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Abstract Background: Older adults with newly diagnosed ALL treated with conventional chemotherapy have poor survival due to high rates of toxic death and disease relapse. The Alliance A041703 trial (NCT0373981) tested chemotherapy-free treatment with the anti-CD22 antibody-drug conjugate inotuzumab ozogamicin (InO) followed by the anti-CD19-CD3 bifunctional T-cell engager blinatumomab (blina) without maintenance in older adults to reduce toxicity and increase efficacy of therapy for this patient (pt) population. We previously reported with 22-month (mo) median follow-up that the study met its primary endpoint with a 1-year (yr) event-free survival (EFS) of 75% (90% confidence interval [CI] 63-89% lower bound exceeding null rate of 10%; JCO 2023 41, 7006). Here we report secondary outcomes with 45-mo median follow-up: 3-yr EFS, 3-yr overall survival (OS), response, and relapse characteristics. Methods: Eligible pts were ≥60 yrs old with newly diagnosed, Ph-negative, CD22-positive (≥20% of blasts) B-cell ALL without planned allogeneic HCT (alloHCT), liver disease, or CNS involvement at enrollment. Induction IA was InO 0.8 mg/m2 day (d) 1, 0.5 mg/m2 d8, d15 IV on a 21d cycle. Pts with adequate cytoreduction (marrow blasts reduced ≥50% or marrow cellularity ≤20%) after IA went to IB if in CR/CRi (InO 0.5 mg/m2 d1, d8, d15 IV; 28d cycle) or IC if no CR/CRi (InO 0.8 mg/m2 on d1 and 0.5 mg/m2 on d8 and d15 IV; 28d cycle). Those without cytoreduction to IA started course II blina. Pts without events in IA/B/C received course II blina continuous IV (9 mcg/d x 7d then 28 mcg/d x 21d; 14d break; 28 mcg/d x28d). Pts with CR/CRi to InO received 2 more 28d cycles of blina; others received 3 more. CNS prophylaxis was methotrexate 15 mg intrathecal x 8 doses. EFS was time from therapy start to failure to achieve CR/CRh/CRi by the end of course II, progression, relapse, or death, whichever occurred first, censored at last follow up. OS was time from registration to death from any cause censored at the last known alive date. Results: The median age of the 33 treated pts was 71 yrs (range 60-84). Eight pts had prior therapy for alternate malignancy in CR for >2 yrs prior to enrollment (6 multiple myeloma, 1 non-Hodgkin lymphoma, 1 breast cancer). Median CD22 expression was 92% (range 21-100%) and 49% had NCCN poor-risk genetics. Five pts underwent alloHCT in first CR/CRi and 2 pts received POMP maintenance after early discontinuation of blina (1 toxicity, 1 physician choice). The CR/CRi rate after InO was 85% (1 early death/refractory, 2 refractory, 2 undetermined due to low marrow cellularity on remission assessment marrow) with CR/CRi rate of 97% by completion of course II blina. With 45 mo median follow-up, the estimated 3-yr EFS was 48% (95% CI 33-70%) with a median EFS of 31 mo (95% CI 17.4-not reached [NR]) and no events after 31 mo. Sixteen events occurred: 12 relapses, 1early death, and 3 deaths in remission (1 encephalopathy, 1 relapse of multiple myeloma, 1 pulmonary complications after alloHCT). No isolated CNS relapse has been reported. Among relapses, 10 had immunophenotyping. Four (40%) were CD19-negative, one of which was also CD22-negative. Among CD19-negative relapses, genetics were hypodiploid (2), Pax5alt (1), and ZNF384-like (1, also CD22-negative). TP53 mutation or loss was observed in 5/12 (42%) relapses. Thirteen pts died. The estimated 3-yr OS was 59% (95% CI 44-79%) with median OS NR (95% CI 32-NR) with no deaths after 36 mo. In univariate analysis, EFS and OS were not impacted by age, gender, genetic risk (NCCN), prior therapy for alternate malignancy, or alloHCT in first remission. EFS was better with higher CD22 expression at diagnosis (≥90% vs <90%, 3-yr EFS 60% vs 25%, P=0.044). EFS and OS were worse for detectable minimal residual disease (MRD) at any timepoint by ASO-PCR. Undetectable MRD after course IA (1 cycle InO induction) was associated with EFS with a 3-yr EFS of 52% vs 0% for detectable MRD (median NR vs 8 mo, hazard ratio [HR] 0.07, P=0.004) and a 3-yr OS of 100% vs 0% for detectable MRD (median NR vs 20 mo, HR 0.00, P=0.0014). Conclusions: Longer follow-up of chemotherapy-free treatment with InO and blina for older pts with newly diagnosed, Ph-negative, CD22-positive, B-cell ALL reveals durable remissions and survival. The A041703 regimen is a compelling option for first-line treatment of this pt population. Support: U10CA180821, U10CA18088; https://acknowledgments.alliancefound.org.

