Litzow, Mark R.

Abstract INTRODUCTION Allogeneic hematopoietic cell transplantation (alloHCT) is indicated in patients (pts) with FLT3-ITD mutated AML. The randomized BMT CTN 1506 trial (Levis et al. JCO) demonstrated that maintenance with FLT3 inhibitor gilteritinib (gilt) significantly improved relapse-free survival (RFS) among pts with detectable peri-alloHCT minimal residual disease (MRD) but was also associated with a greater degree of myelosuppression and infections. In older pts, aged >60 years, increasing post-HCT toxicity may adversely impact outcomes. On this basis, we performed a post-hoc analysis of pts aged > 60 years enrolled onto BMT CTN 1506 to examine the impact of gilteritinib maintenance in older pts. METHODS Pts ≥60 years randomized on BMT CTN 1506 (gilt=47, placebo=57; N=104) were included. The primary endpoint of this post-hoc analysis was RFS. We additionally assessed overall survival (OS), incidence of relapse, non-relapse mortality (NRM) in all pts and in pts with detectable MRD. RESULTS Baseline characteristics were balanced. Age was similar (65.2 vs 64.7 years; p = 0.12), as was prior TKI exposure, and NPM1 mutation status. Myeloablative conditioning (MAC) was used in 8 (17%) pts randomized to gilt and 18 (32%) pts randomized to placebo (p=0.08). Median f/u of survivors was 43.8 months (range:1-61 mo.). Estimated RFS and OS at 48 months were not different between groups (RFS: gilt: 57.0%, 95%CI 44.1-73.7%, placebo: 57.1%, 95%CI 45.4-71.8%; OS: gilt: 56.9%, 95%CI 42.9-46.7%, placebo: 58.4%, 95%CI 46.7-73.1%). While gilt assignment did not affect survival, several predictors of poorer survival were identified including use of reduced intensity conditioning (RIC) (HR = 3.46; p = 0.014), use of calcineurin inhibitor/MTX for graft-vs-host disease (GVHD) prophylaxis (HR = 2.29; p = 0.041), high-risk cytogenetics (HR = 2.64; p = 0.021), and MRD (+) pre-HCT (HR = 2.29; p = 0.018). Finally, relative to gilt assignment, opposing rates of relapse and NRM were observed. The incidence of relapse was lower with gilt (16%, 95%CI 6.8-28% vs 32%, 95%CI 20-45%, p=0.046) but NRM was higher (27%, 95%CI 15-41% vs 11%, 95% CI 4.3-21%, p=0.033). We next analyzed the 49 pts (gilt=22, placebo=27) with detectable peri-HCT MRD. RFS and OS again were not different (RFS: gilt: 44.4%, 95%CI 27.1-72.7%, placebo: 43.8%, 95%CI 28.4-67.5%, OS: gilt: 49.2%,95%CI, 31.3-77.4%, placebo: 55.6%, 95%CI 39.4-77.8%). The incidence of relapse trended lower in gilt pts (25%, 95%CI, 5.3-44.7% vs 45% (95%CI, 25-63%), p=0.2) while NRM trended higher (31%, 95%CI 12-52% vs 11%, 95%CI, 2.7-26%, p=0.12). Seventeen (36%) patients completed planned 2 year maintenance with gilt compared to 29 (51%) completing therapy with placebo. Median time on gilt was 13.2 months. The most common reason for discontinuation was adverse events (n=19, 40%), of which cytopenias (n=8) and infections (n=4) were most frequent. Non-relapse causes of death among gilt treated pts included infections (n=8), intracranial hemorrhage related to thrombocytopenia (n=1), second cancer (n=1), and Guillain-Barre syndrome (n=1). Most infections (n=5) were attributed to GVHD as an underlying cause. CONCLUSION Among pts aged ≥60 years, gilt maintenance did not improve RFS or OS. Gilt use was associated with reduced relapse regardless of peri-HCT MRD status demonstrating disease effect; however, higher NRM limited overall benefit. In older FLT3 mutated pts, employing strategies to mitigate HCT related toxicity, e.g. alternative GVHD prophylaxis strategies, may better accommodate use of maintenance therapy including gilt. Lower doses of gilt (particularly with azole co-use) may be worth exploring to mitigate drug AEs, improve compliance, thus further improving benefit.

