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Incidence of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), infections and cardiovascular events across different chimeric antigen receptor (CAR) T-cell therapy products in large B-cell lymphoma (DLBCL): A
Mahadevia, Himil , Modi, Karnav , Shah, Raj, Modi, Shivani , Khumri, Taiyeb, Vodnala, Deepthi, Cossor, Furha, Vojjala, Nikhil

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 8012-8012

10.1182/blood-2025-8012 Get It

Abstract Introduction: CAR T-cell therapy is an important treatment option for patients with relapsed or refractory (R/R) DLBCL. Three CAR T-cell products have received approval: axicabtagene ciloleucel (Yescarta), lisocabtagene maraleucel (Breyanzi), and tisagenlecleucel (Kymriah). Although direct head-to-head studies comparing the three therapies do not exist, clinical trials have revealed notable differences in response rates and remission rates among them. All three products induce CRS and ICANS; however, variations in the incidence and severity of these adverse effects have been observed. We utilized data from the National Inpatient Sample (NIS) to gain further insights into the incidence of various adverse events associated with different CAR-T products in DLBCL. Method: In this retrospective study, the 2022 NIS database was used to identify hospitalizations with DLBCL and those who received Yescarta, Breyanzi, or Kymriah using appropriate ICD-10-CM diagnostic and ICD-10-PCS procedure codes. Data on CRS, ICANS, infections, and adverse cardiac events were extracted using relevant ICD-10-CM codes. These outcomes were compared across different CAR-T products using Pearson's chi-square analysis. Multivariate logistic regression was also performed, adjusting for demographics, hospital-specific characteristics, and comorbidities. Results: We identified 1440 patients with DLBCL. Among these, 1100 patients (64.6% male; 70.7% Caucasian, 8.8% African American, 20.5% other ethnicities) received Yescarta, 90 patients (66.7% male; 82.4% Caucasian, 0% African American, 17.7% other ethnicities) received Kymriah and 250 patients (64% male; 82.6% Caucasian, 10.9% African American, 6.5% other ethnicities) received Breyanzi. The incidence of CRS was 52% for Breyanzi, 44.4% for Kymriah and 68.6% for Yescarta, and the difference was statistically significant by chi-square analysis (p = 0.03). This difference remained statistically significant for Kymriah after multivariate analysis [Adjusted Odds ratio (OR) = 0.3, CI 0.1 to 0.9, p=0.032], but not for Breyanzi (Adjusted OR = 0.3, CI 0.1 to 0.9, p=0.032) in comparison to Yescarta. The incidence of ICANS was 16% for Breyanzi, 22.2% for Kymriah, and 33.2% for Yescarta, with a statistically significant difference observed by chi-square analysis (p = 0.05). This difference remained statistically significant for Breyanzi after multivariate analysis [Adjusted OR = 0.3, CI 0.1 to 0.6, p=0.002], but not for Kymriah (Adjusted OR = 0.6, CI 0.1 to 2.9, p=0.551) in comparison to Yescarta. Among cardiovascular events, there was no significant difference in the incidence of acute myocardial infarction (Yescarta vs Kymriah vs Breyanzi, 0.5% vs 0% vs 0.2%, p = 0.487), stroke (0.5% vs 5.6% vs 2%, p = 0.07), cardiogenic shock (0.5% vs 0% vs 0%, p = 0.880), and arrhythmias (20.9% vs 27.8% vs 32%, p = 0.258) among these CAR T-cell therapies. Furthermore, there were no significant differences in the incidence of infectious complications, including pneumonia (5.9% vs 5.6% vs 2%, p = 0.510), sepsis (5% vs 5.6% vs 6%, p = 0.962), or septic shock (2.3% vs 0% vs 0%, p = 0.535) among these CAR T-cell therapies. There was no difference in all-cause in-hospital mortality across these therapies (2.3% vs 5.6% vs 2%, p = 0.692). Conclusion: Kymriah showed lower CRS rates and Breyanzi showed lower ICANS rates in comparison to Yescarta in our study. All CAR T-cell therapies have the potential to cause infections and cardiac events, which require monitoring, early identification and prompt treatment. When selecting among various CAR T-cell products, several factors must be considered, including the patient's lymphoma type, prior treatment history, manufacturing turnaround time, cost, availability, and potential short-term and long-term side effects. The limitations of our study include its retrospective nature, reliance on ICD-10 codes to identify patients with adverse events, and the absence of longitudinal data on long-term adverse events. Nevertheless, this study provides essential insights for hematologists regarding the incidence of specific adverse events associated with different CAR T-cell products within the real-world population.
Trends and disparities in mortality from chronic lymphocytic leukemia in the geriatric population in the United States from 1999 to 2020: A nationwide analysis
Mannan, Muhammad Shaheer, Khan, Allahdad , Ahmad, Arfa, Fatima, Ayesha , Noor, Huzaifa, Manzoor, Anisha, Talha, Muhammad , Agha, Mohammad, Aslam, Saad , Sadiq, Muhammad Hussnain, Cheema, Muhammad Hassan, Naz, Tahreem, Khan, Abdul basit, Muhibullah, Fnu, Basharat, Ahmad , Yasir, Muhammad , Fatima, Ayesha , Ahmad, Arfa, Javed, Hafiz Muhammad Hannan, Noor, Huzaifa, Manzoor, Anisha, Agha, Muhammad Asim, Sadiq, Muhammad Hussnain, Cheema, Muhammad Hassan, Naz, Tahreem, Khan, Abdul basit, Muhibullah, Fnu

