High-dose Cytarabine Research Articles

Decitabine/Cedazuridine (ASTX727) Combined with a Molecularly-Targeted Agent (Venetoclax, Gilteritinib, Ivosidenib, or Enasidenib) As Personalized Maintenance Therapy in Acute Myeloid Leukemia: First Results from a Phase 1b Study

Background: Disease relapse is the major cause of treatment failure and death in acute myeloid leukemia (AML). Currently, oral azacitidine (CC-486) is the only drug approved in the maintenance setting in patients with AML who are unable to complete standard therapy. The ECOG ACRIN E2906 trial suggested an overall survival (OS) benefit with 3-day IV decitabine maintenance. Decitabine/cedazuridine (ASTX727) is an oral formulation of decitabine that achieves systemic exposures as seen with IV decitabine. Multiple small-molecule agents are now available targeting key leukemic drivers (BCL-2, FLT3, and IDH1/IDH2 inhibitors). We developed a multi-arm phase 1b study (NCT05010772) to evaluate an oral maintenance regimen composed of an ASTX727 backbone combined with a molecularly-targeted agent (venetoclax, gilteritinib, ivosidenib, or enasidenib). Methods: Patients ≥ 18 years with AML in first complete remission (CR) or CR with incomplete blood count recovery (CRi) not currently eligible for stem cell transplantation (SCT) and unable/unwilling to complete standard therapy were eligible. Patients having received either intensive induction (at least 2 cycles of therapy based on intermediate to high dose cytarabine) or low-intensity induction (at least 3 cycles based on low-dose cytarabine or a hypomethylating agent) were permitted. Other inclusion criteria were ECOG ≤ 3, adequate hepatic/renal function, absolute neutrophil count > 0.5 x 10 9/L, and platelets > 50 x 10 9/L. Patients were enrolled in one of five arms per physician choice based on molecular profile. Arm A consisted of ASTX727 35/100 mg PO on D1-3. All other arms combined this ASTX727 backbone with either venetoclax 400 mg (adjusted for azoles) PO on D1-5 (arm B), gilteritinib 120 mg PO on D1-28 (arm C), enasidenib 100 mg PO on D1-28 (arm D), or ivosidenib 500 mg PO on D1-28 (arm E). Treatment was administered in 4-week cycles, up to 24 cycles. Each arm initially consisted of a safety lead-in cohort with predetermined dose reductions for dose-limiting toxicity (DLT) per a 3+3 dose de-escalation design. Prophylactic antibiotics, antifungals, and antivirals were encouraged. The primary objective was safety and tolerability. Secondary objectives included relapse-free survival (RFS) and OS. Patients becoming eligible for SCT were taken off study and censored at the time of SCT for time-to-event endpoints. Results: 23 patients, with a median age of 68 years (range 33-83), have been enrolled (3 on arm A, 19 on arm B, and 1 on arm C). 12 (52%) were enrolled following intensive induction and 11 (48%) after low-intensity induction. 16 (70%) had prior venetoclax. Best response at enrollment was CR in 22 (96%) patients and CRi in 1 (4%). 6/22 (27%) patients with available testing were measurable residual disease (MRD)-positive. 2 (9%) patients had antecedent myelodysplastic/myeloproliferative neoplasms and 1 (4%) had therapy-related AML. ELN 2022 risk was favorable in 10 (43%), intermediate in 3 (13%), and adverse in 10 (43%) patients. The most common grade 3/4 adverse events were neutropenia (96%), thrombocytopenia (74%), anemia (39%), lung infection (22%), hypertension (17%), and neutropenic fever (17%). Cycle 2 dose reductions due to myelosuppression occurred in 5/23 (22%) patients. No DLTs were observed. No deaths occurred on protocol. Two patients died in remission from SCT-related complications after going off maintenance. The current median follow-up time is 5.3 months (m). The median number of cycles given is 3 (1-15). Three relapses have occurred to date (1 in arm A, 2 in arm B). The median RFS for the full cohort is not reached (NR, 1-year 71%). The median OS for the full cohort (figure 1A) is NR (1-year 100%). The median RFS for arms A, B, and C are NR (1-year 67%), NR (1-year 84%), and NR, respectively (figure 1B). The median RFS is 14.5 m (1-year 50%) for patients who received intensive induction and NR (1-year 75%) for those who received low-intensity induction. The median RFS for patients who were MRD-negative and MRD-positive at enrollment were NR (6-month 93%) and NR (6-month 75%), respectively (p=0.50). Of the 6 MRD-positive patients, 2 (33%) cleared their MRD while on maintenance (both patients in arm B). Conclusions: A fully oral, targeted maintenance regimen is feasible in AML. Early results show encouraging RFS and OS. Further enrollment and follow-up are required to better assess the safety and efficacy of these regimens.

Outcomes in Patients with Acute Myeloid Leukemia Treated with CLAG (cladribine, cytarabine, filgrastim) and/or Mitoxantrone with Venetoclax

Introduction: CLAG (cladribine, cytarabine, filgrastim) with or without M (mitoxantrone) has anti-leukemic activity in newly diagnosed (ND) and relapsed/refractory (R/R) AML (Wierzbowska et al. 2008, Jaglal et al. 2014, Seiter et al. 2016). Venetoclax (Ven) with hypomethylating agents (HMA), approved for patients (pts) who are not candidates for intensive chemotherapy (IC), is increasingly being employed even for pts who are fit for IC. R/R disease remains a major cause of mortality in fit pts with AML, and thus improved IC regimen is an area of active research. Various combination of IC with Ven are ongoing with promising early findings (DiNardo et al. 2021, Reville et al. 2022). In this study, we examined the outcomes of AML patients treated with CLAG and/or mitoxantrone with Ven, CLAG(M)/Ven. Methods: This was a retrospective study of pts with AML who received CLAG(M)/Ven (Days 2-8) in 2022-2023. Clinical responses were reported using ELN 2022 criteria. Kaplan-Meier analyses were used to estimate overall survival (OS) from the date of CLAG(M)/Ven initiation. Results: This cohort of 19 pts (8M/11F with median age of 60 [23-74] at diagnosis) is comprised of 68.4% (13/19) R/R and 31.6% (6/19) ND AML who had prior MDS directed therapy. There were 57.9% (11/19) with secondary/therapy-related AML and when including de novo AML pts who had mutations highly specific for secondary AML ontogeny, it increased to 78.9% (15/19). Most of the pts (68.4%, 13/19) had adverse risk disease by ELN 2022. Common mutations being TP53 (26.3%, 5/19) followed by IDH1/2 (21.1%), ASXL1 (15.8%), and RUNX1 (15.8%). There were 36.8% (7/19) who had received allogeneic hematopoietic cell transplant (alloHCT) (Table 1). Similar number of pts received CLAG/Ven (47.5%) and CLAG-M/Ven (52.6%). Pts received on average 2.6 lines of treatment prior to CLAG(M)/Ven with 1 pt received 5 prior lines of treatment after AML diagnosis. Most of the pts, 78.9% (15/19), had prior HMA/Ven. The 30-day and 60-day morality was 5.3% (1/19) (disease status unknown at the time of death) and 26.3% (5/19) (disease status: 3 yes, 1 no, 1 unknown), respectively. Among these 5 early deaths within 60 days, 3 were ND AML that were heavily pretreated for prior MDS (average 3 lines of prior therapy) and 2 were R/R AML. All of them had prior HMA/Ven. Eighty percent (4/5) had adverse risk disease and received CLAG-M/Ven. Forty percent (2/5) had TP53 mutation. Objective response rate (ORR) of the entire cohort was 26.3% (5/19) (2 CR, 1 CRi, and 2 MLFS). Among those with evaluable response (n=10), ORR was 50%. Two CR/CRi pts achieved undetectable MRD by flow cytometry. MRD was not tested in the other 3 pts. Notably, ORR was higher in pts who received CLAG/Ven (44.4%, 4/9) compared to CLAG-M/Ven (10%, 1/10). No response in ND AML and 38.5% (5/13) ORR in R/R AML. Of the 47.4% (9/19) nonevaluable pts, 6 had aplastic marrow (2 died while getting induction, 2 transitioned to alloHCT, 1 moved onto next line of treatment, and 1 lost to follow up) and 3 had recovery marrow pending. For pts who achieved a response, 60% (3/5) underwent alloHCT (all of them alive without disease at data cutoff). The median time to count recovery was 42.5 days (27 days to never recovered). Prior HMA/Ven failure, high dose cytarabine failure, and mutations did not significantly impact response in this small cohort. The median OS from the time of CLAG(M)/Ven initiation was 5.5 months with a median follow up of 8.6 months (Figure 1). OS from the date of CLAG(M)/Ven was significantly shorter in pts with TP53 mutation vs. wild-type (2 vs. 11.2 months, p=0.031). Conclusions: Our findings showed the combination regimen CLAG(M)/Ven is feasible in pts with AML. It also provided better characterization in terms of early mortality and survivals in these pts, which can help inform future clinical trial design. ORR was similar to what was previously reported with CLAG(M); however, it is encouraging that those who achieved CR/CRi and had MRD testing also achieved MRD negativity. Outcomes of TP53-mutated subset is dismal suggesting IC-based approach in this setting is limited. Larger cohort and longer follow up is needed to confirm the impact of factors such as specific regimen, mutations, and prior therapies on outcomes.

