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Introduction Patients (pts) with relapsed/refractory (R/R) myelodysplastic syndromes (MDS) have a poor prognosis and, until recently, lacked therapeutic options. Ivosidenib (IVO) is an oral, targeted, small-molecule inhibitor of mIDH1. In October 2023, IVO was granted FDA approval for the treatment of adult pts with mIDH1 R/R MDS on the basis of results from the pivotal AG120-C-001 MDS substudy (NCT02074839); IVO showed an acceptable safety profile and induced durable remissions, with a high rate (38.9%) of complete remissions (CR) per International Working Group (IWG) 2006 criteria (DiNardo et al. Blood Adv 2024; bloodadvances.2023012302.). Response criteria evolve to better reflect clinical benefit in specific pt populations and reduce interobserver variability. The updated IWG 2023 criteria for higher-risk MDS lowered the hemoglobin threshold for CR, added response categories for pts with <5% blasts or limited count recovery, and eliminated the marrow CR (mCR) category. Herein we analyze responses, transfusion independence (TI), and survival outcomes of pts treated with IVO according to IWG 2023 criteria. In addition, responses assessed per IWG 2023 and IWG 2006 criteria are compared. Methods Pts with mIDH1 R/R MDS who had received prior SOC therapy were eligible. Oral IVO 500 mg was administered daily on days 1-28 of 28-day cycles. Responses were assessed per IWG 2023 criteria, and a composite CR (CRc) category was included in the analysis, which comprises all CR categories: CR + CR equivalent (CRe) + CR with limited count recovery (CRL) + CR with partial hematologic recovery (CRh). Overall response rate (ORR) was defined as CR + mCR + partial remission (PR) per IWG 2006 criteria, and as CRc + PR + hematologic improvement (HI) per IWG 2023 criteria. For TI analysis, non-CRc was defined as HI + PR + no response (NR)/not evaluable + progressive disease. TI was defined as requiring no transfusion for ≥56 days. Results In total, 19 pts were enrolled (median age: 73 yr; prior hypomethylating therapy: 78.9%) and data from 18 efficacy-evaluable pts were analyzed. CR + PR rate (primary endpoint) per IWG 2006 was 38.9%, with all 7 (38.9%) responders having CR. CRc + PR rate per IWG 2023 was 66.7% (n=12), with all responders having CRc, including 5 (27.8%) pts with CR, 3 (16.7%) with CRe, and 4 (22.2%) with CRL (CR unilineage [CRLuni], n=2 [11.1%]; CR bilineage [CRLbi], n=2 [11.1%]); no pt had CRh or PR. ORR was 83.3% per IWG 2006, with 7 (38.9%) pts having CR and 8 (44.4%) mCR; 4 (22.2%) pts with mCR had HI. Per IWG 2023 criteria, the ORR was 72.2%, with 12 (66.7%) pts having CRc and 1 (5.6%) HI with neutrophil response. The 8 mCR per IWG 2006 criteria were reclassified as 1 CR, 4 CRL (2 CRLuni and 2 CRLbi), 1 HI, and 2 NR per IWG 2023. Median time to CRc was 1.58 mo. Median duration of CRc was not reached and Kaplan-Meier (KM) estimates at 3, 6, and 12 mo were 90.9%, 81.8%, and 68.2%, respectively. Five (CRc group n=4; non-CRc group n=1) of 7 (71.4%) and 3 (CRc, n=1; non-CRc, n=2) of 4 pts requiring red blood cell (RBC) and platelet transfusion at baseline, respectively, had TI. Median time to any (RBC/platelet) TI was 2.64 and 2.43 mo for pts with CRc and non-CRc, respectively. Moreover, 10 of 12 (83.3%) pts with CRc and 3 of 6 (50%) with non-CRc had or maintained TI during the study. Median duration of TI was not reached and KM estimates at 3 and 6 mo were 90.0% and 65.6%, respectively, for pts with CRc and 100% and 66.7% for non-CRc. Median event-free survival (EFS) was not reached for pts with CRc (n=12) or NR (n=5), and KM estimates at 1 yr were 68.2% and 53.3%, respectively. Median overall survival (OS) was not reached for pts with CRc and was 16.5 mo for pts with NR. For pts with CRc, OS KM estimates at 1, 3, and 5 yr were 90.9%, 51.1%, and 51.1%, respectively. For pts with NR, OS KM estimates were 75% at 1 yr and not estimable at 3 and 5 yr. For the pt with HI, the EFS estimate at 1 yr was 100% and OS estimates were 100% at 1, 3, and 5 yr. Conclusions IVO resulted in a high ORR (72.2%) according to IWG 2023 criteria, including a 66.7% CRc rate, despite the removal of the mCR category. Of 8 mCR per IWG 2006 criteria, 5 (62.5%) were reclassified as CRc per IWG 2023 criteria. By eliminating mCR and assessing response in a high-risk population with <5% blasts, IWG 2023 criteria accurately capture the clinical benefit of IVO in R/R MDS. While comparison of survival outcomes between IWG 2006 and IWG 2023 is limited by the small sample size, a similar trend with response-dependent EFS and OS outcomes was observed.