Abstract Background Primary CNS lymphoma (PCNSL) is a rare, aggressive diffuse large B-cell lymphoma confined to the CNS, with poor outcomes. Virally associated PCNSL, including AIDS-related PCNSL (AR-PCNSL) and CNS post-transplant lymphoproliferative disorder (CNS-PTLD) accounts for ~10% of cases and is strongly linked to EBV infection and poor prognosis. In our prior Blood (Gandhi et al. 2021) study, targeted sequencing showed that EBV⁺ PCNSL lacks canonical MYD88, CD79B, and PIM1 mutations and retains intact HLA class I/II, suggesting distinct immunobiology. However, questions remain regarding the immune microenvironment, broad mutational landscape, and intratumoral heterogeneity. Here, we present the first large-scale comprehensive integrated analysis of virally associated PCNSL to define subtype-specific vulnerabilities and therapeutic implications. Methods FFPE brain biopsies from 72 PCNSL patients (40 EBV- de novo PCNSL, 32 EBV+ PCNSL including 18 AR-PCNSL and 14 CNS-PTLD) were analyzed. Immune gene expression was profiled using the NanoString PanCancer Immune Panel. Whole exome sequencing (WES) defined recurrent driver mutations, tumor mutational burden (TMB), and LymphGen classification (excluding A53 subtype). Single nuclei RNA sequencing (snRNA-seq) using the 10x Genomics Chromium Flex platform characterized cellular heterogeneity. Results WES demonstrated a marked reduction in canonical mutations (MYD88L265P, CD79B, PIM1, CARD11) in CNS-PTLD (0%) and AR-PCNSL (29%) vs. de novo PCNSL (87.5%; p<0.0001). AR-PCNSL had a distinct mutational signature when compared with CNS-PTLD and de novo PCNSL. NOTCH1/2 mutations were significantly enriched in AR-PCNSL (71%) vs. CNS-PTLD (9%) and de novo PCNSL (33%) (p<0.01). NLRC5 mutations were present in 64% of AR-PCNSL cases, higher than the 25% observed in de novo PCNSL and were absent in CNS-PTLD. TMB was significantly elevated in AR-PCNSL (mean 26.27 mutations/Mb) vs. de novo PCNSL (17.22) and CNS-PTLD (11.01; p=0.0018) underscoring pronounced genomic instability and suggesting HIV may exert a mutagenic influence beyond immunosuppression. EBV driven subtypes lacked MCD features and were more often classified as ST2 or unassigned. Despite NOTCH2 mutations, AR-PCNSL cases were not classified under the BN2 subtype, further highlighting limitations in current molecular classification systems to accurately stratify virally associated PCNSL. Immune transcriptomic profiling revealed further distinctions within EBV+ PCNSL. CNS-PTLD showed increased expression of genes related to antigen presentation (p<0.0001), cytotoxicity (p=0.0019), and T cell function (p<0.0001), suggesting retained immune responsiveness. AR-PCNSL exhibited significant suppression of HLA class I/II genes (p=0.0027 and p<0.0001 respectively), despite intact genomic loci, implicating post-transcriptional or epigenetic silencing. Immune cell composition revealed reduced macrophage infiltration and suppressed CD4 expression in AR-PCNSL. CNS-PTLD showed higher expression of checkpoint molecules LAG3, TIM3, and CTLA4, consistent with T cell exhaustion. snRNA-seq profiling of AR-PCNSL identified distinct malignant and non-malignant cell populations, including a reduced CD4⁺ compartment and altered microglial/macrophage populations and cell states compared to de novo PCNSL, corroborating bulk transcriptomic data, amongst other ongoing analysis. Conclusion This study represents the largest and most comprehensive immunogenomic investigation of virally associated PCNSL. AR-PCNSL and CNS-PTLD lack canonical PCNSL driver mutations and instead harbor distinct mutational signatures, including NOTCH pathway alterations in AR-PCNSL. These findings underscore divergent pathogenic mechanisms and support tailored therapies. AR-PCNSL is marked by high TMB, suppressed antigen presentation, and reduced CD4⁺ infiltration, indicating profound immune dysfunction. CNS-PTLD retains immune functionality but shows checkpoint upregulation and T cell exhaustion. Despite both being EBV-driven and CNS-restricted, they display distinct molecular and immunological programs, suggesting context specific EBV mechanisms. These findings challenge existing classification systems and support CNS-specific molecular frameworks to guide therapeutic interventions including BTK inhibition for NOTCH-mutated lymphoma. They lay the foundation for precision approaches in EBV⁺ PCNSL, including immune restoration, antigen-specific T cell therapy, and epigenetic modulation.

