Citations

Abstract A systematic approach to identifying novel therapeutic strategies is essential for expanding curative options in hematopoietic malignancies such as acute myeloid leukemia (AML). We have recently established a high-resolution genetic platform that enables de novo therapeutic development through the CRISPR-Tiling Instructed Computer-Aided (CRISPR-TICA) workflow (Nat Struct Mol Biol 2024, PMID: 38316881). Using this approach, we further identified a new therapeutic pocket and its lead compound for AML treatment (Sci Adv 2024, PMID: 38394203). Here, we present an integrative pipeline, CRISPR-TICA.ai, which combines CRISPR-based functional genomics with generative artificial intelligence (GenAI)-driven ligand modeling to perform high-throughput evaluation of the top 100 leukemia-essential genes and their therapeutic potential in AML. We first used the CRISPR screen dataset published by Novartis (Cancer Discov 2016, PMID: 27260157), which tile-scanned 68 genes in three cancer cell lines, as the initial training dataset to establish the CRISPR-TICA.ai pipeline. Structurally, ligandable protein surface pockets were identified by employing the P2Rank algorithm (J Cheminform 2018, PMID: 30109435). For each pocket, we used the structure-guided diffusion model DiffSBDD (Nat Comput Sci 2024, PMID: 39653846) to generate previously unseen chemical structures that differ substantially from existing drugs, thereby enabling the exploration of novel chemical space. The model was further fine-tuned using direct preference optimization (NeurIPS 2023) against a curated dataset of known inhibitors to enrich for favorable binding profiles (low binding free energy, ΔG) and calibrated against drug-likeness (QED), synthetic accessibility (SA), lipophilicity (logP), and Lipinski's rule compliance. Additionally, our pipeline integrates ligand–protein contact maps with CRISPR-hypersensitive positions to assess spatial interactions, prioritizing ligands that effectively mask biologically essential residues with high affinity. The utility of CRISPR-TICA.ai in AML drug discovery was evaluated- we selected the top 100 leukemia-essential genes from the DepMap database (https://depmap.org/portal/) and generated custom CRISPR libraries for high-resolution gene tiling screens. These libraries comprised 20,233 sgRNAs to tile-scan all 100 genes (47,901 amino acid residues) in Molm13 AML cells at an average resolution of 2.4 amino acids per sgRNA. This dataset provided in-depth structural and functional input for CRISPR-TICA.ai to examine AI-enabled ligand design for over 300 high-confidence druggable pockets in AML. We further developed a user-friendly, web-based 3D visualization platform that interactively maps functional CRISPR hotspots alongside predicted pockets and ligands to enhance accessibility and reproducibility. This tool allows visualization of CRISPR tiling scores, predicted binding pockets, and ligand prioritization, enabling interactive exploration and application. To annotate therapeutically relevant sites, we incorporated data from multiple genomic and proteomic resources, including AlphaFold protein models, Pfam domain annotations, post-translational modification (PTM) sites, and COSMIC leukemia mutational data. Exportable files and GitHub integration are also provided for advanced users to deploy CRISPR-TICA.ai within their facilities.In summary, our study introduces a scalable, leukemia-focused framework for de novo therapeutic discovery. By integrating high-density CRISPR mutagenesis with diffusion-based GenAI modeling, CRISPR-TICA.ai provides a rational roadmap for compound design targeting residues essential for leukemia maintenance. Importantly, the CRISPR-TICA.ai pipeline is adaptable to CRISPR tiling datasets from solid tumors (e.g., the Novartis dataset), highlighting its versatility across diverse cancer types. This approach is especially promising for addressing historically undruggable and resistance-prone targets in AML and beyond.

