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Abstract Introduction The LEO Comorbidity Index (LCI), comprising ten equally weighted comorbidity categories (respiratory, cardiovascular, digestive, hepatic, renal, autoimmune, diabetes, cancer history, HIV, and stroke), has demonstrated prognostic utility in patients with non-Hodgkin lymphomas. However, its predictive accuracy may vary with increasing age, due to age-related rises in comorbidity burden and physiological vulnerability. To investigate these dynamics, we evaluated the age-stratified predictive performance of LCI in patients with large B-cell lymphoma (LBCL), with a focused analysis on individuals aged 80+ years. We also examined which specific comorbidities most strongly influenced overall survival (OS) and developed a simplified, clinically applicable index tailored to this population. Methods We first included adults ≥40 years with newly diagnosed LBCL and recorded comorbidities from the LEO registry (USA, 2015–2020; n=1,652) to assess age-stratified predictive performance of LCI using the C-index. Next, we focused on patients 80+ years (n=263), pooled from the LEO cohort (n=147) and NiHiL registry (restricted to General Hospital, Prague, Czech Republic, 2010–2023; n=116). Comorbidities were collected from patient self-reports (LEO) and/or medical records (LEO/NiHiL). Univariate and multivariate Cox models were used. The primary endpoint was OS. Results Among the total LBCL population (n=1,652), LCI predictive performance improved by age category with C-index for patients <65 of 0.584, 65–79 years 0.579, and ≥80 years 0.647, indicating stronger discrimination in the 80+ group. Subsequent analysis focused on patients aged 80+ years (n=263; median age 83). Within this cohort, 34% had ECOG performance status (PS) 2–4, 66% stage III–IV disease, 59% elevated lactate dehydrogenase, 35% >1 extranodal site involved, and 58% International Prognostic Index (IPI) score of 3–5. A total of 377 comorbidities were reported, averaging 1.43 per patient (1.22 in LEO; 1.61 in NiHiL). LCI distribution was: 0 points in 24% (n=62), 1 point in 33% (n=88), and 2–5 points in 43% (n=113). Higher LCI scores had worse ECOG PS 2–4: 19% (LCI=0), 33% (LCI=1), and 43% (LCI ≥2; P=0.01), and inferior OS (median 6.9 years LCI=0, 3.0 years LCI=1, and 2.8 years LCI≥2, resp.; P=0.02). Presence of ≥1 comorbidity was associated with shorter OS compared to no comorbidities (HR=1.67, P=0.01). The LCI was an independent predictor of OS after adjusting for age (HR=1.18, P=0.01, C-index 0.623), IPI (HR=1.16, P=0.03, C-index 0.628) as well as for recently proposed SENIOR-IPI (HR=1.14, P=0.049, C-index 0.665). When evaluating individual comorbidities, heart disease (HR=1.54, P=0.01), stroke (HR=1.89, P=0.03), and recent malignancy (HR=1.99, P=0.02) were independent predictors of OS. Based on these findings, we developed a simplified LCI (sLCI) for use in 80+ patients incorporating only the three comorbidities (1 point each). Patients were categorized as sLCI: 0 (49%, n=129), 1 (44%, n=115), and 2–3 points (7%, n=19). sLCI scores 0, 1, 2–3 were associated with ECOG PS 2–4 27%, 37%, and 63%, respectively (P=0.01) and inferior OS: median 5.3 years (0), 2.5 years (1), and 1.4 years (2–3; P<0.01). sLCI remained an independent and strong predictor of OS after adjusting for age (HR=1.71, P<0.01, C-index 0.636), IPI (HR=1.66, P<0.01, C-index 0.635), and SENIOR-IPI (HR=1.60, P<0.04, C-index 0.659). The results were consistent in both NiHiL and LEO cohorts and remained significant among patients treated with anthracyclines (sLCI adjusted for age: HR=1.58, P<0.01, C-index 0.607; for IPI: HR=1.53, P=0.01, C-index 0.623; for SENIOR-IPI: HR=1.51, P=0.01, C-index 0.633). Conclusion Comorbidity burden becomes increasingly prognostic with higher age in LBCL patients. In the 80+ individuals, comorbidities – particularly heart disease, recent cancer, and stroke – have an independent impact on OS. While the original LCI captures the impact of broadly defined comorbidities, its prognostic utility attenuates in the 80+ patients, likely reflecting limited relevance of indolent chronic conditions in this population's constrained survival horizon. The sLCI, focused on the most prognostically relevant comorbidities, offers practical risk stratification. Incorporation of sLCI into clinical decision-making – alongside other prognostic indices – could better identify high-risk individuals and guide treatment strategies. Funding: NU21-03-00411, U01 CA195568.

