment groups made via linear (for HT / PDH) or Cox proportional hazard (for OS) regression models adjusted for age &amp; ELN risk. PDH was further adjusted for log of follow up time. Median OS was calculated via the Kaplan-Meier method. Results: 197 individuals were identified. Mean age was 71 (range 60-95), 79% were white, and 59% male. 38% received high-intensity therapy, 33% received low, and 29% intermediate. Mean age was lower in the high-intensity group (66 vs 74 in low, 75 in intermediate; Kruskal-Wallis p &lt; 0.0001). Mean HT was 284 days, and median survival was 10.3 months (95% CI 8.4-12.7). Mean HT was greater in the high-intensity group at 409 days (CI 310-508) vs. 243 (158-328) in low and 169 (121-216) in the intermediate group (Table). The high-intensity group had greater median OS at 19.9 months vs. 8.8 (low) or 7.7 (intermediate) but a lower mean adjusted PDH (high: 0.60 vs. low: 0.73 vs. intermediate: 0.75; p &lt; 0.0001). In adjusted models, these differences remained statistically significant. Mean HT, median OS, and mean adjusted PDH did not differ significantly between the low &amp; intermediate groups. Conclusions: Older adults with AML spend a tremendous amount of time - roughly 40% of days - engaged in oncology care. Although receiving high-intensity therapy was associated with longer OS, increases in HT were more modest, indicating that much of the survival gains were spent engaged in care. Shared treatment decision-making should incorporate patient preferences for securing HT versus attempting to prolong survival.[Table: see text]

AML-463 AML in Jordan: Analysis According to 2017 European LeukemiaNet Risk Stratification

Cytogenetic features are the main stay to define prognosis and treatment in acute myeloid leukemia (AML). Gene mutations detected by next generation sequencing (NGS) were adopted by the European Leukemia Network (ELN) 2017 risk stratification and changed the therapeutic approach, especially in the intermediate risk category. Here, we report cytogenetic and molecular features of Jordanian AML patients as well as the impact of adopting ELN 2017 risk stratification on survival from a single center in Jordan. Medical records of adult patients with the diagnosis of AML from January 2009 till June 2021 in King Hussein Cancer Center were reviewed. Patients were divided into two cohorts: cohort -1 with no available NGS and cohort -2 with NGS. ELN 2010 and ELN 2017 guidelines were used to risk stratify patients in cohort-1 and cohort-2 respectively. Survival analyses were performed using Kaplan-Meier method. 265 subjects were identified. 135 patients were included in cohort-1 (median age of 39 years) and 130 in cohort -2 (median age of 42 years). High intensity induction was given to 119(88%) patients in cohort-1 and 120 (92%) patients in cohort -2. Among cohort-1 patients, risk stratification was favorable in 13 (9.6%), intermediate in 93 (68.9%) and poor in 29 (21.5%) while in cohort-2, they were 29 (22.3%), 52(40%) and 49 (37.7%) respectively. Allogeneic stem cell transplant (allo-SCT) was done for 84 (62.2%) patients in cohort -1 and 61 (47%) patients in cohort-2. After a median follow up of 35 months (range: 2.4-129 months), median overall survival (OS) was 23 months and leukemia free survival (LFS) was 37 months. 2-year OS and LFS were 50% (43.4,55.8) and 58% (51.0,65) respectively. There was no significant difference in the 2-year OS between the two cohorts (54% versus 48%; P=0.129), but cohort-2 patients had better LFS (63% versus 51%; P=0.03), and a lower 2-year cumulative incidence of relapse (37% versus 49%, P-0.03). Adoption of ELN-2017 risk stratification in Jordanian AML patients markedly increased the percentage of patients in the high and favorable risk categories and contributed improving leukemia free survival as well as decreasing the incidence of relapse.

AML-154 Induction Mortality of Acute Myeloid Leukemia Patients Treated With Purine Analogues-Cytarabine-Anthracycline at General Hospital

