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Background: TP53-mutated (TP53mut) myeloid neoplasms (MN) have particularly poor survival. Discrepancies in defining TP53mut MN have impact on diagnostic work up, therapeutic decisions, and clinical trial enrolment. Methods: MN cases harboring TP53mut (variant allele frequency, VAF ≥2%) were classified based on bone marrow (BM) and peripheral blood (PB) blast % using the 4th revision of the WHO classification (WHO-4R). Biallelic loss was defined as (i) ≥2 mutations each with VAF ≥2%; (ii) single TP53mut VAF ≥2% plus 17p loss detected on karyotype, FISH, or SNP; or (iii) single TP53mut VAF ≥50%, whereas monoallelic loss was defined as single TP53mut VAF <50% without 17p loss. Primary endpoint was overall survival (OS) from diagnosis. Conditional Inference Trees (CIT) analysis was used to determine the true effect of a predictor. Results: We identified 580 cases including WHO-4R defined acute myeloid leukemia (AML, BM/PB blasts ≥20%, n=219, 37.8%), myelodysplastic syndrome (MDS) with excess blasts-2 (EB-2, BM 10-19% or PB 5%-19%, n=92, 15.9%), MDS with excess blasts-1 (EB-1, BM 5-9% or PB 2-4%, n=75, 12.9%), and the remaining were MDS with low blasts (-LB, BM <5% and PB ≤1%, n=194, 33.4%). Of the 578 cases evaluable for allelic status, 437 (75.6%) and 141 (24.4%) had biallelic and monoallelic TP53 loss, respectively. Higher frequency of biallelic loss was observed with increasing blasts. 63.2%, 73.3%, 78% and 86.3% of cases with MDS-LB, MDS-EB1, MDS-EB2, and AML had bi-allelic TP53 loss (P<0.0001). In a multivariable analysis, WHO-4R categories, VAF ≥10%, and biallelic loss were independent predictors of poor survival. CIT analysis further stratified the cohort into 4 groups with distinct survival: (1) MDS-LB (n=194, 33.4%); (2) MDS-EB1/EB2 and AML with VAF <10% (n=38, 6.6%); (3) MDS-EB1/EB2 with VAF ≥10% (n=149, 25.7%); and (4) AML with VAF ≥10% (n=199, 34.3%). MDS-LB cases could be further stratified based on allelic status and complex karyotype (CK): OS was poor for cases with biallelic TP53 loss and monoallelic TP53mut with CK compared to monoallelic TP53mut without CK, who had the most favorable survival (12.7 vs. 13 vs. 34.8 months, P<0.0001).MDS-EB1/EB2/AML with VAF<10% could also be stratified by CK: MDS-EB1/EB2/AML with VAF<10% cases without CK had the favorable survival compared to their counterparts with CK and MDS-EB1/EB2 with VAF ≥10% cases (26.2 vs. 5.6 vs. 6.3 months, P=0.003).MDS-EB1/EB2 with VAF ≥10% was a homogenous subgroup: Biological characteristics including the proportion of cases with biallelic TP53 loss, CK (P>0.9), monosomal karyotype (MK, P>0.9), del 5q (P=0.6), del 7q (P=0.4), and del 17p (P=0.2) were comparable between MDS-EB1 and -EB2 with VAF ≥10%. Importantly, median OS of MDS-EB1 and EB2 with VAF ≥10% was comparable (9.6 vs. 7.2 months, P=0.12). OS in this group was comparable regardless of the blast %, allelic status, or presence of CK.AML with VAF ≥10% had extremely poor survival: Median OS was 3.9 months. Survival of AML was equally poor irrespective of the mono- or biallelic (3.6 vs. 3.9, P=0.89) and non-CK vs. CK (1.8 vs. 3.9 months, P=0.09). Combined, our model would acknowledge poor survival of 514 (89.1%) cases. In contrast, retrospective application of the 5th edition of the WHO classification (WHO-5) and International Consensus Classification (ICC) would classify only 211 (36.4%) and 468 (80.7%) cases as biallelic/multi-hit TP53mut MN, respectively. Finally, the Harrell's c-index of the proposed model, WHO-5, and ICC was 0.66, 0.571, and 0.617, respectively. Conclusion: We provide evidence for subsequent refinements in classifying MN harboring TP53mut. Our salient findings include: (i) acknowledgement of CK as ‘biallelic equivalent’ in MDS-LB; as well as EB1/EB2/AML with VAF 2 to <10% cases; and (ii) demonstration of poor survival of MDS-EB1 and -EB2 with VAF ≥10% regardless of the allelic status. In conclusion, our proposed model acknowledged poor survival of a higher proportion of cases as TP53mut MN compared to the current models with a higher c- index.