Abstract Background Chimeric antigen receptor T cell (CART) therapy has revolutionized treatment for hematologic malignancies. However, durable remission following anti-CD19 CART therapy (CART19) remains limited to 40–50% of patients, often due to tumor relapse and CART dysfunction (PMID:31501612). We previously demonstrated that tumor-derived extracellular vesicles (EVs) from patients with chronic lymphocytic leukemia (CLL) can directly impair CART function (PMID:33388419). In this study, we aimed to identify tumor-derived EV microRNA (miRNA) cargo associated with clinical CART failure in B cell malignancies and define how they mechanistically drive CART cell dysfunction. Methods To achieve these aims, we profiled tumor-derived EV miRNA cargo using small RNA sequencing (RNAseq) in two independent patient cohorts. Cohort 1 compared plasma-derived EVs from untreated CLL patients to those from healthy donor EVs to identify miRNAs enriched in CLL (n=23). Cohort 2 included patients with diffuse large B cell lymphoma (DLBCL) treated with axicabtagene ciloleucel (CART19, n=12). Here, plasma EV miRNAs were analyzed at baseline (pre-CART treatment) and 1-month post-CART treatment and compared between CART responders (complete remission at 6 months) and nonresponders (no response at 1 month). Enriched miRNAs from both cohorts were identified following miRNA count normalization and differential expression analysis using adjusted p values of ≤0.05. Functional studies were conducted by transfecting CART19-28ζ cells with synthetic miRNA mimics or scrambled controls. CART cells were also generated with stable overexpression of miRNA via lentiviral shRNA delivery. CART function was assessed via in vitro killing, proliferation, apoptosis assays, RNAseq, and in vivo tumor xenograft models. Results In Cohort 1, we identified several miRNAs including miR-125a to be significantly enriched in CLL-derived EVs relative to healthy controls. Similarly, in Cohort 2, miRNA-125a was also identified among the miRNAs enriched in nonresponders vs. responders to CART treatment; Notably, miR-125a was significantly enriched in nonresponders at baseline (pre-CART treatment) and 1-month post-CART treatment (p=0.0177, p=0.0196). To define the functional effects of miR-125a, we delivered synthetic mimics or stable shRNA constructs encoding miR-125a into CART cells. Delivery of miR-125a was confirmed by RT-qPCR (p<0.0001 for mimic vs. scramble, p=0.0069 for shRNA vs. scramble). Here, miR-125a delivery and overexpression impaired CART cytotoxicity/killing of target tumor cells (~25% reduction, p= 0.0039), decreased antigen-specific proliferation (~47% reduction, p=0.0002), and increased apoptosis following antigen stimulation (1.8-fold increase, p=0.0002) as compared to scramble controls in vitro. We next studied how miR-125a impacts CART functions in vivo. Here, tumor-bearing mice treated with miR-125a–overexpressing CART cells (CART sh125a) exhibited accelerated tumor progression (4.1-fold increase, p=0.0019) and significantly reduced survival as compared to mice treated with scramble control CART treatment (CART shScr) (20% vs 80% survival at day 35, p=0.0064), underscoring the dramatic detrimental impact of miR-125a on therapeutic efficacy. To uncover changes in CART gene expression induced by miR-125a delivery, RNAseq was also performed across stimulated CART sh125a vs. CART shScr cells. CART sh125a cells demonstrated broad transcriptional changes, with gene set enrichment of E2F targets, G2/M checkpoint, and apoptosis pathways (FDR p<0.0001, p<0.0001, and p=0.006) further validating the role of miR-125a in disrupting CART cell cycle control, proliferation, and survival. Conclusion In summary, our study identifies miR-125a as a tumor-derived EV cargo that drives CART dysfunction in two separate B cell malignancies (CLL and DLBCL). miR-125a was enriched in both CLL EVs and nonresponders to CART19 therapy at baseline prior and post CART treatment. Functional studies demonstrate that miR-125a delivery and overexpression directly impair CART cytotoxicity and proliferation, increase CART apoptosis, reduce therapeutic efficacy in tumor xenograft models, and disrupt key pathways related to CART cell cycle regulation and survival. These findings position miR-125a as both a key mechanistic driver of CART failure and a potential predictive biomarker for treatment response, while highlighting it as a possible therapeutic target to improve CART outcomes in the clinic.