Background: Acute promyelocytic leukemia (APL) is one of the most treatable leukemias in the current era, with cure rates upwards of 90%. Early mortality due to coagulopathies often seen at diagnosis is a major driver of adverse outcomes. Prompt initiation of all-trans retinoic acid (ATRA) is crucial for suspected APL, as it is known to reverse these coagulopathies. Chemotherapy-free protocols consisting of arsenic trioxide (ATO) and ATRA have become the standard of care for low-risk APL with high cure rates and reduced hematologic toxicities. For high-risk disease, there are multiple treatment options that have not been compared. Since APL is rare, there is a lack of real-world data for this disease. This retrospective review aimed to assess the outcomes of APL patients (pts) across multiple institutions and to examine the most common induction regimens, characteristics linked to early (30-day) mortality, and supportive care strategies. Methods: This retrospective study involved 9 institutions in the US and was conducted through the Consortium on Myeloid Malignancies and Neoplastic Diseases (COMMAND). Data included pts admitted from 8/5/2006 through 2/3/2024 with a confirmed diagnosis of APL. Each institution received a data-collection form and contributed data on APL pts from presentation to last follow-up. Key data categories included patient demographics, presenting laboratory and molecular data, treatment regimen, supportive care, and patient outcomes. Results: Data for 412 pts were identified with a median age of 51 (range 17-90) and 49% were female. Cardiovascular comorbidities were present in 44% of pts and 16% had a known pulmonary comorbidity. At presentation 109 (27%) had high risk-disease, defined as a white blood cell count (WBC) greater than 10 x 109/L. A FLT3 mutation was seen in 50% of tested pts, WT1 (22%), KRAS (3.6%), and NRAS (6.5%). The median WBC at presentation was 2 x 109/L (range: 0-166 x 109/L) and the median platelet count was 27 x 109/L (range: 2.0-315 109/L). Twenty-six percent presented with grade 2+ thrombosis, bleeding, or both. A higher percentage of pts with high-risk vs. low-risk disease presented with grade 2+ thrombosis, bleeding, or both (43% vs. 20%), DIC (60% vs. 36%), and mutated FLT3 (81% vs. 37%). The majority of pts received a chemotherapy-free induction regimen consisting of ATRA plus ATO. It was determined that 36 (8.7%) pts received induction with intermittent ATO plus ATRA (Burnett AK, Lancet Oncol 2015), 276 (67%) received daily ATO plus ATRA (Ravandi F, J Clin Oncol 2009 and Lo Coco, NEJM 2013), and 70 (17%) received a regimen inclusive of an anthracycline plus ATRA. Eleven pts did not start an induction regimen other than single-agent ATRA due to early death, while 19 had their regimen classified as “other” because they did not follow a conventional induction path. In total, 295/358 (82%) received ATRA within 24 hours of admission. At least 1 dose of gemtuzumab ozogamicin was given to 58 (14%) pts, of which 35 (60%) were considered high risk. The incidence of differentiation syndrome (DS) was 37% (n=154). Among the 243 pts who received steroid prophylaxis, 30% developed DS, compared to 52% of those who did not receive prophylaxis. Among the 360 pts with at least 1 available PCR result after starting induction, 94% achieved PCR-negativity. The 30-day mortality rate was 6.6%. On univariate analysis, presenting variables associated with a higher 30-day mortality include older age, diabetes, cardiovascular comorbidities, thrombosis or bleeding, DIC, eGFR < 60, elevated total bilirubin and D-dimer levels, and high-risk disease. The median overall survival (OS) of the cohort was not reached, and the 5- and 10-year OS was 88% (95% CI: 84-91%) and 79% (95% CI: 72-87%) respectively. The cumulative incidence of relapse at 3 years was 2.7% (95% CI: 1.4 - 5.1%), with no additional relapses observed. The incidence of CNS relapse at 3 years was 0.9% (95% CI: 0.3% - 2.8%), with 2 of the 4 pts classified as high-risk. Conclusion: This is the largest real-world evidence data collection in the US evaluating the outcome of pts with APL in the current era, inclusive of ATO as front-line induction. Outcomes for this disease remain extremely positive, with low 30-day mortality rates noted in this study along with durable OS rates and low incidence of relapse. Additional information on outcomes, safety, and supportive care will be presented at the meeting.

