Litzow, Mark R.

Abstract Background: Isocitrate dehydrogenase (IDH) mutations are frequently implicated in the development of acute myeloid leukemia (AML). In a recent study (Salman MY, Blood Adv 2025), it was reported that IDH2 mutation subtypes, R140 and R172, may respond differently to intensive chemotherapy. In this study, we evaluated mid-cycle and end-of-cycle bone marrow blast responses in AML patients with IDH2 R140, IDH2 R172, and IDH1 R132 mutations, aiming to determine whether these subtypes exhibit different response dynamics. Methods: We reviewed the charts of AML patients diagnosed at Mayo Clinic, Rochester, between the years 2016 - 2023 that had available next generation sequencing (NGS) data. Institutional review board approval was obtained. All data were recorded at the time of AML diagnosis. Patients without molecular data or not treated with intensive chemotherapy (7+3 or CPX-351) were excluded from this study. Bone marrow blast percentages were assessed at mid-induction (days 14-21) and end of cycle (counts recovery). Blast clearance dynamics and complete remission rates were compared across IDH mutation subgroups and correlated with outcomes. GraphPad Prism 10.0.0 was used for statistical analysis. Results: Out of 381 AML patients, 31 had IDH2 mutations (23 with R140 and 8 with R172), and 8 had IDH1 mutations (all R132). Among patients with IDH2 mutations, those with R172 had numerically higher median mid-cycle bone marrow blast percentage compared to R140 (10% vs. 4%, p = 0.37). There was no significant difference in mid-cycle blast percentages between patients with IDH1 and IDH2 mutations (4.5% vs. 4%, p = 0.8). At mid-cycle, 68% of patients with IDH2 R140 had blast counts <5%, compared to 38% of those with IDH2 R172, suggesting a trend for faster mid-cycle clearance in the R140 group, though not statistically significant (OR 3.57, p = 0.2). In a broader comparison, 60% of IDH2-mutated patients and 50% of IDH1-mutated patients achieved blast clearance (blasts <5%) at mid-cycle, though not statistically significant (p = 0.7). At the end of the induction, patients with IDH2 R140 had significantly lower median bone marrow blast percentages compared to those with R172mutations (2% vs. 4%, p = 0.01). Similarly, patients with IDH1 mutations showed low blast counts compared to the IDH2 group (1.5% vs. 3%, p = 0.1). A higher proportion of IDH2 R140 patients achieved blast clearance compared to those with R172 mutations (100% vs. 75%, p = 0.06), while proportion of patients who achieved blast clearance were similar between IDH1 and IDH2 patients (87.5% vs 93.1%, P = 0.5). Analysis of overall complete remission rates (including both complete remission [CR] and CR with incomplete hematologic recovery [CRi]) within the IDH2-mutated group showed a higher rate in patients with the R140 mutation compared to those with R172 (87% vs. 75%), though the difference was not statistically significant (p = 0.5). When comparing IDH1- and IDH2-mutated patients, overall complete remission rates were 75% and 84%, respectively, with no significant difference observed (p = 0.6). Kaplan–Meier analysis of time to end-of-induction blast clearance revealed no statistically significant difference between IDH2 R140 and R172 patients (median time to clearance: 31 vs. 37 days, p = 0.3). Similarly, no difference was observed between IDH1 and IDH2-mutated patients (33 vs. 31 days, p = 0.9). Overall survival analyses showed no significant difference between IDH2 R140 and R172 groups (median 66.8 months vs not reached, P = 0.4). Likewise, no difference was observed between IDH1 and IDH2 patients (44.4 months vs not reached, P = 0.7), indicating similar overall survival across mutation subtypes. Conclusion: IDH2-R140 was associated with more effective blast cytoreduction following intensive induction compared to IDH2-R172. Although not statistically significant, IDH2 R172consistently showed trends toward higher blast percentages, delayed response, and lower overall complete remission rates. These findings align with the recent study reporting significantly slower blast reduction and delayed response in R172-mutated AML. Also, no significant differences were found between IDH1- and IDH2-mutated patients in terms of response kinetics or overall survival. Together, these findings highlight potential biological differences among IDH mutation subtypes that may impact treatment response and require further investigation in larger prospective cohorts.

