Citations

T cell fitness has emerged as a critical determinant of the efficacy and persistence of Chimeric Antigen Receptor (CAR)-T cell therapy. Defined by the capacity of T cells to proliferate, resist exhaustion, persist in vivo , and exert sustained effector functions, T cell fitness reflects the integration of a dynamic network of intrinsic and extrinsic regulatory mechanisms. In this review, we present a comprehensive synthesis of the molecular and cellular foundations underlying T cell fitness, emphasizing the influence of differentiation trajectories, signaling pathways, metabolic reprogramming, and epigenetic modifications. We further discuss the impact of patient-specific conditions such as age as well as disease biology, prior therapeutic exposures, and timing and quality of T cell collection, on the phenotypic and functional efficacy of CAR-T cell products. Beyond delineating these determinants, we highlight emerging strategies aimed at enhancing T cell fitness. Importantly, we propose T cell fitness as an integrated, multi-layered systems property emerging from the interaction between differentiation state, signaling architecture, metabolic–mitochondrial competence, epigenetic stability, and host-specific inflammatory and treatment-related pressures. We introduce a mechanistic framework that links these layers across the CAR-T therapeutic timeline from leukapheresis to post-infusion tumor engagement and outline how this framework can be operationalized into measurable parameters to guide patient stratification, manufacturing decisions, and rational therapeutic interventions.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Hodgkin lymphoma provide expert, multidisciplinary recommendations for the diagnosis and treatment of Hodgkin lymphoma. The panel convenes annually to update recommendations based on a review of recently published clinical trials. This selection from the NCCN Guidelines for Hodgkin Lymphoma focuses on the management of newly diagnosed and relapsed/refractory classic Hodgkin lymphoma in adults aged 18 to 60 years.

Abstract TP53 and PPM1D are key regulators of DNA damage response and repair, and somatic mutations in these genes often co-occur in hematopoietic cells, expanding under genotoxic stress. Unlike TP53 mutations, where mechanisms of progression are defined, pathways underlying clonal fitness and transformation in PPM1D mutant cells remain unclear. In collaboration with 5 academic institutions, we analyzed the clinical and molecular landscape of 337 patients with clonal hematopoiesis (CH) and clonal cytopenia of undetermined significance (CCUS) across 4 genotypes: PPM1Dmt/TP53wt (n = 170 [50%]), PPM1Dmt/TP53mt (n = 25 [7%]), TP53mt/PPM1Dwt (n = 17 [5%]), and TP53wt/PPM1Dwt (n = 125 [38%]). All PPM1D variants were truncating, located in exon 6 of the gene, with a median variant allele frequency (VAF) of 6% (range, 0.3%-64%). The PPM1Dmt/TP53mt genotype was most frequently encountered in therapy-related CH/CCUS (t-CH/t-CCUS; 80%, 66.5%, 76.5%, and 19%; P ≤ .001) and had a shorter time interval to detection from last genotoxic exposure (6.2, 5.9, 11.25, and 24.5 months; P ≤ .001) compared with PPM1Dmt/TP53wt, TP53mt/PPM1Dwt, and TP53wt/PPM1Dwt genotypes, respectively. Acknowledging the short follow-up duration, rates of malignant transformation were lower in the PPM1Dmt/TP53wt (2%) and PPM1Dmt/TP53mt (4%) groups compared with PPM1Dwt/TP53wt (12%) and PPM1Dwt/TP53mt (17%) groups (P ≤ .001), respectively. In summary, PPM1D mutations are frequently observed in t-CH/t-CCUS, with low median VAFs, and are associated with low rates of progression, even when comutated with TP53.