Abstract Therapy-related myeloid neoplasm (t-MN), characterized by its association with prior exposure to cytotoxic therapy, remains poorly understood and is a major impediment to long-term survival even in the era of novel targeted therapies due to its aggressive nature and treatment resistance. Previously, cytotoxic therapy–induced genomic changes in hematopoietic stem cells were considered sine qua non in pathogenesis; however, recent research demonstrates a complex interaction between acquired and hereditary genetic predispositions, along with a profoundly senescent bone marrow (BM) microenvironment. We review emerging data on t-MN risk factors and explore the intricate interplay among clonal hematopoiesis, genetic predisposition, and the abnormal BM microenvironment. Significance: t-MN represents a poorly understood blood cancer with extremely poor survival and no effective therapies. We provide a comprehensive review of recent preclinical research highlighting complex interaction among emerging therapies, hereditary and acquired genetic factors, and BM microenvironment. Understanding the risk factors associated with t-MN is crucial for clinicians, molecular pathologists, and cancer biologists to anticipate and potentially reduce its incidence in the future. Moreover, better understanding of the molecular pathogenesis of t-MN may enable preemptive screening and even intervention in high-risk patients.

AbstractBackground and PurposeSpinal cord stimulation (SCS) is approved by the Food and Drug Administration for treating chronic intractable pain in the back, trunk, or limbs through stimulation of the dorsal column. Numerous studies have used swine as an analog of the human spinal cord to better understand SCS and further improve its efficacy. We performed high‐resolution imaging of the porcine spinal cord with intact dura mater using micro‐computed tomography (μCT) to construct detailed 3‐dimensional (3D) visualizations of the spinal cord and characterize the morphology of the dorsal and ventral rootlets.MethodsWe obtained spinal cords from Yorkshire/Landrace crossbred swine (N = 7), stained samples with osmium tetroxide, and performed μCT imaging of the T12‐T15 levels at isotropic voxel resolutions ranging from 3.3 to 50 μm. We measured the anatomical morphology using the 3D volumes and compared our results to measurements previously collected from swine and human spinal cords via microdissection techniques in prior literature.ResultsWhile the porcine thoracic‐lumbar spinal cord is a popular model for SCS, we highlight multiple notable differences compared to previously published T8‐T12 human measurements including rootlet counts (porcine dorsal/ventral: 12.2 ± 2.6, 26.6 ± 3.4; human dorsal/ventral: 5.3 ± 1.3, 4.4 ± 2.4), rootlet angles (porcine ventral‐rostral: 161 ± 1°, ventral‐caudal: 155 ± 6°, dorsal‐rostral: 148 ± 9°, dorsal‐caudal: 142 ± 6°; human ventral‐rostral: 170 ± 3°, ventral‐caudal: 22 ± 10°, dorsal‐rostral: 171 ± 3°, dorsal‐caudal: 15 ± 7°), and the presence and count of dorsal rootlet bundles.ConclusionsDetailed measurements and highlighted differences between human and porcine spinal cords can inform variations in modeling and electrophysiological experiments between the two species. In contrast to other approaches for measuring the spinal cord and rootlet morphology, our method keeps the dura intact, reducing potential artifacts from dissection.

