Improving Unrelated Donor Equity: Assessing Mismatched Donor Opportunities with Real-World Data in a Minority-Predominant Cohort.

Recent advances in graft-versus-host disease (GVHD) prophylaxis including post-transplant cyclophosphamide (PTCy) and abatacept have significantly improved outcomes following HLA-mismatched allogenic hematopoietic stem cell transplantation (allo-HSCT) and have tremendous potential for reducing racial disparities in donor availability. A recent small study employing bone marrow as the source of stem cells showed similar outcomes after 5/8 versus 7/8 matches and is currently being tested in a larger study using peripheral blood stem cells. In this study, we examine real-world alternative donor HSCT options for a minority-predominant cohort in the Bronx, NY, focusing on the availability of lesser-matched (5/8 to 7/8) donors. Records of patients who underwent HLA typing at Montefiore Medical Center (2019 to 2022) were reviewed. The National Marrow Donor Program registry was queried to evaluate the availability of donors with at least 99% likelihood of HLA match at various levels (5/8, 6/8, 7/8, 8/8). Two hundred forty-one patients were included, 70% were non-White. Although the availability of ≥7/8 donors was less common in non-White patients, 100% of patients from each group had at least one or more 5/8 and 6/8 HLA-matched donors and more than 80% of these patients had >100 potential 5/8 and 6/8 HLA-matched donors. There was no statistical difference by race or ethnicity in the mean number of donors at 5/8 and 6/8 HLA-match levels. We demonstrate through real-world data that patients from diverse ethnic and racial backgrounds have access to 5/8 and 6/8 HLA-matched donors for allo-HSCT, potentially eliminating disparities in donor availability and allowing prioritization of other donor selection characteristics such as donor age, sex, ABO, and B leader matching. Further work is needed to study whether the use of mismatched donors offers a more potent graft-versus malignancy effect and optimal GVHD prophylaxis.

A Co-Management Model for Myeloid Malignancies That Evolved during the COVID-19 Pandemic.

INTRODUCTION: Myeloid malignancies are a heterogeneous group of clonal bone marrow disorders that are complex to manage in the community and therefore often referred to subspecialists at tertiary oncology referral centers. Many patients do not live in close proximity to tertiary referral centers and are unable to commute long distances due to age, comorbidities, and frailty. Interventions that minimize the travel time burden without compromising quality of care are an area of unmet need. We describe a cancer care delivery model for patients with myeloid malignancies that is built around telehealth and enables this vulnerable population access to care at an NCI-designated cancer center while receiving majority of their care close to home. METHODS AND MATERIALS: We report on a cohort of patients with myeloid malignancies who were co-managed by a general community oncologist and an academic leukemia subspecialist at Montefiore Einstein Cancer Center in New York. Patients were initially referred to our institute for a second opinion by community practices that are in partnership with Montefiore Health System, and initial visits were in-person or via telehealth. Treatment plans were made after discussion with patient's local community oncologist. Patients then continued to receive majority of their treatment and supportive care including transfusion support with their local oncologist, and follow-up visits were mainly via telehealth with the academic leukemia subspecialist. RESULTS: Our cohort of 12 patients had a median age of 81 years (range, 59-88 years). Patients remained on active treatment for a median time of 357 days (range, 154-557 days). Most of our patients had a performance status of ECOG 2 or higher. Three patients had myelodysplastic syndromes, 7 patients had acute myeloid leukemia, and 2 patients had myelofibrosis. The median number of hospitalizations over the total treatment time period was one. CONCLUSION: We demonstrate a shared academic and community care co-management model for the treatment of myeloid malignancies in elderly, frail patients using telehealth as a backbone with a very low hospitalization rate.

High-sensitivity next-generation sequencing MRD assessment in ALL identifies patients at very low risk of relapse.

Measurable residual disease (MRD) is highly prognostic for relapse and overall survival (OS) in acute lymphoblastic leukemia (ALL), although many patients with apparent "MRD negativity" by standard assays still relapse. We evaluated the clinical impact of a highly sensitive next-generation sequencing (NGS) MRD assay in 74 adults with ALL undergoing frontline therapy. Among remission samples that were MRD negative by multiparameter flow cytometry (MFC), 46% were MRD+ by the NGS assay. After 1 cycle of induction chemotherapy, MRD negativity by MFC at a sensitivity of 1 × 10-4 and NGS at a sensitivity of 1 × 10-6 was achieved in 66% and 23% of patients, respectively. The 5-year cumulative incidence of relapse (CIR) among patients who achieved MRD negativity by MFC at complete remission (CR) was 29%; in contrast, no patients who achieved early MRD negativity by NGS relapsed, and their 5-year OS was 90%. NGS MRD negativity at CR was associated with significantly decreased risk of relapse compared with MRD positivity (5-year CIR, 0% vs 45%, respectively; P = .04). Among patients who were MRD negative by MFC, detection of low levels of MRD by NGS identified patients who still had a significant risk of relapse (5-year CIR, 39%). Early assessment of MRD using a highly sensitive NGS assay adds clinically relevant prognostic information to standard MFC-based approaches and can identify patients with ALL undergoing frontline therapy who have a very low risk of relapse and excellent long-term survival.