Abstract Introduction: The CAR-T therapies ide-cel and cilta-cel are approved for patients (pts) with relapsed/refractory multiple myeloma (RRMM). The aim of this study was to determine the incidence, subtypes, and associated risk factors for subsequent primary malignancies (SPMs) in MM pts treated with CAR-T therapy in the real-world setting. Methods: A retrospective, multicenter observational cohort study was conducted of pts who received CAR-T therapy between May 2021 and Dec 2024 at 15 centers within the US Multiple Myeloma Immunotherapy Consortium. Logistic models were used for univariable analyses of invasive SPMs (excluding non-melanoma skin cancers). Variables significant at p < 0.10 were included as candidate variables in the multivariable analysis. Time to event endpoints were analyzed using Kaplan-Meier curves. Results: Of n=1460 CAR-T recipients, median follow-up from the time of CAR-T infusion for the entire cohort, ide-cel, and cilta-cel pts was 13.1, 16.9, and 10 months, respectively. A total of 55 invasive SPMs were noted in 53 pts (SPM incidence 3.6%). The incidence rate of SPMs was 4.55 per 1,000 person-years, based on 53 SPMs occurring over 11,646.14 person-years (calculated from CAR-T to the SPM diagnosis, death, or last follow-up). Baseline characteristics were similar for pts with no SPM versus SPM including: age at CAR-T (median 67 vs 65), female (36% vs 43%), Black (13% vs 16%), prior autologous transplant (87% vs 80%), lenalidomide for ≥2 years (31% vs 27%), high risk cytogenetics (23% vs 29%), and known clonal hematopoiesis (7.5% vs 9.9%). Differences were observed in baseline characteristics among pts with SPM versus no SPM for ≥2 prior alkylator lines of therapy (LOT) (82% vs 60%, p=0.002) and median prior LOT (6 vs 5, p=0.008). There was a trend for more patients with SPMs being age ≥70 (35% vs 37%, p=0.074). Of the 53 SPMs, 26 (49%) were myeloid (MDS or AML), 19 (35.8%) were solid, 7 (13.2%) were of T-cell origin, and 1 was a B-cell lymphoma. Of the T-cell SPMs, three were of T-LGL, though one of the T-LGL pts later developed an invasive CNS T-cell lymphoma (CAR-negative). There were four cases of confirmed CAR-positive T-cell SPMs (all pts treated with cilta-cel), of which two were indolent T-cell lymphoma of the GI tract and two were cutaneous PTCL. There was no difference in total incidence of SPMs among pts who received ide-cel (total=4.4%; myeloid=2.2%, T-cell=0.04%) versus cilta-cel (total=3%; myeloid=1.4%; T-cell=0.5%) (p=0.21). Median OS from the time of CAR-T therapy was 40.8 months for pts without SPM compared to 27.6 months for pts with SPM (p=0.4). Median OS did not differ by myeloid, solid, and T-cell subgroup: 26.4, 37.2, and 24 months, respectively (p=0.21). Median time from CAR-T cell to SPM was 12 months overall, and by subtypes of myeloid, solid, and T-cell was 13.2, 9.6, and 9.6 months, respectively (p=0.74). There was no difference in time to any SPM among pts receiving ide-cel versus cilta-cel (p=0.61). An earlier time to diagnosis of myeloid SPM was observed for cilta-cel versus ide-cel (4.8 vs 20.4 months; p=0.003). Median OS from the time of diagnosis of any SPM, myeloid, solid, or T-cell SPM was 9.6, 7.2, 15.6, and not reached in months, respectively (p=0.006), demonstrating that pts diagnosed with myeloid subtype SPM had inferior OS from the time of their SPM diagnosis compared to other subtypes. The cause of death of 4/11 myeloid SPM pts was the myeloid SPM itself. In univariable analysis for the entire cohort, age ≥70 (p=0.079), ≥5 prior LOT (p=0.012), and ≥2 prior alkylator LOT (p<0.001) were associated with higher risk for SPM. In multivariable analysis, ≥2 LOT containing alkylators was associated with higher risk of SPM (p=0.005). For the univariable analysis of the myeloid subgroup, ≥2 prior alkylator LOT (p=0.016) and ≥2 years of lenalidomide maintenance (p=0.063) were associated with higher risk of SPM. In multivariable analysis, ≥2 years of lenalidomide (p=0.065) was associated with a trend toward increased risk of myeloid SPM. Conclusions: With a median follow up of 13.1 months, the incidence of developing a SPM following CAR-T in pts with RRMM was 3.6%, of which approximately half were myeloid malignancies. There was no difference in SPM incidence when comparing the two CAR-T products. Pts treated with ≥2 alkylator LOT had a higher risk of SPM in multivariable analysis and may warrant additional monitoring for SPM development.