ImportanceUtilization of hematopoietic cell transplantation (HCT) for hematologic cancers previously demonstrated race, ethnicity, and age-based disparities.ObjectiveTo evaluate utilization over time by race, ethnicity, and age to determine if disparities persist in light of recent significant increases in HCT volume.Design, Setting, and ParticipantsThis US population-based retrospective cohort study includes patients who received transplants from January 2009 to December 2018. Data collection and cleaning occurred from February 2019 to November 2021, and data analysis occurred from January 2022 to October 2023. Method 1 restricted the analysis to Surveillance, Epidemiology and End Results (SEER) reporting areas for cases and transplants. Method 2 applied SEER age-, race-, and ethnicity-specific incidence rates to corresponding US census population and included all transplants reported to the Center for International Blood and Marrow Transplant Research. Race and ethnicity groups were hierarchically defined as Hispanic (any race), non-Hispanic White, non-Hispanic Black, and non-Hispanic Other (Asian and American Indian).ExposureReceipt of HCT.Main Outcomes and MeasuresUtilization rate of autologous or allogeneic HCT for patients with hematologic cancers by age, race, and ethnicity.ResultsFrom 2009 to 2018, 136 280 HCTs were analyzed for 6 hematologic cancers comprising 16.7% pediatric/adolescent/young adults (0-39 years), 83.3% adults (40-84 years), 58% male, 10.3% Hispanic, 11.4% non-Hispanic Black, 3.8% non-Hispanic Other, and 74.5% non-Hispanic White patients, with 49 385 allogeneic and 86 895 autologous HCTs performed. HCT utilization increased over time for all disease, age, race, and ethnic groups. From 2017 to 2018, adult (40-84 years) allogeneic transplant utilization for acute myeloid leukemia and myelodysplastic syndrome (MDS) was similar for Hispanic and non-Hispanic White or Other patients but was lower for non-Hispanic Black patients (acute myeloid leukemia: 19% vs 13%; MDS: 9%-10% vs 5%). Similarly, autologous transplant utilization for lymphoma was similar for all race and ethnicity groups; however, autologous transplant for multiple myeloma was highest for non-Hispanic White patients and lower for all other groups (31% vs 26%-27%). In patients aged 0 to 39 years, utilization of allogeneic transplant for acute lymphoblastic leukemia was highest in Hispanic patients, followed by non-Hispanic White, Black, and Other races (acute lymphoblastic leukemia: 19%, 18%, 17%, and 16%, respectively).Conclusions and RelevanceIn this cohort study of autologous and allogeneic transplant utilization for hematologic cancers, disparities persisted for non-Hispanic Black patients. Hispanic, non-Hispanic Other, and younger age groups had increased utilization over time that was on par with non-Hispanic White patients in the most recent cohort.

BACKGROUND: Transcatheter mitral valve-in-valve replacement offers a less-invasive alternative for high-risk patients with bioprosthetic valve failure. Limited experience exists in intermediate-risk patients. We aim to evaluate 1-year outcomes of the PARTNER 3 mitral valve-in-valve study. METHODS: This prospective, single-arm, multicenter study enrolled symptomatic patients with a failing mitral bioprosthesis demonstrating greater than or equal to moderate stenosis and regurgitation and Society of Thoracic Surgeons score ≥3% and <8%. A balloon-expandable transcatheter heart valve (SAPIEN 3, Edwards Lifesciences) was used via a transeptal approach. The primary end point was the composite of all-cause mortality and stroke at 1 year. RESULTS: A total of 50 patients from 12 sites underwent mitral valve-in-valve from 2018 to 2021. The mean age was 70.1±9.7 years, mean Society of Thoracic Surgeons score was 4.1%±1.6%, and 54% were female. There were no primary end point events (mortality or stroke) through 1 year, and no left-ventricular outflow tract obstruction, endocarditis, or mitral valve reintervention was reported. Six patients (12%) required rehospitalization, including heart failure (n=2), minor procedural side effects (n=2), and valve thrombosis (n=2; both resolved with anticoagulation). An additional valve thrombosis was associated with no significant clinical sequelae. From baseline to 1 year, all subjects with available data had none/trace or mild (grade 1+) mitral regurgitation and the New York Heart Association class improved in 87.2% (41/47) of patients. CONCLUSIONS: Mitral valve-in-valve with a balloon-expandable valve via transseptal approach in intermediate-risk patients was associated with improved symptoms and quality of life, adequate transcatheter valve performance, and no mortality or stroke at 1-year follow-up. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03193801.