A Retrospective Study of Patient Characteristics, Treatment Patterns and Outcomes in Patients with Primary CNS Lymphoma

INTRODUCTION: Primary CNS lymphoma (PCNSL) is a rare lymphoma subtype. Treatment with whole brain radiotherapy (WBRT) resulted in high response rates but poor overall survival and modern therapy typically involves combination chemotherapy regimens that include rituximab and high dose methotrexate and, in some cases, followed by consolidative chemotherapy such as autologous stem cell transplantation (ASCT). However, there is no standard regimen, and the choice is institutional and/or physician preference. We performed a single institution retrospective study evaluating the outcomes of patients with PCNSL with focus on outcome stratified by POD24. METHODS: We performed a retrospective analysis of patients with PCNSL at Cleveland Clinic between January 1, 2010 to December 31, 2020, at the Cleveland Clinic. Patients were excluded if there was any evidence of disease outside of the CNS. Progression-free survival (PFS) and overall survival (OS) after diagnosis were estimated using the Kaplan-Meier method and compared by log rank test. OS was estimated for patients with an event within 24 months (POD24) from the time of this event to death or last follow up. RESULTS: Data from 80 consecutive eligible patients were analyzed with a median follow up of 44 months. The median age at diagnosis was 63 (range 24-87) and 55% were female. Only a small minority of patients were being treated with immunosuppressants at diagnosis (12%). Of the patients receiving induction therapy, 35% received R-MPV, 20% received R-HDMTX, 4% received HD-MTX alone, 4 % received WBRT as a frontline treatment. 16% of patients received no therapy. The overall response rate to induction therapy was 62% (56% CR and 6% PR). The majority of patients did not receive consolidation treatment (59%). Of those who did receive consolidative therapy, non-myeloablative high dose cytarabine was the most frequently used strategy. Thirty-six patients progressed (45%) and of these, the majority (67%) occurred within 24 months of starting therapy. For the entire cohort, the median PFS was 16 months, and the median OS was 32 months. The 1-year and 5-year OS rates were 66% and 34%, respectively. An ECOG performance status of 0 or 1 was associated with significantly improved PFS and OS (p < 0.0001 for both. Median OS after PD for patients with POD24 was 6 months [95% confidence interval (CI) 4-NA] with only 42% alive at 1 year. CONCLUSION: This large retrospective study evaluating all patients with B-cell NHL PCNSL with extended follow up shows that the majority of progressive events occur within 24 months and is associated with poor outcomes. Rituximab and polychemotherapy regimens are now favored over rituximab and methotrexate alone to improve response rates. Our data show that emphasis on strategies for consolidation such as high dose chemotherapy and autologous transplantation are needed to prevent progression.

Updated Results on a Multicenter Phase II Study of a Dose Intensified Pediatric Regimen in Adults with Acute Lymphoblastic Leukemia: The 06-254 DFCI ALL Consortium Trial

Background: Adolescent and young adult (AYA) patients (pts) with acute lymphoblastic leukemia (ALL) have good outcomes when treated with pediatric regimens (DeAngelo Leukemia 2014; Stock Blood 2019). Here we update our multi-center Phase II study (06-254) applying the DFCI pediatric regimen to young adults, as well as our post-trial experience. The 06-254 protocol is based on the very high-risk arm of the DFCI Pediatric Protocol 05-001. This report focuses on Philadelphia negative (Ph-) pts. Methods: Pts between 18-50 years (yrs) with de novo ALL were eligible. The primary objective was to determine the feasibility of a single dose of pegylated-asparaginase (PEG-ASP) during induction followed by a 30 week PEG-ASP consolidation. Induction chemotherapy included doxorubicin, prednisone, vincristine, PEG-ASP, and intra-thecal chemotherapy (IT). Consolidation I consisted of high-dose methotrexate (A), followed by a BFM-like intensification (B), and a course of high-dose cytarabine, etoposide and dexamethasone (C). Central nervous system prophylaxis included intrathecal therapy and cranial radiation. Intensification therapy consisted of eight 3-week courses of doxorubicin, vincristine, dexamethasone, 6-MP and 30 weeks of PEG-ASP. Dosing of PEG-ASP was initially 2500 IU/m2 every 2 weeks but due to toxicity was reduced to 2000 IU/m2 every 3 weeks and given concomitantly with consolidation. Body surface area was capped at 2.3m2 for PEG-ASP dosing. Continuation therapy consisted of 3 week courses of vincristine, dexamethasone, methotrexate, and 6-MP until 2 yrs from complete remission (CR). Additional consecutive Ph- pts treated “as per” 06-254 (2009-2021) were identified; these pts received treatment following 06-254 including PEG-ASP 2000 IU/m2 every 3 weeks in consolidation. Median follow-up was calculated with the reverse Kaplan Meier indicator. The chi square test was used to compare categorical characteristics. Overall survival (OS) and event free survival (EFS) among groups were compared with the log rank test. Results: A total of 152 Ph- pts were treated from 2007 to 2021 (89 pts on protocol and 63 “as per”). Median follow up was 3.5 yrs for pts treated on protocol and 3.8 yrs for pts treated “as per.” Characteristics at diagnosis: Median age 27.9 yrs (82, 54% < 30 yrs); 39.5% female; 31.6% T-lineage; 53.3% overweight/obese BMI per CDC criteria. Older pts (30-50 yrs) were more likely to be overweight/obese than younger (18-29y) pts (71.4% vs. 37.8%, p < 0.001) and were more frequently allografted in CR1 (21.4% vs. 9.8%, p = 0.045). CR was achieved by 142 (92.1%) pts. Among 81 (53.3%) pts with known end-induction measurable residual disease (MRD) status, 68 (84.0%) were MRD negative. In total, 88 (57.9%) pts completed all protocol treatment, 9 (5.9%) had induction failure, 3 (2.0%) died during treatment, 13 (8.6%) relapsed during treatment, 16 (10.5%) exited the protocol for other reasons, and 22 (15.1%) were consolidated with bone marrow transplant (BMT) in CR1. Among the 95 patients who remained on protocol for at least 1 year, 73 (76.8%) had ≥ 26 wks of asparagine depletion. Regarding toxicity: 21 pts (13.8%) had clinical pancreatitis, 98 (64.5%) experienced grade 3-4 laboratory hepatotoxicity, and 20 (13.1%) had allergic reactions to ASP. OS of the entire cohort was 84.4% (95% CI 77.4-89.3) at 3 yrs and 75.8% (95% CI 67.0-82.6) at 5 yrs. Pts aged 18-29 yrs had superior 5-yr OS to those aged 30-50 yrs (82.4% [95% CI 69.4-90.2] vs. 67.1% [95% CI 53.3-77.7], p = 0.004), and pts with a BMI < 25 at diagnosis had superior 5-yr OS than those with BMI ≥ 25 (87.1% [95% CI 73.5-94.0] vs. 66.5% [95% CI 53.9-76.5], p = 0.002). Patients with negative MRD at end of induction had a 5-yr OS of 80.7% (95% CI 66.7-89.3) and those with positive MRD 59.1% (95% CI 21.8-83.4) (p = 0.16). Pts treated “as per” had superior 5-yr OS to those treated on protocol (86.0% [95% CI 71.3-93.5] vs. 68.7% [95% CI 56.5-78.1], p = 0.012). EFS was 77.1% (95% CI 69.0-83.3) at 3 yrs and 70.6% (95% CI 61.4-78.0) at 5 yrs. Pts aged 18-29 yrs had superior 5-yr EFS compared to those aged 30-50 yrs (76.3% [95% CI 63.0-85.3] vs. 62.8% [95% CI 48.8-74.0], p = 0.033). Treatment on trial (compared to “as per”), BMI, and MRD status were not statistically associated with EFS. Conclusions: The administration of a pediatric regimen with dose intensified PEG-ASP to population between 18-50 is feasible and results in a high remission rate with 5-yr OS 75.8%.

Final Results of the AIEOP (Associazione Italiana Ematologia/Oncologia Pediatrica) AML 2013 Prospective Randomized Trial in Childhood Acute Myeloid Leukemia (AML)