Despite the fact that purine analogs (fludarabine/cladribine) in combination with cytarabine and idarubicin (FIA/CLIA) have a higher CR rate than '3+7' (historically, 60%), cytarabine-anthracyclines (7+3) induction chemotherapy (IC) remains the standard acute myeloid leukemia (AML) IC. Cytarabine-anthracyclines (7+3) IC has been the mainstay therapy for over four decades, and it remains the standard AML IC regimen internationally. Triplet IC using FIA/CLIA is superior to the standard 7+3 regimen but is challenging to administer in general hospital settings due to myelosuppression. We reviewed the AML induction mortality (IM) rate in patients induced with (fludarabine/cladribine) combined with cytarabine and idarubicin (FIA/CLIA) at Memorial Hermann Hospital, Texas Medical Center. Of 44 AML patient records reviewed from January 2013 to January 2022, 40 received 5 days FIA/CLIA IC and four received 3-4 days due to age and comorbidities. Clinical characteristics analyzed included gender, race, ECOG PS, ELN risk stratification, molecular characteristics, and disease origin. The median age was 51.5 years (range: 18-68). Three patients died before assessment. The composite CR (CR+CRi) was 82.9% (34/41) after 1 cycle and 87.8% (36/41) after 2 cycles. MRD-negative composite CR was 92%. Four patients had adverse risk cytogenetics and primary induction failure (modified FIA). Thirty-seven percent had febrile neutropenia, 25% had bacteremia, 15% required ICU admission, and 4% required mechanical ventilation. The 30-day induction mortality was 9%. FIA/CLIA has a higher CR rate than '3+7' (historically, 60%). Given the fact that in AML, achieving CR is the most important factor to improve survival with adequate treatment expertise, a triplet IC regimen can be safely administered with low IM and superior results.

AML-396 Venetoclax-Containing Regimens Improve Outcomes of Intensive Treatment and Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Extramedullary Acute Myeloid Leukemia

The optimal treatment strategy for patients with extramedullary acute myeloid leukemia (eAML) is questionable, especially as applied to extramedullary tumor persistence while bone marrow response is achieved. To determine whether venetoclax-containing regimens, intensive treatment, and allogeneic hematopoietic stem cell transplantation (alloHSCT) can improve outcomes in patients with eAML. Overall, 27 patients with verified eAML were included: 14 were male and 13 were female with a median age of 40 years (13-84). Standard ("7+3"), high-intensity ("HiDAC", "FLAG±Ida"), and low-intensity chemotherapy regimens were administered to all patients. Ten patients (37%) received venetoclax with 5-azacytidine (VEN-AZA) because of comorbidities or refractory disease. AlloHSCT was performed in 17 patients (63%). According to the 2017 ELN risk stratification system, 18.5% (5/27) were favorable risk, 25.9% (7/27) were intermediate risk, and 55.6% (15/27) were adverse risk. Patients with favorable genetic alterations achieved bone marrow remission more frequently (100% vs. 44%, P=0.044) but did not have advantages in the rate of complete extramedullary response (75% vs. 68%, P>0.05). Using HiDAC enabled eradication of extramedullary lesions in case of failure of standard and low-intensity regimens (85% vs. 0%, P=0.044) and decreased the rate of early (during the first 12 months) relapse (38% vs. 100%, P=0.019). The overall response rate to VEN-AZA was 70% (7/10). Five patients (50%) achieved complete eradication of extramedullary tumor after venetoclax; among them, 3 still had persistent extramedullary disease after HiDAC. Performing alloHSCT in first complete remission decreased the risk of early relapse (12% vs. 80%, P=0.015) and demonstrated better median overall survival (38.85 vs. 7.57 months, P=0.013) and relapse-free survival (38.85 vs. 3.78 months, P=0.0021) compared to alloHSCT performed in second and subsequent complete remissions. Favorable genetic aberrations do not increase the frequency of extramedullary response. Intensive treatment helps to achieve complete eradication of extramedullary tumor and reduces early relapse rate. Using VEN-AZA is effective among patients with eAML, including patients who were refractory to intensive treatment, and allows complete response achievement before alloHSCT. The best time to perform the alloHSCT among patients with eAML is the first complete remission.

An immunity and pyroptosis gene-pair signature predicts overall survival in acute myeloid leukemia

Treatment responses of patients with acute myeloid leukemia (AML) are known to be heterogeneous, posing challenges for risk scoring and treatment stratification. In this retrospective multi-cohort study, we investigated whether combining pyroptosis- and immune-related genes improves prognostic classification of AML patients. Using a robust gene pairing approach, which effectively eliminates batch effects across heterogeneous patient cohorts and transcriptomic data, we developed an immunity and pyroptosis-related prognostic (IPRP) signature that consists of 15 genes. Using 5 AML cohorts (n = 1327 patients total), we demonstrate that the IPRP score leads to more consistent and accurate survival prediction performance, compared with 10 existing signatures, and that IPRP scoring is widely applicable to various patient cohorts, treatment procedures and transcriptomic technologies. Compared to current standards for AML patient stratification, such as age or ELN2017 risk classification, we demonstrate an added prognostic value of the IPRP risk score for providing improved prediction of AML patients. Our web-tool implementation of the IPRP score and a simple 4-factor nomogram enables practical and robust risk scoring for AML patients. Even though developed for AML patients, our pan-cancer analyses demonstrate a wider application of the IPRP signature for prognostic prediction and analysis of tumor-immune interplay also in multiple solid tumors.