Abstract Background: Parenteral DNA methyltransferase inhibitors (DNMTi) such as azacitidine and decitabine (DEC), including an attenuated 3-day regimen, are recommended in the NCCN Guidelines for patients (pts) with lower-risk myelodysplastic syndromes (LR-MDS) with clinically significant cytopenias. However, parenteral administration requires frequent clinic visits, which imposes a substantial burden on pts, particularly those requiring long-term therapy. Oral DMTIs offer more flexible dosing and maintenance of pts' autonomy. Oral DEC-cedazuridine (DEC-C) is a fixed-dose combination tablet containing DEC (35 mg) and cedazuridine (100 mg). ASTX727-03 (NCT03502668) is a randomized, open-label, multicenter, phase 1/2 clinical trial evaluating safety, efficacy, and pharmacokinetics (PK) of various DEC-C doses and regimens in pts with LR-MDS. Phase 1 identified a 5-day regimen of DEC 10 mg/cedazuridine 100 mg as the optimized low-dose (LD) regimen. Phase 2 compares this LD regimen with the attenuated standard-dose (SD) regimen. Here, we report phase 2 results on efficacy, safety, PK, and pharmacodynamic (PD) data. Methods: Adults (aged ≥18 years) with International Prognostic Scoring System (IPSS) low-risk or Intermediate-1 MDS, ECOG PS 0−2, and ≥1 cytopenia or red blood cell (RBC) transfusion dependence were randomized 1:1 to receive oral DEC-C LD (10 mg x 5 days) or SD (35 mg x 3 days). The primary endpoint was hematologic response. Secondary endpoints included PK, PD (by LINE-1 demethylation), time to bone marrow blasts >5%, leukemia-free survival (LFS), overall survival (OS), and safety. Results: As of October 31, 2024, 81 pts were treated (LD arm: n=40; SD arm: n=41) and completed a median of 8.8 months on treatment. At cutoff, 17 (42.5%) and 12 (28.6%) LD and SD pts, respectively, were still continuing the study; 9 (22.5%) and 6 (14.6%) pts respectively, had discontinued treatment due to hematopoietic stem cell transplant. Median age was 70 (LD) and 75 (SD) years; 75.0% (LD) and 68.3% (SD) had IPSS Int-1 risk MDS and 60.0% vs 41.5% had IPSS-Molecular Lower-Risk MDS (very low, low, or moderate-low). Low-risk prognostic scoring system risk distribution was similar: Category 1 (2.5% vs 4.9%), Category 2 (47.5% vs 46.3%), and Category 3 (50.0% vs 48.8%). After a median follow-up of 29.3 months, median OS was 23.9 months (95% confidence interval [CI]: 13.0, not estimable [NE]) in the LD arm vs 26.0 months (95% CI: 19.4, 28.5) in the SD arm. Median LFS was 23.8 months (95% CI: 13.0, NE) and 25.7 months (95% CI: 17.8, 26.5), respectively. Hematologic improvement per International Working Group 2006 criteria was achieved in 27.5% (LD) and 26.8% (SD) of pts. Among RBC transfusion–dependent pts, 52.4% (LD) and 37.5% (SD) achieved ≥56-day independence and 47.6% (LD) and 20.8% (SD) achieved ≥112-day independence. Pts received a median of 10 (LD) and 9 (SD) cycles. Delayed cycles occurred in 72.5% (LD) vs 82.9% (SD) of pts; dose reductions occurred in 40.0% (LD) and 46.3% (SD) of pts. Both treatment regimens caused a decrease in blood counts, reaching a nadir before recovering in each cycle. Neutropenia was more pronounced during early cycles and was more severe in the SD arm. Blood counts across all lineages remained stable or improved through ≥12 cycles with the LD arm, suggesting a more favorable safety and tolerability profile. Grade ≥3 adverse events (AEs) occurred in 85.0% and 90.2% of pts in the LD and SD arms, respectively; treatment discontinuation due to AEs occurred in 2.5% and 17.1% of