Abstract Background: Population registries and the Alliance co-operative group database have highlighted racial disparities in AML survival attributed to differential prevalence and impact of oncogenic drivers on disease biology. However, the small number of Black patients with well-annotated genomic profiles limits the validity of these findings. The current study leverages ECOG-ACRIN cytogenetic and outcomes data from newly diagnosed adult AML patients treated on intensive chemotherapy-based clinical trials over three decades. Methods: Self-reported race was categorized as White, Black or Other. Descriptive statistics were used to summarize baseline characteristics using the Wilcoxon rank-sum and Fisher's exact tests. Multivariable Cox proportional hazards regression models evaluated the association between race and survival outcomes adjusting for age, hemoglobin, platelet count, white blood cell count, blast percentage, performance status and ELN cytogenetic risk score (RS). All Cox models were stratified by protocol. Subgroup analyses of overall survival (OS) and disease-free survival (DFS) were performed using Kaplan-Meier curves stratified by race using log-rank tests. All statistical tests were two-sided. Analyses included only patients with complete data for the variables of interest. Results: Data was collected across 10 phase II and III interventional trials for newly diagnosed adult AML that accrued patients between 1984 and 2019. The study population included 3469 White, 184 Black, and 156 Other patients with a Black representation of 1.1-11% across trials. Blacks were significantly younger at diagnosis with a median age of 47.9 years compared to 53.5 years in Whites (p<0.001). Racial groups were well matched for gender and performance status. Black race was an independent prognostic factor for inferior OS (HR 1.212, CI 1.01 – 1.453; p = 0.0383) and DFS (HR 1.313, CI 1.05-1.641; p = 0.017). Complete cytogenetic results were available for 117 Black and 2162 White patients and revealed no significant racial differences in the distribution of ELN 2017 cytogenetic RS, although core binding factor AML was non-significantly enriched in Black patients (12.8% vs 8.3%). No difference was observed between Blacks and Whites in the prevalence of complex karyotype (CK), CK with -5/del(5q), -7/del(7q), or -17/del(17p), and AML-MRC including +8 and del(20q). Notably, the ELN 2017 cytogenetic RS effectively predicted OS in Black (57.8 vs 14.2 vs 5.8 months in favorable, intermediate and adverse RS, p = 0.018), and White patients (60.1 vs 15.2 vs 7.1 months, p < 0.0004 for Whites) but only predicted DFS for White AML patients (p < 0.0001 for Whites, p=0.48 for Blacks). In patients with molecular data for FLT3-ITD (n=1218), CEBPA (n=576), TP53 (n=572), or NPM1(n=683), no racial difference in the prevalence of these mutations was observed. However, NPM1 mutations were associated with inferior OS in Blacks compared to Whites (19.1 vs 8.9 months; p = 0.0095). Black and White AML patients had similar responses with complete remission rates of 58.2% vs 57.5%, p=0.55, and treatment tolerability with 30-day mortality of 7.1% vs 8.9%, p=0.50. However, consolidation approaches differed significantly. Among patients that underwent stem cell transplant (SCT), a significantly higher percentage of White patients received allogenic SCT compared to Blacks (48.5% versus 37.1%, p <0.01). Conclusions: This study represents one of the largest race-based comparisons of cytogenetic abnormalities and clinical outcomes in prospective trials of intensive chemotherapy in AML . Our data confirms the independent prognostic relevance of race in AML survival and validates the predictive ability of the ELN 2017 cytogenetic RS for OS across racial groups. There is ancestry-based attenuation of the survival benefit of NPM1 mutations as previously reported, underscoring the need to tailor the current treatment approach to NPM1 mutated AML based on race. The availability of NGS data limited the genomic analysis to a subset of patients. Future studies should examine the depth of treatment response incorporating MRD biomarkers and explore the effect of race on co-occurring mutations and the leukemic stem cell transcriptome to better explain the observed disparities. Finally, persistent disparities in access to allo-SCT even within the context of clinical trials reinforces the need to address diversity in the stem cell donor pool and social barriers to transplant.