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 8016-8016

10.1182/blood-2025-8016 Get It

Abstract Background: Chronic Lymphocytic Leukemia (CLL) is the most prevalent leukemia among adults in Western populations, disproportionately affecting the elderly, with a median age at diagnosis of approximately 70 years. Over the past two decades, significant advancements in therapeutic options, including Bruton tyrosine kinase (BTK) inhibitors, BCL-2 antagonists, and monoclonal antibodies, have improved clinical outcomes. However, despite these advances, limited data exist on long-term mortality trends and disparities in CLL outcomes among older adults in the United States. Understanding such patterns is critical to guiding geriatric oncology care, identifying gaps in healthcare delivery, and informing public health strategies. Methods: We conducted a population-based analysis using the Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (CDC WONDER) Underlying Cause-of-Death database. We identified all deaths among individuals aged ≥65 years from 1999 to 2020 in which CLL (ICD-10 code C91.1) was listed as the underlying cause. Mortality data were stratified by sex, age group (65–74, 75–84, ≥85), U.S. Census region, urban-rural classification, state, and place of death. We calculated crude mortality rates (CMRs) and age-adjusted mortality rates (AAMRs) per 100,000 persons, standardized to the U.S. 2000 population. Joinpoint regression analysis was used to assess temporal trends in AAMRs and compute annual percent changes (APCs) and average annual percent changes (AAPCs), with statistical significance set at p<0.05. Results: Between 1999 and 2020, a total of 85,371 CLL-related deaths occurred among U.S. adults aged ≥65 years. The overall AAMR declined from 11.18 per 100,000 in 1999 to 7.75 in 2020, reflecting a significant downward trend (AAPC: -1.86%; 95% CI: -2.18 to -1.54; p<0.0001). Men consistently exhibited higher mortality rates (AAMR: 13.48) than women (AAMR: 6.45), though the mortality decline was more pronounced among women (AAPC: -2.10% vs. -1.65%, respectively; both p<0.0001). Regional disparities were evident, with the Midwest reporting the highest AAMR (10.63), and the West the lowest (8.71). Urbanization analysis revealed higher mortality in non-metropolitan areas (AAMR: 10.33) than metropolitan ones (AAMR: 9.08), though both experienced significant declines over time. Age-stratified analysis showed the steepest declines in the 65–74 age group (AAPC: -3.91%; p<0.0001), followed by those aged 75–84 years (AAPC: -1.96%) and ≥85 years (AAPC: -0.25%). States with the highest mortality included Minnesota, Iowa, and South Dakota, while Hawaii, Nevada, and New Mexico had the lowest. Most deaths occurred in medical facilities (43.8%), followed by home (26.7%), nursing homes/long-term care (19.5%), and hospice (5.6%). Conclusion: CLL-related mortality among the U.S. geriatric population declined significantly between 1999 and 2020, likely reflecting the impact of therapeutic innovations and improved disease management. However, substantial disparities persist across sex, age, region, urbanization, and state-level subgroups. These findings underscore the importance of equitable access to modern CLL treatments and the need for targeted interventions to reduce mortality in high-risk, underserved older populations. Efforts to close these gaps will be essential in optimizing outcomes in the era of personalized cancer care for aging Americans.
Volume and nature of classical hematology outpatient consults within a national cancer institute-designated comprehensive cancer center
Wolf, Emily, Neitzke, Michelle, Abeykoon, Jithma P. , Elliott, Michelle A. , Gentzler, Brooke, Pruthi, Rajiv K. , Rouse, Rachelle, Padrnos, Leslie , Tippitt, Amanda, Rivera, Candido E., Shaikh, Marwan , Wysokinska, Ewa , Godby, Richard , Siddiqui, Mustaqeem , Sridharan, Meera , Shah, Surbhi , Davis, Jordan, Wolanskyj, Alexandra P. , Go, Ronald S.

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 8208-8208

10.1182/blood-2025-8208 Get It

Abstract Introduction A 2017 survey by the American Society of Hematology found a widespread perceived shortage of classical hematologists in the US, which was compounded by a low trainee interest in the field (<5%) (Masselink LE, Blood Adv 2019). Recently, we reported that among hematologist/oncologists at the 64 National Cancer Institute (NCI)-designated cancer centers with clinical programs, only ~5% identify as classical hematologists, despite 15% of them including classic hematology (CH) patients in their practice (Go LT, Blood Adv, in press). However, there remains limited data on CH consult volumes at NCI-designated cancer centers (West CV, JCO Oncol Pract 2023). This study aimed to evaluate the volume and nature of CH outpatient consults at the Mayo Clinic Comprehensive Cancer Center (MCCC). Methods We reviewed electronic medical records to identify all completed outpatient consults in CH, malignant hematology (MH), and solid tumor oncology at MCCC in Rochester, Minnesota from January 1 to December 31, 2024. Consults were defined as either external or internal referrals for new patients seen in CH outpatient clinic. CH consults were further categorized by referral reasons and the type of physician (CH, MH, or fellow) performing the consultations. CH physicians were defined as those whose clinical practice primarily focuses on non-malignant hematologic conditions; one advanced practice provider (APP) was included in this group. Inpatient consults, electronic consults, and return visits were excluded. Results In 2024, a total of 17,153 outpatient consults were completed. Of these, 13.4% were CH, 30.5% were MH and 56.1% were solid tumor oncology. Among CH consults, the most common referral reasons were abnormal blood counts (68.3%), bleeding disorders (10.6%), thrombosis (11.8%), and other hematologic diagnoses (9.3%). Within abnormal blood counts, the leading indications were anemia (50.7%), thrombocytopenia (15.3%), leukopenia (11.0%), leukocytosis (9.1%), and pancytopenia (7.0%). Among bleeding disorders, the top reasons included suspected bleeding diathesis (49.4%), von Willebrand disease (24.5%), Hemophilia A (4.1%), Factor VII deficiency (3.7%), and platelet qualitative defect (3.4%). Thrombosis-related consults were most often for pulmonary embolism or deep vein thrombosis (43.2%), antiphospholipid syndrome (17.7%), thrombophilia (16.2%), portal vein thrombosis (4.1%), and splenic infarct (2.6%). The top ten referrals for a specific hematologic diagnosis were iron deficiency anemia (29.2%), pulmonary embolism or DVT (13.5%), immune thrombocytopenic purpura (10.3%), von Willebrand disease (6.9%), hemoglobinopathy (5.5%), antiphospholipid syndrome (5.5%), thrombophilia (5.1%), anemia of chronic kidney disease (2.4%), aplastic anemia (1.5%), and hereditary spherocytosis (1.4%). Of the 114 physicians at MCCC during the study period, 55 (48.2%) were medical oncologists, 54 (47.4%) primarily practiced MH, and only 5 (4.4%) were dedicated CH physicians. Despite comprising only 4.4% of the hematology/oncology workforce, CH physicians or fellows completed the majority (86.1%) of CH consults; MH physicians completed 13.8%. Conclusion CH consults represent a substantial portion of outpatient hematology referrals at MCCC, primarily for diagnostic evaluation of cytopenias or thrombotic/bleeding symptoms. However, a striking mismatch exists between CH physician representation (4.4%) and CH consult volume (13.4%). This imbalance has implications for quality, timeliness, and continuity of care for patients with non-malignant hematologic conditions. Our findings underscore the urgent need to expand recruitment and career development pathways in CH to address a huge clinical demand.
Fixed-duration subcutaneous (SC) mosunetuzumab, with maintenance therapy, in patients (pts) with previously untreated high-tumor burden follicular lymphoma (HTB FL): Longer follow-up and exploratory circulating tumor (ct)DNA analysis of the Phase II Mornin
Burke, John M. , Sharman, Jeff P. , Anz, Bertrand, Zuniga, Richard, Wright, David , Jani, Prachi, Biondo, Juliana M.L., Wu, Mei , Mun, Yong, Chopra, Vivek S. , Farighi, Rona, Budde, Elizabeth, Tun, Aung M. , Villasboas, José C. , Budde, Elizabeth, Flinn, Ian W.