Abstract Introduction: Clinical outcomes for patients (pts) with Philadelphia chromosome positive (Ph+) B-cell precursor Acute Lymphoblastic Leukemia (B-ALL) have significantly improved with the incorporation of tyrosine kinase inhibitors (TKI) and immunotherapy. Although the incidence of central nervous system (CNS) relapse in Ph+ B-ALL is rare, it has become an emerging challenge with chemotherapy-free approaches. While IKZF1, CDKN2A/B and emergence of T315I kinase domain mutations in ABL1 have been associated with worse outcomes (Foà R, JCO, 2024),further characterization of patients with CNS relapse could prove useful in risk stratification and optimizing treatment intensification. Currently, high white blood cell count (WBC) is being assessed as a marker to identify pts who may benefit from addition of CNS penetrant chemotherapy (ex. cytarabine or high-dose methotrexate (HD-MTX)) to TKI and immunotherapy protocols (Short NJ, J Hematol Oncol, 2025). Methods This is a multicenter retrospective study of relapsed/refractory Ph+ B-ALL pts under the COMMAND consortium. Age, gender, induction regimen and TKI of choice during induction were descriptively reported for the entire cohort. Categorical variables were compared, using Fisher's exact test, between pts with CNS relapse and pts with systemic relapse. Variables of interest were the presence of IKZF1 or CDKN2A/B alterations, emergence of T3151 mutation, CNS disease at diagnosis (dx), WBC >70K/microliter at dx, use of high-dose methotrexate (HD-MTX) during induction or consolidation, and use of TKI as part of the induction regimen. Odds ratio (OR) and 95% confidence intervals (CI) were reported for each variable. Results A total of 654 Ph+ B-ALL pts were initially identified across multiple centers in the United States, of whom 20 (3%) experienced a CNS relapse and 157 (24%) experienced a systemic relapse on median follow up of 29 months (range, 0-207). A total of 15 pts with CNS relapse and 114 pts with systemic relapse were used for this analysis after exclusion of pts without molecular data. The median age for the 129 pt cohort was 55 years (range 22-85), of whom 65 pts (50%) were male. Induction regimens used were intensive chemotherapy (IC)+TKI for 79 pts (61%), low-intensity chemotherapy or steroids (LDC-S)+TKI for 40 pts (31%), IC without TKI during induction for 5 pts (4%) and blinatumomab+TKI for 1 pt (1%). TKI of choice during induction included second-generation TKIs (dasatinib, nilotinib) for 77 pts (60%), imatinib for 30 pts (23%), ponatinib for 15 pts (12%) and none during induction for 5 pts (4%). CNS disease at dx was found in 6/15 pts (40%) with CNS relapse and 9/114 pts (8%) with systemic relapse, which was a statistically significant difference (p=0.002, OR= 7.57, 95% CI= 1.81 - 31.08). The systemic treatment regimens for the 15 pts with CNS disease at x were IC+TKI for 10 pts (66%) and LDC-S+TKI for 5 pts (33%), 9 of the pts (60%) received HD-MTX during induction. Intrathecal (IT) chemotherapy administration data at dx was available for 8 pts (53%) with CNS disease at dx, of whom 2 pts received <9 doses, 4 pts received 9-12 doses and 2 pts received >12 doses of IT chemotherapy. Although not statistically significant, pts with CNS relapse were more likely to have IKZF1 or CDKN2A/B alterations (p = 0.648, OR= 1.44, 95% CI= 0.14-7.78), WBC >70K/mcl (p = 0.472, OR= 1.73, 95% CI= 0.34-7.41), emergence of T3151 mutations (p = 0.123, OR= 2.54, 95% CI= 0.72-8.84) and use of HD-MTX during induction or consolidation (p = 0.262, OR= 2.15, 95% CI= 0.61-8.61); while they were less likely to have received a TKI during induction (p = 0.106, OR= 0.18, 95% CI= 0.02-2.34). Conclusion This data confirms that the presence of CNS disease at dx is associated with CNS relapse. Despite recent incorporation into clinical trials, WBC≥70K/mcl and omission of HD-MTX were not seen more frequently in pts with CNS relapse in this cohort. However, this analysis is limited by the small number of pts who experienced CNS relapse. With the rising use of chemotherapy-free regimens, prospectively trialing treatment intensification, such as with additional IT chemotherapy or HD-MTX, could be prospectively trialed in pts with CNS disease at dx to potentially improve outcomes for this subset of pts. The impact of increasing IT chemotherapy doses or additional cycles of systemic chemotherapy in this pt population is yet to be elucidated.

Abstract Background: Post-transplant lymphoproliferative disorder (PTLD) occurs in up to 30% of high-risk solid organ transplant recipients and is strongly associated with the intensity and duration of immunosuppression. While Epstein-Barr virus (EBV)-positive monomorphic PTLD and diffuse large B-cell lymphoma (DLBCL) share overlapping morphologic features and expression of canonical B-cell markers, they exhibit distinct EBV transcriptional programs. Immunosuppressive regimens, essential for preventing graft rejection, impair EBV-specific cytotoxic T lymphocyte (CTL) responses, thereby promoting EBV-driven lymphomagenesis. We hypothesized that these differences in viral transcription and immune evasion reflect fundamentally distinct immune microenvironments and host responses in EBV-positive PTLD compared to DLBCL. Methods This prospective, non-interventional study has been conducted at Moffitt Cancer Center since 2019. To characterize tumor-specific T-cell responses in EBV-positive PTLD versus DLBCL, peripheral blood mononuclear cells (PBMCs) from enrolled patients were infected with EBV (ATCC VR-1492) to generate autologous, immortalized lymphoblastoid B-cell lines (LCLs). EBV antigen-specific immune responses were quantified using an IFN-γ ELISpot assay targeting EBNA1, LAMP1, LAMP2A, BARF1, and