pts, respectively. Most commonly reported treatment-emergent AEs were anemia (42.5% LD, 39.0% SD), fatigue (32.5% LD, 43.9% SD), and thrombocytopenia (37.5% LD, 39.0% SD). Three deaths occurred in the trial: 2 in the LD arm, which were both unrelated to study treatment, and 1 in the SD arm (Pseudomonal bacteremia in Cycle 1), which was treatment related. Total AUC0–24 was 199 ng*h/mL in the LD arm and 465 ng*h/mL in the SD arm; AUC for all cycles of the LD arm was approximately half of the SD arm. Maximal % LINE-1 demethylation rate was lower with LD than SD, but narrowed by Cycle 3. Conclusion: LD oral DEC-C demonstrated comparable clinical benefit to SD oral DEC-C, with improved safety and tolerability, including fewer dose modifications and less severe myelosuppression. These findings support LD DEC-C as a potential optimal regimen for pts with LR-MDS. Clinical trial registration: NCT03502668

Abstract Introduction: The first-generation BCL2 inhibitor,venetoclax, is an effective treatment for CLL/SLL, but its usage may be limited by toxicity. Sonrotoclax, a next-generation BCL2 inhibitor, is a more selective and pharmacologically potent inhibitor of BCL2 than venetoclax, with a shorter half-life and no drug accumulation. BGB-11417-101 (NCT04277637) is an ongoing, phase 1/1b, dose-escalation/expansion study in patients with B-cell malignancies. Presented here are preliminary data for sonrotoclax + obinutuzumab in patients with treatment-naive (TN) CLL/SLL in BGB-11417-101. Methods: Obinutuzumab is administered intravenously at 100 mg on day (D) 1, 900 mg on D2, 1,000 mg on D8 and D15 of cycle (C) 1, and then 1,000 mg on D1 of C2-6 of each 28-day cycle. Beginning on C2D1, sonrotoclax is administered orally once daily with ramp-up to the target doses, 160 or 320 mg. Patients can continue treatment until progressive disease (PD), unacceptable toxicity, or undetectable minimal residual disease (uMRD4; <1 CLL cell per 10,000 leukocytes [<0.01%]) in peripheral blood (PB) by next-generation sequencing (NGS; ClonoSEQ) after 15 treatment cycles. Study endpoints include safety per NCI-CTCAE v5.0, overall response rate (ORR) per iwCLL guidelines, and MRD status in PB per modified ERIC flow cytometry (FC) assay or NGS, depending on the timepoint. Tumor lysis syndrome (TLS) is assessed per Howard (2011) criteria. Results: As of May 16, 2025, 55 patients with TN CLL/SLL were enrolled (160 mg, n=20; 320 mg, n=35), and 21 patients (all 320 mg) have discontinued sonrotoclax + obinutuzumab (due to uMRD4 per NGS as protocol-mandated [n=17], PI decision uMRD4 per FC [n=2], and PD [n=2]). Four patients discontinued obinutuzumab only per PI decision (160 mg, n=1), thrombocytopenia (320 mg, n=2), and prostate cancer prior to starting sonrotoclax (160 mg, n=1). For all patients, the median age was 62 y, 65% were male, and 89% were White. At baseline, 14% of patients (8/55) had high tumor burden and 58% (31/53) had unmutated IGHV. Median study follow-up was 8.9 months (range, 0.4-25.4 months) for all patients; 6.4 months (range, 0.4-9.0 months) for 160 mg; and 16.0 months (range, 2.9-25.4 months) for 320 mg. Maximum tolerated dose was not reached. The most common any-grade treatment-emergent AEs (TEAEs) were thrombocytopenia (56%), infusion-related reaction (56%), and neutropenia (49%). Neutropenia was the most common grade ≥3 TEAE (38%). No deaths due to TEAEs occurred, and no TEAEs led to sonrotoclax discontinuation. Two cases of laboratory TLS occurred after C1D1 of obinutuzumab prior to starting sonrotoclax; no