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 228-228

10.1182/blood-2025-228 Get It

Abstract Background: Mosunetuzumab, a CD20xCD3 bispecific antibody, can be administered in the outpatient setting for a fixed duration. Mosunetuzumab by intravenous (IV) administration is FDA- and EMA-approved in relapsed/refractory (R/R) FL after ≥2 prior lines of therapy. Interim results from the Phase II MorningSun study (NCT05207670) demonstrated promising efficacy and manageable safety of mosunetuzumab SC in pts with previously untreated HTB FL (Flinn et al. ASCO 2025). We report 12-month follow-up efficacy and safety data of mosunetuzumab SC in pts with previously untreated HTB FL in the MorningSun study, including pts who received optional maintenance therapy. Methods: Pts with previously untreated HTB FL, per Groupe D'Etude des Lymphomes Folliculaires criteria, and Eastern Cooperative Oncology Group performance status of 0–2 were enrolled, primarily from United States (US) community sites. Mosunetuzumab SC was administered as step-up dosing in Cycle (C)1 (Day [D]1, 5mg; D8, 45mg; D15, 45mg) followed by 45mg on D1 of each 21-day cycle, for up to 17 cycles (1 year). Pts with a partial or complete metabolic response (CMR) after C17 could receive optional mosunetuzumab maintenance treatment (45mg every 8 weeks for up to 1 year). The primary endpoint was progression-free survival (PFS) rate at 1 year. Key secondary endpoints included objective response rate (ORR), duration of response (DOR), duration of complete response (DOCR) and safety. Exploratory analysis of ctDNA levels was performed using the AOA-NHL assay. Results: As of February 10, 2025, 103 pts were enrolled (n=82 pts from community sites, n=21 pts from academic sites). Overall, the median age was 65 years (range: 24–86), 51.5% of pts were female and most pts had Ann Arbor stage III/IV disease (91.3%) and a FLIPI score ≥2 (78.6%). In total, 69 pts completed initial treatment (17 cycles), 33 discontinued (primarily due to progressive disease [PD; n=18] and adverse events [AEs; n=5]), and 1 pt was continuing treatment. After 17 cycles, 68 pts were eligible for maintenance treatment, of whom 46 received maintenance, and 15 were continuing maintenance treatment at the time of data cut-off. Median duration of follow-up was 22.3 months (95% confidence interval [CI]: 20.9–24.1). The 12-month PFS rate was 85.5% (95% CI: 76.2–91.3). The ORR was 87.4% (95% CI: 79.4–93.1); 64.1% of pts had a CMR. The 12-month OS rate was 91.9% (95% CI: 84.5–95.9); the 12-month DOR and DOCR rates were 89.6% (95% CI: 80.2–94.7) and 91.1% (95% CI: 79.4–96.2), respectively. Of the 46 pts who received maintenance, no pts experienced PD, and 1 pt died (reason unknown). Of the 22 pts who were eligible but did not receive maintenance, 1 pt had PD. The most common AEs (≥30%) were injection-site reaction (67.0%), fatigue (44.7%), cytokine release syndrome ([CRS] 34.0%), headache (32.0%), and nausea (32.0%). Grade (Gr) ≥3 AEs and serious AEs were reported in 47.6% and 35.9% of pts, respectively. Five pts experienced Gr 5 AEs: COVID-19 pneumonia (n=2) and cardiogenic shock, unexplained death, pneumonia (n=1 each). Infections occurred in 77.7% of pts and were predominantly Gr 1/2 (Gr 1: 10.7%; Gr 2: 47.6%; Gr 3: 12.6%; Gr 4: 3.9%), with the most common infection being COVID-19 (24.3%). Of 3 (2.9%) Gr 5 infections reported, 1 occurred during initial treatment (COVID-19), 1 during maintenance (pneumonia), and 1 occurred 2.8 months after completion of treatment (COVID-19). AEs were reported in 80.4% of pts in the maintenance phase, mostly Gr 1/2 events. No CRS events occurred during maintenance treatment. Infections were reported in 45.7% of pts during maintenance, with the majority being Gr 1/2 events (37.0%), and were similar types of infection as during initial therapy. ctDNA levels were assessed in a subset of pts who achieved a CMR; 86.4% (19/22) of pts were minimal residual disease (MRD) negative (p-value cut-off 0.005).Conclusions: Longer follow-up of mosunetuzumab SC with optional maintenance treatment continues to demonstrate promising PFS and OS rates, and a manageable safety profile in pts with previously untreated HTB FL. Exploratory analysis of ctDNA in a subset of CMR pts showed MRD negativity in 86.4%, thus supporting fixed treatment duration of mosunetuzumab SC. Overall, these data support the outpatient administration of mosunetuzumab SC in US community practices and further evaluation of mosunetuzumab-based treatment in first-line HTB FL.
Clone-specific epigenetic regulatory mechanisms in ASXL1-mutant chronic myelomonocytic leukemia
Finke, Christy M. , Pradeep, Pankaj, Mangaonkar, Abhishek A. , Yan, Huihuang , Patnaik, Mrinal M. , Binder, Moritz , Lasho, Terra L. , Fernandez, Jenna , Ismail, Wazim Mohammed , Mazzone, Amelia , Steinauer, Nickolas , Wang, Liguo , Gaspar‐Maia, Alexandre