Abstract Introduction There is wide variation in male fertility preservation practices. While physician preference accounts for some of this diversity, practice patterns often reflect multiple extrinsic factors including patient demographics, equipment availability, laboratory protocols, and state law. Objective We sought to characterize national trends in sperm retrieval and storage across reproductive urology practices in the United States. Methods An anonymous 34-item survey characterizing provider demographics, practice settings, fertility preservation procedures, andrology laboratory practices, and cryopreservation expenses was designed. Practicing reproductive urologists were identified using information available through professional societies. Our survey was constructed using the Qualtrics platform and distributed electronically between October 2024 and May 2025. Results 39 responses were received by urologists practicing across 21 states (response rate: 21%, n=189). A majority (74%, n=29) of survey responders practiced at academic medical centers, with others practicing at non-academic hospitals (8%, n=3) and private practices (13%, n=5). The most common indications for fertility preservation reported included oncologic care (42%), gamete storage for planned ART (31%), transgender care (18%), pre-vasectomy sperm banking (10%), and pre-deployment banking for military personnel (5%). Nearly all providers performed microsurgical sperm retrievals (97%, n=38, Figure) and oncologic testicular sperm extractions (85%, n=33) when indicated. More than half of providers offered conventional testicular sperm extractions (72%, n=28), microsurgical epididymal sperm aspirations (59%, n=23), testicular sperm aspirations (56%, n=22), penile vibratory stimulation (54%, n=21), or percutaneous epididymal sperm aspirations (52%, n=20). Fewer providers offered post-mortem sperm retrieval (49%, n=19), pre-pubertal testicular tissue cryopreservation (36%, n=14), or electroejaculation (31%, n=12). Most respondents (62%, n=24) had access to an on-site andrology laboratory. Semen analyses were evaluated using manual (53%, n=20), computer-assisted (11%, n=4), or combinatorial methods (26%, n=10). Though many (37%, n=14) providers were uncertain about institutional costs for semen specimen processing, a plurality of respondents (40%, n=15) reported fees ranging from $100-500 with the remainder (23%, n=9) reporting fees exceeding $500. Respondents most frequently reported semen storage fees ranging between $100-300 per year (39%, n=15), while approximately a third (31%, n=12) estimated these costs to range between $300-600 per year. However, 18% (n=7) of respondents reported higher costs for specimen storage and 13% (n=5) were uncertain about the expense of this service. Conclusions This multi-institutional, geographically diverse survey reveals significant variation in reproductive urology practice patterns and cost associated with semen analyses and storage. Future studies will explore differences in practice patterns to better understand the factors influencing this variation and their effect on male reproductive healthcare. In the absence of society guidelines, reproductive urologists must collaborate, share best practices, and maintain price transparency to ensure sperm retrieval remains accessible and affordable. Disclosure No

Abstract Introduction Fertility preservation is an essential component to cancer survivorship. One third of male survivors experience infertility following gonadotoxic treatments, and expeditious preservation prior to therapy is recommended by oncology guidelines. However, this can be challenging given time constraints, lab expertise, and financial considerations. Objective We describe national practice patterns and identify barriers and facilitators regarding inpatient male fertility preservation. Methods An anonymous 34-item Qualtrics survey was sent to reproductive Urologists in the United States. Email addresses were obtained from public membership databases. Respondents were queried across several domains, including provider demographics, specific inpatient cryopreservation scenarios, and fertility preservation procedures. Results Thirty-nine (21%, n=39/189) responses were received. The majority of respondents were fellowship-trained reproductive urologists 89.7% (35). The majority (97.4%) of respondents offer microdissection testicular sperm extraction (mTESE) for fertility preservation, and many offer conventional TESE (71.8%), traditional ejaculated sperm cryopreservation (71.8%), or microsurgical epididymal sperm aspiration (59%). Only 30.8% of respondents offer electroejaculation. Respondents