clinical or laboratory TLS occurred during sonrotoclax ramp up. No meaningful safety differences were observed among sonrotoclax dose cohorts. In 37 efficacy-evaluable patients (160 mg, n=7; 320 mg, n=30), the ORR was 89%; for the 320-mg cohort, ORR was 93% (28/30). Complete response (CR) rates (CR + CR with incomplete marrow recovery [CRi]) were 46% (all patients) and 43% (320 mg). For 23 patients in the 320 mg cohort who reached the C15 MRD assessment, the best C15 uMRD4 rate per FC was 87% (20/23; 2 not evaluable; 1 missing); per NGS, the uMRD4 rate at C15 was 78% (18/23; 5 missing). All patients with an available C15 MRD assessment achieved uMRD4 and remain in remission as of the data cutoff date. The median time from reaching sonrotoclax target dose to uMRD4 was 2.3 months (range, 1.4-5.6 months) in the 320-mg cohort. Three patients experienced PFS events: 1 died from an indeterminate cause (160 mg, discontinued treatment after C1D9 of obinutuzumab) and 2 had PD (320 mg; both Richter's transformation at C6 and C2). Conclusions: Sonrotoclax + obinutuzumab was generally well tolerated in patients with TN CLL/SLL, with no sonrotoclax discontinuations or deaths due to TEAEs. No laboratory or clinical TLS events occurred during sonrotoclax ramp-up. Encouraging antitumor activity was observed with sonrotoclax 320 mg. High rates of blood uMRD4 occurred early and deepened over time. All patients with an available C15 MRD assessment by NGS or FC achieved uMRD4 and remain in remission. A registrational phase 3 study (CELESTIAL-RRCLL, BGB-11417-303) assessing this combination with sonrotoclax 320 mg is currently recruiting.

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.

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.

Abstract Introduction: BGB-16673 is an orally available protein degrader that blocks BTK signaling by tagging BTK for degradation through the cell's proteasome pathway, leading to tumor regression. CaDAnCe-101 (BGB-16673-101; NCT05006716) is an ongoing open-label, phase 1/2 study evaluating BGB-16673 monotherapy in patients with B-cell malignancies. Here, updated safety and efficacy results of BGB-16673 are presented in patients with WM in the phase 1 portion of the study. Methods Eligible patients had confirmed relapsed/refractory (R/R) WM (≥2 prior therapies), an ECOG performance status of 0-2 (0-1 in the EU), and previous treatment with an anti-CD20 antibody and, in the US, Japan, and EU, a covalent BTK inhibitor. BGB-16673 was dosed once daily orally. The primary objectives of this phase 1 study were to evaluate safety and tolerability (NCI-CTCAE v5.0) and establish the maximum tolerated dose and recommended dose for expansion. A secondary objective was to evaluate the overall response rate (ORR; modified IWWM-6 consensus criteria), with the first assessment after 4 weeks of treatment. Results As of May 23, 2025, 42 patients with WM were enrolled and treated (100 mg, n=15; 200 mg, n=14; 350 mg, n=13). Median age was 72.0 years (range, 46-81 years), and the median number of prior therapies was 3 (range, 2-11), including prior covalent BTK inhibitors (n=42 [100%]), BCL2 inhibitors (n=10 [23.8%]), noncovalent BTK inhibitors (n=7 [16.7%]), anti-CD20 monoclonal antibodies (n=42 [100%]), and chemotherapy (n=39 [92.9%]). In total, 33.3% of patients (12/36) had WM with BTK mutations, 85.7% (36/42) with MYD88 mutations, 51.3% (20/39) with CXCR4 mutations, 52.8% (19/36) with TP53 mutations, and 5.6% (2/36) with PLCG2 mutations. Median follow-up was 8.8 months (range, 0.8-31.0 