Introduction: Thrombotic thrombocytopenic purpura (TTP) has been previously described in pregnancy, however there is limited data available on the impact of TTP in this subset of patients. In this analysis, we evaluate the maternal and fetal morbidity outcomes of TTP in hospitalized pregnant patients. Methods: We used retrospective data from the National Inpatient Sample (NIS) to identify all hospital admissions of pregnant patients with and without TTP from 2012 to 2021 using ICD-9/10 codes. To describe the impact of TTP on maternal and fetal morbidity, we identified different morbidity indicators using standard Centers for Disease Control and Prevention (CDC) definitions with a particular focus on preeclampsia/eclampsia, thromboembolic events (venous and arterial), other organ failure, maternal morbidity and fetal outcomes including intrauterine growth restriction (IUGR) and fetal loss. To account for the effects of acute TTP during pregnancy versus a history of TTP, we separately analyzed hospitalizations that included plasma therapeutic plasma exchange (TPE). Predictors of maternal/fetal morbidities in pregnant TTP patients were determined using multivariable logistic regression analysis. Results: We identified 7,514,304 pregnancy hospitalizations with a mean age of 29 years. Of these, 234 women had a diagnosis of TTP, with 74 receiving TPE during admission (acute TTP during pregnancy). Compared to pregnancy-related hospitalizations in women without TTP, those with TTP were more likely to be African American, admitted to urban teaching hospitals, have lower income, and have a higher Charlson Comorbidity Index (CCI). Most maternal morbidity outcomes were significantly higher in hospitalizations with TTP as compared to those without TTP including increased eclampsia (2.1% vs 0.08%), acute myocardial infarction (1.7% vs 0.01%, p<0.001), puerperal cerebrovascular disorders (8.1% vs 0.7%, p<0.001), cardiac arrest (0.9% vs 0.01%), acute renal failure (35% vs 0.2%, p<0.001), adult respiratory distress syndrome (ARDS) (6.4% vs 0.06%, p<0.001), disseminated intravascular coagulation (DIC) (18% vs 0.2%, p<0.001), pulmonary edema/acute heart failure (5.1% vs 0.1%, p<0.001), sepsis (9% vs 0.22%, p<0.001), shock (6.4% vs 0.1%, p<0.001), air/thrombotic embolism (3.0% vs 0.05%, p<0.001), blood transfusion requirement (25.6 vs 1.28%, p<0.001), and ventilation requirement (6.4% vs 0.06%, p<0.001). There was also a higher need for cesarean sections in TTP hospitalizations compared to non-TTP (57.1% vs 36.9%). For fetal morbidity outcomes, intrauterine growth restriction (IUGR) was more common in TTP hospitalizations (6.8% vs 2.4%, p<0.001), while there was no statistical difference between the two groups in the rates of preterm delivery (3.9% vs 3.3%, p=0.651). In-hospital mortality (1.7% vs 0.02%, p<0.001), and length of stay (11 vs 3 days, p<0.001) were also significantly higher in hospitalizations with TTP. Patients with TTP who received TPE during the hospital stay had worse maternal morbidity outcomes than those who did not, likely reflecting the active nature of the disease in this cohort. In the multivariate analysis, CCI ≥ 1 (OR 3.52, 95% CI, 1.64-7.54) and receipt of TPE (OR 2.99, 95% CI, 1.52-5.86) were associated with higher likelihood of maternal/fetal morbidity in TTP hospitalizations. Conclusion: In conclusion, TTP has a significant impact on hospitalized pregnant patients, both on maternal and fetal outcomes. Further studies are needed to assess risk factors associated with TTP in pregnancy and ideal treatment regimens for these patients.

Mantle cell lymphoma (MCL) is a rare lymphoma with a median age at diagnosis of 60-70 years. Front line therapy has traditionally been bendamustine-rituximab (BR) in older patients and then Bruton Tyrosine kinase inhibitors (BTKi) for relapsed disease. Due to their efficacy, BTKi are now being combined with chemotherapy as induction treatment. The TRIANGLE trial of R-CHOP/R-DHAP +/- ibrutinib +/- transplant showed the benefit of adding a BTKi in young patients (Dreyling M, 2022). The SHINE trial, a phase III trial of BR +/- ibrutinib in patients >65 years, showed a significant improvement in median PFS (81 months vs. 53 months) (Wang M, 2022). However, this came with an increase in toxicity with more treatment related deaths in the ibrutinib arm (11% vs. 6%) and no difference in overall survival. Therefore, a better tolerated approach is still needed in older patients. A phase II study of rituximab + indefinite ibrutinib in 50 patients >65 years demonstrated efficacy of frontline BTKi with a 96% ORR and 71% CR (Jain P, 2021). However, a disadvantage of BTKi therapy is continuous treatment until disease progression or intolerance. In this study half of patients required dose reductions and almost a third of patients stopped treatment due to drug toxicity, most frequently atrial fibrillation or bleeding. If front line intermittent BTKi therapy is as effective as continuous therapy, it could minimize cumulative toxicity. A052101 (NCT05976763), an Alliance for Clinical Trials in Oncology trial, is a randomized phase 3 multicenter trial of upfront zanubrutinib that asks the question “in older patients with previously untreated MCL who obtain a CR with zanubrutinib-rituximab, is it safe and equally effective to stop treatment and restart it upon disease progression rather than continuing indefinitely?” The A052101 trial is enrolling pts with previously untreated MCL who are either >70 years old or 60-69 years old but are not transplant candidates due to cardiac ejection fraction <45%, DLCO <60% of predicted, creatinine clearance <70, Eastern Cooperative Oncology Group (ECOG) performance status of >2, or a Cumulative Illness Rating Scales score of >6. Key exclusion criteria include: history of a severe bleeding disorder or clinically significant cardiac arrhythmias. Patients will take zanubrutinib 320 mg daily and rituximab/rituximab biosimilar once monthly for 6 cycles. Patients with less than partial response after 6 cycles will go off study treatment. Patients with a complete remission will be randomized in a 1:1 manner to intermittent treatment versus continuous treatment. Randomization will be stratified by age (60-69 years vs ≥70 years) and MIPI score. Those randomized to the continuous arm will receive zanubrutinib until intolerance or disease progression. Those randomized to the intermittent arm will stop all study drugs after those initial 6 cycles and will restart zanubrutinib at first disease progression and continue it until intolerance or second disease progression. In order to make the study results generalizable to clinical practice, disease progression will be defined by clinical parameters rather than minimal residual disease testing. The primary objective of this study is to compare time from randomization to first progression or death (PFS1) in the continuous treatment arm to the time to second progression or death (PFS2) in the intermittent treatment arm. The primary evaluation will be to determine whether, for patients in a CR, active monitoring followed by retreatment with zanubrutinib therapy upon disease progression will result in non-inferior clinical outcomes compared to indefinite zanubrutinib. Serial quality of life testing and adverse event monitoring will be performed throughout the study to gain a full understanding of the impact of continuous vs intermittent zanubrutinib on patients' lives. A052101 has the potential to change management of older patients with previously untreated MCL. If our study demonstrates that the time to second progression/death when using the stop and retreat strategy is non-inferior to time to first progression/death when using continuous BTK therapy, then it might lead to a new standard of care in this patient population. This could result in decreased health care costs, decreased toxicity and improved quality of life for older patients with mantle cell lymphoma. Support: U10CA180821, U10CA180882; https://acknowledgments.alliancefound.org

Introduction: Ibrutinib, a Bruton tyrosine kinase inhibitor (BTKi), changed the treatment landscape by demonstrating improved overall survival (OS) compared with chemotherapy/chemoimmunotherapy across multiple phase 3 trials in patients (pts) with CLL, including those with high-risk genomic features. Recently, data were reported for pts treated with ibrutinib in the phase 3 RESONATE-2 trial with up to 10 years of follow-up, representing the longest follow-up of any BTKi used in first-line treatment of CLL. With the most robust long-term follow-up data among BTKis, ibrutinib therapy trials are uniquely positioned to assess the long-term OS benefit of first-line BTKi treatment in pts with CLL across pt subgroups. We previously demonstrated that first-line ibrutinib is associated with OS rates that are similar to those in the age-matched general population, with a median follow-up of 5.9 years since initial diagnosis (Ghia P et al. HemaSphere 2024), but it remains unclear whether this holds true for pts with high-risk genomic features. This updated analysis evaluated long-term OS outcomes with a median follow-up of 8 years since randomization and 10 years since initial diagnosis in a pooled population of pts with previously untreated CLL, including those with high-risk features, who received first-line ibrutinib treatment in 2 phase 3 trials with comparison of survival estimates to the US age-matched general population. Methods: Data were pooled for pts who received first-line treatment with single-agent ibrutinib or ibrutinib + rituximab in the RESONATE-2 (NCT01722487) and ECOG-ACRIN E1912 (NCT02048813) trials, respectively. OS probabilities from the time of randomization and from the time of initial diagnosis for ibrutinib-treated pts were compared with an age-matched general population using 2021 life tables for the total US population published by the Centers for Disease Control and Prevention using the Kaplan-Meier method. Subgroup analyses were performed for high-risk pts, defined as those with del(11q), del(17p), mutated TP53, and/or unmutated IGHV (uIGHV). Results: A total of490 pts were pooled across the 2 studies: 352 pts (71.8%) were treated with ibrutinib + rituximab, and 135 pts (27.6%) were treated with single-agent ibrutinib; 3 pts did not receive study treatment. The median age at time of randomization was 61 years; 36.5% (179/490) were aged ≥65 years, 21.8% had del(11q), 7.8% had del(17p) and/or mutated TP53, and 54.7% had uIGHV. The median time from initial CLL diagnosis to randomization was 20.9 months (range, 0.0-341.8); the median follow-up was 123.5 months (10.3 years) from initial diagnosis and 99.2 months (8.3 years) from the time of randomization. From the time of randomization, estimated 9-year OS rates were 81.2% (95% CI, 76.8-84.9) in all ibrutinib-treated pts versus 82.0% (95% CI, 78.3-85.2) in the age-matched population (hazard ratio [HR] 1.17; 95% CI, 0.86-1.58). In high-risk pts, estimated 9-year OS rates were 79.5% (95% CI, 73.5-84.3) for ibrutinib-treated pts versus 83.2% (95% CI, 78.5-86.9) in the age-matched general population (HR 1.24; 95% CI, 0.84-1.84). In pts aged ≥65 years, estimated 9-year OS rates were 68.7% (95% CI, 60.5-75.6) for ibrutinib-treated pts and 68.7% (95% CI, 61.4-75.0) in the age-matched general population (HR 1.12; 95% CI, 0.77-1.63). In pts aged <65 years, estimated 9-year OS rates were 89.3% (95% CI, 84.6-92.7) for ibrutinib-treated pts and 90.0% (95% CI, 86.1-92.9) in the age-matched general population (HR 1.15; 95% CI, 0.68-1.94). From the time of initial diagnosis, estimated 15-year OS rates were 78.4% (95% CI, 72.8-83.0) in all ibrutinib-treated pts versus 72.0% (95% CI, 67.8-75.7) in the age-matched general population (HR 0.83; 95% CI, 0.62-1.11). Study treatment had been discontinued in 59.8% (293/490) of pooled ibrutinib-treated pts; the most frequent reasons for discontinuation were adverse events (43.0%; 126/293) and progressive disease (20.5%; 60/293). Study treatment was ongoing in 31.8% of pooled pts (156/490). Conclusions: With the longest follow-up time for any commercially available targeted therapy, this pooled analysis demonstrates that, regardless of evaluation from randomization or initial diagnosis, and irrespective of age or high-risk features, first-line treatment with ibrutinib provides long-term OS benefit with survival estimates that appear similar to those of a US age-matched cohort.