LBA7005 Background: Despite recent advances, there remains a need for novel therapies for pts with R/R DLBCL. BV, an anti-CD30 antibody-drug conjugate, has shown efficacy and safety when combined with lenalidomide (len) and with rituximab (R) in heavily pretreated populations (Bartlett 2022; Ward 2022). The double-blind, global phase 3 ECHELON-3 study (NCT04404283) compared BV with R+len (R2) vs R2 in pts with R/R DLBCL who are ineligible for HSCT or CAR T-cell therapy. Here, we present results from the interim analysis (IA) for overall survival (OS). Methods: Pts with R/R DLBCL received BV+R2 or placebo+R2 (randomized 1:1). Pts received BV (1.2 mg/kg) or placebo q3w, R (375 mg/m2) q3w, and len (20 mg) qd. The primary endpoint was OS in the intent-to-treat population. Secondary endpoints were investigator-assessed progression-free survival (PFS), objective response rate (ORR), and complete response (CR) rate. The preplanned IA was performed at 134 OS events with a prespecified efficacy boundary of 2-sided P=0.0232. Results: 230 pts were randomized: 112 to BV+R2 and 118 to R2; all but 2 pts (both in R2 arm) received ≥1 dose of study drug. Median age was 71 yrs (range, 21-89), 56.5% were male, and 10.9% had an ECOG of 2. Median prior lines of therapy was 3 (range, 2-8); 29% had prior CAR T-cell therapy and 68% were CD30- (<1% CD30 tumor expression). At median follow-up of 16.4 months (mos) (range, 0.1-31.5) (cut-off: January 22, 2024), median OS was 13.8 mos (95% CI: 10.3-18.8) with BV+R2 vs 8.5 mos (95% CI: 5.4-11.7) with R2 (HR 0.629; 95% CI: 0.445-0.891; P=0.0085); OS benefit was consistent across key subgroups. Median PFS was 4.2 mos (95% CI: 2.9-7.1) with BV+R2 vs 2.6 mos (95% CI: 1.4-3.1) with R2 (HR 0.527; 95% CI: 0.380-0.729; P<0.0001). ORR was 64.3% (95% CI: 54.7-73.1) with BV+R2 vs 41.5% with R2 (95% CI: 32.5-51.0; P=0.0006); CR rate was 40.2% vs 18.6%, respectively. In CD30+ vs CD30- subgroups, ORR/CR was 72.2%/38.9% vs 60.5%/40.8% with BV+R2, respectively, and 50.0%/26.3% vs 37.5%/15.0% with R2, respectively. Efficacy analysis including cell of origin will be presented. The safety profile of BV+R2 was tolerable vs R2: Grade (Gr) ≥3 treatment-emergent adverse events (TEAEs) were 88% vs 77%, serious TEAEs were 60% vs 50%, and Gr 5 TEAEs were 12% vs 8%, respectively. Most common TEAEs were neutropenia (46% vs 32%), anemia (29% vs 27%), and diarrhea (31% vs 23%). Rates of peripheral neuropathy for BV+R2 vs R2 were 31% vs 24% (all Gr) and 6% vs 2% (Gr 3). Median treatment duration was 3.6 mos with BV+R2 vs 2.0 mos with R2. Conclusions: Treatment with BV+R2 triplet, compared to R2, demonstrated statistically significant and clinically meaningful improvements in all key efficacy outcomes including OS in high-risk subgroups, with manageable safety. This triplet regimen represents a novel treatment option for pts with heavily pretreated R/R DLBCL. Clinical trial information: NCT04404283 .