months). Overall, 97.6% of patients experienced treatment-emergent adverse events (TEAEs) of any grade (grade ≥3, 59.5%; serious TEAEs, 35.7%). The most common (≥20% incidence) TEAEs (any grade; grade ≥3) were neutropenia (38.1%; grade ≥3, 33.3%, most common grade ≥3 TEAE), diarrhea (26.2%; no grade ≥3), contusion/bruising (26.2%; no grade ≥3), and thrombocytopenia (21.4%; grade ≥3, 7.1%). No atrial fibrillation was observed. Grade 3 febrile neutropenia and major hemorrhage (grade 3 hematemesis caused by concurrent gastritis/duodenitis unrelated to treatment) occurred in 1 patient (2.4%) each. Seven patients (16.7%) had a grade ≥3 infection, including 2 patients with fungal infections. Three patients (7.1%) had TEAEs that led to treatment discontinuation (anemia, cerebral aspergillosis, pericardial effusion/pleural effusion; n=1 each), and 2 patients (4.8%) had a TEAE that led to dose reduction. Two patients (4.8%) died due to TEAEs (septic shock in the context of progressive disease [PD] and cerebral aspergillosis; n=1 each). All 42 patients were response-evaluable and the ORR (minor response [MR] or better) was 83.3% (n=35), the major response rate (partial response [PR] or better) was 64.3% (n=27), and the very good partial response (VGPR) rate was 26.2% (n=11). Median time to first overall response was 1.0 months (range, 0.9-3.8 months) and to best overall response was 1.9 months (range, 0.9-7.4 months). Responses deepened over time: of 9 patients with stable disease at first disease assessment, 3 transitioned to MR and 2 to PR; of 20 patients with initial MR, 10 transitioned to PR and 2 to VGPR; and of 13 patients with initial PR, 7 transitioned to VGPR. Thirty patients (71.4%) remain on treatment. Two deaths were due to PD. Responses were seen in patients previously treated with a covalent BTK inhibitor (35/42 [83.3%]) and a noncovalent BTK inhibitor (7/7 [100%]) and in patients who discontinued a prior BTK inhibitor due to PD (28/35 [80%]). Responses were independent of mutations in BTK (with, 12/12; without, 17/24), MYD88 (with, 30/36; without, 5/6), CXCR4 (with, 18/20; without, 14/19), TP53 (with, 16/19; without, 13/17), and PLCG2 (with, 1/2; without, 28/34). The 9-month duration of response rate was 84.1% (95% CI, 63.1%-93.7%). Conclusions Data from this ongoing phase 1 study demonstrate that the novel BTK degrader BGB-16673 was well tolerated and continued to show substantial antitumor activity in patients with heavily pretreated BTK inhibitor–exposed R/R WM, including those with BTK, MYD88, CXCR4, and TP53 mutations. Enrollment is ongoing in the phase 2 portion of the study.

Abstract Introduction Short diagnosis-to-treatment interval (DTI) is associated with aggressive disease biology and inferior outcomes in diffuse large B-cell lymphoma (DLBCL), and is recognized as a potential source of selection bias in clinical trials if not properly addressed. However, its prognostic significance in follicular lymphoma (FL) remains poorly characterized. We aimed to evaluate the prognostic significance of DTI in newly diagnosed FL patients who received frontline (1L) immunochemotherapy (IC), using a large international dataset and an independent external validation cohort. Methods For the discovery dataset, we evaluated patients diagnosed between 2002 and 2018 from ten observational cohorts as part of the FLIPI24 Consortium. External validation was conducted using data from patients enrolled in the Lymphoma Epidemiology of Outcomes (LEO) Cohort between 2010 and 2015. All patients had FL