a CEF peptide pool as a control. To optimize cell viability and functional readout post-thaw, we implemented an overnight resting protocol for PBMCs, which demonstrated superior IFN-γ release compared to the conventional 1-hour rest. Results We present pilot data from 11 consecutive patients (55% male; median age 63.4 years), including 3 with PTLD (2 EBV-positive; 2 monomorphic) and 8 with EBV-negative DLBCL. A total of 12 evaluable PBMC samples were analyzed: 7 pre-treatment, 1 mid-treatment, and 4 post-treatment. Successful generation of autologous LCLs was predominantly achieved using pre-treatment samples, whereas samples collected after B-cell–targeted therapy (Rituximab ± CHOP) showed reduced transformation efficiency. Notably, early pre-treatment samples exhibited a relative enrichment of CD27⁺ memory B cells. Baseline flow cytometric profiling of B cells undergoing LCL transformation revealed low CD19 expression (range <1%–15%). Repeat immunophenotyping at 3 weeks identified residual T cells within cultures, suggesting ongoing B-cell clearance. In matched flow cytometry and ELISpot assays from 7 evaluable patients with pre-treatment samples, EBV-positive PTLD cases demonstrated pronounced overexpression of PD-1 and TIM-3, but not LAG-3, alongside markedly diminished T-cell responses to EBV antigens. This distinct immunophenotypic and functional signature suggests T-cell exhaustion or dysfunction, likely driven by prior immunosuppression, which may impair immune surveillance and facilitate EBV-driven lymphomagenesis. Conclusions Our findings reveal distinct immunologic profiles in EBV-positive monomorphic PTLD compared to EBV-negative DLBCL, characterized by immune exhaustion and impaired T-cell functionality. Specifically, overexpression of PD-1 and TIM-3—but not LAG-3—in EBV-positive PTLD correlated with diminished antigen-specific T-cell responses, as measured by ELISpot, underscoring the role of prior immunosuppression in shaping ineffective tumor-specific immunity. Successful generation of autologous LCLs was predominantly achieved from pre-treatment PBMCs, highlighting the impact of B-cell–depleting therapies (Rituximab ± CHOP) on downstream immune profiling feasibility. The persistence of residual T cells in long-term LCL cultures suggests ongoing B-cell clearance and may reflect previously unrecognized immune dynamics in PTLD. Collectively, these data provide novel insights into the immune landscape of EBV-driven PTLD and support the rationale for therapeutic strategies aimed at reversing T-cell exhaustion—such as immune checkpoint blockade or adoptive T-cell therapies—to restore anti-EBV immunity in transplant recipients.

Abstract Background Nodal peripheral T-cell lymphomas (nPTCLs) are a challenging group of non-Hodgkin lymphomas that frequently recur after or are refractory to first line (1L) treatment. Chemotherapy options in the relapsed or refractory (R/R) setting are limited. The incorporation of non-cytotoxic agents including antibody drug conjugates, immune checkpoint inhibitors, epigenetic modifiers, and phosphatidylinositol 3-kinase inhibitors offers new therapeutic potential and possibly better outcomes. We report on outcomes for patients (pts) with R/R nPTCL enrolled in the multi-center LEO-MER prospective cohort study (NCT02736357) who received second line (2L) therapy. Methods Six hundred and three adult pts with newly diagnosed nPTCL were prospectively enrolled in the University of Iowa/Mayo Clinic MER observational cohort (2002-2015) or the expanded LEO cohort (2015-2020). Secondary overall survival (sOS) was calculated from date of 2L treatment initiation to date of death or last follow-up. Secondary event-free survival (sEFS) was calculated from date of 2Ltreatment initiation to disease progression, initiation of 3rd line therapy, or death from any cause. sEFS and sOS were evaluated using Cox model and Kaplan-Meier estimator. Log-rank test was used to test the significance of difference between groups. Pts with concomitant B-cell lymphomas were excluded from this analysis. Results Thus far, 169 pts with nPTCL initiating 2L therapy were evaluated. Of these, 75 (44.4%) had PTCL-NOS, 63 (37.3%) had angioimmunoblastic T-cell lymphoma (AITL, inclusive of nodal T-follicular helper cell lymphoma), 20 (11.8%) had ALK-negative anaplastic large cell lymphoma (ALCL), and 11 (6.5%) had ALK-positive ALCL. At 2L treatment initiation, the median age was 64 with 86.1% of pts having advanced stage disease. Of the 108 pts with available international prognostic index (IPI) scoring, 46.3% had an IPI of ≥3. Thirty-four (20.1%) pts had received a consolidative autologous stem cell transplant (ASCT) in the 1L. A total of 86 pts (50.1%) had primary refractory disease (partial response, stable or progressive disease as best response to 1L therapy), 45 (26.6%) experienced early relapsing disease within 6 months of 1L therapy, and 38 (22.5%) had relapsed disease >6 months from 1L therapy. After a median follow-up of 7.1 years (yrs), median sOS was 1.52 yrs, and sEFS was 3.2 months (mos). There was no difference in sOS or sEFS regardless of timing of relapse. In keeping with other studies, ALK-positive ALCL pts had the best 5-year OS (70.1%) compared to other subgroups (ALK-negative ALCL 45.0%, AITL 30.4%; PTCL-NOS 21.3%). Lymphoma was the leading cause of death following 2L therapy, with a 2-year cumulative incidence of 49.2%. Eighty pts (47.3%) received only cytotoxic chemotherapy as second line (2L) therapy; ICE (41 (51.3%)) and gemcitabine-containing regimens were most common (14 (17.5%)). Seventy-five pts (44.4%) were treated with non-cytotoxic agents given as monotherapy or in combination with chemotherapy. The most common non-cytotoxic therapies