Introduction BCL-2 inhibition with venetoclax (ven) was a major advance in CLL treatment, but the 5-week dose ramp-up to mitigate the risk of tumor lysis syndrome and drug-drug interactions (DDIs) challenge treatment optimization. Lisaftoclax is an investigational, oral BCL-2i with a short half-life, allowing it to be ramped-up on a daily schedule. We present updated results of a phase 1b/2 study of lisaftoclax alone or combined with acalabrutinib or rituximab in pts with treatment-naïve (TN; lisaftoclax-acalabrutinib arm), relapsed/refractory, or prior ven-treated CLL/SLL (NCT04215809). Methods Pts were treated with a rapid 4- to 6-day daily ramp-up of lisaftoclax from 20 mg to a target dose of 400, 600, or 800 mg, receiving daily oral lisaftoclax alone or, plus continuous acalabrutinib or 6 cycles of rituximab in 28-day cycles, starting on Cycle 1 Day 8 (C1D8) until disease progression, complete response by C24, or unacceptable toxicity. Intensive blood samples were collected for pharmacokinetic (PK) and exposure-response (E-R) analyses. Results From March 20, 2020, to June 27, 2024, 176 pts were enrolled: 46 in monotherapy and 39 and 91 in rituximab and acalabrutinib combination cohorts, respectively; 154/176 (87.5%) were R/R and 22/176 (12.5%) TN. The median (range) age was 63 (34-80) years; 67% were male; 25.6% had del(17p) and/or TP53 mutation; and 70.6% had unmutated IGHV. Median (range) duration of treatment with lisaftoclax was 16.5 (1-54; monotherapy), 24 (3-39; rituximab), and 27 (1-43; acalabrutinib) months. In R/R pts, the median (range) number of prior lines of therapy was 2 (1-15), and 14 (9%) pts had been treated with ven. Prior ven pts had a median (range) age of 65 (51-78); 79% were male; of evaluable pts, 50% had del(17p), 36% TP53 mut, 64% del(11q), 38% complex karyotype (≥ 3 abnormalities), and 92% unmutated IGHV; 57% were BTKi naïve; and the median (range) number of prior therapies was 3 (1-6). Incidence and severity of TEAEs were similar across cohorts. Common (>10%) any-grade TEAEs in all cohorts combined were neutropenia (59 [33.5%]), diarrhea (38 [21.6%]), anemia (27 [15.3%]), and thrombocytopenia (26 [14.8%]). Grade ≥ 3 TEAEs were neutropenia in 15 (32.6%), 10 (25.6%), and 22 (24%) pts and anemia in 10 (21.7%), 5 (12.8%), and 12 (13.2%) pts in monotherapy, rituximab, and acalabrutinib combination cohorts, respectively. Comprehensive E-R analyses indicated that lisaftoclax had similar systemic exposure as monotherapy or when combined with acalabrutinib or rituximab; lisaftoclax had no DDI when combined with acalabrutinib or rituximab. No discontinuations were attributed to lisaftoclax TRAEs. Forty-four (95.7%) pts in monotherapy discontinued treatment. Most discontinuations were due to progressive disease (n = 41 [23.3%]) and 13 (7.4%), AEs; 9 (5.1%) pts withdrew consent; 7 (4%) achieved complete response or MRD negativity after ≥ 24 cycles; 5 (2.8%) died; and 18 (10.2%) discontinued for other reasons. Clinical (n = 2) and laboratory (n = 3) TLS was observed in 5 (2.8%) pts on lisaftoclax (by Howard/Cairo-Bishop criteria), with cases rapidly resolving to resume lisaftoclax safely. ORR for lisaftoclax plus acalabrutinib in 87 pts was 96.6%, and the median DOR (95% CI, 23-NR) and median PFS (95% CI, 34-NR) were not reached. The 12- and 18-month PFS rates were 89% and 86%, respectively. Fourteen R/R CLL ven-exposed pts received lisaftoclax plus acalabrutinib, of whom 9 had progressed on ven, 3 relapsed after completing ven, and 2 discontinued due to ven intolerance. Median (range) duration of treatment was 16 (3-25) months. Safety profile was similar to that of other study cohorts. ORR was 85.7% (12/14), 100% (8/8), and 66.7% (4/6) in the ven-exposed, ven-exposed but BTKi-naïve, and ven- and BTKi-exposed pts, respectively. The median duration of response (DOR) and progression-free survival (PFS) were not reached. The 12- and 18-month PFS rates were 84% and 73%, respectively. Conclusions Our data suggest that lisaftoclax combined with acalabrutinib is effective for pts with prior ven exposure, including those with progression on ven. In this updated analysis with longer follow-up, no DDIs or new safety findings were observed in TN or R/R CLL/SLL pts treated with lisaftoclax monotherapy/combinations. We continue to accrue pts with prior ven exposure to further evaluate this promising signal. A global registrational phase 3 study GLORA (NCT06104566) is recruiting.