Abstract Introduction Nadir bone marrow biopsies (BM Bx) are routinely performed around day 14 to assess early response to AML intensive induction therapy. The presence of residual disease prompts initiation of reinduction therapy, often with another cycle of intensive chemotherapy. Whether there are characteristics of nadir BM Bx that predict for response to intensive reinduction is unknown. To evaluate this, we analyzed data from ECOG-ACRIN clinical trials in AML of intensive induction chemotherapy with nadir biopsy information available to determine predictors of outcomes after reinduction. Methods We included patients from ECOG-ACRIN E1900 (Fernandez NEJM 2009) and arm A of E2906 (Foran ASH 2015) who received induction therapy with daunorubicin and cytarabine (7+3), had residual disease (blasts ≥5% or cellularity ≥20%) at nadir BM Bx and received reinduction chemotherapy. Nadir BM Bx characteristics that were evaluated included blast percentage and cellularity as well as both absolute and relative (percentage change, e.g. 20% to 10% = -50%) differences calculated between diagnosis and nadir for each parameter. Complete remission (CR) after reinduction therapy, disease free survival (DFS) and overall survival (OS) were outcomes for all analyses. Logistic regression models were used to evaluate associations with CR, and Cox proportional hazards models were used for DFS and OS. For models evaluating changes in blast percentage or cellularity as predictors, baseline blast percentage or cellularity was included as a covariate, respectively. Results Of 1013 patients identified, 750 (74%) had a nadir biopsy, 233 (23%) had evidence of residual disease, received reinduction therapy, and were included in the primary analysis. The median age was 58 and 42% were female. Cytogenetic risk category (by ELN2017) was adverse in 31%, intermediate in 66% and favorable in 3%. The median nadir BM Bx blast was 30% (range 0 to +97%) and cellularity was 20% (0 to +100%). The median absolute difference in blast percentage between baseline and nadir BM Bx was -15% (-95% to +66%) with a median relative difference of -36% (-100% to +400%). After reinduction, 118 patients (52%) achieved a CR. Neither absolute difference in blast percentage (OR 0.99, 95%CI 0.98-1.00, p=0.20) nor relative difference (OR 1.00, 95%CI 0.99-1.00, p=0.33) predicted CR. There was similarly no association with DFS (HR = 1.00, 95%CI: 0.99-1.01, p=0.65) or OS (HR = 1.00, 95%CI 0.99-1.01, p=0.76). Blast reduction ≥50% similarly did not predict these outcomes. We also evaluated the impact of any reduction in blast percentage (responders) from baseline to nadir and again found no association with CR (OR 1.65, 95%CI 0.90-3.03, p=0.11). Similarly, there was no association with DFS (HR 0.74, 95%CI 0.51-1.09, p=0.13) or OS (HR 0.81, 95%CI 0.58-1.13, p=0.21) in responders vs nonresponders. No association with CR, DFS or OS were identified when performing the same analysis in intermediate and adverse cytogenetic subgroups. We found no association with CR when nadir cellularity was assessed as a continuous variable (OR 0.99, 95%CI 0.98-1.00, p=0.10) or by relative difference (OR 0.99, 95%CI 0.99-1.00, p=0.10). There was a trend towards association with absolute reduction in cellularity from baseline to nadir and CR (OR 0.99, 95%CI 0.98-1.00, p=0.06). No association was identified between relative difference in cellularity and DFS and OS, nor was there an association among cytogenetic risk subgroups with any outcome. Discussion In intensively treated patients with residual disease at nadir BM Bx (i.e. day 14) who received intensive reinduction, the likelihood of achieving a CR was not influenced by the magnitude of disease reduction nor the extent of disease at the time of nadir biopsy. Similarly, there were no nadir biopsy features that predicted DFS or OS after intensive reinduction therapy. Given alternative reinduction therapies such as hypomethylating agents and venetoclax are available, these results suggest that the decision to attempt a second intensive induction cycle following the unequivocal presence of residual disease should not be influenced by characteristics of the nadir BM Bx. Although patient-specific factors such as patient fitness may favor a switch to less intensive options, these results support consideration of intensive reinduction therapy in patients with residual disease at nadir biopsy, even without changes in blasts or cellularity.