rate non-urology provider awareness of male cancer fertility preservation options at 5.05/10 on a Likert scale. Many (65%) respondents provide formal materials or education to nonurology providers to address this deficit. On average, respondents reported 2.6 inpatient oncofertility preservation consults per month (range 0-25, median=1). Most (60%) of respondents reported that <25% of these patients ultimately complete inpatient preservation. Financial burdens (97%), logistical hurdles (97%), limited awareness (97%), and concern for delay of oncologic care (92%) were identified as the most common barriers for patients precluding fertility preservation. In addition, 85% of respondents also listed difficulty coordinating with other specialists as a barrier. On free-text queries, respondents identified facilitators of fertility preservation as automatically triggered consults, use of an urgent cryopreservation pager, formal fertility preservation pathway within the order set, and utilization of an inpatient coordinator as facilitators that aid in achieving timely fertility preservation prior to gonadotoxic therapies. Conclusions Despite all reproductive urologists offering cryopreservation services and education regarding the urgency and priority of inpatient fertility preservation, less than a quarter of patients complete this process during hospitalization prior to initiation of treatment. This remains the consequence of numerous patient, provider, and facility level barriers, even in systems with robust referral processes. Inpatient fertility preservation remains an underutilized and often missed opportunity. Multidisciplinary interventions are needed to address ongoing barriers. Disclosure No

Abstract Introduction Oncologic testicular sperm extraction (oncoTESE) remains a poorly defined concept that is a heterogeneous and understudied fertility preservation option for cancer patients with male gonads. Given variation in practice patterns, reproductive insurance coverage, and provider availability, there is significant diversity among the accepted indications, desired evaluations, and surgical practices afforded to patients facing a cancer diagnosis. Objective This study aimed to characterize and help further define oncoTESE practice patterns across the United States. Methods A 34-item, anonymized survey assessed provider demographics and oncoTESE practice patterns, including indications, contraindications, workflows, and institutional barriers surrounding OncoTESE procedures. A survey was created and electronically distributed to reproductive urologists across the United States using email addresses obtained via society membership websites. Results Thirty-eight urologists (20%, 38/189) from 21 states responded to the survey. Most (95%, 36/38) were fellowship-trained reproductive urologists, and nearly all (87%, 33/38) reported offering oncoTESE to indicated patients. The most cited indications for oncoTESE were azoospermia (78%, 28/36), anejaculation (72%, 26/36), and severe oligozoospermia or cryptozoospermia on ejaculated specimen (53%, 19/36). Less commonly reported indications included prepubertal or peripubertal status (33%, 12/36) and elevated sperm DNA fragmentation (19%, 7/36). Relative contraindications included inability to consent (86%, 31/36), clinical instability (83%, 30/36), thrombocytopenia (61%, 22/36), and a history of remote chemotherapy (58%, 21/36). When asked how many semen analyses are obtained to confirm azoospermia before proceeding to oncoTESE in patients able to ejaculate, the majority reported two analyses (67%, 24/36), while 28% (10/36) reported one. There was stronger consensus that oncoTESE includes sperm retrieval during back-table orchiectomy (94%, 34/36) and ipsilateral microTESE during partial orchiectomy (86%, 31/36). Greater variability was noted regarding contralateral microTESE at the time of orchiectomy (64%, 23/36), procedures for non-genitourinary malignancies (61%, 22/36), and delayed procedures performed years after diagnosis (42%, 15/36). (Figure 1) Estimated patient costs for oncoTESE were most commonly reported as $2,000–$5,000 (39%, 14/36), followed by $500–$2,000 (22%, 8/36), $5,000–$10,000 (19%, 7/36), and over $10,000 (3%, 1/36); 14% (5/36) were unsure. On a 10-point Likert scale, the most significant barriers to performing oncoTESE were logistical challenges (mean 6.6, median 8), followed by patient cost (mean 5.4, median 5.5) and patient illness (mean 5.3, median 5.0). Conclusions This multi-institutional survey found strong agreement among reproductive urologists on core procedural elements, but substantial variation on oncoTESE definition, patient selection criteria, pre-procedural evaluation, and fertility preservation management. Similar institutional barriers across centers highlight opportunities to improve accessibility and standardize oncoTESE practices. Disclosure No