Vitamin C Deficiency in Patients With Acute Myeloid Leukemia.

Vitamin C has been shown to play a significant role in suppressing progression of leukemia through epigenetic mechanisms. We aimed to study the role of vitamin C in acute myeloid leukemia (AML) biology and clinical course. To this purpose, the plasma levels of vitamin C at diagnosis in 62 patients with AML (including 5 cases with acute promyelocytic leukemia, APL),7 with myelodysplastic syndrome (MDS), and in 15 healthy donors (HDs) were studied. As controls, vitamins A and E levels were analysed. Expression of the main vitamin C transporters and of the TET2 enzyme were investigated by a specific RQ-PCR while cytoplasmic vitamin C concentration and its uptake were studied in mononuclear cells (MNCs), lymphocytes and blast cells purified from AML samples, and MNCs isolated from HDs. There were no significant differences in vitamin A and E serum levels between patients and HDs. Conversely, vitamin C concentration was significantly lower in AML as compared to HDs (p<0.0001), inversely correlated with peripheral blast‐counts (p=0.029), significantly increased at the time of complete remission (CR) (p=0.04) and further decreased in resistant disease (p=0.002). Expression of the main vitamin C transporters SLC23A2, SLC2A1 and SLC2A3 was also significantly reduced in AML compared to HDs. In this line, cytoplasmic vitamin C levels were also significantly lower in AML-MNCs versus HDs, and in sorted blasts compared to normal lymphocytes in individual patients. No association was found between vitamin C plasma levels and the mutation profile of AML patients, as well as when considering cytogenetics or 2017 ELN risk stratification groups. Finally, vitamin C levels did not play a predictive role for overall or relapse-free survival. In conclusion, our study shows that vitamin C levels are significantly decreased in patients with AML at the time of initial diagnosis, further decrease during disease progression and return to normal upon achievement of CR. Correspondingly, low intracellular levels may mirror increased vitamin C metabolic consumption in proliferating AML cells.

PB1847: ACUTE MYELOID LEUKEMIA – IS IT MORE BESIDES GENETIC ABNORMALITIES?

Background: Acute myeloid leukaemia (AML) still carries a poor prognosis, despite novel aproaches. Age and previous myelodysplastic syndrome (MDS) are important risk factors. Environmental factors: professional benzene exposure, residential background and exposure to chemotherapy (CT)/radiotherapy (RT) have also been implicated. Aims: To evaluate environmental factors of AML patients, its genetic characteristics and overall survival (OS), in a tertiary centre. Methods: We retrospectively revised newly diagnosed AML in our centre between 2018 - 2020. Clinical and laboratory data were obtained by clinical files review Results: We included 235 patients, 47.2% (n=111) male. Median age 69 (19-97) years. (67 [28.5%]≤60 years old. – YOUNG and 168 [71.5%] with >60 years old - OLD). The most common WHO 2016 category was AML with myelodysplasia-related changes (MRC) (37.0%; n=87), followed by AML NOS (21.3%; n=50); 15 (6.4%) patients had acute promyelocytic leukaemia with PML―RARA, 21 (8.9%) therapy-related myeloid neoplasm and 17 (7.2%) post-myeloproliferative neoplasm (post-NMP) AML. The main category within YOUNG patients was AML with mutated NPM1 (19.4%) and in the OLD group was AML-MRC (45.2%). Genomic classification (GC) (Papaemmanuil, 2016) was available for 117 cases (49.8%): AML with no detected driver mutations (n=28; 23.9%); AML with mutated chromatin, RNA-splicing genes, or both (n=26; 22.2%). Considering YOUNG vs OLD patients, the main category was AML with mutated NPM1 (25%) vs AML with no detected driver mutations (32.3%). Regarding ELN risk stratification: 20.0% were low-risk, 27.1% intermediate risk and 52.9% high-risk category. OS for total cohort was 4.2 months, with 177 events (75.3% of included patients). The YOUNG patients had a median OS of 18,7 months while the OLD had median OS of 2,6 months, with P<0,001 (HR 2,31). Ninety nine (42.1%) patients lived in industrial regions. We found no correlation between living place and dysplasia, even after adjusting for age, ELN risk or GC. We found an apparent association of WHO subtype with living place (p=0.013), as post-MPN AML was more common in non-industrial (10.3 vs 3.0%) and AML with mutated NPM1 in industrial areas (11.1 vs 7.3%), but they were lost after adjusting for age. There was no OS difference between industrial and non-industrial places even after adjusting for age. Regarding professional exposure (available for 85 patients), 7.1% were exposed to benzene, 2.4% to agricultural activities and 31.8% to other chemicals, 58.8% with no significant exposure, with no differences in WHO classification, GC nor age. Smoking appeared associated with longer OS (6.6 vs 34.9%; p=0.026; HR 0.53), but this effect is lost after adjusting for age, as smoking was more common in YOUNG (65.7 vs 25.0%). There was no correlation with AML subtype or risk. Concerning other risk factors like alcohol consumption, obesity, family history of cancer, previous solid neoplasm, previous chemotherapy or previous radiotherapy none of them had impact in AML subtype, ELN risk or OS (p=NS). Summary/Conclusion: In our cohort, the majority of patients were over 60 years old and presented with AML-MRC, as described in the literature. Concerning GC, the dominant category was AML with no detected driver mutations. Looking at environmental factors, in our cohort only residential background correlated with AML subtype, despite non-significance impact in prognosis.