Abstract Background Secondary central nervous system lymphoma (SCNSL) is a rare but significant complication, affecting approximately 2–10% of patients with diffuse large B-cell lymphoma (DLBCL), often leading to poor outcomes. The CNS-International Prognostic Index (CNS-IPI) remains a widely adopted tool for estimating CNS relapse risk; however, recent advances in molecular profiling and evolving treatment paradigms have challenged the adequacy of CNS-IPI alone in guiding risk assessment. This study evaluates the prognostic relevance of CNS-IPI in conjunction with molecular and clinical factors, specifically cell-of-origin (COO), gene expression, and frontline treatment regimens. The aim is to refine risk stratification and identify patients at highest risk for SCNSL. Method Building on our previous study, we analyzed data from patients with newly diagnosed DLBCL between 2002 and 2023, enrolled in the Mayo Clinic/University of Iowa Lymphoma Molecular Epidemiology Resource. Patients with primary CNS lymphoma, CNS involvement at diagnosis, or who received CNS-directed therapy were excluded. COO was determined using the Hans algorithm and/or Nanostring profiling. Multivariate cause-specific Cox regression models were used to estimate hazard ratios (HR) and 95% confidence intervals (CIs) for predictors of CNS relapse that were measured at the time of initial DLBCL diagnosis. Cumulative incidence with competing risks and cause-specific Cox models were used to analyze relapse risk. Result We included 2137 patients in our analysis, median age at diagnosis was 63 (IQR 53-72), with 41.6% (n=890) females. The albumin level was below normal in 32.5% (n=350), 64.0% (n=1367) had CNS-IPI of intermediate/high, 37.5% (n=586) had non-germinal center B-cell (GCB) COO, and 14.5% (n=309) were double expressor positive. At a median follow-up of 83 months (IQR 42 -143), 82 (3.8%) SCNSL relapses were observed; the 3 and 5 yrs cumulative incidence for SCNSL from time of DLBCL diagnosis were 3.7% (95% CI 3.0-4.7) and 3.8% (95% CI 3.1-4.8) respectively. In models accounting for death as a competing risk, the 5-year cumulative SCNSL incidence estimate for patients with a CNS-IPI low was 1.5% (95% CI 0.8-2.7), Intermediate was 4.9% (95% CI 3.7-6.4), and high was 6.1% (95% CI 3.8-9.6). The 5-year cumulative SCNSL incidence estimate for patients with non-GCB COO was 5.2% (95% CI 3.6-7.4) compared to 2.4% (95% CI 1.6-3.6; p=0.001) for GCB patients, and the 5-year cumulative SCNSL incidence for double expressor positive patients was 8.6% (95% 5.8-12.6) compared to 1.5% (95% CI 0.8-2.7; p<0.001) for double expressor negative patients. In a multivariable model (including CNS-IPI, COO, double expressor, treatment group, extranodal involvement, and albumin group), CNS-IPI intermediate (HR 2.85 [1.58-5.14]; p<0.001) and high (HR 4.31 [2.15-8.65]; p<0.001), non-GCB COO (HR 2.36 [1.37-4.06]; p=0.002], double expressor (HR 5.56 [2.88-10.73]; p<0.001), and below normal albumin (HR 1.89 [1.02-3.50]; p=0.042) were independently associated with increased risk of SCNSL. The majority of the SCNSL relapse occurred within the first 2 years after DLBCL diagnosis; 81.7% (n=67), with only 6.1% (n=5) occurring after 5 years. For patients who developed SCNSL, the median OS from the time of SCNSL diagnosis was 24 months (95% CI 17-34), with 5 years OS of 31% (95% CI 22-43). These findings are being validated using an external, international cohort, and final analysis will be presented at the time