Abstract Background A previous multicenter study of patients with TP53-mutated myeloproliferative neoplasms showed a significantly shorter survival in chronic phase myelofibrosis (MF-CP) that included primary (PMF) and secondary MF and was mostly based on research-based mutation screening and was not systematically controlled for patients without TP53 mutations (AJH 2025;100:552). The objective of the current study was to examine the prognostic impact of TP53 mutations (VAF ≥2%) that were discovered during clinical NGS testing among consecutive patients with PMF-CP. Impact on overall (OS) and leukemia-free (LFS) survival was analyzed in the context of other genetic risk factors and calculated from the time of mutation detection. Methods The current retrospective study includes consecutive patients with PMF-CP who underwent clinical NGS testing at the Mayo Clinic between 2015 and 2025. Diagnoses of PMF-CP and leukemic transformation (LT) were retrospectively fitted to be in accordance with the International Consensus Classification criteria (Blood 2022;140:1200). Mutation and cytogenetic analyses were performed according to institutional protocols for clinical use and reported in conformity with international guidelines. OS and LFS analyses were censored for treatment with allogeneic stem cell transplantation (ASCT) and calculated from the date of NGS. Conventional statistical methods were utilized (JMP Pro 17.1.0, SAS Institute, Cary, NC, USA). Results A total of 633 patients with PMF-CP underwent clinical NGS testing prior to LT and prior to ASCT (median age 65 years; males 59%). Median interval from initial diagnosis/referral to NGS testing was 2 months; 357 (56%), 392 (62%), and 429 (68%) patients had NGS performed within 3, 6 and 12 months of diagnosis, respectively. Risk distribution according to the dynamic International Prognostic Scoring System (DIPSS; Blood 2010;115:1703) were low (19%), intermediate-1 (44%), intermediate-2 (31%), or high (6%). TP53 mutations (TP53MUT) with variant allele frequency (VAF) of ≥2% were detected in 28 (4.4%) patients with a median VAF of 25.3% (range 2.4-85; ICC-defined multihit 43%). Patients with TP53MUT were more likely to harbor IDH2MUT (14% vs. 3%; p<0.01), EZH2MUT (14% vs. 4%; p=0.03), and unfavorable karyotype (36% vs. 19%; p=0.047) and less likely to harbor CALR type 1/like (4% vs. 18%; p=0.02) and SF3B1MUT (0% vs. 6%; p=0.07). The association with unfavorable karyotype was mainly driven by multihit configuration. No significant associations with clinical features were apparent. At a median follow-up of 40 months for surviving patients, 157 (25%) deaths, 48 (8%) LTs and 135 (21%) ASCTs were documented. A near-two-fold lower, albeit not statistically significant OS was observed in the presence of TP53MUT (median 123 vs. 228 months; HR 1.9, 95% CI 0.94-3.7; p=0.074); the difference reached significance for multihit TP53MUT (median 81 months; HR 3.6, 1.7-7.7; p<0.01) but not for non-multihit TP53MUT (median not reached; HR 0.7, 0.2-2.8; p=0.6), both compared to TP53WT (median 228 months). The significant impact of multihit TP53MUT on OS was confirmed in multivariable analysis (MVA) that included other high molecular risk (HMR) mutations and unfavorable karyotype: multihit TP53MUT (HR 2.5, 1.1-5.5; p=0.02), SRSF2MUT (2.4, 1.5-3.8; p<0.01), ASXL1MUT (1.8, 1.2-2.6; p<0.01), U2AF1MUT-Q157 (4.8, 2.6-8.6; p<0.01), and absence of CALR type 1/like (4.0, 2.0-7.8; p<0.01); additional prognostic contribution was not evident for unfavorable karyotype (p=0.17), EZH2MUT (p=0.3), IDH1MUT (p=0.6), IDH2MUT (p=0.7), or any other HMR mutation. Multihit TP53MUT was also associated with inferior LFS (10-year risk 62% vs. 32% for non-multihit TP53MUT vs. 15% for TP53WT; p=0.03) but significance was lost during MVA that included SRSF2MUT, which was the only HMR mutation showing a significant effect on LFS (HR 5.0, 2.5-9.8; p<0.01). Post-ASCT survival among 135 transplanted patients was significantly shorter for patients with multihit TP53MUT (N=4; median 5 months) vs. those with non-multihit TP53MUT (N=7; median not reached) vs. patients with TP53WT (N=124; median not reached) [p=0.02]. Conclusion The current study implicates multihit TP53MUT as an HMR mutation-independent prognostic factor for OS in PMF-CP. By contrast, prognosis in PMF-CP patients with non-multihit TP53MUT was more likely to be influenced by other HMR mutations, as was the case for those with TP53WT.