were brentuximab vedotin (33 (44.0%)), romidepsin (17 (22.7%)) and immune checkpoint inhibitors (9 (12.0%)). Fourteen pts (8.3%) underwent palliative interventions involving radiation, steroids, or cyclosporine alone. Intent to proceed to transplant in the 2L was known in 158 pts (101 (63.9%) not intended, 57 (36.1% intended)). Following 2L treatment, 18 (10.7%) pts proceeded to consolidative ASCT and 10 (5.9%) to allogeneic transplant. Only 21 (12.9%) were treated on a clinical trial. Pts who received a non-cytotoxic agent had superior outcomes compared to pts receiving only chemotherapy; the median sOS was 30.4 mos (95% confidence interval [CI] 15.3, 53.52 mos) vs 11.7 mos ((95% CI 7.95,19.58); p=0.04; HR 0.67) and the median sEFS was 4.83 mos (95% CI 3.38, 10.09) vs 2.33 mos ((95% CI 1.71,3.02); p=0.02; HR=0.65). Conclusions We report here one of the largest prospective cohorts in R/R nPTCL. The LEO-MER cohort, despite its association with academic centers, shows poor outcomes regardless of refractory or relapsed disease, frequent inability to proceed to intended consolidative transplant, and low clinical trial participation in 2L, which corroborates findings from other registries (Jain 2025, Stuver 2019). Outcomes improved for pts treated with non-cytotoxic agents. Updated data including additional pts and subgroup analyses will be reported at the meeting.

Abstract Background: MM is the second most common hematologic malignancy, which despite significant therapeutic advancements, remains incurable. The complexity of MM and its intricate management creates substantial informational demands for patients navigating their care. Methods: A cross-sectional survey study (Mayo Clinic IRB # 25-004671) was conducted to assess MM patients’ awareness about disease basics. A voluntary English language survey (47 questions) encompassing multiple domains of patient MM awareness was administered (REDCap) via the patient EMR portal (Mayo Clinic) and MM support groups nationally. Responses were analyzed using descriptive and inferential statistics (R; Bluesky Statistics, V 10.3.4). Multiple model logistic regression was used for multivariate analysis using age (≤70 or >70 yrs), gender, education (high school or less vs bachelor's and above), income (≤$74999 vs ≥$75000) and insurance status (private vs public). Results: The survey was completed by 2353 patients (pts) with 2177 MM (83.4% active, 16.6% smoldering) and 176 MGUS. Among MM pts median age was 63 yrs with 52.5% males, 91.5% white and 95.7% non-Hispanic. 17.5% had a prior diagnosis of MGUS and 20.2% of smoldering MM prior to MM, and 79.5% were not aware of MM prior to their own diagnosis. Majority (77%) depended most on their doctors to gain MM information but 24.3% reported not having sufficient discussion about MM at diagnosis. 31.2% were not sure what type of MM they had, 22.9% could not correctly report the cell of MM origin (plasma cell), 40.6% did not receive MM stage information at diagnosis, 45.4% were either unsure or reported wrong risk factors for MM and 22% were unsure or mistaken about MM symptoms. Majority (62.9%) did not understand genetic risk categories of MM, 32.3% did not report adequate understanding of MM tests and 31.9% did not understand the difference between response and remission. 57.5% reported not understanding about MRD status and 57.1% never had MRD testing. Majority (86.8%) felt they got adequate opportunity to participate in treatment decisions but only 54.2% felt confident in managing MM with their current knowledge and 28.2% had not discussed their prognosis although 77.7% wanted to know about it. Majority (64.4%) felt they had knowledge gaps about MM and its management. Multivariate analysis showed that females were less likely (OR 0.67) while those with public insurance were more likely (OR 1.35) to report receiving adequate information at diagnosis. Older pts (OR 0.55), males (OR 0.43), with lower education (OR 0.5), lower income (OR 0.5) and public insurance (OR 0.72) were less likely to identify the cell of MM origin correctly. These same groups were significantly less likely to be aware of types of MM as well. Older pts (OR 0.73), with lower education (OR 0.6), lower income (OR 0.77) and public insurance (OR 0.76) were less likely to be aware of MM genetic risk categories. Females (OR 0.81), with lower education (OR 0.68) and lower income (OR 0.63) were less likely to understand MM lab tests. Females and those with lower income were significantly less likely to report receiving adequate information about treatment options. Females reported that they did not get adequate opportunities to participate in treatment decisions (OR 0.65). Older pts, and those with lower income, lower education or public insurance were less likely to understand minimal residual disease (MRD) and all these groups were less likely to have had MRD testing. Those with lower income (OR 0.75) and lesser education (OR 0.72) felt less confident in managing MM with current knowledge. Older pts, females and those with lesser education, lower income and public insurance were also significantly less likely to have discussed about MM prognosis. Conclusion: This study demonstrates substantial basic knowledge deficits integral to managing and prognosticating MM among patients. Patients from unfavorable sociodemographic-economic groups were more likely to have awareness gaps and report lack of information which is integral to having adequate understanding of MM being provided to them. These findings highlight the critical need for structured, comprehensive educational interventions that address fundamental disease concepts to empower pts, overcome healthcare disparities, and engage pts in shared decision-making.