Abstract Background: Relapsed or refractory (R/R) acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LL) remain challenging to treat, particularly in older patients and those with a T-cell phenotype. Venetoclax (VEN), a selective BCL-2 inhibitor, has shown preclinical synergy with vincristine (VCR) in multiple preclinical ALL models. Following the previously reported establishment of the recommended Phase II dose (RP2D), we now report the results of the Phase II (Ph2) portion of EA9152 (VEN 600 mg daily with weekly L-VCR 2.25 mg/m² IV or VCR 1.5 mg/m2 IV capped at 2 mg), evaluating efficacy and safety in this high-risk population. Methods: This open-label, multicenter Phase II study enrolled adults (≥18 years) with R/R B- or T-cell ALL or LL. The phase II portion of this trial was a single-arm, open-label study evaluating the combination of VEN (600 mg po D1–28) with either L-VCR (2.25 mg/m² IV weekly x4) or vincristine sulfate (VCR) (1.4 mg/m² IV weekly x4). Following the market withdrawal of L-VCR in the United States in April 2022, no new patients were initiated on this formulation and patients already receiving L-VCR were transitioned to VCR at the start of their next treatment cycle or sooner if necessitated by drug availability. Prior VCR but not VEN exposure was permitted in Ph2. The primary endpoint was achievement of a complete response or complete response with incomplete count recovery CR + CRi rate by end of cycle 3. Secondary endpoints included measurable residual disease (MRD) response, progression free survival (PFS), overall survival (OS), and safety. The association of phenotype with response and time-to-event were evaluated using Fisher's exact test and the Cox proportional hazards model, respectively. Results: Twenty-one eligible patients were treated (B-cell ALL/LL: n=12; T-cell ALL/LL: n=9). The trial was terminated early after 22/56 patients were accrued on account of withdrawal of sponsor support. Median age was 50 years and 76.2% were male. Performance status was 0–1 in 85.7%. All patients had received prior chemotherapy; 47.6% had undergone prior transplant. Median number of treatment cycles was 1 (2 for B-cell, 1 for T-cell). By end of cycle 3, no patients in the B-cell cohort (0/12; 90% CI, 0.00–0.22) achieved CR or CRi, 8 had stable disease (SD). In the T-cell cohort, 1 of 9 patients (11.1%; 90% CI, 0.01–0.43) achieved CR, 1 achieved PR and 1 had SD. There was no statistically significant difference in CR + CRi rate between phenotypes (p=0.43). None of the patients achieved an MRD-negative CR/CRi by flow cytometry or molecular methods. At the time of this analysis, 16 of 21 patients had died. Median overall survival (OS) was 4.3 months (95% CI, 1.5–22.0) for B-cell and 10.2 months (95% CI, 2.0–16.4) for T-cell patients (HR 1.32, p=0.60). Median PFS was 2.9 months (95% CI, 1.7–3.7) for B-cell and 1.2 months (95% CI, 0.7–4.6) for T-cell cohorts (HR 2.18, p=0.18). Grade 3–5 treatment-related adverse events occurred in most patients. One T-cell patient experienced grade 5 respiratory failure. Among 16 patients enrolled under the revised protocol using VCR, only 1 experienced grade 3 peripheral motor neuropathy, and no peripheral sensory neuropathy was reported (combined AE rate 0.06; 90% CI, 0.00–0.26). Tumor lysis syndrome was not observed in this cohort. Conclusions: The combination of VEN at the established RP2D and L-VCR/VCR was feasible and had an acceptable safety profile in heavily pretreated patients with R/R ALL/LL. However, response rates, including CR/CRi and MRD negativity, were limited, particularly in the B-cell cohort. Median OS and PFS remain poor in both subtypes, highlighting the need for improved strategies in this high-risk population. Venetoclax, in combination with other chemotherapy regimens, has shown encouraging response rates warranting continued exploration of its benefit in ALL.