Background: Treatment of children with newly diagnosed AML is based on induction therapy, followed by consolidation approaches which differ according to the group of risk patients (pts) are allocated to. In this respect, most treatment protocols stratify pts into 3 risk groups, namely standard (SR), intermediate (IR) and high-risk (HR), mainly based on the molecular/cytogenetic characterization and values of measurable residual disease (MRD) at the end of induction therapy. We report the outcomes of 371 pts with de novo AML other than acute promyelocytic leukemia (aged 0-18) enrolled in the randomized trial AIEOP AML 2013 (EudraCT:2014-000652-28). Patients and methods: pts were diagnosed and enrolled in the trial from 06/2015 to 06/2022 at 33 Centers affiliated to the AIEOP group. Main pt characteristics and criteria used for stratification are shown in Table 1. A marker of recurrent molecular lesions was detected at diagnosis for 247 cases out of the 371 enrolled (67%). Monitoring of flow-cytometry MRD at the end of the 1 st and 2 nd induction course was centrally performed in all pts but 7. The 1 st induction course was common for all pts (ICE scheme), while, then, SR pts were treated with 4 additional chemotherapy courses, all including high-dose cytarabine (HD-Ara-C). IR and HR pts were randomized to receive either a 2 nd ICE or the FLA-Liposomal Doxorubicin (L-Doxo) scheme as 2 nd induction course. IR pts were given 3 additional consolidation courses including HD-Ara-C with other agents or, in the presence of an HLA-compatible sibling, 1 consolidation course followed by allogeneic hematopoietic stem cell transplantation (HSCT). Pts of the HR group were consolidated with 2 courses of HD-Ara-C combined with other cytotoxic agents and, then, had an indication to receive HSCT from either a donor compatible for > 9/10 HLA loci or from an HLA-partially matched relative. Data cut-off for the analysis was March 31, 2023. Results: The proportion of pts allocated to the SR, IR and HR groups were 19% (72 pts), 23% (81 pts) and 58% (218 pts), respectively. Overall, 92% of pts obtained morphological complete remission (CR) at the end of the 2 induction courses [as compared to 87% of the previous AIEOP AML 2002 study (Pession et al. Blood 2012), p<0.05]. Twenty-five pts (7%) experienced a primary induction failure. Only 3 pts died during or after the 2 induction courses, while the subsequent cumulative incidence of 3-yr non-relapse mortality in continuous CR was 6.8%. Leukemia recurrence occurred in 63 pts, this leading to a 3-yr cumulative incidence of relapse of 18.9%. With a median follow-up of 4.5 yrs (range 0.8-8), the 3-yr probabilities of overall (OS) and event-free survival (EFS) were 83.9% and 68.5% (Figure 1), respectively, both values being significantly better (p<0.01) than those of the AIEOP AML 2002 study. The 3-yr OS of SR, IR and HR pts were 99.2%, 84.2% and 79.4%, respectively (p=0.01). The 3-yr estimate of disease-free survival (DFS) was 74.3%, with no difference among the 3 risk groups. The EFS did not differ in IR and HR randomized to receive either a 2 nd ICE or the FLA-L-Doxo scheme as second induction course. Levels of flow-cytometry MRD after the 2 nd induction course strongly influenced the probability of EFS which was 76% and 48% in pts with an MRD value < or >0.1%, respectively (p<0.01). Allogeneic HSCT was performed in 160 pts; in these pts, the 3-yr probabilities of OS and DFS were 87.7% and 85.1%, respectively, with no difference according to the type of donor employed. The DFS of the 10 IR pts given HSCT was 100% as compared to 72.1% of the 71 not transplanted (p=0.07). The outcome of infants treated in this study was particularly good, since their 3-yr probability of EFS was 78.3%. The 3-yr EFS of the 35 pts with FLT3-ITD and of the 75 with KMT2-A rearrangements were 57.1% and 64.7%, respectively. Conclusions: These results indicate that in children enrolled in the trial AIEOP AML 2013 the 3-yr OS and EFS overcomes 80% and approaches 70%, respectively, with a significant improvement as compared to the previous AIEOP protocol. Disease recurrence/primary resistance were the main cause of treatment failure, while the probability of DFS did not differ among the 3 different risk groups, this finding indicating that tailoring of consolidation therapy according to the risk profile was successful in improving the outcome of pts with worse prognostic characteristics. The use of FLA-L-Doxodid not offer any advantage over repeating a 2 nd ICE.

Intensification of Therapy and Pharmacogenetic Personalization Mitigate Racial Disparities in Pediatric Acute Myeloid Leukemia Outcomes

Introduction Recent reports have highlighted disparities in outcomes for black children, adolescents, and young adults with acute myeloid leukemia (AML) compared to their non-Hispanic white counterparts. An analysis of pediatric AML patients treated from 1996-2013 revealed that black race was associated with inferior event-free survival (EFS) and overall survival (OS) (Conneely 2021). In a study of adolescent and young adult patients with AML, black race was a predictor of poor outcome, particularly among patients 18-29 years old (Larkin 2022). Addressing these outcome disparities and developing treatment strategies to overcome them is crucial. In this study, we evaluated the interactions between outcomes by race and cytarabine pharmacogenomics in pediatric AML patients treated on two multi-institutional clinical trials. Methods Pediatric patients with newly diagnosed AML treated on AML02 (NCT00136084) or AML08 (NCT00703820) were included. Patients received high-dose cytarabine, daunorubicin, and etoposide (HDAC), low-dose cytarabine, daunorubicin, and etoposide (LDAC), or clofarabine and cytarabine (Clo/AraC) as initial therapy. The pharmacogenomics ACS10 scores, derived from combination of 10 single nucleotide polymorphisms, were calculated as reported (Elsayed 2022). Results Overall, 86 patients were black and 359 were white; 68 had other or unknown racial backgrounds and were not included in this analysis. Complete remission rates after two courses of induction therapy did not differ between black and white patients (92.6% vs 95.0%, p=0.63), nor did the rates of MRD negativity after one course of therapy (55.8% vs 55.4%, p=0.85). The EFS rates of black and white patients were nearly identical, with 5-year estimates of 58.3% (95% CI = 48.8%-69.8%) and 58.2% (95% CI = 53.2%-63.6%; p=0.89, Fig 1). Likewise, OS did not differ between black and white patients (63.8%; 95% CI = 54.3%-74.8% vs 69.4%; 95% CI = 64.7%-74.5%; p=0.24). The cumulative incidence (CI) of relapse did not differ by race (26.0% vs 26.1%, p=0.99), nor did the CI of treatment-related mortality (7.0% vs 6.8%, p=0.78). The prevalence of core binding factor (CBF) leukemia was higher in black patients as compared with white patients (30% vs 19%, p=0.04), but we did not find differences in EFS between black and white patients with or without CBF AML. We recently showed that low ACS10 scores were associated with worse outcomes in patients treated with low-dose cytarabine-based induction. In the present study, there was a significant difference in the distribution of ACS10 scores according to race, with low scores occurring in 73% of black patients compared with 30% of white patients (p<0.001). When patients on all treatment regimens were considered, there were no differences in EFS between black and white patients with low (p=0.88) or with high ACS10 scores (p=0.72). However, black patients with low ACS10 scores had significantly better outcomes after treatment with Clo/Ara-C induction compared with LDAC induction (p=0.01 for EFS and p=0.04 for OS, Fig 2). In multivariable model adjusting for age, risk group, and leukocyte count, Clo/Ara-C induction was identified as the best treatment option for black patients with low ACS10 scores (EFS: HR = 0.2, p=0.03). Discussion Our findings contrast with recent reports, as we did not observe significant outcome differences between black and white patients in terms of complete remission rates, EFS, OS, CI of relapse, or CI of treatment-related mortality. The higher prevalence of low ACS10 scores in black patients compared with white patients likely contributes to outcome disparities observed among patients treated with LDAC in the present study and those in the literature, which have included patients who almost exclusively received low-dose cytarabine-based induction therapy. In the present study, black patients with low ACS10 scores had significantly worse outcomes compared to those with high scores when treated with LDAC. However, these differences in outcome were eliminated by the use of HDAC or Clo/Ara-C induction. By contrast, black patients with high ACS10 scores did not appear to benefit from HDAC or Clo/Ara-C induction. Our results suggest that pharmacogenomics differences between black and white patients should be considered when tailoring induction regimens to improve outcomes of black patients and bridge the racial disparity gap in AML treatment.

Kinetics of Complete Remission (CR) and CR Duration and Its Impact on Overall Survival (OS) and Event-Free Survival (EFS) in Quantum-First