Abstract Introduction: Elranatamab (Elra) is a bispecific antibody (BsAb) targeting BCMA that is approved for patients with triple class exposed relapsed refractory myeloma (RRMM) on the basis of the MagnetisMM-3 phase 2 trial. For BCMA naïve patients, an overall response rate (ORR) of 61.0% and median progression free survival (PFS) of 17.2m was observed with a median overall survival (OS) of 24.6m. However, efficacy and safety information in the real world is lacking. Methods: This was an international retrospective study of patients with RRMM treated with Elra monotherapy outside of clinical trials. Data was collected through the International Myeloma Foundation Immunotherapy Database from 7 countries (UK, USA, Canada, Greece, Spain, Czech Republic and Singapore). High-risk cytogenetic abnormalities (HRCA) were defined as 1q+, t(4;14), t(14;16), t(14;20), and/or del(17p). Response was assessed using IMWG consensus criteria. Patient characteristics were summarized by frequency (percentage) or median (range). PFS, OS were evaluated using the Kaplan-Meier method and reported with 95% confidence intervals. Results: 79 patients were included. Median age was 67 years (range: 41-95y) with 20% ≥75 years. Racial distribution was: 75% White, 16% Black/African American, 8% Asian/Pacific. 55% were ECOG performance status (PS) 1-2. Patients received a median of 5 prior lines (range 1-11), and 35% were BCMA exposed (9% CAR-T, 5% ADC, 7% BsAb, 8% BsAb plus CAR-T, 4% ADC plus BsAb). Of those with available data, 45% had HRCA,13% had extramedullary disease (EMD) and 32% had penta-drug refractory RRMM. Overall, 48% would not have been eligible for the MagnetisMM-3 trial. Median follow-up was 6.3m (range 0.5-35.0). ORR was 53% (PR 11%, VGPR 33%, CR 8%, sCR 1%) and 67% for BCMA naïve patients. Responses were significantly lower for BCMA exposed patients (ORR 31%) but did not differ by age (51% <75yrs vs 60% ≥75yrs). On univariate analysis, prior BCMA exposure, platelets <50, presence of HRCA and penta-refractoriness were significantly associated with a lower response rate. PFS for the whole cohort at 6 and 12m was 64% (95%CI, 54-77%) and 52% (40-67%); for BCMA naïve patients, it was 77% (65-90%) and 67% (54-84%), respectively. Within the whole cohort, PFS was shorter for: BCMA exposed (median 4.0m vs not reached (NR)), platelets <50 (2.0 vs 21.7m), HRCA (7.2m vs NR), penta-refractory (4.3m vs NR). PFS did not differ significantly by EMD, PS, age, or creatinine clearance. OS for the whole cohort at 6 and12m was 74% (64-85%) and 58% (45-74%); for BCMA-naïve patients, it was 80% (43-85%) and 70% (57-87%), respectively. Within the whole cohort, OS was shorter for: BCMA exposed (median 10.3m vs NR), platelets <50 (4.3m vs NR), HRCA (10.7m vs NR) and penta-refractory (10.3m vs NR). Univariate regression analysis demonstrated that prior BCMA exposure, platelets <50 and penta-refractoriness were significantly associated with a worse PFS and OS, and HRCA predicted poorer survival CRS was observed in 41% of patients (grade(G)1: 35%, G2: 5%, ≥G3: 0%) with most occurring with the first step up dose (SUD): SUD1: 29%, SUD2: 15%, full dose: 4%. Tocilizumab was used in 20% and steroids in 3%. ICANS was observed in 4 cases (5%): G1: 2, G2: 1, G4: 1. Treatment was with steroids (n=3) and tocilizumab (n=2). G3-4 thrombocytopenia was observed in 19% and 14% required platelet transfusions. G3-4 neutropenia occurred in 25% with overall 31% requiring GCSF. Infections were reported in 33 (42%) patients with median time to infection of 41 days. A total of 94 infection episodes were observed over 581 personal months. There were 2 infection-related deaths reported (1 had IVIG, 1 did not). 64% had hypogammaglobulinemia (IgG < 400mg/dl) and IVIG was given in 65% of patients. Conclusions: In this first international real world analysis, Elranatamab achieved a response rate of 67% and a 12m PFS of 67% in BCMA naïve patients, similar to the MagnetisMM-3 trial despite almost half not meeting trial eligibility. However, prior BCMA exposure, platelets <50, high risk cytogenetics and penta refractory status were predictors of poorer outcomes. Acknowledgements: The International Myeloma Foundation, International Myeloma Working Group (IMWG)