Abstract Introduction: MyeloMATCH (mM), is an National Cancer Institute (NCI)-sponsored precision medicine initiative for newly diagnosed AML/MDS. It consists of an initial screening study (Master Screening and Reassessment Protocol, or MSRP) that involves centralized testing of bone marrow/whole blood, leading to assignment into several genetically driven treatment subprotocols within the mM portfolio. MSRP employs karyotype, 8-15 probe fluorescence in situ hybridization (FISH) and NCI-myeloid (NMAv2) assays to determine ploidy, translocations and mutational status needed for accurate disease subclassification, risk stratification as well as for theragnostic determination. NMAv2, a rapid next generation sequencing assay (TAT<48 hrs), interrogates 45 DNA and 35 RNA fusion driver genes to report 1661 hotspot DNA mutations and 779 targeted RNA fusions, including all relevant fusions in AML except Inv3/t(3;3)/MECOM rearrangement (Yeung et al, 2025). The initial mM MSRP workflow relied on karyotype and FISH assay results to identify fusion positive AML/MDS as per the current testing guidelines/ recommendations as well as to abide by the FDA's requirements under the investigational device exemption (IDE). Here we present concordance analysis between karyotype, FISH and NMAv2 assay to identify relevant fusions in AML/MDS. Methods: First 400 participants enrolled in the mM MSRP were included in this analysis. We examined the results from karyotype analysis analyzing 20 metaphase cells, 8-15 probe FISH analyzing 500 nuclei per probe, and NMAv2 curating fusion read counts greater than 100, performed at the mM labs to determine the prevalence of fusions in this cohort. Concordance analysis was performed to determine clinical utility of the NMAv2 assay to report relevant fusions at the time of initial diagnosis. The concordance analysis excluded biomarkers including Inv3/t(3;3)/MECOM rearrangement, KMT2A-PTD and other rare fusions that are beyond the scope of detection by NMAv2 and/or FISH assay. Results: Of the 400 patients analyzed in this cohort (median age 64, [range 20-95]; 43% female; 15.5% non-white; 9.5% Hispanic), translocations/fusions were reported in 67, 73 and 95 patients by karyotype, 8-15 probe FISH and NMAv2, respectively. The karyotypic analysis reported inv(16)/t(16;16) [15], t(11q23) [13], t(9;22) [10], inv3/t(3;3) [9], t(8;21) [6], t(15;17) [5], t(6;9) [4], t(21q22) [3], t(9q34) [1] and t(10;11) [1]. The FISH reported inv(16)/t(16;16) CBFB::MYH11 [15], t(11q23) KMT2A rearrangement [14], t(9;22) BCR::ABL1[10], inv3/t(3;3) MECOM rearrangement [10], t(8;21) RUNX1::RUNX1T1 [7], t(15;17) PML::RARA [5], t(6;9) DEK::NUP214 [5], t(21q22) RUNX1 rearrangement [3], t(11p15.4) NUP98 rearrangement [3], and t(9q34) ABL1 rearrangement [1]. The NMAv2 reported KMT2A-PTD [26], CBFB::MYH11 [15], KMT2A fusion [14], BCR::ABL1[12], RUNX1::RUNX1T1 [8], PML::RARA [5], DEK::NUP214 [5], RUNX1 fusion [4], NUP98 fusion[3], t(9q34) ABL1 fusion [1], PICALM::MLLT10 [1] and ETV6::MECOM [1]. The concordance analysis between NMAv2 and karyotype assay demonstrated positive percent agreement(PPA) of 100%, negative percent agreement(NPA) of 96.81% and overall agreement (OA) of 97.25% when using karyotype as reference. The concordance analysis between NMAv2 and FISH assay demonstrated PPA of 100%, NPA of 98.81% and OA of 99% when using FISH as reference. Of the 12 cases with discrepant results, 7 were due to presence of cryptic translocations missed by karyotype assay, 3 had suboptimal specimen submitted for karyotype/FISH analysis, 1 had false positive BCR::ABL1 fusion reported by NMAv2 due to low level contamination and 1 had minor subclonal population of leukemic blast with BCR::ABL1 fusion detected only by NMAv2. Conclusion: NMAv2 shows high concordance with karyotype and FISH assays which are the most commonly utilized assays to identify fusions/translocations in AML/MDS. NMAv2 is a faster, relatively cheaper and sample conserving method to identify fusions and is less prone to false negative results than karyotype/FISH assay from suboptimal specimen acquisition and testing. Based on the results above, mM MSRP workflow has been amended with FDA concurrence such that a combination of NMAv2, karyotype and MECOM breakapart FISH assay will be used to identify relevant fusion variants in all patients enrolled in mM, whereas additional specific FISH assay will be limited to cases where discrepant results between karyotype and NMAv2 are reported.