grade 1–3A and received 1L IC within 100 days of diagnosis. Patients with a concurrent DLBCL were excluded. Missing baseline laboratory values were addressed via multiple imputation. The primary endpoint was event-free survival at 24 months (EFS24); secondary endpoint was 5-year overall survival (OS), both calculated from treatment initiation. DTI was analyzed as continuous (via splines) and dichotomized variable (≤14 vs >14 days; as defined in DLBCL). Results In the discovery cohort (n=3,907), median age was 61 years (IQR 53–69), and 50% were male; 49% of patients were high-risk according to FLIPI, 26% according to PRIMA-PI, and 38% according to FLIPI24. Included patients received R-CHOP (54%), R-CVP (26%), or B-R (20%) as 1L treatment, followed by anti-CD20 maintenance in 60%. The median DTI was 30 days (IQR 17–48). Using the 14-day cut-off, 851 patients (22%) had short DTI. These patients had more adverse baseline characteristics, including B symptoms (42% vs 32%, P<0.01), ECOG performance status ≥2 (15% vs 8%, P<0.01), elevated LDH (51% vs 40%, P<0.01), hemoglobin <12 g/dL (30% vs 17%, P<0.01), and elevated β2-microglobulin (56% vs 44%, P<0.01). Prognostic indices (PIs) were also more frequently high-risk in the short-DTI group: FLIPI (56% vs 47%), PRIMA-PI (36% vs 24%), and FLIPI24 (51% vs 34%, all P<0.01). Spline modeling showed a decreasing EFS24 rate with increasing DTI, reaching a plateau at 30–40 days. In logistic regression model, each additional week of DTI improved EFS24 (OR 0.92, P<0.01). DTI attenuated but remained prognostic after adjusting for PIs (OR 0.93 for FLIPI, 0.95 for PRIMA-PI, 0.96 for FLIPI24, all P<0.01). When analyzed as a dichotomized variable, short DTI was associated with inferior EFS24: OR 1.74 adjusted for FLIPI, 1.63 for PRIMA-PI, and 1.53 for FLIPI24 (all P<0.01). The 2-year EFS of short vs long DTI groups was 71% vs 82% (HR 1.50, 95% CI 1.34–1.67, P<0.01), 5-year OS was 80% vs 86% (HR 1.38, 95% CI 1.21–1.56, P<0.01), and the 5-year cumulative risk of histologic transformation was 7.7% vs. 5.4% (P<0.01). In the validation cohort (n=516), median age was 61 years (IQR 52–69 years), 55% were male; 36% of patients were high-risk according to FLIPI; 29% according to PRIMA-PI, and 33% according to FLIPI24. Patients received B-R (59%) or R-CHOP (41%) as 1L treatment. The median DTI was 31 days (IQR 19–48), 84 patients (16%) had DTI ≤14 days. Similar patterns were observed; patients with short DTI had adverse baseline characteristics, PIs, and shorter 2-year EFS (72% vs 84%, HR 1.69, 95% CI 1.13–2.55, P=0.01). DTI remained associated with EFS24 when analyzed as a continuous variable (per week: OR 0.88 unadjusted, 0.90 with FLIPI, 0.89 with PRIMA-PI, and 0.89 with FLIPI24), and dichotomized (≤14 vs >14 days: OR 1.83 adjusted for FLIPI, 1.88 for PRIMA-PI, and 1.73 for FLIPI24). Conclusion Short DTI, defined as ≤14 days (observed in 22% of FL patients vs 46% in DLBCL), is a strong and independent predictor of inferior outcomes in newly diagnosed FL patients treated with IC. While DTI correlates with adverse baseline features and established PIs, it retains independent prognostic value. Although a 14-day threshold is reasonable for risk modeling, DTI contains greater informational value when modeled as a continuous variable. Among PIs, FLIPI24 most strongly attenuated the DTI effect, underscoring its superior discriminative power over FLIPI and PRIMA-PI. Clinical trials designs should mitigate any potential barriers to enrollment of FL patients requiring urgent therapy.