Abstract Introduction: DDX41 (DEAD-box helicase 41) mutations (mt) represent the most prevalent germline predisposition syndrome (GPS) in adult patients (pts) with myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). This molecular subtype is typically associated with late-onset disease, runs an indolent clinical course, with a relative absence of high-risk co-mutations. While several retrospective studies have reported favorable responses to venetoclax (VEN)-based therapies, anecdotal observations suggest variable outcomes. We aimed to evaluate the clinical characteristics and treatment outcomes of patients with DDX41-mt MDS/AML treated at the Mayo Clinic. Methods: We conducted a retrospective study of pts diagnosed with DDX41-mt germline predisposition syndrome with concurrent myeloid neoplasms at our institution. Germline testing was conducted under an IRB approved protocol (Mayo Clinic IRB# 16-004173; clinical-trials gov. Identifier: NCT02958462). Of 198 pts with DDX41-mt myeloid neoplasms, 77 had high-risk disease—43 with MDS with increased blasts (MDS-IB1, n = 11; IB2, n = 32) and 34 with AML (WHO 2022). We assessed how clinical, and disease features influenced outcomes in this subgroup. Among these pts, 69 (90%) pts had likely pathogenic/pathogenic variant (DDX41path) variants and 8 (10%) pts had variant of undetermined significance (DDX41VUS) according to variant classification criteria from the American College of Medical Genetics/ the Association of Medical Genetics/ the Association for Molecular Pathology (ACMG/AMP) guidelines. Results: The median age was 68 years (yrs) (range [R],34-92), 70% were male and the median bone marrow blast % was 15 (R,5-60). The most common DDX41 germlinevariants (> 5% cases) included p.D140fs (26%), p.M1I (22%), and p.P258L (6.5%). 74% had DDX41 truncating variants. Thirty-one (40%) acquired a somatic DDX41-mt (R525H [81%]) and 43 (56%) had other somatic mutations. Among these, the most frequent were ASXL1 (n= 9, 21%), TP53 (n= 8, 10%), splicing factor (n= 7, 9%), and DNMT3A (n= 5, 6%). Twenty-six, (34%), 26 (34%), 15 (19%) and 9 (12%) pts were treated with hypomethylating agents (HMA), HMA+VEN, intensive chemotherapy (IC) and active surveillance/supportive care, respectively. Overall, the composite complete remission rate (cCR) in high-risk MDS and AML was 56%. The cCR rates (41%, 59% and 68.7%, p= 0.10) and median duration of response (DOR; 43.7, 44.9 and 28.9 months [mo], p= 0.46) were not significantly different with HMA, HMA+VEN, and IC induction. Thirty-one (40%) pts received allogeneic stem cell transplantation (allo-HCT); 4 (36%), 15 (47%) and 12 (35%) in MDS-IB1, MDS-IB2 and AML groups, respectively (p= 0.56). With a median follow up of 34.7 mo (R, 0.7-136.7), the median overall survival (OS) from the time of diagnosis was 56.9 mo (95% CI, 50.7-63.0) and was not significantly (NS) different between MDS-IB1 (not reached, 70% at 3 yrs), MDS-IB2 (56.9 mo, 86% at 3 yrs) and AML (55.7 mo, 60% at 3 yrs) groups, p= 0.16). The median OS was NS different between DDX41path and DDX41VUS (58.6 vs 55.7 mo, p= 0.50), respectively. We conducted a multivariable analysis for OS using variables that showed significance or trend towards significance in univariable analysis. Concurrent splicing factor mutations (HR; 5.29, 95% CI: 1.29-21.6, p= 0.02) remained negatively prognostic, while there was a trend towards better survival outcomes with allo-HCT (HR; 0.48, 95% CI: 0.21-1.07, p= 0.07). Bone marrow blast ≥ 20% (HR; 1.87, p= 0.12) and TP53-mt (HR; 2.14, p= 0.12) did not retain significance. Conclusion: In our cohort of patients with germline DDX41-mt high-risk MDS and AML, VEN-based regimens were not superior to HMA alone or IC, in terms of response rates and outcomes. On multivariable analysis, the presence of concurrent splicing factor mutations independently and negatively impacted survival with a trend towards better outcomes with allo-HCT. These findings highlight the heterogeneity within DDX41-mt myeloid neoplasms and underscore the need for future studies in larger cohorts to better define predictors of response and survival.