P500: A REAL WORLD MULTI CENTRE STUDY OF CPX-351 REVEALS NO DIFFERENCE IN OVERALL SURVIVAL WHEN COMPARED WITH FLAG-IDA AND 3 + 7 IN HIGH RISK AML.

Background: CPX-351 is a liposomal formulation of daunorubicin and cytarabine in a fixed synergistic ratio of 5:1. It has been approved by both the FDA and EMA for use in high-risk AML including therapy related AML (t-AML) and AML with myelodysplastic related change (AML-MRC). However, this is little data of CPX-351 in a real-world setting. There is also no data comparing CPX-351 to FLAG-IDA which is used in our institution front line for high-risk AML Aims: The objective of our multi-centre study was to assess outcomes of CPX-351 and then compare these outcomes in patients who received FLAG-IDA and 3 + 7 for high risk AML(tAML and AML-MRC). Methods: Patients aged 18 and over who were treated with induction chemotherapy and who met the WHO criteria for t-AML and AML-MRC were included in the study. Retrospective data was collected from 10 centres throughout Canada for CPX-351. The Princess Margaret Cancer Centre database was used to collect data for patients who received induction with FLAG-IDA and 3 + 7. Targeted sequencing was performed on DNA samples using the TruSight Myeloid Sequencing Panel. Overall survival (OS) and progression free survival (PFS) rates were calculated using the Kaplan-Meier method. Results: 76 patients treated with CPX-351 were identified with baseline characteristics seen on Table 1. Targeted sequencing was performed on 72% of patients (55/76) and the average number of mutations was 2(0-7). RUNX1 was the most commonly mutated gene found in 22% (12/55), followed by ASXL1 mutated in 19% (10/55) and SRSF2 in 15%. Assessing treatment responses, 53% (38/76) of patients achieved a complete remission (CR) or a complete remission with incomplete recovery (CRi). The median CR duration was short at 7.3 months. Median follow up was 7.78 months (range 0.2 to 20 months). OS was 57% at 12 months and 38% at 18 months. PFS was 40% at 12 months and 23% at 18 months. There were no differences in OS when stratified by ELN risk (p=0.46), adverse risk cytogenetics (p=0.1485), or poor risk mutations such as RUNX1 (p=0.73), ASXL1 (p=0.47) or TP53(p=0.53).Patients who received an ASCT had significant improvement of OS of 82% at 18 months compared to those who did not receive a transplant of 15% at 18 months (Fig 2; p=0.0001). Patients who received 3 + 7 and FLAG-IDA for the same indications as CPX-351 (tAML and AML-MRC) were identified. Baseline characteristics are shown in Table 1. 69% of patients receiving FLAG-IDA and 67% of those receiving 3 + 7 had adverse ELN risk stratification. CR rates were highest with FLAG IDA with 75% achieving a CR or CRi. 68% of patients who received CPX-351 proceeded to ASCT compared with 59% with FLAG-IDA and 57% with 3 + 7. OS at 18 months was 42% for FLAG-IDA and 39% for 3 + 7. There was no statistical difference in OS when comparing CPX-351 to FLAG-IDA and 3 + 7 (p=0.855) (Figure 1). Similarly, there was no difference in PFS when comparing all 3 inductions (p=0.26). Patients who received a ASCT had significant improvement of OS of 59% at 18 months compared to those who did not receive a transplant of 24% at 18 months (p=<0.0001)irrespective of what induction was used. Image:Summary/Conclusion: High risk AML remains an unmet clinical need which is supported by our study which reveals no difference in OS or PFS when treated with either CPX-351, FLAG-IDA or 3 + 7. Unsurprisingly, ASCT improved OS across all patients irrespective of induction type. Further study with a prospective randomised control trial is required.