Background Results from the phase 3 QuANTUM-First study (NCT02668653) showed that in patients (pts) with newly diagnosed (nd) acute myeloid leukemia (AML) and positive for FMS-like tyrosine kinase 3-internal tandem duplication ( FLT3-ITD+), the addition of the oral, highly potent, and selective, type 2 FLT3 inhibitor quizartinib (Quiz) to standard chemotherapy ± allogeneic hematopoietic cell transplantation (allo-HCT), followed by continuation monotherapy for up to 3 years, decreased the relative risk of death by 22.4% vs placebo (PBO) (PMID: 37116523). We assessed 1) the impact of CR duration on OS and EFS and 2) the kinetics of CR achievement over time after induction. Methods QuANTUM-First enrolled pts aged 18-75 years with FLT3-ITD+ nd AML, randomized to receive standard induction chemotherapy with either Quiz (40 mg/d) or PBO, and stratified by region (Europe, North America, or Asia/Australia/South America), age (<60 years, ≥60 years), and white blood cell count (WBC; <40×10 9/L, ≥40×10 9/L) at diagnosis. Pts who achieved CR or CR with incomplete hematologic recovery (CRi) received up to 4 cycles of high-dose cytarabine combined with Quiz (40 mg/d) or PBO and/or allo-HCT followed by up to 3 years (36 cycles) of continuation therapy with Quiz (30-60 mg/d) or PBO. OS was the primary endpoint, EFS and rates of CR and composite complete remission (CRc) were secondary endpoints; CR duration was an exploratory endpoint. The impact of CR duration on OS was analyzed by extended Cox regression model stratified by region, age, and WBC count at diagnosis and included treatment group and CR duration status (time-dependent covariate). CR duration status was 0 for pts who did not achieve CR, 1 for CR pts throughout the duration of sustained CR, and 0 for CR pts after they relapsed. Results Of the 539 randomized pts enrolled in QuANTUM-First (Quiz, n=268; PBO, n=271), there were 297 CR pts (Quiz, n=147; PBO, n=150) based on independent review committee assessment after 1 to 2 courses of induction. Among 533 treated pts, 20% had 2 induction cycles. Baseline characteristics in CR pts were well balanced between arms: median age in years (range), 56.0 (23-75) vs 55.5 (20-74); females, 55.8% vs 60.0%; ECOG ≥1, 64.6% vs 63.3%; mutated NPM1 / CEBPA,66.7% vs 64.7% / 25.9% vs 23.3%; variant allele frequency (VAF) >25%, 68.7% vs 66.7%; and WBC count at diagnosis ≥40×10 9/L, 55.8% vs 49.3%. Median OS in CR pts was not reached (95% CI 48.6 months-NE) in the Quiz arm vs 35.4 (95% CI 15.1-NE) months in the PBO arm (HR 0.572, 95% CI 0.400-0.816; Figure 1). Although CR rates were similar between arms (55% in both), median CR duration was longer with Quiz vs PBO (38.6 months, 95% CI 21.9-NE vs 12.4 months, 95% CI 8.8-22.7; HR 0.621, 95% CI 0.451-0.857). Based on the extended Cox model, CR duration status covariate was strongly predictive for OS (HR 0.156, 95% CI 0.113-0.216; nominal P<0.0001; Figure 2). Importantly, the HR for Quiz vs PBO effect on OS in the model with the time-dependent covariate CR duration status was higher (HR 0.851, 95% CI 0.672-1.076) vs the HR of the primary OS analysis (HR 0.776, 95% CI 0.615-0.979), implying that a substantial fraction of OS benefit was mediated through its effects on achieving a durable CR (Figure 2). EFS favored Quiz over PBO when induction treatment failure (ITF) was defined as not achieving CRc or CR, by the end of induction up to day 56 from the last induction cycle, with HR 0.729 (95% CI 0.592-0.897; nominal P=0.0031) and 0.818 (95% CI 0.669-0.999; nominal P=0.032), respectively. EFS was similar between arms when ITF was defined, according to FDA guidance, as not achieving CR by day 42 from the start of the last induction cycle (HR 0.916, 95% CI 0.754-1.114; P=0.24; primary EFS analysis). Between day 42 and the end of the induction phase, there were 51 pts who achieved CR (Quiz, n=33; PBO, n=18), and they were considered as ITF with EFS event on day 1 in the primary analysis of EFS. Among these 51 pts, 9 (Quiz, n=5; PBO, n=4) had CRi by day 42 and became CR after day 42 in the induction phase. Conclusions These analyses demonstrated that in QuANTUM-First: 1) a substantial fraction of the estimated effect of Quiz on OS was mediated through its effect on achieving a durable CR and 2) more pts in the Quiz arm vs the PBO arm achieved CR after day 42 of the last induction cycle, suggesting that there was a delay in CR achievement with Quiz. Longer EFS was observed in Quiz over PBO based on the EFS definition including CRs between day 42 and end of induction.

Care Patterns and Barriers to Outpatient Care for Adults with Acute Myeloid Leukemia (AML) Following Intensive Chemotherapy at National Comprehensive Cancer Network (NCCN) Institutions

Background: Prolonged hospitalization following intensive (re)induction chemotherapy until resolution of cytopenias is the current standard of care for adults with acute myeloid leukemia (AML), but this approach is costly, resource intense, contributory to hospital bed shortages, and negatively impacts patients' quality of life (QOL). Early hospital discharge (EHD) immediately following completion of chemotherapy has been proposed as an alternative and has proven safe at select institutions. Here, we conducted a National Comprehensive Cancer Center (NCCN) survey, through its Best Practices Committee (BPC), to examine discharge practices for adults with AML at other major cancer centers to better understand interest in, and barriers to, adopting an EHD approach more broadly. Methods: NCCN is a non-profit alliance of 33 cancer centers in the U.S. The survey was developed by 2 physicians at one center and piloted at 2 other centers. The NCCN BPC, which is composed of senior physician, nursing, and administrative leaders from NCCN Member Institutions, distributed the survey in early 2023 via a web-based survey tool (SurveyMonkey, San Mateo, CA) to a representative at each center, requesting completion by a content area expert. No incentives were offered for completion. Data were analyzed using descriptive statistics. Results: 30/33 (91%) centers completed the survey, 60% of which treat >100 AML patients annually and 45% treat over half of their patients with intensive chemotherapy (7+3 or regimens with a high-dose cytarabine backbone). All centers perform allogeneic hematopoietic cell transplantations (HCT). There was no difference in the proportion of intensively treated patients across centers by patient volume. Following (re)induction therapy, 80% of institutions keep patients hospitalized until blood count recovery, whereas 20% attempt to discharge patients early if medically stable and logistics permit. Concerns regarding patient safety, housing, and caregiver availability were the main reasons for keeping patients hospitalized ( Figure 1). In contrast, following post-remission (“consolidation”) therapy, 87% of centers discharge patients early. Concerns regarding increased care needs, worse functional status, and higher complications risks following induction relative to post-remission therapy accounted for the main reasons for this difference ( Figure 2). 80% of centers were interested in exploring EHD after (re)induction but noted barriers including affordable local housing (71%), transportation (50%), high toxicity/infection rate (50%), high transfusion burden (50%) and limited bed availability when re-hospitalization is necessary (50%). Among the 6 centers that practice EHD, all have infusion centers with full weekday hours, 5 have full weekend/holiday hours, 3 more have evening hours, and 1 has reduced holiday/weekend hours. All can provide blood product support within 4 hours from ordering and administer IV antimicrobials within 1 hour from ordering in outpatient clinic. In 4 centers, evaluation of a patient with presumed neutropenia contacting the clinic with fever during regular hours can occur in the outpatient clinic, with subsequent admission if necessary; at one center the patient would be referred to the ED and at one center the patient would be directly admitted to an inpatient ward. If a patient needs admission, a bed would be available for direct admission to the inpatient ward in 4/6 of the centers >75% of the time, at 1 center 26-50% of the time, and at 1 center <25% of the time. EHD was not practiced at any centers in cities with population of >1 million, citing local housing availability as a major EHD barrier. There was no correlation between the ability to practice EHD and annual AML patient volume, treatment intensity patterns, or hospitalization practices following HCT. Conclusions: Hospitalization and care patterns following AML therapy are highly variable across major U.S. cancer institutions. While only 20% of major cancer centers surveyed practice EHD following intensive (re)induction chemotherapy, 87% do so following post-remission therapy. There is interest in exploring this approach despite medical and logistical barriers. Given potential advantages of EHD for both patients and healthcare systems, strategies to address these barriers should be explored to reduce healthcare resource utilization and improve patients' QOL.

High-dose cytarabine induction therapy and flow cytometric measurable residual disease monitoring for children with acute myeloid leukemia.

High-dose cytarabine induction therapy and flow cytometric measurable residual disease monitoring for children with acute myeloid leukemia.

Venetoclax Plus High-Dose Cytarabine and Mitoxantrone (HAM-Ven) As Salvage Treatment for Relapsed/Refractory AML: Updated Results of the Phase-I/II SAL Relax Trial

Background Primary refractory disease and relapse remain the main obstacles for cure in AML. In fit patients, several salvage cytostatic options based on higher doses of cytarabine have been published, with complete remission (CR) rates ranging from 40-55%. The BCL2 inhibitor venetoclax has demonstrated impressive antileukemic activity when combined with hypomethylating agents or low-dose cytarabine in newly diagnosed unfit AML patients. In the phase-I part of the RELAX trial of the Study Alliance Leukemia (SAL), we demonstrated the feasibility of combining venetoclax with higher-dose cytarabine plus mitoxantrone (HAM) in relapsed AML, resulting in a CR/CRi rate of 92%. Here, we report the updated results from the phase-I and additional patients from the phase-II dose expansion in relapsed or refractory (r/r) AML patients. Methods Patients with r/r AML fit for intensive salvage treatment were eligible. Based on the safety results from the phase-I part, patients were treated with the recommended phase-II dose combination of 400 mg venetoclax PO QD (d1-14) including a 2-day ramp-up, followed by cytarabine 1000 mg/m 2 IV BID (d3-5) in combination with mitoxantrone 10 mg/m 2 IV QD (d5-7). Concomitant CYP3A inhibitors were allowed with the appropriate dose adjustments, patients did not receive G-CSF. Patients achieving a CR could enter a maintenance phase with 400 mg venetoclax PO QD over twelve 28-day cycles. This research was supported by a grant from AbbVie Inc. The trial is registered under NCT04330820. Results Between April 2020 and June 2023, 12 patients were enrolled in the dose-escalation part and 40 patients in the expansion part, of whom 38 were evaluable for response by the time of writing. Median follow-up was 6.7 months. Among the 12 patients in the dose-escalation part, 3 received 200 mg/m 2 cytarabine QD over seven days, 3 received 500 mg/m 2 BID over three days and 3 received 1000 mg/m 2 BID over three days, each with identical doses of venetoclax (400 mg PO QD d1-14) and mitoxantrone (10 mg/m 2 IV QD d5-7). Of all 38 evaluable patients, 17 (44.7%) had adverse genetic risk according to ELN2022, and 1 (2.6%) had progressed from antecedent MDS. Median age was 56 years (range, 26-74 years). All patients experienced CTCAE grade ≥3 cytopenias. A median number of two non-hematologic grade 3 and 4 adverse events (AEs) in 32 patients with sufficient data were recorded. Grade 3 and 4 AEs occurring in ≥ 10% of patients included febrile neutropenia, pneumonia, sepsis and gastrointestinal disorders. The 30- and 60-day mortality was 2.6% and 5.2%. Remission assessment showed CR/CRi in 31/38 patients (81.6%). Among the seven patients with no CR/CRi, six showed refractory disease and one died in aplasia before response assessment. CR/CRi rate was 100% (8/8), 81,8% (9/11) and 70.6% (12/17) in patients with favorable, intermediate, and adverse risk, respectively. Utilizing LAIP-based DFN MRD approach, 7/32 (21.9%) evaluable patients were classified as MRD negative (CR/CRi MRD-). In 7/25 (28%) CR/CRi MRD+ patients, the MRD burden was below 0.1% CD45 + events. Of all 31 CR/CRi patients, 26 are in ongoing CR/CRi, 16 received allogeneic HCT as postremission treatment. Three patients died in CR from infectious complications after allogeneic HCT or post-remission treatment and two relapsed and succumbed to progressive disease. Six patients commenced maintenance treatment, of whom four are in ongoing remission. Discussion The combination of venetoclax with higher doses of cytarabine and mitoxantrone (HAM-Ven) is a well-tolerated and very efficacious treatment option leading to complete remissions in 81.6% of patients with r/r AML studied in the RELAX trial. Safety and efficacy compare favorably with published results from the FLAG-Ida-Ven regimen, thereby providing a less dose-intense, fludarabin-free approach for the treatment of fit r/r AML patients. Enrollment into the RELAX trial is currently ongoing. Updated results will be presented at the meeting.