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 234-234

10.1182/blood-2025-234 Get It

Abstract Introduction: ASXL1-mutant (mt) Chronic Myelomonocytic Leukemia (CMML) is an aggressive myeloid neoplasm characterized by increased proliferation, resistance to epigenetic therapies, and poor survival. Epigenetic remodeling and up-regulation of leukemogenic driver genes are hallmarks of ASXL1mt CMML. Truncating mutations in ASXL1 activate enhancers that drive the expression of key leukemogenic driver genes such as HOXA9 and its co-factor MEIS1. Here, we investigate the chromatin accessibility of these leukemogenic enhancers by ASXL1 genotype at single-cell resolution (GoT-ChA-seq). Methods: After IRB approval, we performed bulk RNA-seq and ChIP-seq (H3K4me1, H3K4me3, H3K27ac, H3K27me3, H2AK119ub, H2BK20ac) on bone marrow (BM) mononuclear cells from 40 patients with CMML (19 ASXL1mt, 21 -wildtype/wt). After quality control, differential analyses of gene expression and histone modification occupancy between ASXL1mt and wt patients were conducted. A consensus peak calling framework was used to define genomic regions with ASXL1mt-specific histone modifications. Canonical enhancers were defined as genomic regions with a co-occupancy of H3K4me1 and H3K27ac. We then added regions marked by H2BK20ac to capture regulatory regions associated with p300 (Narita et al. Nat Genet 2023). We used an in silico prediction strategy to associate regulatory regions marked by strong histone modification occupancy with highly up-regulated leukemogenic driver genes (HOXA6-10, MEIS1). The ReMap database (Hammal et al. Nucleic Acids Res 2022) was queried for transcription factor binding in the genomic regions of interest. We then performed GoT-ChA-seq (Izzo et al. Nature 2024) to investigate chromatin accessibility for ASXL1mt (n=3) and wildtype BM single cells from CMML patients. In vitro colony forming assays were conducted on primary CMML BM cells (11- ASXL1mt and 9 wt CMML), assessing the efficacy of EP31670, a novel, oral, dual inhibitor of p300/BRD4. Results: This study included 40 patients with CMML, 19 ASXL1mt and 21 wt. The variant allele frequencies for ASXL1 were compatible with heterozygosity (median 0.41) and TET2 mutations were balanced between the two groups. We identified 149 candidate regulatory regions correlating with the expression of up-regulated target genes of interest (HOXA6-10, MEIS1) by bulk ChIP- and RNA-seq. Publicly available ChIP-seq data from myeloid cell lines demonstrated enrichment of p300 (in THP-1 cells, enrichment effect size +2.58, p=0.002) and BRD4 (in K-562 cells, enrichment effect size +1.58, p=0.045) in these candidate regulatory regions. Next, we interrogated the chromatin accessibility of ASXL1mt (n=13620) and ASXL1wt (n=24269) single cells from 3 CMML patients using GoT-ChA-seq. Differential accessibility analysis revealed 144 genomic regions, all of which were preferentially accessible in ASXL1mt cells compared to ASXL1wt cells (p<0.05 for all regions). Four of these preferentially accessible genomic regions (p<0.001 for all regions) overlapped with the previously identified candidate regulatory regions for MEIS1. The H3K27ac and H2BK20ac occupancy levels in these regions was strongly associated with the expression of MEIS1 (median Pearson r=0.73, p=1.16x10-7). These candidate regulatory regions were annotated in ENCODE as distal and proximal enhancers. Targeting this biology with the dual p300/BRD4 inhibitor EP31670 in progenitor colony forming assays led to a preferential therapeutic effect in ASXL1mt BM samples (median IC50 = 25nM) compared to in ASXL1wt samples (median IC50 = 74nM, p=0.03). Treatment with EP31670 was also associated with increased differentiation (increased blast forming units-erythroid; BFU-E) and organization of colonies in ASXL1mt vs wt CMML. Conclusions: ASXL1mt CMML is characterized by the up-regulation of several leukemogenic driver genes including HOXA9 and its co-factor MEIS1, secondary to the activation of genotype-specific enhancers. The preferential accessibility of these enhancers can be defined between ASXL1mt and ASXL1wt cells within patients. The enhancers of interest interact with p300 and BRD4 in myeloid cell lines and targeting them with the novel dual p300/BRD4 inhibitor, EP31670, induces therapeutic responses at low nanomolar drug concentrations in vitro, preferentially in ASXL1-mutant cells. These data solidify the biological rationale for targeting p300/BRD4 in ASXL1mt chronic myeloid neoplasms for therapeutic benefit (NCT05488548).
Hypomethylating agent with venetoclax versus hypomethylating agent alone in frontline management of myelodysplastic syndrome - impact of subgroups on clinical outcomes
Ball, Somedeb , Haddadin, Michael , Feld, Jonathan , Cohen‐Nowak, Adam , Hawkins, Hayley, Shukla, Asmita, Tan, Virginia, Dulak, Dominika, Tawfiq, Reema, Dworkin, Emily , Feng, Amber , Foucar, Charles , Shallis, Rory M. , Im, Annie , Winer, Eric S. , Murthy, Guru Subramanian Guru , Abaza, Yasmin , Abboud, Ramzi , Balasubramanian, Suresh , Kishtagari, Ashwin , Guerra, Veronica , Weiss, Julian J , Gonzalez‐Lugo, Jesus D. , Dhakal, Prajwal , Leonard, Jessica T , Badar, Talha , Patel, Shyam A. , Lin, Chenyu , Patel, Anand , Atallah, Ehab , Komrokji, Rami S.