of presentation at ASH. Conclusion In this large, prospectively followed cohort with long-term follow-up data, SCNSL remains a rare but devastating complication of DLBCL, with a 5-year cumulative incidence of 3.8% and it is associated with very poor long-term survival. While CNS-IPI remains a strong predictor of SCNSL risk, our study identifies non-GCB COO and double expressor phenotype as independent, additive molecular risk factors. These findings suggest that current risk stratification tools may underestimate the risk of CNS relapse in molecularly defined high-risk subgroups. Considering the poor outcomes linked to SCNSL and the absence of a connection with frontline treatment types, future research should aim to enhance risk prediction models through molecular profiling and explore prophylactic strategies to reduce the likelihood of SCNSL.

Abstract Background Primary central nervous system lymphoma (PCNSL) is a rare but aggressive non-Hodgkin lymphoma with limited prospective data to guide optimal therapy. This study evaluates real-world treatment patterns and survival outcomes using a large national cohort. Methods We analyzed data from the National Cancer Database (NCDB) for patients diagnosed with PCNSL between 2004 and 2020. Baseline demographics and treatment characteristics were analyzed using descriptive statistics. Survival outcomes were estimated using the Kaplan-Meier method and compared using log-rank tests. Multivariable Cox proportional hazards models were constructed to identify independent predictors of overall survival (OS). Results A total of 14,450 patients with PCNSL were included; 14,439 had first-line treatment data available, and 13,390 had survival data. Median age at diagnosis was 67 years (range 18-90), 49.2% were female, and 6.6% were African American. Chemotherapy alone was the modality of treatment for 81.6% (n=11,787), 12.2% (n=1,769) received chemoradiation, 3.8% (n=545) received chemotherapy and underwent autologous stem cell transplant (ASCT) but no radiation, and 2.4% (n=348) received radiation only. The median follow-up time was 73.5 months (95% CI 71.4-75.6), and the median OS for the group was 17.4 months (95% CI 16.2-18.6). Survival differed significantly by age group (median OS: <65 yrs, 46.1 months [95% CI 41.7 -50.6]; 65-79 yrs, 12.5 months [95% CI 11.2-13.7]; ≥80 yrs, 3.2 months [95% CI 2.9-3.5]; p<0.001), by year of diagnosis (median OS: 2004-2009, 11.0 months [95% CI 9.9-12.1]; 2010-2015, 20.0 months [95% CI 17.4-22.6], 2016-2020, 29.7 months [95% CI 26.0-33.4]; p<0.001), and by frontline treatment strategy (p<0.001). Patients treated with chemotherapy followed by ASCT had the longest median OS (not reached), while those receiving radiation alone had the poorest outcomes with a median OS of 3.9 months (95% CI 3.2-4.7); chemoradiation patients had a median OS of 31.8 months (95% CI 27.5-36.1), and chemotherapy only patients had a median OS of 13.9 months (95% CI 12.7-15.1)(p<0.001). African American patients had an inferior outcome with a median OS of 10.2 months [95% CI 7.2-13.1], compared to “other” races with a median OS of 36.9 months [95% CI 27.6-46.1] (p<0.001), although this is more similar to the median outcome for white patients (17.0 months [95% CI 15.8-18.3]). Treatment at an academic center (25.7 vs 11.0 months) and a high case-volume center (defined as >median number of cases per facility) (18.6 vs 10.5 months), and lower Charlson-Deyo comorbidity scores (CDS) (defined as CDS 0-1) (21.7 vs 6.8 months) were also associated with superior OS (p<0.001). In multivariable analysis, increasing age ( 65-79 y.o HR 1.60 [1.52-1.1.68], ≥80 y.o HR 2.95 [2.75-3.17]), CDS≥2 (HR 1.36 [1.28-1.44]), and African American race (HR 1.12 [1.02-1.24]) were adverse predictors of OS (all p<0.001), while treatment strategy (ASCT [HR 0.17], chemoradiation [HR 0.53], chemotherapy only [HR 0.68] compared to radiation alone), more recent year of diagnosis (2010-2015 [HR 0.81], 2016-2020 [0.70]), and treatment at an academic center [HR 0.81] remained predictors of superior OS (all p<0.001). Conclusion In this large national cohort of patients with PCNSL, treatment with chemotherapy followed by ASCT was associated with the most favorable survival outcomes. Patients treated with chemoradiation or multi-agent chemotherapy also demonstrated improved survival compared to those receiving radiation monotherapy or single-agent chemotherapy alone, respectively. Age, comorbidities, race, and treatment at academic centers were also significant independent predictors of OS. These findings highlight substantial disparities in outcomes and underscore the importance of optimizing treatment strategies, improving access to high-intensity therapies, and supporting timely referral to academic or high case-volume centers, particularly for younger and medically fit patients.

Abstract Background: Given a potential risk of extravasation with vesicants and irritants, central venous catheters (CVCs), such as port-a-cath or peripherally inserted central catheters (PICC), are commonly used for the administration of anthracycline-based chemotherapy. However, CVC placement can result in treatment delay, deep vein thrombosis (DVT), catheter malfunction, and added burdens (eg, financial, travel, etc), partly due to the need for regular flushing. Peripheral intravenous (PIV) access is often utilized in the academic setting with select frontline chemotherapy regimens. However, there is limited data reporting on the safety of PIV in this setting. This large, multicenter RWA evaluated the use and associated complications of PIV and CVC for administering CHOP- or ABVD-based chemotherapy in patients (pts) with lymphoma. Methods: We conducted a retrospective RWA across 8 U.S. centers among pts aged ≥18 years with non-Hodgkin lymphoma and Hodgkin lymphoma who were consecutively treated with ABVD or CHOP-based anthracycline chemotherapy via PIV or CVC access between 2010-2024. Choice of catheter placement was at the discretion of the pt's treating physician. Detailed baseline and safety data were collected. The primary outcome was extravasation; secondary outcomes included infiltration, DVT, cellulitis, erythema, and pain. Standard definitions of extravasation and other complications were used (Jackson-Rose J. CJON 2017). Rates of complications were compared via Fischer exact testing. Results: A total of 1,414 pts were included in the analysis: 790 in each arm (ie, PIV vs CVC). Of these, 624 were unique to each group, while 166 pts received chemotherapy via both modalities (PIV and CVC during the treatment course). Overall, 78.9% of pts completed all treatment as planned via PIV. Median age was 63 years (IQR 45–75) in the PIV group and 61 years (IQR 40–73) in the CVC group. Male sex comprised 57% vs 51%, ECOG 0–1 performance status was 83% vs 76%, and advanced-stage disease (stage III/IV) was present in 51% vs 62%, respectively. Lymphoma subtypes were comparable: DLBCL/high-grade/B-cell NOS (54.5% vs 56.1%), Hodgkin lymphoma (27.2% vs 27.5%), T-cell lymphoma (12.4% vs 6.6%), and indolent/mantle cell lymphoma (5.6% vs 6.7%). Among those receiving chemotherapy via CVC, 78.5% were treated through a port-a-cath and 21.5% via PICC. CHOP-based and ABVD-based regimens were administered to 68% and 32% of PIV pts, and 69.6% and 30.4% of CVC pts, respectively. A total of 4,084 (PIV) vs 3,859 (CVC) treatment cycles were delivered, corresponding to 4,347 (PIV) vs 4,884 (CVC) anthracycline infusion days. There was 1 documented case of extravasation in the CVC group and 2 suspected cases in the PIV group (p=0.9); for PIV, this translates to a per pt risk of 0.3% (or 0.05% of infusion days). The two PIV cases involved elderly women with DLBCL receiving CHOP. Both developed localized symptoms post-infusion and were treated conservatively (DMSO/warm compresses or dexrazoxane/ice), with full symptom resolution within 1 week and 1 day, respectively. No tissue or