Background: Immune dysfunction is a hallmark of chronic lymphocytic leukemia (CLL), and several studies suggest that hypogammaglobulinemia at the time of CLL diagnosis may predict shorter time to first therapy (TTFT; Parikh et al, 2015). However, it is unclear if hypogammaglobulinemia can predict TTFT independent of the CLL-International Prognostic Index (CLL-IPI) and the tumor mutational load (TML). We sought to determine if serum immunoglobulin (Ig) levels at diagnosis can independently predict outcomes in patients with CLL and its precursor, high-count monoclonal B-cell lymphocytosis (MBL). Methods: We used the Mayo Clinic CLL Database to identify newly diagnosed CLL/MBL consented within 2 years of diagnosis. Next generation sequencing (NGS) was performed using a 59 gene panel (SureSelect) to detect mutated CLL genes. Serum Ig levels were quantitated by radial immunodiffusion (Immunoplates). Serum Ig levels below the lower limit of normal were defined as hypogammaglobulinemia. We used Chi-squared or Fisher's exact tests to compare discrete variables and the Kruskal Wallis test for continuous variables. TTFT was calculated from date of diagnosis to date of first treatment or date last known to be untreated. We used Cox regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for TTFT and overall survival (OS) associations. Results: We identified 895 newly diagnosed patients (588 CLL and 307 MBL) who had undergone NGS for recurrent somatic mutations and had serum Ig levels available at the time of diagnosis. The median absolute B-cell count was 6.7 x109/L; 613 (69%) were male, 375 (42%) had unmutated IGHV genes, and 81 (9%) had TP53 disruption. Based on CLL-IPI, 412 (46%) patients had low risk, 285 (32%) had intermediate risk, and 198 (22%) had high/very high risk. The most commonly mutated genes were NOTCH1 (14%), SF3B1 (11%), TP53 (10%), NFKBIE (8%), ATM (6%), and BIRC3 (6%). Based on the number of genes with high impact or hotspot mutations, we classified 40%, 29%, and 31% patients with TML scores of 0, 1, or 2+, respectively. At CLL/MBL diagnosis, the median serum IgG, IgA, and IgM was 891 mg/dL (111-2620), 121 mg/dL (1-1150), and 44 mg/dL (5-1320), respectively; 284 (32%) patients had low serum IgG, 128 (17%) had low serum IgA, and 322 (42%) had low serum IgM. Low serum IgA was associated with mutations in NOTCH1, SF3B1, ATM, BIRC3 and NFKBIE, low IgM was associated with SF3B1 and BIRC3 mutations (all comparisons, P < .05), and low IgG was associated with BIRC3 mutation (P = .05). The median follow-up for the cohort was 8.4 years. A total of 359 patients progressed requiring therapy (299 CLL and 60 MBL), and 265 patients died (177 CLL and 88 MBL). The TTFT was significantly shorter for patients with low serum IgG compared to normal serum IgG at diagnosis (median 4.4 vs 10.8 years) and similar findings were observed in individuals with low serum IgA (1.7 vs 10.8 years) and those with low serum IgM (4.6 vs 11.1 years). On univariable analysis, the following were associated with a shorter TTFT: low serum IgG (HR: 1.8, 95% CI 1.4-2.2), low serum IgA (HR: 3.5, 95% CI 2.7-4.4), low serum IgM (HR: 1.9, 95% CI 1.5-2.3), TML score of 1 (HR: 1.7, 95% CI 1.3-2.2), TML of 2+ (HR: 4.4, 95% CI 3.4-5.7), CLL-IPI intermediate risk (HR: 3.7, 95% CI 2.8-4.8), and CLL-IPI high/very high risk (HR: 7.6, 95% CI 5.8-10.1) (all comparisons, P < .0001). In multivariable analyses after adjusting for CLL-IPI and TML, low serum levels of IgG (HR: 1.8, 95% CI: 1.5-2.3), IgA (HR: 2.4, 95% CI: 1.8-3.0), and IgM (HR: 1.8, 95% CI: 1.5-2.3) were independently associated with a shorter TTFT (all comparisons, P < .0001). No significant differences in OS were detected between patients with low and normal serum IgG, IgM, and IgA on univariate analysis. Similar results for TTFT and OS were observed after adding clonal B-cell count to the Cox model. Conclusions: Our study shows that low serum Ig levels at the time of initial diagnosis is predictive of TTFT independently of the CLL-IPI and TML, which can further risk stratify individuals with newly diagnosed CLL/MBL. Additionally, low serum IgA, IgM, and IgG levels at diagnosis are significantly associated with specific somatic mutations in individuals with newly diagnosed CLL/MBL.

Background: Multiple myeloma (MM) is an incurable plasma cell malignancy with several recurrent primary cytogenetic abnormalities including t(11,14)(q13;q32), resulting in increased expression of CCND1. Although 40% of patients with t(11;14) MM respond favorably to the BCL-2 inhibitor venetoclax (ven), 60% fail to achieve an objective response. Previous studies have suggested upregulation of PMAIP1, encoding the pro-apoptotic NOXA protein, in association with ven sensitivity (Leblay, Blood, 2024). Here we sought to evaluate the role for NOXA in ven response in t(11;14) MM. Methods: We analyzed whole exome, whole genome and RNA sequencing data of CD138+ tumor cells from 1,359 patients with MM in the CoMMpass and Mayo Clinic cohorts. The histone mark H3K27ac was assessed in t(11;14)+ KMS12PE and U266B1 human myeloma cell lines using ChIP-seq. Gene expression and protein levels of PMAIP1 (NOXA) were also detected by qRT-PCR and Western blot, respectively. Live cell detection was evaluated by Annexin V and PI using flow cytometry and by YoYo3 dye using IncuCyte following treatment with ven. Results: The t(11;14) MM subtype was associated with a 1.6-5.5-fold increased expression of PMAIP1 compared to non-t(11,14) MM in the CoMMpass and Mayo Clinic cohorts (p<0.0001). These findings are consistent with a significant correlation between CCND1 and PMAIP1 expression in both cohorts (p<0.001). To evaluate whether cyclin D1 is directly associated with increasing expression of PMAIP1 in t(11;14) MM, we generated a cyclin D1 knock out (KO) version of the U266B1 line using CRISPR/cas9. Two independent U266B1 KO cell lines showed reduced expression of PMAIP1 and NOXA protein compared to the WT U266B1 consistent with a role for cyclin D1 in regulating PMAIP1 expression. In addition, the KO lines had a 4.8-fold reduced H3K27ac signal at the PMAIP1 locus in comparison to the WT control suggesting a role for cyclin D1 in promoting H3K27ac. We previously observed increased expression of CCND1 in association with the G allele compared to the A allele of rs9344 in both the CoMMpass and Mayo Clinic cohorts (Leukemia, in press). We next asked whether the G risk allele of rs9344 within CCND1 impacted gene expression and H3k27ac levels at the PMAIP1 locus. To study the allele specific effect of CCND1, we used the CRISPR/cas9 edited KMS12PE WT (rs9344 AA) and Knock In (KI) (rs9344 GG) cell lines. In the KI cells, the G allele was accompanied by an ~2-fold increased expression of PMAIP1 and NOXA protein detected by western blot (<0.05). Increased PMAIP1 expression in KI lines was also accompanied by a 2.2-fold increased H3K27ac further suggesting a role for the G allele of rs9344 in promoting H3K27ac and gene expression at the PMAIP1 locus. Finally, we evaluated the consequence of PMAIP1 expression levels in relation to ven response. Increased expression of PMAIP1 and elevated levels of NOXA protein in the KMS12PE KI lines was associated with increased sensitivity to ven resulting in ~50% increase in cell death of KI vs. WT lines (p<0.02). Conclusion: We demonstrate a role for cyclin D1 in regulating PMAIP1 expression through H3K27ac resulting in increased NOXA protein. Levels of NOXA are associated with the G allele of rs9344 and increased venetoclax response.