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 239-239

10.1182/blood-2025-239 Get It

Abstract Background: Hypomethylating agent (HMA) with venetoclax (VEN) is used in clinical practice for frontline management of patients with myelodysplastic syndrome (MDS) based on encouraging data from phase 1 clinical trial (Garcia JS et al. Blood 2025). While the randomized clinical trial (VERONA-NCT04401748) did not show a survival benefit of azacitidine-VEN, the study had important differences such as exclusion of therapy related MDS and being conducted in several non-academic US centers. To better understand the impact of this regimen and its effects in subgroups, we conducted a real-world analysis of frontline MDS patients treated mainly at academic medical centers with HMA-VEN and compared to HMA monotherapy. Methods: This is a multicenter retrospective study of 19 US academic medical centers. We included contemporary cohorts of adults (age≥18 years) with MDS (intermediate, high or very high risk by IPSS-R) who were treated outside of clinical trials with either upfront combination of HMA-VEN or HMA monotherapy. Data on patient-related, disease-related and treatment-related variables were collected through chart review. Descriptive statistics were used for baseline characteristics. Overall survival (OS) and event free survival (EFS: progression, leukemic transformation, death as events) analysis was conducted using Kaplan-Meier method. Determinants of outcomes were analyzed using multivariable regression models. All analyses were conducted at a significance level of p<0.05. Results: Among 1198 patients with intermediate, high or very-high risk MDS, 313 patients received upfront VEN in combination with HMA [HMA-VEN] and 885 patients received HMA monotherapy. Median age was 70 (63-76) years and majority of patients had MDS with excess blasts-1 (34% overall, HMA-VEN=26%, HMA=37%) or MDS with excess-blasts-2 (41% overall, HMA-VEN=60%, HMA=34%). Disease risk by IPSS-R was intermediate (29% overall, HMA-VEN=18%, HMA=33%), high (30% overall, HMA-VEN=31%, HMA=30%) or very-high risk (41% overall, HMA-VEN=51%, HMA=37%, p<0.001). Therapy related MDS (t-MDS) was seen in 27% of patients (HMA-VEN=33%, HMA=25%, p=0.004), 34% had TP53 mutation (HMA-VEN=40%, HMA=32%, p=0.005) and 33% underwent allogeneic hematopoietic stem cell transplantation (AHSCT) (HMA-VEN=42%, HMA=30%, p<0.001). The most common mutations detected at baseline included TP53 (34%), ASXL1 (22%), DNMT3A (16%), RUNX1 (16%), TET2 (14%), SRSF2 (13%), and U2AF1 (11%). The response rate by IWG 2006 criteria was significantly higher with HMA-VEN than HMA monotherapy (overall 81% vs 39%, CR: 17% vs 9.6%; marrow CR: 56% vs 14%, p<0.001). In multivariable analysis accounting for upfront treatment, AHSCT, genomic mutations, baseline bone marrow blasts and t-MDS, patients treated with HMA-VEN in the upfront setting had significantly improved EFS (median EFS 10.7 vs. 7.8 mon, HR 0.83, 95%CI 0.72-0.96, p=0.01) and OS (median OS 22.4 vs. 18.1 mon, HR 0.79, 95%CI 0.64-0.97, p=0.02). In addition, TP53 mutation status (OS: HR 1.88, 95% CI 1.57-2.26, p<0.001, EFS: HR 1.43, 95% CI 1.23-1.65, p<0.001), subsequent AHSCT (OS: HR 0.34, 95% CI 0.27-0.41, p<0.001; EFS: HR 0.47, 95% CI 0.40-0.54, p<0.001), and therapy related MDS (OS: HR 1.20, 95% CI 1.00-1.44, p=0.04, EFS: HR 1.10, 95% CI 0.96-1.27, p=0.2) were significant predictors on multivariable analysis. When separately investigated in subgroups, an OS benefit of HMA-VEN over HMA was seen in patients undergoing subsequent AHSCT (median OS 40.6 vs. 30 mon, p=0.05), bone marrow blast 10-19% (median OS 25.1 vs. 17.4 mon, P=0.01), de novo MDS (median OS 30 vs. 20.1 mon, P=0.003) and absence of TP53 mutation (median OS 34.9 mon vs. 23.1 mon, p=0.004). The benefit of HMA-VEN over HMA was also seen across molecular mutations including presence of ASXL1 mutation (median OS 35.2 vs 20.9 mon, p=0.03). Conclusions: In this large multicenter retrospective analysis from US academic medical centers, we found that HMA-VEN therapy significantly improved OS in certain subsets of high risk MDS including patients with 10-19% blasts, denovo MDS, subsequent AHSCT and those without TP53 mutation. While our analysis is limited by its retrospective design, prospectively exploring subgroups of MDS patients who could benefit from HMA-VEN therapy is needed.
Radiomics-based identification of high-risk disease in newly diagnosed multiple myeloma
Janda, Guneet, Howe, Michael J. A., Shreve, Jacob , Dasari, Surendra , Abdallah, Nadine , Cook, Joselle , Kourelis, Taxiarchis , Hayman, Suzanne R. , Kumar, Shaji, Guzman, Emmanuel Contreras , Howe, Michael, Gonsalves, Wilson I. , Buadi, Francis K. , Cook, Joselle , Gertz, Morie A. , Fonseca, Rafaël , Dispenzieri, Angela , Rajkumar, S. Vincent , Thorpe, Matthew , Kumar, Shaji , Binder, Moritz

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 924-924

10.1182/blood-2025-924 Get It

Abstract Introduction: Suboptimal response to therapy, early disease relapse, and limited long-term survival remain critical challenges in a substantial number of patients with multiple myeloma (MM). While cross-sectional imaging studies are commonly obtained in clinical practice, only limited information is currently incorporated into risk stratification efforts and clinical decision making. Here, we investigate the use of novel image-based biomarkers to identify patients at high risk for adverse outcomes. Methods: We obtained the pretreatment 18F-FDG PET/CT scans of patients with newly diagnosed MM with available clinical and laboratory data seen at Mayo Clinic between 2006 and 2022. In this analysis, we included 637 patients with detectable metabolic tumor volume on their pretreatment scan. The native DICOM images were pre-processed and subjected to automated image segmentation using nnU-Net (nnU-Net v1.0, inference using a pre-trained hematologic malignancies model). Limitations of this automated segmentation approach include heterogeneity introduced by varying image quality, technical variability in PET reconstruction, and potential inclusion of non-neoplastic FDG-avid lesions in segmented regions. PyRadiomics was used to extract quantitative radiomics features for clinical prediction modeling. We evaluated the predictive power of tumor size-, shape-, and texture-related radiomics features for identifying high-risk disease (advanced ISS stage at diagnosis, the presence of high-risk FISH abnormalities, failure to achieve a stringent complete response [sCR] to first-line therapy by IWMG criteria, and early mortality). All radiomics features were quantile-normalized for downstream modeling. Forward and backward feature selection as well as testing for multicollinearity were used to remove redundant features. Results: Median age at diagnosis of the 637 myeloma patients was 64 years (range 22–90), and 387 patients (61%) were male. After a median follow-up of 4.4 years (95% CI 0.2–11.7), median overall survival (OS) was 7.3 years (95% CI 6.3–8.3). Increased total tumor volume (upper tertile vs lower tertiles), measured by the total tumor surface area, was associated with advanced ISS stage (III vs I+II; OR 1.73, 95% CI 1.24–2.42, p=0.001, n=637). Increased tumor density (dichotomized at the median), measured by the median gray level intensity (OR 1.93, 95% CI 1.94–3.12, p=0.007, n=303), and decreased tumor heterogeneity (lower tertile vs upper tertiles), measured by the variability of gray-level intensities (OR 1.88, 95% CI 1.49–3.12, p=0.012, n=303), were associated with the presence of high-risk cytogenetics. Both increased total tumor volume (4.9% increase per tertile, 95% CI 2.2–7.6, p<0.001, n=600) and tumor density (8.9% increase per tertile, 95% CI 4.5–13.3, p<0.001, n=600) were independently associated with more extensive bone marrow involvement at diagnosis. Increased tumor heterogeneity (upper tertiles vs lower tertile), as measured by rapid changes of gray level intensities, was associated with failure to achieve a stringent complete response to first-line therapy (OR 0.50, 95% CI 0.30–0.82, p=0.006, n=351). Increased tumor volume was associated with shorter OS (HR 1.35 per tertile, 95% CI 1.11–1.63, p=0.002, n=301), independent of age, sex, ISS stage, and the presence of high-risk cytogenetics. A simple additive score consisting of tertiles of total tumor volume, ISS stage, and plasma cell labeling index ≥2% identified patients at risk of mortality within 3 years of diagnosis (OR 2.00, 95% CI 1.40–2.85, p<0.001, n=126), with moderate discrimination (AUC=0.71). Sensitivity analysis demonstrated total tumor volume and texture as most predictive of overall survival in a random forest survival model (C-index 0.712, 95% CI 0.649–0.775) and tumor texture as most predictive of response to therapy in a random forest classification model (C-index 0.693, 95% CI 0.607–0.779). Conclusions: Automated image segmentation and radiomics feature extraction from 18F-FDG PET/CT scans produces biomarkers that capture disease stage, burden, and risk in newly diagnosed MM. Total tumor volume and heterogeneity are strongly associated with important disease characteristics and can be used to identify patients at high risk for therapeutic resistance, early mortality, and inferior long-term outcomes.
Mismatching of unrelated donors beyond a single HLA-locus does not adversely impact outcomes at one year following transplantation: Results from the NMDP sponsored ACCESS study
Bo‐Subait, Stephanie, Logan, Brent R. , Smith, Sarah , Leckrone, Erin , Stefanski, Heather, Malmberg, Craig, Modi, Dipenkumar , Meade, Javier Bolaños, Rao, Uttam K. , Milner, Jordan , Jamieson, Katarzyna , Carrum, George, Kosuri, Satyajit, Cook, Rachel J. , Ballen, Karen K. , Loren, Alison W. , Arai, Sally , Choi, Sung Won , Shaw, Bronwen E. , Larkin, Karilyn , Malki, Monzr M. Al , Auletta, Jeffery J. , Spellman, Stephen R. , Askar, Medhat , Cusatis, Rachel , Shaffer, Brian C. , Khimani, Farhad , Gooptu, Mahasweta , Hamadani, Mehdi , Maiers, Martin , Stanek, Joseph , Abboud, Ramzi , Dholaria, Bhagirathbhai , Hogan, William J. , Reshef, Ran , Qayed, Muna , Broglie, Larisa , Devine, Steven M. , Jiménez, Antonio