Outcome of Acute Myeloid Leukemia in Adults Treated with Standard Chemotherapy-a Single Center Retrospective Study

Background: Acute Myeloid Leukemia (AML) is a heterogenous Hematopoietic stem cell disorder and standard therapy being intensive chemotherapy (IC) followed by consolidation with either high dose Cytarabine or Allogeneic Hematopoietic stem cell transplantation in intermediate and high-risk patients. Though the outcome in younger & fit patients with IC in terms of CR rates and survivability are reasonable, however patients above 60 years may not benefit owing to increasing frailty, co-morbidities, adverse disease risk factors, chemo resistance and toxicities. Newer approaches with Novel/Targeted agents are being incorporated in treatment strategies in order to acheive better results and long-term survival. We report outcome of AML patients treated on standard chemotherapy at our institution. Methods: Total 208 Acute Myeloid Leukemia (AML) patients were treated at our institution between January 2017 and December 2022 and analyzed after institutional review board (IRB) approval. Data was collected from institutional data base and summarized by medians and Range for continuous variables, numbers and percentages for categorical variables & Survival estimates were obtained by Kaplan-Meier method. Results: Median age of our cohort was 46.5 years (range,17-90), Male patients were 57% (n-118) and 43% (n-90) were Female. Seventy-five (36%) were locals and 133 (64%) of other nationalities. Median WBC 11.5 x10^9/L (range 0.60-381); Hemoglobin 83 g/L (range 27-103), Platelets 53x10^9/L (range 2-791), Median Bone marrow blast were 50% and median LDH 357 U/L. Normal cytogenetics was present in 54.4% (n-111); 19%(n-39) were Core binding Factor (CBF), 3.5% trisomy 8 and 3.5% were complex cytogenetics. Major molecular mutations included FLT3-ITD (21%), NPM1 (18.3%), DNMT3A (11%), IDH1&2 (7%), TET2(5%), TP53(3.5%) and ASXL1(3%). As per European Leukemia Net (ELN 2017) risk stratification, Intermediate risk were 50% (n-104), Favorable 30% (n-63) and Adverse 20% (n-41). Total of 164 (79%) patients received intensive chemotherapy, 13(7%) Azacytidine and Venetoclax, 16(8%) low intensity and 12(6%) best supportive care (BSC). Intensive chemotherapy included Anthracyclines +Cytarabine and FLAG/FLAG-Ida (Fludarabine, Idarubicin, Cytarabine and G-CSF). Total of 136(65%) of patients achieved Complete Remission (CR/Cri) after 1 or 2 inductions. Major adverse events during induction were grade 4 cytopenia's and pneumonias. There were 26(13.6%) deaths during induction. Majority of patients received consolidation therapy with high dose cytarabine 1-3 g/M2 twice a day for 3 days for two to 3 cycles and 28(14%) underwent Allogeneic stem cell Transplantation. At a median follow up of 9.1 months, the 2 year and 5-year overall survival (OS) were 65% and 57% in whole cohort. ELN Favorable Risk group had a better survivability at 2 years (80%). Two-year OS in Patients above 60 and less than 60 years were 37% and 75% respectively. Conclusion: Intensive chemotherapy resulted in significant survival improvement in AML and has been standard of care for more than 3 decades. However significant advances in understanding the biology, risk categorization and development of newer novel therapies has led to alter the treatment strategy with better outcome. Our study underlines the fact that we need to incorporate the newer therapies in treatment plan to achieve these goals.

Hyperleukocytosis Does Not Present a Worse Prognosis in Acute Myeloid Leukemia (Non-APL) with Favorable Risk According to ELN-2022 Criteria: A Retrospective Study

Introduction: Acute myeloid leukemia (AML) with hyperleukocytosis, characterized by a white blood cell count ≥100,000/µL, is usually considered a subtype associated with poor prognosis. For AML patients with hyperleukocytosis, more aggressive treatment approaches, such as allogeneic hematopoietic stem cell transplantation (allo-HSCT), are commonly considered. However, when favorable-risk AML accompanies hyperleukocytosis, it is unclear whether the risk level needs to be redefined. There is also no universally accepted treatment strategy for this subtype. We conducted a retrospective, single-center study to investigate the impact of hyperleukocytosis on the response and prognosis of favorable-risk AML according to ELN-2022 risk classification. Method: We retrospectively enrolled 217 favorable-risk AML patients, excluding acute promyelocytic leukemia (APL), treated at Zhejiang University School of Medicine's First Affiliated Hospital from October 1st, 2021, to April 30th, 2023. Some of them have been treated in other hospitals. The diagnosis, risk classification, and response evaluation were determined according to ELN-2022 criteria. Patients were divided into two groups: the hyperleukocytosis group (white blood cell count ≥100,000/µL) and the non-hyperleukocytosis group (white blood cell count <100,000/µL). We compare these two groups on the response rate after the induction chemotherapy, the median overall survival (mOS), and median disease-free survival (mDFS), then evaluate different treatments and other prognostic factors associated with outcomes. Statistical analyses were carried out using SPSS 24.0. The Kaplan-Meier method and log-rank test were used to assess and compare the survival outcomes. Univariate Cox proportional hazards regression was used to determine associated risk factors for overall survival. A two-tailed P value <0.05 was considered statistically significant. Result: Totally 217 patients were enrolled. To balance the impact factors, 12 patients who received high-dose cytarabine were excluded from the non-hyperleukocytosis group. The cohort ready for analysis had 45 patients in the hyperleukocytosis group and 160 patients in the non-hyperleukocytosis group. Two groups had no significant differences in age; gender, FAB classification; platelet counts and hemoglobin level at initial diagnosis; co-existing intermediate/high-risk mutations according to 2022 ELN risk stratification; treated with high-dose cytarabine, or receiving bone marrow transplantation (all P＞0.05). The median follow-up time was 29.5 months, and 154 patients were still alive at the study endpoint. There were no significant differences in the composite complete remission (CRc) rates (73.3% vs. 79.3%, P= 0.389), mOS (65.0m vs. 56.0m, P= 0.574), and mDFS (54.0m vs. 35.0m, P= 0.855) between two groups. With high-dose cytarabine (2.0-3.0 g/m2 q12h X 3 days for at least three courses) as consolidation chemotherapy, the two groups had no significant difference in mOS (Not reached vs. Not reached, P=0.143) and mDFS (21.0m vs. 35.0, P= 0.352). In order to understand the impact of allo-HSCT on the hyperleukocytosis group, we divided this group into the allo-HSCT subgroup and the non-HSCT subgroup. After balancing on age, gender, presence of high-risk mutations, and MRD negativity after the first remission (all P>0.05), the mOS in the allo-HSCT subgroup (n=16) was significantly longer than the non-HSCT subgroup (n=16) (Not reached vs. 46.0m, P= 0.007). However, the mDFS had no significant difference between the two sub-groups (63.0m vs. 43.0m, P= 0.341). The univariate Cox proportional hazards regression analysis revealed that only age had a significant impact ( P= 0.01), all other factors had no significant effects, including hyperleukocytosis, gender, hemoglobin level, platelet count, intermediate/high-risk mutations, or bone marrow transplantation. Conclusion: In favorable-risk AML, hyperleukocytosis does not lead to an adverse prognosis. Received high-dose cytarabine as a consolidation therapy, favorable-risk AML patients with hyperleukocytosis do not have worse OS or DFS than those without hyperleukocytosis. Allo-HSCT may bring longer OS for hyperleukocytosis patients at favorable risk but may not bring longer DFS. Our results suggest favorable-risk AML patients with hyperleukocytosis can be managed equally as non-hyperleukocytosis patients.