Background: Previously published risk variables for chronic myelomonocytic leukemia (CMML) included age, gender, CMML subtype, red blood cell (RBC) transfusion status, hemoglobin, leukocyte, monocyte, lymphocyte and platelet counts, immature myeloid cells, peripheral blood (PB) or bone marrow blast percentage, and mutations including ASXL1, RUNX1, NRAS, and SETBP1. Recent studies have reported on additional prognostically favorable (TET2) or unfavorable (DNMT3A, ASXL1, NRAS, SETBP1) mutations. In the current study, we took advantage of a clinically well-characterized and molecularly annotated cohort of CMML patients, in order to revisit the prognostic interaction between the aforementioned risk factors, with emphasis on mutations. Methods: The current study was conducted under an institutional review board approved protocol that allowed retrospective collection and analysis of data from Mayo Clinic patient records. Mutations were screened by multi-gene next-generation sequencing (NGS). Diagnostic criteria were according to the International Consensus Classification (Blood 2022; 140:1200). Conventional statistical methods were employed (JMP Pro 17.0.0 software SAS Institute, Cary, NC, USA). Survival analysis was censored for allogeneic stem cell transplantation (ASCT). Receiver Operating Characteristic (ROC) plots and Akaike Information Criterion (AIC) were used to compare predictive performance of the new model (MMMv2) vs. the Mayo Molecular Model (MMM) vs. the CMML-specific prognostic scoring system (CPSS). Results: The study cohort included 416 patients with CMML that were fully annotated for mutations. Cytogenetic information was available in 404 patients. At a median follow-up of 18 months, 302 (72%) deaths, 72 (18%) leukemic transformations, and 44 (11%) ASCTs were documented. Age-adjusted multivariable analysis (MVA) of mutations identified the following as risk factors: DNMT3A (HR 5.5; p<0.01), PHF6 (HR 0.3; p<0.01), TET2 (HR 0.6; p<0.01), PTPN11 (HR 2.5; p=0.01), NRAS (HR 1.6; p<0.01), ASXL1 (HR 1.3; p=0.02), and SETBP1 (HR 1.8; p=0.01). A separate MVA of clinical and cytogenetic variables identified RBC transfusion need, leukocyte count ≥13 x 109/L, peripheral blood blast ≥1%, abnormal karyotype, older age, and male sex to be independently associated with inferior survival (p<0.04 in all instances). All-inclusive MVA identified the following as independent risk factors for survival (p <0.01): DNMT3A mutation (HR 3.7; 95% CI 2.0-6.7), absence of PHF6 mutation (HR 2.8; 1.3-5.8), RBC transfusion need (HR 2.3; 1.7-3.1), leukocyte count ≥13 x 109/L (HR 2.0; 1.5-2.6), abnormal karyotype (HR 1.6; 1.2-2.2), and absence of TET2 mutation (HR 1.4,1.1-1.8). An HR based prognostic model was subsequently constructed by assigning 3 points to DNMT3A mutation, 2 points each for RBC transfusion need, leukocyte count ≥13 x 109/L, and absence of PHF6 mutation and one point each for abnormal karyotype and absence of TET2 mutation, resulting in a 4-tiered survival risk model (MMMv2): low risk (0-2 points; N=103) with median survival of 74 months; intermediate-1 (3 points; N=65) with median 37 months; intermediate-2 (4-5 points; N=126) with median 19 months; and high (6 points; N=88) with median 12 months (p<0.01). Independent genetic risk factors associated with inferior leukemia-free survival included DNMT3A (HR 5.5), PHF6 (HR 0.2), abnormal karyotype (HR 2.0), PTPN11 (HR 5.2), ASXL1 (HR 2.0), and BCOR (HR 8.7). Leukocyte count ≥13 x 109/L (p=0.01) but not RBC transfusion need (p=0.2) was additionally significant. However, presence of immature myeloid cells (p<0.01) and circulating blasts ≥1% (p<0.01) were prognostically more relevant than leukocyte count ≥13 x 109/L and independently predicted leukemic transformation, along with DNMT3A, PTPN11 and ASXL1 mutations. Predictive performance was superior for MMMv2 (AUC 87, AIC 137) vs. MMM (AUC 74, AIC 194) vs. CPSS (AUC 76, AIC 177). Conclusion: The revised Mayo Molecular Model (MMMv2) provides a contemporary risk model for CMML that recognizes DNMT3A as the most unfavorable and PHF6 as the most favorable mutation and confirms the mutation-independent prognostic contribution from red cell transfusion need and sustained leukocytosis (≥13 x 109/L). Mutations were also important in predicting leukemic transformation, notably DNMT3A, PTPN11 and ASXL1.