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 936-936

10.1182/blood-2025-936 Get It

Abstract Allogeneic hematopoietic cell transplantation (HCT) remains inaccessible to many patients, particularly those of non-European ancestry, due to the limited availability of matched unrelated donors (URD). While single-HLA mismatched donors (7/8) often yield acceptable outcomes, URD HCT mismatched at ≥ 2 HLA alleles (<7/8) has historically been associated with poor survival and prohibitive toxicity. Post-transplant cyclophosphamide (PTCy) has improved outcomes following mismatched unrelated donor (MMUD) HCT, potentially enabling less stringent donor matching. Whether the degree of donor-recipient HLA disparity remains prognostic after MMUD HCT when PTCy is used is unknown. The ACCESS trial (NCT04904588) was conducted by the Center for International Blood and Marrow Transplant Research Clinical Research Organization and prospectively evaluated PTCy-based graft versus host disease (GVHD) prophylaxis in adult recipients of 4–7/8 (HLA-A, -B, -C and -DRB1) MMUD peripheral blood stem cells (PBSC) from donors age ≤35 years old following either myeloablative (MAC) or reduced intensity/non-myeloablative (RIC/NMA) conditioning. This analysis focused on all adult recipients of <7/8 grafts enrolled on the study across both conditioning strata, with descriptive comparison to patients who received 7/8 MMUD PBSC grafts. The primary endpoint was 1-year overall survival (OS). Secondary endpoints included primary graft failure (PGF), non-relapse mortality (NRM), relapse, acute and chronic GVHD, and GVHD-free relapse-free survival (GRFS). A total of 268 adults received MMUD PBSC grafts: 85 with <7/8 matches (MAC: n=23; RIC/NMA: n=62) and 183 with 7/8 matches (MAC: n=52; RIC/NMA: n=131). Among <7/8 recipients, median age was 57 years old (range, 24–78), 49% were male, with diagnoses of acute myeloid leukemia (AML) (55%), myelodysplastic syndromes (MDS) (15%), and lymphoma (14%). HLA mismatch distribution in the <7/8 group was 6/8 in 82%, 5/8 in 14%, and 4/8 in 4%. Most received fludarabine/melphalan (44%) or myeloablative busulfan/fludarabine (21%). Median CD34+ cell dose was 5.5 ×10^6/recipient kg (range: 3.2-8.0) and 75% of grafts were cryopreserved prior to infusion. Median donor age was 25.8 (range: 18.7-35.7) in the 7/8 group and 25.0 (range: 18.3-34.8) in the <7/8 group. The <7/8 cohort was racially and ethnically diverse, with 61% identifying as other than non-Hispanic white. The 7/8 cohort had a median age of 63 years old (range, 20–79), with 52% male. Disease distribution, conditioning intensity, and infused cell doses were similar to the <7/8 group. A smaller proportion of grafts were cryopreserved (61%), and 47% of patients identified as other than non-Hispanic White. One-year OS for <7/8 recipients was 86% (95% CI: 76–92%), compared to 79% (95% CI: 72–84%) in 7/8 recipients. One-year incidence of relapse was 23% (95% CI: 14–33%) in the <7/8 group and 17% (95% CI: 12–23%) in 7/8 recipients; NRM was 8% (95% CI: 4–16%) and 14% (95% CI: 9–19%), respectively. GRFS was 55% (95% CI: 43–65%) for <7/8 and 51% (95% CI: 44–58%) for 7/8 recipients. PGF occurred in 8% (95% CI: 3–18%) of <7/8 RIC recipients and 3% (95% CI: 1–8%) of 7/8 RIC recipients; no MAC recipients had PGF. At 6 months post-HCT, grade II–IV acute GVHD occurred in 34% (95% CI: 24–44%) of <7/8 patients and 39% (95% CI: 32–46%) of 7/8; grade III–IV acute GVHD was observed in 7% (95% CI: 3–14%) and 8% (95% CI: 5–13%), respectively. Moderate to severe chronic GVHD (NIH consensus criteria) at one year occurred in 8% (95% CI: 3–15%) of <7/8 recipients and 11% (95% CI: 7–16%) of 7/8 recipients. When grouped by conditioning intensity, 1-year outcomes within the <7/8 cohort were: OS 91% after MAC and 84% after RIC/NMA; relapse in 32% after MAC and 20% after RIC/NMA, respectively; GRFS was 53% for MAC and 55% for RIC/NMA; and NRM remained low at 9% after MAC and 8% after RIC/NMA. In this cohort of adult recipients of <7/8 MMUD PBSC grafts with PTCy-based GVHD prophylaxis enrolled on the ACCESS study, 1-year OS exceeded 80% and was comparable to 7/8 recipients. Relapse, NRM, and GVHD rates were similarly favorable and consistent with outcomes reported in 7/8 donor recipients. These findings support extending suitable MMUD match considerations to include 4-6/8 in the context of PTCy, potentially enabling near-universal donor access, while allowing for optimization of other non-HLA donor factors.
Pirtobrutinib in post-cbtki CLL/SLL: Final update from the Phase 1/2 BRUIN study with more than 5 years follow-up
Wierda, William, Brown, Jennifer, Ghia, Paolo, Roeker, Lindsey, Patel, Krish, Eyre, Toby, Munir, Talha, Lech-Maranda, Ewa, Lamanna, Nicole, Tam, Constantine, Seymour, John, Tessoulin, Benoit, Shah, Nirav, Ujjani, Chaitra, Fakhri, Bita, Coombs, Catherine, Flinn, Ian, Patel, Manish, Nasta, Sunita Dwivedy, Cohen, Jonathon, Alencar, Alvaro, Cheah, Chan, Ma, Shuo, Rhodes, Joanna, Jagadeesh, Deepa, Zinzani, Pier Luigi, Österborg, Anders, Izutsu, Koji, Fukuhara, Noriko, Tsai, Donald, Abada, Paolo, Balbas, Minna, Li, Jian, Wang, Ying (denise), Jurczak, Wojciech, Woyach, Jennifer, Fakhri, Bita , Fakhri, Bita , Wierda, William, Brown, Jennifer, Ghia, Paolo, Roeker, Lindsey, Patel, Krish, Eyre, Toby, Munir, Talha, Lech-Maranda, Ewa, Lamanna, Nicole, Tam, Constantine, Seymour, John, Tessoulin, Benoit, Shah, Nirav, Ujjani, Chaitra, Coombs, Catherine, Flinn, Ian, Patel, Manish, Nasta, Sunita Dwivedy, Cohen, Jonathon, Alencar, Alvaro, Cheah, Chan, Ma, Shuo, Rhodes, Joanna, Jagadeesh, Deepa, Zinzani, Pier Luigi, Österborg, Anders, Izutsu, Koji, Fukuhara, Noriko, Tsai, Donald, Abada, Paolo, Balbas, Minna, Li, Jian, Wang, Ying (denise), Jurczak, Wojciech, Woyach, Jennifer