Outcomes in Mantle Cell Lymphoma with Central Nervous System Involvement - a Dual Center Study

Background Central nervous system (CNS) involvement is a rare complication (<5% of cases) of mantle cell lymphoma (MCL) and is associated with poor outcomes, highlighting the need for novel treatment approaches. We report the outcomes of a large cohort of patients (pts) with CNS MCL from Mayo Clinic and Memorial Sloan Kettering Cancer Center (MSKCC). Methods MCL pts with CNS involvement seen at Mayo Clinic and MSKCC between 1/2000-1/2021 were included. CNS involvement was defined by histologically confirmed CNS MCL, CSF analysis demonstrating lymphoma cells, and/or neuroimaging findings compatible with CNS lymphoma. Medical records were reviewed for baseline characteristics, treatment, and outcomes. First-line MCL chemotherapy was categorized into higher intensity chemotherapy (i.e., anthracycline-based +/- high-dose cytarabine), moderate intensity chemotherapy (i.e., bendamustine-based regimens or single agent chemotherapy), and other. CNS treatment regimens were categorized as intrathecal (IT) therapy alone, systemic therapy (with CNS penetration such as IV cytarabine or IV methotrexate) with/without IT therapy, regimens with Bruton's tyrosine kinase inhibitors (BTKi), chimeric antigen receptor T cell (CAR-T) therapy, or radiation alone. Kaplan-Meier method was used for time to event analysis. Forest plots were developed using univariable Cox proportional hazards models. Results Seventy patients were included in the cohort, 34 from MSKCC and 36 from Mayo Clinic. Median age at MCL diagnosis was 65 years (range 56-72) and 52 were male (74%). MIPI score was available in 60 pts: low (n=10, 17%), intermediate (n=20, 33%), and high (n=30, 50%) risk. First line therapy included: higher intensity chemotherapy (n=42, 60%), moderate intensity chemotherapy (n=25, 36%) and other (n=3, 4%). Twenty-five (36%) pts underwent autologous hematopoietic cell transplantation in CR1. Median time from initial MCL diagnosis to CNS involvement was 24 months (m) (range 0-167). Four (6%) pts had CNS involvement at initial diagnosis. Abnormal CNS imaging was reported in 53 (76%) pts: leptomeningeal (n=37), leptomeningeal and parenchymal (n=4), parenchymal (n=8), orbital (n=4). The most common regimen following CNS diagnosis was systemic therapy with or without IT therapy (n=34, 54%) followed by treatment including BTKi (n=13, 21%), IT alone (n=10, 16%), radiation alone (n=3, 5%), and treatment including CAR-T (n=3, 5%). Three patients elected hospice care and four patients had missing/unknown CNS treatment. The overall CNS response to therapy was available in 54 patients: CR in 22 (41%) pts, PR in 8 (15%), SD in 11 (20%), and PD in 13 (24%) pts. Of the 70 patients, 63 died. Median follow up was 6.9 years (range: 1.6-11.2) from initial MCL diagnosis and 2.1 years from CNS diagnosis (range: 0.4-7.9). Median OS from MCL diagnosis was 3.4 years (95% CI: 2.4-4.6). In univariable Cox models, sex, stage, performance status, Ki67, or first line systemic chemotherapy type were not significantly associated with OS from MCL diagnosis. Low risk MIPI score (score < 5.7) was associated with favorable OS (HR 0.31, 94% CI: 0.12-0.77; p value 0.01) compared to high risk. First-line treatment and treatment intensity were not associated with a significant difference in OS. Median PFS for the first CNS-directed therapy was 2.4 m (95% CI: 1.7-4.3). Cause of death was disease-related in a majority (n=49, 78%) of pts and therapy-related in 10% (n=6). The remaining 8 deaths had cause of death reported as missing or other (13%). Median OS from CNS involvement was 5.1 m (95% CI: 3.3-10.0) (Figure 1). When assessing OS from time of CNS diagnosis, treatment regimens incorporating BTK inhibitors were associated with a more favorable OS compared to systemic therapy +/- IT therapy (HR=0.37, 95% CI: 0.16-0.89, p value=0.03) (Figure 2). Conclusions Our dual center series confirms patients with CNS involvement by MCL have poor outcomes. When evaluating OS from the time of CNS diagnosis, novel therapies, including BTKi and CAR-T, may be more effective than CNS-penetrant chemotherapy for treatment of CNS relapse suggesting newer therapeutic approaches are required to improve outcomes.

Significance of the Apoptotic Regulators BAX, BCL2, BCL- XL and MCL1 in Newly Diagnosed AML

Introduction: In acute myeloid leukemia (AML), cytogenetics and molecular mutations remain important prognostic tools for tailoring treatment after induction therapy. Abnormalities in multiple components of apoptotic pathways have been identified as potential drivers of AML. Identifying other biomarkers may help us further refine prognosis and identify other therapeutic strategies. B-cell lymphoma 2 (Bcl2), Bcl-xL and myeloid cell leukemia-1 (Mcl1) are commonly expressed prosurvival proteins in hematologic malignancies, whereas Bax acts as a promoter of apoptosis. We retrospectively evaluated the significance of Bax, Bcl2, Bcl-xL and Mcl1 expression in newly diagnosed AML patients using the Beat AML program 1. Methods: We analyzed RNA-expression data from The Beat AML study (672 tumor specimens collected from 562 patients) 1. Data was extracted from the public database. Different expression levels of the above genes were compared using t-tests. Results were considered significant with p-value < .05. Kaplan-Meier curves were used to estimate survival. Results: For the correlative survival analyses, Bax, Bcl2, Bcl-xL and Mcl1 mRNA expression and clinical information were both obtained from the BeatAML cohort 1. Patients were categorized into high expressers (≥ median) and low expressers (<median). In total, 461 patients had available gene expression data. The mean age of diagnosis was 57 years, and 56.6% of patients were male. The most common specific diagnosis at inclusion was AML with mutated NPM1 (22%), followed by AML with myelodysplasia related changes (21%) and AML, NOS (11%). Complete response to induction was seen in more than half (56%) of the patients for which response was recorded (n=369). Others developed refractory AML (32%). No data was available for 12%. Standard chemotherapy (induction therapy with idarubicin and cytarabine (7+3) and consolidation therapy with high dose cytarabine) was used in 98.4% of these patients. Over half of the analyzed samples were peripheral blood (52%), and the remaining samples were either bone marrow aspirate (46%) or from leukapheresis (2%). Most of the specimens were collected at initial acute leukemia diagnosis (62.2%), others were collected with residual disease or post chemotherapy (25.1%). The mean survival for this cohort was 13.7 months. Above median expression of Mcl1 was associated with longer survival (33 vs. 20 months; p = 0.0262). Above median expression of Bax was also associated with longer survival (32 vs. 18.2 months; p = 0.0114). In the Bax analysis, gene expression was further subdivided into 4 quartiles which showed correlation of expression levels with length of survival (Figure 1). The prognostic significance of the ratio Bax/ (Mcl1+Bcl2+Bcl-xL) was also analyzed given the mechanism of action of these various regulators. A higher ratio was associated with longer survival (40.7 vs. 18.7 months; p = 0.0095) (Figure 2) Conclusions Bcl-2, Bcl-xL and Mcl-1 are commonly expressed antiapoptotic proteins, whereas Bax is a promoter of apoptosis. The results with Bax are consistent with previous literature. Our results with Mcl1 expression differed from what we may have expected. This may be due to the sample size or methodology. However, it may also be due to the fact that a ratio of the actors is needed to help predict prognosis (as we analyzed in Figure 2). The overall survival between Bcl-2 and Bcl-xL was compared independently, however, they did not appear to have a significant difference in survival between high and low expression groups. We are currently working to see if this ratio can be validated in a prospective cohort of relapsed/ refractory AML patients treated on clinical trial and this data will be presented at the meeting. The Bcl-2 inhibitor venetoclax has demonstrated promising results in treating AML. However, venetoclax appears to have limited activity as a single agent. Our study suggests that potentially a combination of agents targeting factors such as Bcl-2, Bcl-xL and Mcl-1 may be associated with improved survival in patients with AML. Further validation of these biomarkers is warranted, and Mcl-1 inhibitors are currently in clinical trials.

Characteristics and Clinical Outcomes of Patients with Acute Myeloid Leukemia with TP53 Mutations - a Single Center Experience

Introduction TP53-mutated acute myeloid leukemia (AML) carries a dismal prognosis. Optimal induction therapy is uncertain, and it remains unclear whether allogeneic stem cell transplant (allo-SCT) improves survival. Methods We investigated 89 cases of TP53-mutated AML diagnosed at or referred to Thomas Jefferson Hospital between April 2016 and May 2023 and reviewed clinical characteristics and outcomes. Remission status was determined by bone marrow biopsy and aspiration after at least 1 cycle of anti-leukemic therapy (ALT). ALT was classified into high- or low-intensity treatment. High-intensity treatment was defined as regimens containing high-dose cytarabine (≥ 200 mg/m 2/day) for at least five consecutive days in combination with an anthracycline. Low-intensity treatment was defined as hypomethylating agent (HMA)-based therapy containing either azacitidine or decitabine with or without venetoclax. Results Median age at diagnosis was 66 (range, 23-91). Forty-nine percent had de novo AML, and the rest had secondary AML. Ninety-one percent had newly diagnosed AML and 9% were found to have a TP53 mutation at relapse. Median somatic mutation count as detected by next-generation sequencing (NGS) was 2 (range, 1-9). Thirty percent were treated with high-intensity treatment, 46% with low-intensity treatment, and 22% received supportive care only. Detailed patient characteristics are in Table 1. Median overall survival (OS) for the entire group was 3.17 months [95% confidence interval (CI) 1.90-5.13 months], and 5.13 months (95% CI 3.83-8.00 months) for patients who received any ALT. Of 69 patients who received ALT, composite complete remission (CRc) rates were 26% with high-intensity treatment and 34% with low-intensity treatment ( p = 0.56). Fifty-six percent did not achieve a remission, and 12% were not able to be assessed due to early mortality. The 30-day mortality was 15% and 7% with high- and low-intensity treatments, respectively. OS was not different between patients who received high- and low-intensity treatments (5.13 months vs 5.27 months, p = 0.65). Twenty-four percent underwent allo-SCT with a median follow-up of 15.2 months. The median time to transplant was 180 days from time of diagnosis (range, 119-341). Median hematopoietic cell transplantation-specific comorbidity index was 3 (range, 1-7). The majority of patients (69%) received a reduced intensity or non-myeloablative regimen, and 63% received a haploidentical transplant. Eighty-one percent of transplant recipients were in CR or CR with incomplete count recovery at the time of transplant; the remaining had either primary induction failure or relapsed disease. Median OS was significantly longer for patients who received allo-SCT compared to those who received chemotherapy only (18.0 months vs 3.7 months, p <0.0001) (Figure 1). Cumulative incidence of relapse post-transplant was 36% at 1 year and 79% at 2 years. Conclusions TP53-mutated AML is associated with a dismal outcome. In our single-center analysis, approximately one-third of patients achieved remission after initial ALT. Consolidation with allo-SCT is associated with improved survival, however relapse risk remains high. Treatment strategies aimed at reducing disease relapse post-transplant are warranted.