Abstract The incidence of venous thromboembolism (VTE) in patients with acute lymphoblastic leukemia (ALL) receiving asparaginase-based induction is high despite primary thromboprophylaxis. Our aim was to derive and externally validate a VTE risk prediction model in patients with ALL receiving asparaginase-based induction. We conducted a multicenter retrospective cohort study of patients (aged ≥18 years) with newly diagnosed ALL receiving asparaginase-based induction. The derivation and external validation cohorts included 306 and 94 patients, respectively. Primary outcome was VTE at any site. A cause-specific Cox proportional hazards model stratified by thromboprophylaxis and center was performed to identify VTE risk factors in the derivation cohort. A risk prediction model for VTE at 30 days was derived using variables with P value < .05 in the multivariable model and was tested in the validation cohort. VTE risk factors on multivariable analysis in the derivation cohort included D-dimer ≥1 μg fibrinogen equivalent unit per mL (hazard ratio [HR], 2.64; 95% confidence interval [CI], 1.07-6.5) and hemoglobin (HR for each 1 g/dL increment, 1.19; 95% CI, 1.06-1.34) at ALL diagnosis. A VTE risk score based on these variables distinguished between a 4% (95% CI, 0.72-12) and 20% (95% CI, 14-27) 30-day cumulative incidence of VTE in the derivation cohort, with similar findings in the validation cohort (area under the curve, 0.56). The negative predictive value for VTE at 30 days was 96% and 93% in the derivation and validation cohorts, respectively, and the positive predictive value was 20% in both. We derived and validated a model using D-dimer and hemoglobin, which stratifies VTE risk in patients with ALL receiving asparaginase-based induction.

Abstract Acute lymphoblastic leukemia (ALL) is a hematologic malignancy characterized by the proliferation of immature lymphoid cells. Despite advances in chemotherapy, a significant proportion of patients continue to have poor outcomes. Immunotherapy has emerged as a transformative approach in the treatment of ALL, offering new hope for these patients. This advances viewpoint article provides a comprehensive overview of the role of immunotherapy in ALL, focusing on the mechanisms of action, the timing of its use, the patient populations most likely to benefit, and drug resistance. We discussed the major immunotherapeutic modalities, including monoclonal antibodies, bispecific T-cell engagers, and chimeric antigen receptor T-cell therapy. We review key clinical trials that have shaped the current landscape of immunotherapy in B-cell precursor (BCP)–ALL, along with future directions in this rapidly evolving field and discussed our perspective on how best to exploit the use of immunotherapy for patients with newly diagnosed adult BCP-ALL.

PURPOSE Older patients with ALL receiving conventional chemotherapy have poor survival due to toxic death and relapse. We hypothesized that a chemotherapy-free, targeted regimen using the anti-CD22 antibody-calicheamicin conjugate inotuzumab ozogamicin followed by the bispecific anti-CD19/CD3 T-cell engager blinatumomab would reduce toxic death and yield high rates of prolonged remission and survival. METHODS Eligible patients were age 60 years and older with untreated, Philadelphia chromosome (Ph)–negative, CD22-positive, B-cell ALL. Patients received up to two cycles of inotuzumab ozogamicin followed by four or five cycles of blinatumomab with intrathecal methotrexate CNS prophylaxis. The primary end point was 1-year event-free survival (EFS). RESULTS The 33 eligible patients had a median age of 71 years (range, 60-84) and a median CD22 expression of 92% (range, 21%-100%). Eight (24%) had previous chemotherapy or radiation for other cancers, six for multiple myeloma. The composite complete remission rate was 85% after two cycles of inotuzumab ozogamicin and 97% by the end of two cycles of blinatumomab. At a median follow-up of 30 months, the 1-year EFS and overall survival were 75% (95% CI, 61 to 92) and 85% (95% CI, 73 to 98), respectively. EFS was shorter with lower CD22 expression or detectable measurable residual disease at any time point. CONCLUSION Inotuzumab ozogamicin then blinatumomab without maintenance chemotherapy in older patients with untreated, Ph-negative, CD22-positive, B-cell ALL yields a high remission rate and excellent EFS. Given the lack of standard, safe, and effective therapies in this population, the regimen should be considered a standard treatment option.