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 2115-2115

10.1182/blood-2025-2115 Get It

Abstract Background: Covalent Bruton tyrosine kinase inhibitors (cBTKi) have dramatically changed the treatment (tx) landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), especially in the first-line setting. However, cBTKi resistance or intolerance eventually occurs. Pirtobrutinib is a highly selective, non-covalent BTKi that inhibits BTK with low nM potency throughout the daily dosing interval. Pirtobrutinib demonstrated safety and efficacy in the phase 1/2 BRUIN study among patients (pts) with R/R CLL/SLL, including pts previously treated with a BTKi. Pirtobrutinib is approved for treating CLL in adults in the EU after prior tx with a BTKi, and in the USA for adults with CLL/SLL who have received at least 2 prior lines of therapy, including a BTKi and a BCL-2i. Here, we report the final results from the phase 1/2 BRUIN study (NCT03740529) with more than 5 years (yrs) follow-up (f/u), focusing on efficacy and safety of pirtobrutinib in pts with CLL/SLL in the post-cBTKi setting. Methods: Pts with prior cBTKi-exposed CLL/SLL were eligible for tx with pirtobrutinib. Endpoints included overall response rate (ORR) per 2018 iwCLL criteria, ORR including partial response with lymphocytosis (PR-L), duration of response (DOR), and progression-free survival (PFS), assessed by independent review committee (IRC; presented herein) and investigator, overall survival (OS), and safety. Data cut was 27 January 2025, providing a median study f/u of 34.1 months (mos; range, 0.5-69.8). Results: Among the 282 pts with CLL/SLL who were cBTKi-exposed and treated with pirtobrutinib, of which 84.4% (238/282) received 200 mg as the starting dose, the median age was 69 yrs (range, 36-88). The median number of prior therapies was 4 (range, 1-11), with 45.4% of pts having received prior BCL2i, and 77.0% having discontinued prior cBTKi due to progressive disease (PD), 19.5% due to toxicity, and 3.5% due to other reasons/missing. High-risk features were frequent: unmutated IGHV in 85.8% (193/225), mutated TP53 in 40.4% (99/245), and del(17p) in 29.2% (59/202). The ORR was 72.3% (95% CI, 66.7-77.5). ORR including PR-L was 81.6% (95% CI, 76.5-85.9), which was consistent across subgroups including BCL2i-exposed (80.5%; 95% CI, 72.5-86.9), BCL2i-naive (82.5%; 95% CI, 75.5-88.1), unmutated IGHV (82.9%; 95% CI, 6.8-87.9), del(17p) (88.1%; 95% CI, 77.1-95.1), and prior cBTKi discontinuation due to PD (79.7%; 95% CI, 73.8, 84.9) or toxicity (87.5%; 95% CI, 76.8-94.4). The median DOR was 18.4 mos (95% CI, 14.82-20.27), with 36-mos DOR rate of 28.0% (21.6-34.7). The median PFS was 18.7 mos (95% CI, 16.6-21.8) among all pts and the 36-mos PFS rate was 25.0% (95% CI, 19.4-31.0) with 44 mos of f/u. Further, the median PFS was 22.3 mos (95% CI, 19.3-27.6) for BCL2i-naive pts, and 15.9 mos (95% CI, 13.6-17.5) for BCL2i-exposed pts; 16.6 mos (95% CI, 13.8-19.4) among those who discontinued prior cBTKi therapy due to PD, and not estimable (NE) (95% CI, 25.2-NE) in those who discontinued due to toxicity. Among all pts with CLL/SLL, with a median f/u of 46.5 mos, the median OS was NE (95% CI, 47.8-NE), with the 36-mos OS rate of 62.0% (95% CI, 55.8-67.7). Median time on pirtobrutinib was 20.0 mos (range, 0.2-69.8), and 43 (15.2%) pts were still on tx at data cutoff. The most frequent TEAEs, regardless of attribution, were fatigue (38.7%), neutropenia/neutrophil count decreased (35.8%), diarrhea (30.5%), cough (29.8%), COVID-19 (28.4%), and contusion (27.7%). The most frequent grade ≥3 TEAEs were infection (36.5%) and neutropenia/neutrophil count decreased (29.8%). Low rates of grade ≥3 TEAE of hypertension (5.3%), hemorrhage/hematoma (2.5%), and atrial fibrillation/flutter (2.1%) were observed. Grade 5 TEAEs, regardless of attribution, occurred in 35 (12.4%) pts. Overall, 11 (3.9%) pts had a TRAE leading to a dose reduction, and 9 (3.2%) pts had a TRAE leading to pirtobrutinib discontinuation. Conclusion: In heavily pretreated R/R post-cBTKi CLL/SLL pts, pirtobrutinib continues to show favorable and durable efficacy. Pirtobrutinib is well-tolerated, with low rates of hypertension, hemorrhage/hematoma, and atrial fibrillation/flutter, which can be frequently observed with cBTKi. Additionally, dose reductions/discontinuations due to pirtobrutinib TRAEs were low. No new pirtobrutinib safety signals were identified with more than 5 yrs of f/u.
New chronic lymphocytic leukaemia therapies: Does measurable residual disease testing accurately predict progression-free survival
Wang, Yun , Liang, Qi, Wang, Victoria , Huang, Qianqian , Song, Yiling, Wang, Weida , Li, Chunhua, Gale, Robert Peter , Liang, Qi, Kay, Neil E. , Liang, Yang