vascular injury occurred. Additionally, there were no significant differences between the PIV and CVC groups in the rates of induration/swelling (1.8% vs 2.0%, p=0.85), phlebitis/cellulitis (2.4% vs 2.4%, p=0.9), venous thromboembolism (VTE; 1.4% vs 2.0%, p=0.32), or erythema (3.8% vs 5.1%, p=0.27). Pain or tenderness at the infusion site (8.5% vs 2.9%, p=0.001) and infiltration (1.4 vs 0.13%, p=0.006) were more frequent in the PIV group. Chronic vascular complications related to prior VTE was slightly lower in the PIV group (0.13% vs 0.9%, p=0.06), but not significant. Additional details from a propensity score-matched analysis will be presented at the meeting. Conclusions: This is the largest known analysis to date evaluating the safety of PIV access for anthracycline-based chemotherapy in >1,500 lymphoma pts over a recent 15-year period, representing >9,000 total treatments with CHOP or ABVD. PIV access was found to be safe and associated with a low rate of serious complications. Moreover, extravasation was rare and there was not a significant difference observed between PIV and CVC use. While PIV use was associated with higher rates of local pain/tenderness and infiltration, the events were uncommon and self-limited. Despite the widespread default to CVC placement in many centers, these findings support the selective use of PIV in appropriate pts as elucidated here.

Abstract Introduction The monoclonal gammopathies of renal significance (MGRS) are defined by the presence of a nephrotoxic monoclonal protein in the absence of a well-defined malignant entity. Mechanistically it has been postulated that, across the varied subtypes of MGRS, abnormal plasma cell or B-cell clones in the marrow produce nephrotoxic proteins; however, in many cases, no paraprotein is detected by conventional laboratory methods and the bone marrow can be morphologically normal. The genomic underpinnings of MGRS are unexplored and, due to the rarity of this disease, clinicians are often left to unable to determine the exact nature of the clonal cell populations. We carried out a pilot study to characterize ctDNA in MGRS patients (pts). The first phase of the protocol sought to collect peripheral blood samples and, when possible, matched bone marrow aspirates, from MGRS pts to evaluate the feasibility of ultra-low pass whole genome sequencing (ULP-WGS) from peripheral blood to identify and characterize ctDNA. Methods We report ULP-WGS results from peripheral blood samples in the initial phase of the study. Peripheral blood samples were collected from renal biopsy proven non-amyloidosis MGRS pts prior to the initiation of treatment. Cell free DNA (cfDNA) was extracted and quantified. A total of 5-20 ng of cfDNA input was used for ULP-WGS. Libraries were pooled and sequenced using 100-bp paired-end runs to an average genome-wide coverage of 0.5x. After deconvolution and alignment, fragments with size 90-150bp were extracted using samtools. IchorCNA was utilized to calculate tumor fraction based on a panel of normals derived from three plasma samples from healthy controls. Model parameters were optimized for low tumor fraction and a threshold of 3% ctDNA was used to identify positive samples. Renal responses were assessed based on International Kidney and Monoclonal Gammopathy (IKMG) group criteria. Results Nine pts and were consented and gave samples for the study along with 3 healthy controls. Seven pts were sequenced, 4 of which were females and 3 were males. Median age was 58 years. Among sequenced pts, 5 presented with proliferative glomerulonephritis with monoclonal immune deposition (PGNMID) and 2 with light chain deposition disease (LCDD). Both patients with LCDD were kappa predominant and showed detectable plasma clones (8% and 3%). One of these pts displayed t(11:14) on bone marrow FISH testing. Among the 5 pts with PGNMID, 3 had IgG kappa deposition and only one had a detectable plasma clone (5%), which harbored trisomy 9 by FISH. Bone