Impact of the Current Treatments on the Survival of Patients with Mantle Cell Lymphoma (MCL): A Real-Life Study on Behalf of the Spanish Group of Lymphoma (GELTAMO)

Background: MCL remains incurable and its management is highly heterogeneous due to the lack of standard treatment. Since the results from prospective clinical trials are not always reproducible in real-life patients, the aim of this study was to analyze the management in clinical practice of patients with MCL in Spain and its impact on their survival. Methods: We retrospectively analyzed the clinical-biological characteristics and treatment patterns of patients (pts) with MCL from Spanish GELTAMO centers and their impact on overall (OS) and progression-free survival (PFS). First-line treatments (1L) were grouped as HiDAC (high-dose cytarabine or HiDAC-based) or non-HiDAC; second-line treatments (2L) as BTKi (BTK inhibitors), CIT (chemoimmunotherapy) or other (targeted agents other than BTKi). In patients receiving 1L at diagnosis, early progression/relapse (E-POD) was considered when occurring within 24 months (m) from diagnosis and late or L-POD beyond 24 m or no relapse at data cut-off. A follow-up time (FU) of ≥24m was required for patients to be evaluable for POD, except for those dying from MCL <24m, recorded as E-POD. Statistical analyses were performed with the R-4.1.0 software. Results: From January 2000-March 2023, 505 patients were diagnosed with MCL in 17 GELTAMO centers, their baseline characteristics are summarized in Table 1. At data-cut-off, 242 (47.9%) were alive, 17 (3.4%) lost to FU and 246 (48.7%) had died, being the lymphoma the main cause of death (50.4%). Sixty-five (12.8%) pts did not receive treatment at diagnosis, out of which 18 (28%) remain on observation at a median (M) FU=26 m (3-92). Out of 479 pts receiving 1L, 245 (51%) received 2L, 143 (30%) 3L, 75 (15.6%) pts 4L and <10% received 5-8 lines. Among 432 pts treated upfront (no observation prior to 1L), 423 were evaluable for response: 190 (44.9%) HiDAC and 233 (55%) non-HiDAC, with a predominance of anthracycline-based treatments (Figure 1). Overall (OR) and complete responses (CR) were higher with HiDAC vs. non-HiDAC (91%/78.4% vs. 82.8%/65.2%, respectively). In 394/432 pts evaluable for POD (149 E-POD and 245 L-POD), HiDAC was more frequently associated with L-POD (73.2% L-POD vs. 26.8% E-POD) than non-HiDAC (53.1% L-POD vs. 46.9% E.POD). Rituximab maintenance (RM) was given to 167 pts (prior HiDAC 48.5%, non-HiDAC 51.5%) and 80.7% of them were L-POD. ASCT was performed in 135 pts (prior HiDAC 83.7%, non-HiDAC 16.3%, followed by RM in 46%) and 86.1% were L-POD. In 2L, 232/245 were evaluable, 92 (39.6%) received iBTK (60 monotherapy, 11 with CT and/or rituximab), 122 (52.6%) CIT (bendamustine-based 24.6%, gemcitabine-based 36.5%) and 18 (7.75%) other salvage options (Figure 1), with no significant differences between iBTK and CIT regarding baseline characteristics or efficacy (OR/CR 60.8%/39.1% vs. 72%/56.5% for BTKi and CIT, respectively). With a M FU= 87.6m, M OS= 6.56 years (5.6-8.2) and M PFS= 34.3 m (29.86-43.43). Age>65 at diagnosis (HR=2.09, p<.001), blastoid variant (HR=1.77, p=.012), Ki67≥30% (HR=1.93, p=.001), non-CR after 1L (HR=2.20, p<.001) and E-POD (HR=5.21, p<.001) were associated with shorter OS (MVA) and blastoid variant (HR=1.83, p=.001) and Ki67≥30% (HR=1.65, p=.003) with PFS. ASCT and RM were significantly associated with longer PFS (HR=0.33 and HR=0.32, p<.001) in the MVA but only MR had impact on OS (HR=0.62, p=.031). After 2L, M OS-2= 30.01 m (25.23-46.42) and PFS-2= 12.42m (8.97-17.02), with no impact of BTKi in 2L (vs. CIT) on OS-2 (HR=0.64, p=.12) or PFS-2 (HR=0.73, p=.12). E-POD and HR-MIPI, however, were significantly associated with shorter OS-2 (HR=1.72, p=.03 and HR=2.08, p=.03, respectively) and PFS-2 (HR=1.91, p<.001 and HR=1.88, p=.005 respectively). Conclusions: The impact on survival of known risk factors such as older age at diagnosis, high Ki67, HR-MIPI, blastoid morphology, non-CR after 1L or E-POD was confirmed in our series, as well as the advantage in efficacy and risk of E-POD of HiDAC-based regimens vs. non-HiDAC in 1L. Regarding RM and ASCT in 1L, our results are in line with other studies, with RM associated with longer PFS and OS and ASCT showing advantage in PFS but not in OS. In 2L, the rate of OR/CR with BTKi in our cohort is like that reported in pivotal studies, but we did not find the survival advantage of BTKi over CIT observed in other retrospective studies.

Venetoclax Combined with “7+3” Induction Chemotherapy Induces High Rates of MRD-Negative Remission in Newly Diagnosed AML Patients Fit for Intensive Chemotherapy Irrespective of Age

Introduction: Approximately 70% of patients (pts) with acute myeloid leukemia (AML) treated with the “7+3” regimen achieve complete remission (CR), with 30-50% of those attaining measurable residual disease (MRD) negative state by multiparameter flow cytometry (MFC). However, despite initial responses, the majority of pts eventually relapse. Venetoclax (Ven) added to intensive chemotherapy (IC) facilitates apoptosis of leukemic stem cells (LSC), and may result in deeper, more durable remissions. Moreover, IC induces MCL-1 downregulation and may overcome Ven resistance. We present safety and efficacy results from a phase 1b study of escalating cumulative Ven doses combined with daunorubicin (Dauno)+cytarabine (AraC) followed by high-dose cytarabine (HiDAC) chemotherapy in pts with newly diagnosed AML (NCT05342584). Objectives: The primary objective of this study is to determine the optimal dose of Ven in combination with Dauno & AraC and HiDAC chemotherapy. Secondary objectives are response per 2022 ELN, survival (OS), event-free survival (EFS) and duration of response (DoR). A key exploratory objective is to assess rates of LSC eradication by means of MFC and single cell DNA (Tapestri, Mission Bio) and RNA sequencing (“high-resolution MRD assay”). Methods: Eligible pts must have a new diagnosis of AML, be 18-75 yrs of age and deemed fit for intensive chemotherapy. In a 3+3 design, Ven in escalating duration (400 mg D1-8 or -11 or -14, including 2-day ramp-up) is combined with AraC 100mg/m2 (D2-8) and Dauno 60mg/m2 (D2-4) in 2 separate age groups (<60 and ≥60yrs); Dauno 90mg/m2 was initially studied in pts < 60yrs, but since 04/2023 the dose is no longer explored. During consolidation, fixed dose Ven (200 mg x7days) is used in combination with age-adjusted HiDAC (1.5g/m2 in <60yrs and 1g/m2 in ≥60yrs, every 12hrs on days 1,3,5). In the expansion phase, additional pts in each age group will undergo 1:1 randomization between the starting and highest tolerated dose determined during dose escalation, for a total of 20 pts per dose cohort in both phases. Results: Twenty-seven AML pts enrolled and 25 completed the induction phase to date, 2 are actively treated. Median age was 59yrs, 44% were females and 67% ethnic or racial minorities. Fourteen (52%) pts had poor-risk genotypes by ELN 2022. Fourteen pts were treated with Ven x 8d, 11 in Dauno60 and 3 in Dauno90 cohorts, 7 pts with Ven x11d and 6 pts with Ven x14d. No DLTs were observed, and the toxicity profile was similar to historical experience with the “7+3” regimen. There were no induction mortality deaths. Twenty pts (20/25, 80%) achieved a composite complete remission (CRc) with single induction (19 CRs and 1 CRi), 10/13 in <60 and 10/12 in ≥60yr groups. Median time to ANC≥0.5K/uL and PLT≥50K/uL was 26 days and time to CR was 32 days. Of those in CRc, all except three pts < 60yrs were MFC-MRD negative (17/20, 85%). Among 8 patients with available MRD PCR testing, 6 achieved molecular MRD-negative and 2 low-level molecular MRD CRs. With a median 5.6-month follow-up time, median EFS or OS have not been reached, 25/27 (93%) patients are alive (10/12 ≥60yrs), 12 pts have completed the protocol, 5 continue on therapy and 5 underwent allogeneic transplantation. From those in CRc, 7 younger and 8 older pts (75%) remain in remission without evidence of hematologic or molecular relapse. Of 5 pts with complex karyotype plus TP53 mutated AML, 3 did not respond and 2 had an early treatment failure. Table 1 summarizes patient characteristics, toxicity and outcomes. Conclusions: Ven 400mg in combination with “7+3” induction chemotherapy is safe and highly effective in achieving MRD negative remissions in the vast majority of patients. Responses were low in TP53 mutated pts, suggesting no benefit of the addition of venetoclax to intensive chemotherapy, similar to what has been observed when venetoclax is added to standard dose hypomethylating agents in those pts, for whom non-cytotoxic approaches are being explored. The study is completing enrollment in the Dauno60 + Ven x14d cohorts and is entering the expansion phase in order to better explore the optimal Ven dose to combine with the “7+3” regimen. Updated results, as well as rates of LSC elimination post-induction will be presented at the meeting.