Abstract Background: KMT2A-rearranged acute myeloid leukemia (KMT2Ar AML) is characterized by chromosomal translocation involving KMT2A gene at 11q23, resulting in fusion with variety of partner genes. It is usually associated with poor outcomes, high risk of relapses and suboptimal responses to conventional therapies. While NPM1-mutated (mt) AML is considered favorable risk, they are equally dismal in relapse refractory (RR) setting. Menin inhibitors have emerged as a promising therapeutic strategy, particularly in RR AML patients (pts) with KMT2Ar and NPM1-mt genotypes. While revumenib, a menin inhibitor approved for managing RR KMT2Ar acute leukemia, no menin inhibitor is currently approved for NPM1-mt AML. In this study, we evaluated clinical outcomes of adults with KMT2Ar AML and performed a comparative analysis of pts with RR KMT2Ar and NPM1-mt AML using data from the Mayo Clinic. Methods: After screening 102 AML pts with reported KMT2A abnormalities, we identified 33 adults with confirmed KMT2Ar diagnosed between 2012 and 2024 for retrospective analysis. Clinical and molecular/cytogenetics data, induction type (intensive chemotherapy [IC] vs non-intensive chemotherapy [NIC]), response, transplant use, and survival outcomes were reviewed. A separate analysis was performed comparing 20 RR KMT2Ar AML pts with 20 propensity score matched RR NPM1-mt AML pts from a pool of 125 NPM1-mt RR pts. Results: The median age was 50 years (yrs) (range [R], 19.0-75.0), and 60.6% were < 60 yrs. Most cases were de novo AML (64%), and the most frequent translocation was t(6;11)(q27;q23)/MLLT4 (27%), followed by t(10;11)(p12;q23)/MLLT10 (21%), t(9;11)(p21.3;q23.3)/MLLT3 (15%), and t(11;19)(q23;p13.1)/ELL (12%). Other KMT2A fusion partners were rare and collectively accounted for the remaining cases. The median follow-up was 57 months (mo) (R, 7.0-109.0). The overall response rate (ORR) was 91%, and composite complete remission (CRc, , including CR, CRi, and CRh) was 73%. The CRc rates were comparable between IC and NIC (80% vs 62%, p=0.24). CRc were not significantly different by disease type (de novo [71.4%] vs secondary [sAML] [75%], p= 0.82) or KMT2A fusion partner gene (60% for t[9;11]/MLLT3 vs. 57.1% for t[10;11]/MLLT10 vs 55.6% for t[6;11]/MLLT4, p=0.069). Seventeen (52%) pts received an allogeneic stem cell transplantation (allo-HCT). The median overall survival (mOS ) for the entire cohort was 16 mo (R, 11.0-34.0). In subset analysis, IC compared to NIC was associated with significantly longer mOS (30 vs 11 mo, p=0.014). The mOS was also superior in pts <60 vs ≥60 yrs (32 vs 8 mo, p=0.005). Similarly, de novo cases had better mOS than sAML (22.0 vs 9.5 mo, p=0.052). Among KMT2Ar subtypes, t(6;11)/MLLT4 showed the longest mOS (54 mo [R, 30.0-not reached (NR)]), while t(9;11)/MLLT3 had the shortest (11.0 mo, [R 9-NR]), but differences were not statistically significant (p=0.32). The mOS was significantly longer among allo-HCT pts (30 vs 11 mo, p=0.005). Among 29 pts who experienced RR disease, the median relapse free survival (RFS) was 3 mo (R, 2.0-10.0). First salvage therapy yielded a CRc of 43.8% in 16 evaluable pts. When compared to a propensity matched cohort of 20 RR NPM1-mt AML pts, the CRc rates was 57.9% vs 50% in RR NPM1-mt and KMT2Ar AML (p= 0.68). The mRFS was not significantly different between RR KMT2Ar and NPM1-mt AML, (3 vs 4 mo, p=0.9). However, KMT2Ar pts had inferior mOS compared to NPM-mt AML (12 vs 65 mo, p=0.004). We further compared survival between NPM1-mt and KMT2Ar pts stratified by allo-HCT status. Among those who underwent allo-HCT, NPM1-mt pts had longer mOS (NR vs 22 mo, p=0.037). Among non-allo-HCT pts, mOS was numerically higher in NPM1-mt vs KMT2Ar (19 vs 8 mo, p=0.11). Conclusions: This single institusion cohort of adult AML with KMT2Ar underscores the biological and clinical heterogeneity of this high-risk group. IC was associated with a survival benefit, particularly among younger and fit patients. However, the outcomes following relapse remained poor, highlighting the urgent need for improved post-remission and salvage therapies. Comparative analysis with matched RR NPM1-mt AML pts revealed similarly dismal survival outcomes. Emerging data from single-arm studies of menin inhibitors in both frontline and RR settings among pts with NPM1-mt and KMT2Ar AML are encouraging and may represent a paradigm shift in treatment.