marrow flow cytometry was positive in 2 pts. Median 24-hour urine protein content was 7.11g (0.92 – 10.58), median serum albumin 3.20 g/dL (2.90 – 4.90) and median serum creatinine at the time of diagnosis was 2.15 mg/dL (1.30-6.40). CKD was present in 6 of 7 pts at the time of diagnosis. Four pts had known hypertension. One exhibited a history of malignancy and one had a history of autoimmune disease. ctDNA was detectable at a threshold of > 3.0% of cfDNA in 5 of 7 pts. Median ctDNA content was 4.0% (3.18% - 14.97%) of cfDNA. Four of the 5 samples containing ctDNA were hyperdiploid. Chromosome 19 was the most common site of copy number increase whereas chromosomes 6, 10, and 18 exhibited the most frequent decreases in copy number. Two pts with PGNMID had detectable ctDNA without evidence of a serological or marrow-based clone. All pts received daratumumab, cyclophosphamide, bortezomib and dexamethasone as initial treatment. Five pts responded to therapy. Two patients ultimately underwent autologous stem cell transplant and a single patient received venetoclax as second line therapy. Of the patients exhibiting detectable ctDNA, three did not exhibit renal response to initial treatment. Both pts without ctDNA had PGNMID and responded to frontline treatment. Mass spectrometry analysis and deep targeted sequencing of bone marrow aspirates and peripheral blood will be presented. Conclusions To our knowledge, this is the first study to detect ctDNA in MGRS. ULP-WGS, when combined with targeted sequencing and diagnostic modalities such as mass spectrometry, has the potential to not only to aid in diagnosis and treatment selection on a practical basis, but also to begin to unravel the underlying genomics of this rare disease. This approach has potential to serve as a platform for further genomic exploration and biomarker development in MGRS.

PURPOSE STELLAR (ClinicalTrials.gov identifier: NCT02796261 ) was a phase III, randomized, open-label trial of eflornithine + lomustine versus lomustine monotherapy in patients with recurrent grade 3 astrocytoma. METHODS At trial initiation, eligibility criteria included: age ≥18 years, anaplastic astrocytoma (2016 WHO CNS Tumor classification [WHO CNS4]), first recurrence ≥6 months after radiation and temozolomide (TMZ), Karnofsky performance status ≥70, and no imaging findings consistent with grade 4 glioblastoma. Random assignment (1:1) was stratified by isocitrate dehydrogenase ( IDH ) mutation, age, resection extent, and geography. Patients received eflornithine (2.8 g/m 2 orally, every 8 hours [2 weeks on, 1 week off]) + lomustine (90 mg/m 2 orally, once every 6 weeks), or lomustine monotherapy (110 mg/m 2 once every 6 weeks). The primary end point was overall survival (OS). RESULTS Among 343 patients randomly assigned across 74 sites in eight countries, there was no difference in survival between eflornithine + lomustine and lomustine monotherapy (median OS 23.4 v 20.3 months, hazard ratio [HR], 0.94). Following changes in classification and grading in the 2021 WHO CNS5, a subset analysis of patients with IDH- mutant, grade 3 astrocytoma (n = 196), defined in 2024, before unblinding, showed clinically meaningful improvements in median OS with eflornithine + lomustine versus lomustine monotherapy (34.9 v 23.5 months, HR, 0.64) and median progression-free survival (PFS, 15.8 v 7.2 months, HR, 0.57). No differences were observed among patients with CNS grade 4 disease. Grade ≥3 treatment-emergent adverse events of relevance were related to reversible myelosuppression (eflornithine + lomustine 42% v lomustine monotherapy 29% of patients) and hearing impairment (24% v 0%). No new safety signals were identified. CONCLUSION Clinically meaningful improvements were observed; eflornithine + lomustine doubled PFS and improved OS in patients with recurrent IDH -mutant, grade 3 astrocytoma, but not grade 4 tumors, after prior radiotherapy and TMZ, consistent with its cytostatic mechanism of action.