Abstract Aims BMT CTN 1506 (“MORPHO”) was a global phase 3 study of post-hematopoietic cell transplantation (HCT) maintenance with gilteritinib versus placebo for patients with FLT3-ITD-mutated AML in CR1. The study did not meet its primary endpoint of improved relapse-free survival (RFS) for post-HCT gilteritinib, but subgroup analysis indicated a benefit for participants with pre-HCT measurable residual disease (MRD). Subgroup analysis also indicated a statistically significant benefit of post-HCT gilteritinib for participants in North America, but no benefit for those in Europe or Asia. RFS for the control arms in Europe and Asia was higher than anticipated, suggesting that participants with different disease biology may have accrued to the study in these different geographic regions. In the primary analysis of the study, pre-HCT FLT3 inhibitor use and MRD across the entire study population were both found to have impacted outcomes. Time from diagnosis to HCT, a reflection of local practice patterns, is also known to impact outcomes for FLT3-ITD AML. We hypothesized that local practice patterns of pre-HCT FLT3 inhibitor use and time from AML diagnosis to HCT could have influenced the disease biology of study pts at the time of enrollment. This would be predicted to result in pre-HCT MRD levels and could provide an explanation for the regional differences observed in the study outcome. Methods We conducted a post-hoc analysis of the data focusing on days from AML diagnosis to HCT, pre-HCT FLT3 inhibitor use, and FLT3-ITD MRD assessed by a high-sensitivity assay. Eligibility requirements included FLT3-ITD-mutated AML in first remission after intensive chemotherapy and HCT occurring within 12 months of achieving remission. Patients refractory to induction therapy, or those with a history of relapse, were ineligible. Results Accrual took place in 16 different countries, with 5 countries accounting for 79.7% of the total accrual: USA 42.7%; Japan 15.7%; Korea 8.4%; UK 6.7%; Germany 6.2%; other countries 20.2%. In two countries, USA and Germany (48.9% of total enrollment), participants underwent HCT a median of 119 days after AML diagnosis, and 90.2% were treated with a FLT3 inhibitor pre-HCT. In contrast, in Japan, Korea, the UK and the other 11 countries all combined, participants underwent HCT a median of 152.5 days after AML diagnosis, and only 30.8% received any FLT3 inhibitor pre-HCT. Amongst all participants, those transplanted < 120 days from AML diagnosis and/or those treated with FLT3 inhibition pre-HCT were more likely to have improved RFS from post-HCT gilteritinib. RFS was improved with post-HCT gilteritinib in the US and Germany (HR 0.397; CI 0.220-0.718), whereas no benefit was evident in all other countries combined (HR 1.184; CI 0.685-2.048). Pre-HCT MRD levels were significantly higher (P = 0.011) in participants transplanted within 120 days from diagnosis as well as in those treated with a FLT3 inhibitor pre-HCT and also transplanted within 120 days (P = 0.019). Pre-HCT MRD was dependent on both FLT3 inhibitor use and time to HCT, as participants treated with successive courses of chemotherapy + FLT3 inhibition had successively lower MRD by the time of HCT. Conclusions The time from AML diagnosis to HCT and FLT3 inhibitor use pre-HCT both appeared to impact MRD levels immediately prior to HCT, and geographic differences in these two practice patterns likely accounted for the regional differences in benefit from post-HCT gilteritinib observed in BMT CTN 1506. Successive courses of chemotherapy without FLT3 inhibition appears to have selected a more favorable risk (e.g., MRD-lower) population for enrollment. Successive courses of chemotherapy combined with FLT3 inhibition progressively eradicated MRD, such that a majority of participants undergoing HCT after 3 or 4 courses were MRD negative and therefore unlikely to benefit from post-HCT gilteritinib. These findings have implications for clinical practice. Increasing the number of courses of chemotherapy combined with FLT3 inhibition before HCT may lower MRD sufficiently to eliminate the need for post-HCT inhibition for some patients but, alternatively, the additional delay could increase the risk of pre-HCT relapse, preventing patients from receiving HCT in first remission.