Abstract Background: Plasmacytoid dendritic cell-associated acute myeloid leukemia (pDC-AML) is an emerging, rare subtype of AML characterized by the clonal proliferation of plasmacytoid dendritic cells (pDCs) at various stages of maturation. Although infrequent, this leukemia subtype is clinically aggressive and poses significant diagnostic and therapeutic challenges. Objective: This review synthesizes current knowledge on the immunophenotypic, genetic, and clinical features of pDC-AML, explores its prognostic implications, and compares it with the related entity blastic plasmacytoid dendritic cell neoplasm (BPDCN). Methods: A comprehensive literature search was conducted using databases including PubMed, Scopus, and Web of Science. Studies describing the morphology, immunophenotype, cytogenetics, molecular alterations, clinical presentation, and treatment outcomes of pDC-AML were included. Data were extracted and compiled from 16 studies encompassing 231 patients. Results: pDC-AML predominantly affects older adults (median age ~69 years) and exhibits a male predominance (~68%). It presents with diverse AML subtypes, including AML with monocytic differentiation, minimal differentiation, and secondary AML. Bone marrow pDCs range from 2.2% to 30% and exhibit variable maturation, often expressing CD123, CD303, CD304, and variably CD34 and CD117. In contrast to BPDCN, CD56 is rarely expressed, and skin or lymph node involvement is uncommon. Genetically, pDC-AML exhibits a complex landscape. RUNX1 mutations are the most common (14–78%), possibly driving pDC lineage commitment. Additional mutations include ASXL1, DNMT3A, SRSF2, FLT3, and BCOR. Chromosomal abnormalities such as chromosome 7 deletions, trisomy 13, and MLL or CBFA rearrangements are frequently observed. Compared to BPDCN—which shows high CD56 and TCL1 expression and more frequent TET2 mutations—pDC-AML is more genetically and phenotypically heterogeneous. Therapeutic responses are inconsistent. Treatments include induction chemotherapy, hypomethylating agents (e.g., azacytidine plus venetoclax), and allogeneic hematopoietic stem cell transplantation (allo-HSCT). Median overall survival ranges from 9.6 to 20 months, with frequent relapse even post-HSCT. Emerging therapies targeting CD123 (e.g., tagraxofusp) and immune-modulating agents are under investigation. Conclusion: pDC-AML is a clinically aggressive and biologically distinct AML subtype defined by clonal pDC expansion, frequent RUNX1 mutations, and suboptimal responses to current therapies. Accurate diagnosis relies on integrated immunophenotypic and genetic profiling. Despite progress, patient outcomes remain poor, underscoring the need for improved classification, prognostic markers, and targeted therapeutic strategies.

Abstract Background: Leukemia, a type of cancer of the blood forming tissues, compromises the immune system putting the body at risk of aggressive infections like septicemia. This can not only progress to septic shock but also death. The occurrence of the two conditions makes it almost necessary to understand the epidemiological patterns to increase the rates of survival. This study assesses the trends in mortality in patients with leukemia and septicemia in the United States from 1999-2023. Methods : We analyzed death certificates of adults aged 5 to 84 years' from the CDC-WONDER database with Leukemia (ICD-10 codes: C91, C92) and Septicemia (ICD-10 codes: A40, A41) from 1999-2023. Age-adjusted mortality rates (AAMR) per 100,000 population were stratified by gender, race, census region, year and age. Join-Point analysis was performed to estimate annual percent change (APC) and average annual percent change (AAPC) in mortality trends, along with 95% confidence intervals (CIs). Results : Between 1999 and 2023, Leukemia and Septicemia caused 56,497 deaths in patients aged 5 to 84 years. The total AAMR decreased from 0.78 in 1999 to 0.66 in 2023. Demographically, AAMR among the men decreased significantly from 1.04 to 0.85 (AAPC: -0.65; 95% CI: -0.80 to -0.49). Females experienced a decline in mortality from 0.59 to 0.46(AAPC: -0.44; 95% CI: -0.71 to -0.17). In terms of race, a slight decrease in mortality was witnessed in the mortality of Non-Hispanic (NH) Black or African Americans from 0.91 to 0.7 (AAPC:-1.13 ; 95% CI: -1.43 to -0.82), moreover the AAMR in the Hispanics decreased from 0.8 to 0.63 (AAPC: -0.04; 95% CI: -0.04 to -0.58) while those among the white community decreased from 0.78 to 0.68 (AAPC: -0.39; 95% CI: -0.58 to -0.19). Moreover, the Asian community also experienced a declining death rate. Geographically, regions in the Midwest showed the highest overall AAMR (0.75), followed by the West,Northeast and areas in the South with an overall AAMR of 0.72 . Between the urban and rural areas, rural areas had a higher AAMR as compared to the urban areas with an overall AAMR of 0.17. When stratified according to states, AAMRs varied highly from the highest in Kentucky (0.89) to the lowest in Maine(0.26). Conclusion: The overall mortality rates for leukemia and septicemia decreased between the years 1999-2023. The greatest change was seen in males, regions in the Northeast, racially in NH Blacks and the rural areas.