Real-World Treatment Patterns and Clinical Outcomes in Newly Diagnosed Acute Myeloid Leukemia with and without mIDH1 Treated with Intensive Chemotherapy from an International Real-World Database (REAL-IDH)

Introduction Intensive chemotherapy (IC) remains the main backbone therapy in fit, newly diagnosed, acute myeloid leukemia (AML) patients. Clinical trials assessing the efficacy of IC under-represent select subgroups of patients, such as those with certain comorbidities, unique characteristics, or rare genomic abnormalities. Real-world data provides additional insights into treatment patterns and clinical outcomes in patients with AML receiving first-line IC. REAL-IDH is an international network that generates evidence to improve real-world understanding of AML, including patients with a mutation in the gene encoding isocitrate dehydrogenase 1 (m IDH1). This abstract presents data from the REAL-IDH study, specifically on treatment patterns and outcomes in newly diagnosed AML patients who were treated with IC, including those with or without m IDH1 disease. Methods This retrospective, longitudinal, observational study was conducted using databases from the USA (Cancer Outcomes Tracking and Analysis [COTA]), UK (Cancer Analysis System [CAS]), and France (DATAML registry). Data were collected on adult patients with newly diagnosed AML between 2013-2020 (USA and UK) and 2017-2021 (France).Similar inclusion/exclusion criteria were applied across countries. Here we report treatment patterns, efficacy and safety outcomes, including complete (CR) and partial response (PR), CR with incomplete count recovery (CRi), minimal residual disease (MRD), morphological leukemia-free state (MLFS), time to treatment response (TTR), objective response rate (ORR; defined as rate of CR, CRi, PR and MLFS in the total treated population), mortality rate, and overall survival (OS) in patients receiving first-line IC. Results 13,013 patients with AML were included in the REAL-IDH study, with 7406 eligible patients receiving IC as first-line treatment (USA: n=1145; France: n=800; UK: n=5461). In the IC population, of those tested for the IDH mutation, m IDH1 was detected in 70 (6.1%), 84 (10.5%), and 15 (9.3%) patients in the USA, France, and UK, respectively. The most frequent first-line IC, in all three databases, was cytarabine + anthracycline (7+3 regimen) in the total populations and in the m IDH1 and wild-type subgroups. In France, lomustine was added to 7+3 in patients >60 years. The most frequent second-line therapy in the whole IC population was salvage chemotherapy with high-dose or intermediate-dose cytarabine or a combination of either of these with anthracycline (daunorubicin, idarubicin, or amsacrine) in France and decitabine or the combination of cytarabine, etoposide and mitoxantrone in the USA. Azacitidine/venetoclax combination was used in second and third line in France and USA and it was the most frequent third-line therapy (35.8%) in France. Patients received IC in combination with targeted therapies (mainly midostaurin) in 18% of the IC population in France and 12.4% of the IC population in the USA. Rates of CR, MLFS, TTR and ORR were similar in the USA and France ( Table 1). Mortality rates were similar across all three countries ( Table 1). Adverse events (AE) were reported in 43.7% of patients (500; N=1145) in the USA and 76.3% (610; N=800) in France with a reported infection in 13% (149; N=1145; CTCAE coded infection AE) and 43.1% (345; N=800; fungal/bacterial at induction or during treatment; septic shock/pneumopathy at induction or during first 3 months of treatment leading to admission to an intensive care unit; or infection leading to death) of patients in the USA and France, respectively. Conclusion This large-scale population-based study provides insight into treatment patterns and clinical outcomes in patients with AML who received first-line IC in the real-world setting, including patients with or without m IDH1 disease. Intensive treatment combinations have not significantly changed over the past decade with the exception of the addition of targeted therapies. Despite the lack of a common standard IC regimen and protocol across countries, and different healthcare systems, mortality rates were similar with IC across each country. In the REAL-IDH study we observed that treatment patterns in m IDH1 or wild type patients were similar. More specific data is needed regarding the sequencing of treatment regimens and overall outcomes in m IDH1 AML patients.

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.

Deep Sequencing Is a Widely Applicable Tool for Relapse Prediction in Acute Myeloid Leukemia with Mutated NPM1

Analysis of measurable residual disease (MRD) is a powerful tool for assessment of treatment response in acute myeloid leukemia (AML). In patients with mutation in NPM1, reverse transcription quantitative polymerase chain reaction (RT-qPCR) is recommended by European Leukemia Net for refinement of risk stratification and monitoring after treatment. However, since RT-qPCR is mutation-specific and requires stringent quality control, many clinical laboratories restrict NPM1 monitoring to the type A mutation (c.860_863dupTCTG) although >50 mutations have been reported in exon 12. Deep sequencing is an alternative method, performed on DNA, that covers all NPM1 exon 12variants in the same assay. Guidelines for its clinical use are however lacking. We here performed a retrospective analysis in a population-based cohort of AML patients to evaluate if deep sequencing MRD analysis of NPM1 during chemotherapy provides prognostic information. Adult patients with AML with mutated NPM1 treated with curative intent in our region during 2006-2016 who achieved complete remission (CR) or CR with incomplete count recovery (CRi) were eligible for the study. This time period was chosen to avoid inclusion of patients treated based on molecular MRD status. Through review of the national AML registry, clinical charts, and screening of diagnostic samples, 99 patients with mutated NPM1 were identified. Of these, 97 patients (60 women and 37 men, median age 64 years, range 19-82) had bone marrow slides for isolation of DNA from at least one time point during treatment. DNA from 257 bone marrow aspirate slides were assessed for MRD using deep sequencing of NPM1. Based on previous comparison with RT-qPCR (Pettersson et al, Int J Lab Hematol 2021;43:664-674), variant allele frequency (VAF) of ≥0.05% was chosen as cut-off to define deep sequencing MRD positivity (MRD pos). For subgroup analyses, patients were divided into groups of treatment intensity; high-dose (cytarabine- and daunorubicin-based, n=67) or low-dose (cytarabine- and daunorubicin-, or azacytidine-based, n=30) treatment regimens. Thirty-one patients underwent allogeneic stem cell transplantation (alloSCT). We first evaluated if deep sequencing MRD status during consolidation (n=70, analyzed after 2 or 3 cycles) had an impact on prognosis. Both 3-year relapse-free survival (RFS) (26.7±11.4% vs 71.6±6.2%, p=<0.001, Figure) and overall survival (OS) (33.3±12.2% vs 72.7±6%, p=0.004) were lower for patients that were MRD pos at any time point during consolidation than for MRD neg patients. Among MRD pos patients, 12/15 (80%) relapsed and 13/15 (87%) died, compared to 19/55 (35%) and 23/55 (42%) MRD neg patients. In univariate analyses, also age and treatment intensity, but not alloSCT or DNMT3A mutation status, predicted RFS and OS. FLT3-ITD predicted OS but not RFS, and there was no effect of FLT3-ITD allelic ratio. In Cox regression multivariate analysis including MRD, age, FLT3-ITD and treatment intensity, MRD pos was the only significant predictor of RFS (Hazard ratio (HR): 2.54, p=0.019). In the multivariate analysis, FLT3-ITD (HR: 2.43, p=0.014) and treatment intensity (HR: 0.43, p=0.035) were significant for OS (MRD pos HR: 1.75, p=0.13). When dividing the cohort based on treatment intensity, the effect of MRD status was most obvious in patients treated with low-dose regimens. When deep sequencing MRD analysis was performed post first cycle (n=96), it had no statistically significant effect on either RFS or OS. At the end of treatment (n=51), deep sequencing MRD status had a strong prognostic value with 3-year RFS and OS for MRD pos patients 30±14.5% and 40±15.5%, compared to 73.2±6.9% and 78±6.5% for MRD neg patients ( p=0.003 and p=0.006, respectively). In summary, this population-based study shows that MRD status by deep sequencing of NPM1 is predictive of both RFS and OS when assessed during or after consolidation. The study confirms the threshold of deep sequencing MRD pos of VAF 0.05% previously obtained by comparison with RT-qPCR. Since deep sequencing can be used for all NPM1 mutations, it is widely applicable and extends the use of molecular MRD analysis and risk refinement to patients with rare mutations in NPM1.