P1381: EARLY FULL DONOR CHIMERISM AFTER FLAMSA RIC BASED ALLOGENEIC HSCT BUT NOT PRESENCE OF MORPHOLOGICAL REMISSION ASSOCIATES WITH OUTCOMES IN R/R AML PATIENTS

Background: Allogeneic hematopoietic stem cell transplantation (HSCT) is still the only potentially curative treatment for patients (pts) with high-risk acute myeloid leukemia (AML). Despite recent advances, a significant number of pts are primary refractory or have early relapse (r/r) with <6 months (m) remission duration. One strategy to improve the outcomes of r/r AML is to perform HSCT after aplasia-inducing chemotherapy. Here, we report on a series of pts receiving a sequential chemotherapy regimen (fludarabine 30 mg/m2, amsacrine 100 mg/m2, cytarabine 2 g/m2 (FLAMSA)) and reduced-intensity conditioning (RIC) followed by HSCT as well as prophylactic donor lymphocyte infusions (DLI) as described by Schmid et al (JCO 2005). Aims: We aimed to retrospectively analyze the outcome of 82 consecutive pts with r/r AML who underwent FLAMSA RIC based HSCT between 2006 and 2020 at our center. Methods: Median age of the 82 pts was 55 years (y) and 38 pts (46%) were male. ELN risk and revised MRC prognostic classification at diagnosis were favorable in 8% and 4%, intermediate in 28% and 56%, and adverse in 64% and 40% of the pts, respectively. Median time from diagnosis to HSCT was 5 months. At the time of HSCT, only 3 pts (3%) were in complete remission (CR). RIC following the FLAMSA chemotherapy was 4Gy TBI and cyclophosphamide (73%), busulfan and cyclophosphamide (11%), melphalan (13%) or 2Gy TBI only (2%). 95% of pts received peripheral blood stem cells and 5% bone marrow (BM) from a matched unrelated donor (MUD, 63%), matched sibling donor (MSD, 10%), mismatch unrelated donor (MMUD, 23%) or a haploidentical donor (4%). Immunosuppression (IS) consisted of cyclosporine A, mycophenolate mofetil and antithymocyte globuline (MUD and MMUD only) or post transplantation cyclophosphamide, tacrolimus and MMF (haplo-donors only). 12 pts (15%) received ≥ 1 DLI preemptively past d+120 as planned. Results: Median overall survival (OS) and event-free survival (EFS) were 276 and 135 days (d). 33 pts (39%) had an OS >1y, and 22 (27%) an event free survival (EFS) >1y. 49 pts (59%) relapsed within the 1st y. Age at HSCT, type of AML (de novo vs secondary), remission status at time of HSCT, ratio of blasts in blood to bone marrow, donor type, type of RIC, mismatch and MRC risk classification had no significant impact on OS and EFS, whereas the number of treatment lines before HSCT significantly influenced OS (p=.05). Pts with ELN favorable/intermediate risk had longer EFS (p=.04, Figure 1A), but not OS (p=.12). On d+28 after HSCT, 43 pts (52%) had reached morphologic leukemia free state (MLFS), CR with incomplete count recovery (CRi) or CR, which was not associated with better OS or EFS (Figure 1B). In contrast, pts (n=49, 60%) with a donor chimerism (DC) ≥98% in BM had a significantly longer EFS (p<.01, Figure 1C) and OS (p<.01) than those with <98%. At d+100 32 pts (39%) were in MLFS, CRi or CR, and had a significant better for EFS (p<.01, Figure 1D) and OS (p<.05). Pts with a d+100 DC ≥98% in BM also had improved EFS (p=.02, Figure 1E) but not OS (p=.16). Acute Graft-versus-Host-Disease (GvHD) °II-IV occurred in 21 pts (26%). 13 pts (16%) developed any grade of chronic GvHD. Incidence of GvHD did not increase after DLI. Image:Summary/Conclusion: Despite the poor prognosis of r/r AML, a significant number of pts after FLAMSA RIC HSCT survived >1 y. Except ELN risk classification, there was no strong outcome predictor prior to HSCT. D+28 DC but not morphological remission in BM identifies pts at high risk for relapse after HSCT, allowing for additional post-HSCT strategies.