Introduction Somatic mutations in TET2 are present in ~60% of chronic myelomonocytic leukemia (CMML) patients and are associated with improved median overall (mOS) and acute leukemia free survival (mLFS). Multiple TET2 mutations are detected in ~50% of such cases and are thought to confer additional benefit. Whether these benefits apply to the molecularly distinct myelodysplastic (MD) and myeloproliferative (MP) CMML subtypes is unknown. This study assesses the impact of the number and type of TET2 mutations across the MD and MP-CMML subtypes. Methods CMML patients seen at Mayo Clinic (n = 400, 47%) and MD Anderson Cancer Center (n = 449, 53%) were included with IRB approval. Analyses considered the clinical and molecular data at diagnosis or first referral. Truncating (frameshift or nonsense) mutations in TET2 were further annotated by location in either the proximal genome targeting domain (aa 1 - 1128) or distal catalytic domain (aa 1129 - 1936) as described (Coltro, 2020). Categorical variables were compared by Pearson Chi squared and continuous by Mann-Whitney U or Kruskal-Wallis tests. Univariate and multivariate analyses utilized Cox proportional hazards models with continuous variables binarized by receiver operator curves. Kaplan-Meier analyses were censored at hematopoietic cell transplantation (HCT). P < 0.05 was considered significant. Calculations used BlueSky (v10.3.1) or Prism (v10.2.3). Results In a cohort of 849 CMML patients (median age 71 years, 32% female, 90% white), 454 (54%) were classified as MD-CMML and 394 (46%) as MP-CMML. Cumulatively, 664 somatic TET2 mutations were identified across the MD (n = 415, 63%) and MP-CMML (n = 249, 38%) subgroups, with ≥1 TET2 mutation in 57% vs 44% (p < 0.001) and ≥2 TET2mutations in 33% vs 20% (p = 0.001) , respectively. The median (range) number of TET2 mutations in MD vs MP-CMML was 1 (0 - 4) vs 0 (0 - 3; p < 0.001). Truncating frameshift or nonsense mutations comprised 86% vs 78% of mutations in each group with hypomorphic missense mutations comprising 13% vs 20% (p = 0.03). Proximal (48% vs 43%) and distal (38% vs 35%) truncations were evenly distributed between MD and MP-CMML (p = 0.91). In both the MD and MP subgroups as well as the overall cohort (p < 0.01 each), increasing number of TET2 mutations (0 vs 1 vs ≥2) was associated with higher median hemoglobin (10.3 vs 11.4 vs 12.0 g/dL), fewer mean peripheral blasts (1.3% vs 0.5% vs 0.3%), and a higher proportion of normal karyotypes (60% vs 76% vs 79%). Likewise, co-mutations were increasingly frequent in SRSF2 (36% vs 45% vs 53%) and less frequent in IDH2 (9% vs 1% vs 1%) and SETBP1 (14% vs 4% vs 0%) throughout the cohort. TET2 mutations were mutually exclusive with ETV6, GATA2, IDH1, and WT1 mutations. Uniquely, MD-CMML cases with TET2 mutations (0 vs 1 vs ≥2) were enriched for co-mutations in ZRSR2 (5% vs 13% vs 9%) and had fewer co-mutations in both ASXL1 (47% vs 34% vs 28%) and U2AF1 (11% vs 6% vs 3%). In MP-CMML, co-mutations in CBL (11% vs 20% vs 27%) were increased while co-mutations in BCOR (6% vs 1% vs 0%) were decreased. Accordingly, the favorable ASXL1WT/TET2MT genotype was more common in MD (39% vs 22%), while the adverse ASXL1MT/TET2WT genotype was more common in MP-CMML (20% vs 33%; p < 0.001). In multivariate analyses, the presence of ≥2 TET2 mutations was favorably associated with OS and LFS in both MD and MP-CMML (hazard ratios 0.53 - 0.67, p < 0.04) independent of several clinical and genetic features including ASXL1 mutations and abnormal karyotype. Beyond the number of TET2 mutations, however, neither the mutation class (truncating vs hypomorphic) nor location (proximal vs distal) further affected OS or LFS. Likewise, although the median variant allele fraction (VAF) was lower in MD vs MP-CMML (42% vs 46%, p < 0.001), VAF did not impact survival. Accordingly, the mOS for patients with 0, 1, or ≥2 TET2 mutations was 29, 58, and 75 months in MD-CMML and 19, 26, and 39 months in MP-CMML, respectively (p < 0.001 each). The mLFS was similarly improved to 26, 52, and 67 months in MD-CMML (p < 0.001) and 16, 22, and 31 months in MP-CMML (p = 0.003). CONCLUSIONS This multicenter study demonstrates that the favorable impact of multiple TET2 mutations in CMML extends to both the MD and MP subtypes. In MD-CMML, multiple TET2 mutations segregate against adverse ASXL1 mutations while, in MP-CMML, they appear to offset the impact of adverse RAS pathway mutations. Thus, multiple TET2 mutations may identify a lower-risk subgroup of MP-CMML patients.