Abstract Background: Acute myeloid leukemia (AML) with TP53 alteration (TP53alt), including deletion (TP53del) detected by cytogenetics (CG) (karyotype, FISH, or genomic microarray) and/or TP53 mutation (TP53mut) identified by next-generation sequencing, is associated with poor prognosis. However, a subset of patients may achieve long-term survival after allogeneic hematopoietic cell transplantation (allo-HCT). Patient-, disease-, and transplant-related variables may inform risk stratification and improve treatment decision-making in this high-risk population. We used the CIBMTR registry to investigate outcomes of patients with TP53alt AML undergoing allo-HCT. Methods: We included adult patients with 2017 ELN adverse-risk AML who underwent first allo-HCT between 2013–2019 and had available CG and molecular data. TP53del was centrally reviewed by expert cytogeneticist. Patients were stratified into three TP53alt groups: Group 1 (TP53mut+/ TP53del+), Group 2 (TP53mut −/ TP53del+), and Group 3 (TP53mut+/ TP53del −). The control group comprised patients with 2017 ELN adverse-risk AML negative for both TP53mut and TP53del. Patients from embargoed centers, lacking consent or comprehensive research data, or missing CG and molecular information were excluded. Results: Of 6,474 patients with adverse-risk AML, 703 patients with TP53alt met inclusion criteria: Group 1 (n=203), Group 2 (n=271), Group 3 (n=229). The control group included 2,763 patients. Median age was 58 years (44% ≥60); 44% were female; 16% had Karnofsky score <90, and 52% had HCT-CI ≥3. Secondary AML was more frequent in TP53alt groups (32%, 27%, 27%) versus control (21%) (p<.01). Complex and monosomal karyotypes were most common in Group 1 (61%), followed by Group 2 (54%), Group 3 (31%), and control (6%), p<.01. More patients in Groups 1 and 2 (28% each) underwent HCT in primary induction failure/relapse (PIF/Rel) versus Group 3 (19%) and control (19%), p<.01. Median time from diagnosis to transplant was 5 months (1-331). Donor type was matched related in 23%, matched or mismatched unrelated in 50%, haploidentical in 18%, and umbilical cord blood in 7%. Conditioning intensity was myeloablative (MA) in 51%; reduced-intensity (RIC) in 36% , and 13% non-MA (NMA). Post-transplant cyclophosphamide (PTCy) was used in 27%; and in vivo T-cell depletion (ATG or alemtuzumab) in 26%. After median follow-up of 66 months (3-130), 5-yr OS was 18% (Group 1), 18% (Group 2), 35% (Group 3) vs 46% in controls (p<0.001). 5-yr LFS was 14%, 15%, and 28%, respectively, vs 38% (p<0.001). 5-yr CIR was 69%, 66%, and 52% vs 43% (p<0.001). Transplant-related mortality (TRM) was similar across groups (1-year: 12–16%). On multivariate analysis, compared with controls, TP53del (with or without TP53mut) was independently associated with higher relapse risk: Group 1 HR 1.97, Group 2 HR 1.91, Group 3 HR 1.45 (all p<0.001). These findings translated into inferior OS (HR 1.94, 1.87, and 1.45, respectively, p<0.001). PIF/Rel and CR2+ were also associated with worse survival (HR 2.58 (p<0.001) and 1.18 (p<0.001, respectively). No significant difference was observed between MA and RIC for relapse, while non-myeloablative regimens (HR 1.65; p<0.001) were associated with higher CIR. In vivo T-cell depletion increased relapse risk (HR 1.22; p=0.004). TRM was not influenced by TP53alt status; it was impacted by age, KPS, time from diagnosis to HCT, and GVHD prophylaxis regiment (non-PTCy). Conclusions: This large, registry-based study with long term median follow-up showed that among patients with adverse-risk AML, TP53alt is a strong independent predictor of poor post-HCT outcomes in AML, particularly when TP53del is present. Patients with TP53del , with or without concurrent TP53mut, experienced the worst outcomes, followed by those with isolated TP53mut. Despite the limitations of registry data including lack of information on timing of TP53mut, variant allele frequency (VAF), number of mutations, or accurate information on measurable residual disease (MRD), these findings reinforce the adverse prognostic impact of TP53alt and support its inclusion in risk stratification frameworks. While some patients with TP53alt —particularly those with isolated mutations—may benefit from allo-HCT, relapse remains the dominant cause of failure. Future studies incorporating TP53 functional status, VAF, clonal architecture, specific CG, MRD, and novel transplant approaches are warranted.

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.

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.