Abstract Introduction CAR T cell treatment is the standard of care for patients (pts) with primary refractory and relapsed large B-cell lymphoma (LBCL) within the first 12 months of chemoimmunotherapy, or for those unfit for autologous stem cell transplant (ASCT) regardless of timing of relapse. Consequently, the role of ASCT is limited to pts with late relapse (>12 months) who achieve a complete or partial response (CR or PR) to salvage therapy and are deemed eligible for ASCT based on comorbidities and performance status. In this report, we evaluated post-ASCT outcomes in this population of pts. Methods We conducted a retrospective cohort study using publicly available data from the Center for International Blood and Marrow Transplant Research (CIBMTR). Adult pts (age ≥18 years) with DLBCL, NOS, and high-grade large B-cell lymphomas (HGBL) who relapsed after having responded to initial treatment and who remained on response for at least 12 months since diagnosis were selected. We considered for this analysis only pts who achieved a CR or PR after salvage treatment at the time of relapse, documented on pre-ASCT CT or PET scan (per the 2014 Lugano definition). CIBMTR databases used for this study included pts who received ASCT from 2013 to 2021. We compared baseline characteristics between ASCT in CR vs PR using the Wilcoxon rank sum test for continuous variables and the Pearson's χ2 test for categorical variables after ignoring missing data. Primary endpoints included Progression-free survival (PFS) and overall survival (OS). Non-relapse mortality (NRM) and relapse rate were among the secondary endpoints. Results 182 were included in the analysis: 100 were in CR and 82 in PR before ASCT. The median age at ASCT was 60 years (range, 26-79). Race distribution was similar across CR and PR pts. Advanced-stage disease at diagnosis (stage III–IV) was seen in 61% of CR pts and 55% of PR pts. High-grade B-cell lymphoma (HGBL) with MYC and BCL2 and/or BCL6 rearrangements was similar in the CR and PR groups (7% vs 4%). The median number of lines of treatment before ASCT were identical in CR and PR pts (N=2). BEAM was the most frequently used transplant conditioning regimen in both groups (80%). Median follow-up after ASCT was 34 months (range, 1–95): it was 37 months (range 1-95) in the CR group and 26 months (range 1-79) in the PR group For the entire cohort, OS at 3 years was 67.6% and PFS was 50.6%. NRM was 1.7% at 100 days and 3.4% at 1 year. Cumulative incidence of relapse at 3 years was 43.9%. The NRM analysis showed no statistically significant difference between pts in CR and PR. The 3-year OS for CR pts was 73.9%% compared to 59.4% for PR pts (95% CI, 0.334-0.99; p=.044). The 3-year PFS for CR pts was 59.8%, compared to 38.6% for PR pts (95% CI, 0.321-0.784; p=.001). The median PFS for CR pts was 52.01 months, compared to 14.05 months for PR pts. The cumulative incidence of relapse at 3 years in CR and PR pts was 35.2% vs 55.7%, respectively (95% CI, 0.311-0.811; p=.003.). Higher age (HR 1.03; p=.026) and number of previous lines of treatment (HR 1.43; p=.002) were associated with inferior OS. For PFS, no variables showed any significant impact in univariable analysis. The stepwise multivariable analysis showed that only the number of previous treatments had a significant impact on the OS (p=.009), while undergoing ASCT on a PR was the only factor significantly associated with shorter PFS (HR 1.41; 95% CI, 1.09-1.82; p=.029). Conclusion This dataset supports that ASCT provides high efficacy in pts experiencing late relapses (after 12 months) achieving CR following pre-transplant savage and validates the value of achieving CR. Outcomes for PR are inferior, and this analysis provides a benchmark for future investigations. At this time, until convincing on other non-transplant treatment show superior outcomes in this setting, ASCT remains a standard of care for fit pts with chemo-sensitive late relapsed DLBCL. In this group of patients, who have a better prognosis compared to patients who relapse within a year the major hurdle is achieving a remission pre-ASCT.