Mayo Clinic

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 2132-2132

10.1182/blood-2025-2132 Get It

Abstract Measurable residual disease (MRD)-testing is often used to evaluate therapy efficacy in chronic lymphocytic leukaemia (CLL), with undetectable MRD (uMRD) often serving as a surrogate for progression-free survival (PFS). However, its accuracy in predicting PFS with Bruton tyrosine kinase inhibitors (BTKis), with or without venetoclax, remains controversial. We searched PubMed, Web of Science, Embase, and Cochrane Library databases up to February 8, 2025 using terms chronic lymphocytic leukemiaOR small lymphocytic lymphomaAND measurable residual diseaseAND progression-free survival. Bayesian Weibull accelerated failure time models were used for individual-level analyses, while trial-level correlations used weighted Spearman rank tests and weighted least squares regression. A total of 41 trials (9,569 subjects) were included. Therapies tested included BTKis (11 trials), venetoclax (12), the combination (5), and other therapies like chemoimmunotherapy and monoclonal antibodies (23). MRD was assessed in blood (21 trials), bone marrow (7), or both (9). At the individual level, subjects with detectable MRD (dMRD) had a higher progression and/or death risk compared to uMRD (Hazard Ratio [HR] = 3.63; 95% Credibility Interval [CrI] 3.30-4.00; P < 0.01). In sensitivity analysis, MRD-testing showed reduced predictive accuracy for PFS in subjects receiving BTKi-based therapy (HR = 1.52, 1.02–2.19) compared to venetoclax-based (HR = 4.46, 3.61–5.50) or other therapies (HR = 3.86, 3.45–4.34). Across subgroups, dMRD remained consistently associated with increased risk. In subjects with del(17p)/TP53 variants, dMRD predicted greater (HR = 6.52; 3.47–12.79) versus those without (HR = 4.34; 3.24–5.81). By IGHV status, dMRD conferred a 3.54-fold risk in IGHV-mutated (95% CrI: 2.42-5.34) and 2.64-fold in unmutated subjects (95% CrI: 2.10-3.34). Among response categories, risk was higher in partial responders (HR = 2.39; 1.70–3.43) than complete responders (HR = 1.64; 1.24–2.17). dMRD also predicted increased risk in relapsed/refractory (R/R) CLL subjects (HR = 4.11, 2.54-6.84) and untreated subjects (HR = 3.59, 3.25-3.98). Bone marrow MRD testing proved a stronger predictor of PFS than blood (HR = 4.27, 3.42-5.35 versus HR = 3.52, 3.17-3.92). The highest risk was seen with MRD testing 12–32 months post-treatment (HR = 5.37, 4.56-6.40), though differences across timepoints were modest after adjusting for analytical method. At the trial level, correlations between MRD and PFS were weak (Spearman's rho [R] = -0.35; Determination Coefficients [R²] = 0.02). In sensitivity analyses, correlations remained low for BTKi-based therapy (R = -0.19 [-0.73, 0.50]; R² = 0.04) and venetoclax-based therapy (R = -0.32 [-0.85, 0.45]; R² = 0.14), but were stronger for other therapies (R = -0.80; R² = 0.58). For other therapies, MRD tests of bone marrow samples showed higher predictive value than blood (R = -0.94; R² = 0.86 versus R = -0.81; R² = 0.63). Despite blood samples and testing at 9-months of other therapies meeting the validity threshold (R² = 0.63, P = 0.21; R² = 0.63, P = 0.06), the associated P-values preclude definitive conclusions. Additional analyses examining sample source, time points and testing method within treatment classes suggest limited accuracy of predicting PFS in heterogeneous conditions (all R < -0.85, R² < 0.60). In subgroup analyses, untreated trials showed weak associations (R = -0.30 [-0.77, 0.13]; R²= 0.02), while R/R CLL trials were insufficient for analysis. MRD-testing of blood showed lower PFS predictive accuracy than bone marrow(R = -0.26 [-0.71, 0.20]; R² = 0.03 versus R = -0.37 [-1.00, 0.62]; R² = 0.03). MRD-testing at 15 months demonstrated slightly better accuracy than 9-month testing (R = -0.59 [-1.00, 0.61]; R² = 0.27 versus R = -0.26 [-0.88, 0.41]; R² = 0.04).MRD-testing by NGS outperformed MPFC (R = -0.54 [-1.00, 1.00]; R² = 0.45 versus R = -0.30 [-0.76, 0.13]; R² = 0.01), though both methods remained below the pre-specified determination coefficient threshold. Our data indicate accuracy of results of MRD-testing to predict PFS depends on whether used at the subject or trial-level, type of therapy and sample tested. Importantly MRD-testing is not an accurate predictor of PFS for BTKis with or without venetoclax. We suggest results of MRD-testing as a surrogate for PFS should not be used as a surrogate endpoint for studies of BTKis with or without venetoclax.