Ultra-accurate Duplex Sequencing for the assessment of pretreatment ABL1 kinase domain mutations in Ph+ ALL.

Mutations of ABL1 are the dominant mechanism of relapse in Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph + ALL). We performed highly accurate Duplex Sequencing of exons 4-10 of ABL1 on bone marrow or peripheral blood samples from 63 adult patients with previously untreated Ph + ALL who received induction with intensive chemotherapy plus a BCR-ABL1 TKI. We identified ABL1 mutations prior to BCR-ABL1 TKI exposure in 78% of patients. However, these mutations were generally present at extremely low levels (median variant allelic frequency 0.008% [range, 0.004%-3.71%] and did not clonally expand and lead to relapse in any patient, even when the pretreatment mutation was known to confer resistance to the TKI received. In relapse samples harboring a TKI-resistant ABL1 mutation, the corresponding mutation could not be detected pretreatment, despite validated sequencing sensitivity of Duplex Sequencing down to 0.005%. In samples under the selective pressure of ongoing TKI therapy, we detected low-level, emerging resistance mutations up to 5 months prior to relapse. These findings suggest that pretreatment ABL1 mutation assessment should not guide upfront TKI selection in Ph + ALL, although serial testing while on TKI therapy may allow for early detection of clinically actionable resistant clones.

Photoacoustic-based oxygen saturation assessment of murine femoral bone marrow in a preclinical model of leukemia.

A variety of hematological diseases manifest in the bone marrow (BM), broadly characterized as BM failure (BMF). BMF can be caused by acute lymphoblastic leukemia (ALL), which results in an expansion of hypoxic regions in the BM. Because of this hypoxic presentation, there is potential for improved characterization of BMF through in vivo assessment of oxygenation in the BM cavity. Photoacoustic (PA) imaging can provide local assessment of intravascular oxygen saturation (SO2), which has been shown to correlate with pimonidazole-assessed hypoxia. This study introduces an optimized PA imaging technique to assess SO2 within the femoral BM cavity through disease progression in a murine model of ALL. Results show a statistically significant difference with temporal changes in SO2 (from baseline) between control and diseased cohorts, demonstrating the potential of PA imaging for noninvasive, label-free monitoring of BMF diseases.

Assessment of l-Asparaginase Pharmacodynamics in Mouse Models of Cancer.

l-asparaginase (ASNase) is a metabolism-targeted anti-neoplastic agent used to treat acute lymphoblastic leukemia (ALL). ASNase's anticancer activity results from the enzymatic depletion of asparagine (Asn) and glutamine (Gln), which are converted to aspartic acid (Asp) and glutamic acid (Glu), respectively, in the blood. Unfortunately, accurate assessment of the in vivo pharmacodynamics (PD) of ASNase is challenging because of the following reasons: (i) ASNase is resilient to deactivation; (ii) ASNase catalytic efficiency is very high; and (iii) the PD markers Asn and Gln are depleted ex vivo in blood samples containing ASNase. To address those issues and facilitate longitudinal studies in individual mice for ASNase PD studies, we present here a new LC-MS/MS bioanalytical method that incorporates rapid quenching of ASNase for measurement of Asn, Asp, Gln, and Glu in just 10 µL of whole blood, with limits of detection (s:n ≥ 10:1) estimated to be 2.3, 3.5, 0.8, and 0.5 µM, respectively. We tested the suitability of the method in a 5-day, longitudinal PD study in mice and found the method to be simple to perform with sufficient accuracy and precision for whole blood measurements. Overall, the method increases the density of data that can be acquired from a single animal and will facilitate optimization of novel ASNase treatment regimens and/or the development of new ASNase variants with desired kinetic properties.

Mitochondrial Profiling of Acute Myeloid Leukemia in the Assessment of Response to Apoptosis Modulating Drugs.

BH3 profiling measures the propensity of transformed cells to undergo intrinsic apoptosis and is determined by exposing cells to BH3-mimicking peptides. We hypothesized that basal levels of prosurvival BCL-2 family proteins may modulate the predictive power of BH3 profiling and termed it mitochondrial profiling. We investigated the correlation between cell sensitivity to apoptogenic agents and mitochondrial profiling, using a panel of acute myeloid leukemias induced to undergo apoptosis by exposure to cytarabine, the BH3 mimetic ABT-199, the MDM2 inhibitor Nutlin-3a, or the CRM1 inhibitor KPT-330. We found that the apoptogenic efficacies of ABT-199 and cytarabine correlated well with BH3 profiling reflecting BCL2, but not BCL-XL or MCL-1 dependence. Baseline BCL-2 protein expression analysis increased the ability of BH3 profiling to predict resistance mediated by MCL-1. By utilizing engineered cells with overexpression or knockdown of BCL-2 family proteins, Ara-C was found to be independent, while ABT-199 was dependent on BCL-XL. BCL-2 and BCL-XL overexpression mediated resistance to KPT-330 which was not reflected in the BH3 profiling assay, or in baseline BCL-2 protein levels. In conclusion, mitochondrial profiling, the combination of BH3 profiling and prosurvival BCL-2 family protein analysis, represents an improved approach to predict efficacy of diverse agents in AML and may have utility in the design of more effective drug combinations.