P506: ACHIEVEMENT OF MEASURABLE RESIDUAL DISEASE CLEARANCE IS A STRONGER PREDICTOR OF PATIENT OUTCOME THAN TREATMENT INTENSITY IN NEWLY DIAGNOSED PATIENTS WITH ACUTE MYELOID LEUKEMIA

Background: Modern therapy for acute myeloid leukemia (AML) can consist of either intensive or low-intensity regimens selected based on patient (pt) age/comorbidities. Measurable residual disease (MRD) has emerged as a strong independent prognostic factor in AML. It is unknown whether pts who achieve similar levels of MRD clearance experience comparable outcomes irrespective of treatment intensity. Aims: To establish the relative prognostic contribution of treatment intensity and MRD status on overall survival (OS) and relapse-free survival (RFS) in newly diagnosed AML pts who have achieved a first response. Methods: We conducted a retrospective chart review to identify non-CBF, non-APL AML pts treated at our institution between 2010 and 2021 with intensive (IA; int/high-dose cytarabine + anthracycline-based, without venetoclax) or low-intensity (Lo + VEN; low-dose cytarabine/hypomethylating agent-based, with venetoclax) regimens who had achieved CR/CRi/MLFS and undergone MRD testing by multiparameter flow cytometry at time of first response. Differences in baseline pt characteristics were evaluated using the Chi-square or Wilcoxon-Mann-Whitney tests for categorical and continuous variables, respectively. The Kaplan-Meier method was used to estimate median OS and RFS, with pts censored at the time of stem cell transplantation (SCT). Multivariate analysis was performed using a Cox proportional hazards model. Results: We identified 635 pts meeting inclusion criteria. Baseline characteristics are shown in Table 1. Compared to the IA-treated pts (n=385), pts treated with Lo + VEN (n=250) were significantly older, more likely to be male, less likely to achieve MRD clearance, and more likely to be classified as adverse risk by ELN 2017. The SCT rate in the Lo + VEN cohort was half that of the IA cohort (25% vs 50%). Median OS was 51m, 24.6m, 15m, and 9.9m in the IA MRD(-), Lo + VEN MRD(-), IA MRD(+), and Lo + VEN MRD(+) groups, respectively. Median RFS was 27.8m, 15.4m, 7.3m, and 5.2m in the IA MRD(-), Lo + VEN MRD(-), IA MRD(+), and Lo + VEN MRD(+) groups, respectively. Pts within the same MRD category (+ or -) had significantly higher OS and numerically higher RFS if treated with IA versus Lo + VEN. When the analysis was restricted to pts aged ≥ 60 years (n=56 in IA, n=239 in Lo + VEN; Fig. A-B), the differences within MRD categories did not reach statistical significance (median OS NR in IA MRD(-) vs 24.6m in Lo + VEN MRD(-), p=0.08; median OS 13m in IA MRD(+) vs 10.6m in Lo + VEN MRD(+), p=0.50; median RFS NR in IA MRD (-) vs 15.4m in Lo + VEN MRD(-), p=0.07; median RFS 25.1m in IA MRD(+) vs 5.3m in Lo + VEN MRD(+), p=0.24). The SCT rate was 29% (87/295) in the age ≥ 60 cohort. Given the confounding effect of unbalanced pt characteristics between the IA and Lo + VEN cohorts, we performed a multivariate analysis on the full population (n=635) taking into consideration the effects of age, treatment intensity, MRD status, and ELN category on OS and RFS (all significant by univariate analysis). In the multivariate analysis for OS, ELN adverse risk was the strongest predictor (HR 2.09, p<0.001), followed by MRD(+) status (HR 1.68, p<0.001), while treatment intensity and age were not significantly predictive. For RFS, ELN adverse risk (HR 2.31, p<0.001) and MRD(+) status (HR 1.98, p<0.001) were also the only two significant predictors. Image:Summary/Conclusion: In newly diagnosed AML patients, MRD status at time of first response and ELN risk are stronger predictors of pt outcome than intensity of therapy received.