538 Background: The phase 3 PALLAS trial compared 2 years of the CDK4/6 inhibitor palbociclib with endocrine therapy of provider choice, versus endocrine therapy alone, as adjuvant treatment for patients (pts) with Stage II-III hormone receptor-positive HER2-negative (HR+/HER2-) breast cancer. The SET2,3 index adjusts the measurement of SETER/PR index of endocrine receptor-related transcriptional activity with a baseline prognostic index (BPI) derived from tumor size (T), number of involved lymph nodes (N) and gene expression levels of ESR1, PGR, ERBB2 and AURKA (RNA4 subtype score). High SET2,3 (index ≥ 2.10) represents high endocrine sensitivity with favorable prognosis. Clinical outcome results from PALLAS were previously published, and the trial now has 5-year median follow-up. Methods: Participants in PALLAS provided a tumor tissue block prior to randomization. RNA was extracted from samples with sufficient tumor tissue and cellularity (>25mm2 with ≥20% cancer nuclei). SET2,3 index was measured from 300ng total RNA using the QuantiGene Plex platform (ThermoFisher, Waltham, MA) following the manufacturer’s protocol and using pre-defined quality control (QC) parameters and cut point. Results from primary tumor samples prior to systemic therapy were analyzed. Invasive disease-free survival (iDFS) was summarized with Kaplan-Meier plots using log-rank test. Cox models were adjusted for treatment arm assignment, with a treatment arm by SET index value interaction term to test for prediction of palbociclib benefit. The pre-defined level of significance was a two-sided 0.05. Results: There were 4075 pts from the total PALLAS population (N=5796) who provided a primary tumor sample that met pre-analytical requirements to perform the SET assay, from which 3388 (83%) results passed quality control, including 3093 from a sample obtained prior to receiving systemic therapy (1559 in palbociclib arm and 1534 in the control arm). SET2,3 index could not be calculated for 12 pts due to missing tumor or nodal information. There was no evidence of an interaction between treatment arm and SET indices (continuous) for iDFS: SET2,3 index interaction p=0.12 and SETER/PR index interaction p=0.92. Estimated 5-year iDFS was superior for those with high SET2,3: iDFS was 91.4% (95%CI 89.9–92.8) in 1719 (55.8%) pts with high SET2,3, versus 78.5% (95%CI 76.0–80.8) in 1362 (44.2%) pts with low SET2,3 (HR 0.38, 95%CI 0.31–0.47, p<0.0001). The SETER/PR index was also significantly associated with iDFS (HR 0.70 per 0.5 units, 95%CI 0.65–0.77, p<0.0001). Conclusions: There was no evidence that the SET2,3 or SETER/PR index of endocrine-related transcriptional activity predicts benefit from palbociclib treatment. SET2,3 index was strongly prognostic for pts with Stage II-III breast cancer, with excellent 5-year IDFS for pts classified as SET2,3 high. Clinical trial information: NCT02513394 .

Abstract Background Perioperative morbidity and mortality remain a point of concern for the Associating Liver Partition and Portal Vein Ligation for Staged hepatectomy (ALPPS) procedure. Post-hepatectomy liver failure (PHLF) after the second step poses the most significant risk factor for futile outcome. Recovery of liver function after the first step of ALPPS is critically important to allow for sufficient liver function after this surgery. The APRI+ALBI score has been proposed as an easily assessable score to monitor liver function and its dynamic recovery. Aims We explored if the APRI+ALBI score was able to assess liver function recovery after the first step of ALPPS and allow for optimal timing of the 2nd step. Methods Based on the ALPPS registry, patients from 2012 to 2020 with available APRI+ALBI score were included. Postoperative outcomes (PHLF A – C, PHLF B + C, 90-day mortality and severe morbidity) were defined as per standard definitions. The APRI/ALBI score was monitored perioperatively. Results Overall, 464 patients from 16 international participating centers in the ALPPS registry were included. Clinically relevant PHLF (B + C) was observed in 7.5 % and of these 63 % of patients ultimately died due to liver failure. The APRI+ALBI score immediately increased after each surgical intervention and continuously decrease thereafter. Failure of the APRI+ALBI score to decrease until the 2nd step of ALPPS predicted PHLF B+C (p = 0.001; AUC 0.78). Particularly patients with high APRI+ALBI scores and short interstage intervals were at risk to develop PHLF B+C. Conclusion The APRI+ALBI score objectifies liver function recovery after the 1st step of ALPPS and failure to sufficiently decreased is associated with a higher risk for PHLF B+C. This might allow for optimized planning of the 2nd step of ALPPS to allow for sufficient liver function recovery to minimize the risk for PHLF B+C and associated futile outcome.