Abstract Background: Despite the efficacy of covalent Bruton tyrosine kinase inhibitors (cBTKi) in R/R MCL, patients (pts) ultimately discontinue treatment due to intolerance or development of resistance and disease relapse. Pirtobrutinib is a highly selective, non-covalent BTKi that inhibits BTK with low nM potency throughout the daily dosing interval. Pirtobrutinib was safe and effective in the phase 1/2 BRUIN study in pts with R/R B-cell malignancies, including those previously treated with a BTKi. Pirtobrutinib is approved in the EU for adults with R/R MCL after prior treatment with a BTKi (EMA Conditional Approval, Oct 2023), and in the USA for adults with R/R MCL after ≥ 2 lines of systemic therapy, including a BTKi (FDA Accelerated Approval, Jan 2023).Here, we report the final results from the phase 1/2 BRUIN study (NCT03740529), with a follow-up period of up to 5 yrs, focusing on the efficacy and safety of pirtobrutinib in all R/R MCL pts. Methods: Pts with R/R MCL who received ≥1 prior lines of therapy (including BTKi) were eligible for treatment with pirtobrutinib monotherapy. Key endpoints included overall response rate (ORR), duration of response (DOR) and progression-free survival (PFS), all assessed by independent review committee (IRC) per Lugano 2014 criteria (presented here) and investigator, overall survival (OS), and safety. Pts were included across the range of doses evaluated in dose escalation and expansion (25-300 mg/day). A data cutoff on 27 January 2025 was utilized, with a median study follow-up of 17.5 months (range, 0.5-69.6). Results: Among the 166 pts with R/R MCL, 153 (92%) received the pirtobrutinib approved dose of 200 mg/day, 152 (92%) had received prior cBTKi, of which 128 (84.2%) discontinued any prior cBTKi due to progressive disease (PD), and 15 (9.9%) due to toxicity. The cBTKi-pre-treated pts had a median age of 70 yrs (range, 46-88), 52% had intermediate-risk and 28.3% had high-risk sMIPI scores. The median number of prior lines of therapy was 3 (range 1-9), with most pts having received a prior anti-CD20 antibody (96.7%) and chemotherapy (90.1%). Additional prior therapies included hematopoietic stem cell transplantation (21.7%; 19.7% auto and 4.6% allo), BCL-2 inhibitor (15.8%), CAR-T cell therapy (8.6%). As of the data cutoff, 11 (7.2%) pts who received a prior cBTKi and 6 (42.9%) cBTKi naïve pts remained on treatment. The cBTKi pre-treated pts had an ORR of 49.3% (95% CI, 41.1-57.6), including 15.8% complete responses (CR) (n=24) and 33.6% partial responses (PR) (n=51). The 75 responding pretreated pts had a median DOR of 21.6 months (95% CI, 9.2-27.2) at a median follow-up of 24 months. The ORR among 128 pts who had discontinued any prior cBTKi due to PD and 15 pts who discontinued due to toxicity was 43.0% and 93.3%, respectively. The median PFS and OS for cBTKi pre-treated pts were 5.6 months (95% CI, 5.3-9.2) and 23.9 months (95% CI, 17.3-51.5), respectively. Fourteen pts (9.2%) were censored for PFS due to subsequent anticancer therapy without documented PD, including 8 pts who received CAR-T. The cBTKi naïve pts (n=14) had an ORR of 85.7% (95% CI, 57.2-98.2), including 50.0% CR (n=7) and 35.7% PR (n=5). The 12 responding naïve pts had a median DOR of 42.7 months (95% CI, 25.8-NE) at a median follow-up of 43 months. The median PFS and OS in the cBTKi naïve pts were 44.6 months (95% CI, 16.7-NE) and not reached (95% CI, 33.5-NE), respectively. Among all R/R MCL pts (n=166), the most frequent treatment-emergent adverse events (TEAE), regardless of attribution, were fatigue (31.9%), diarrhea (22.9%), anemia (18.1%), and dyspnea (18.1%). The most common Grade ≥3 TEAE was neutropenia/neutrophil count decreased (13.3%), and the rate of Grade ≥3 infections was 21.1%. Grade ≥3 hemorrhage/hematoma (2.4%) and all-grade atrial fibrillation/flutter (3.6%) were infrequent. In total, 13 (7.8%) pts had a fatal TEAE, with 4 (2.4%) classified as infections. Overall, 8 pts (4.8%) had treatment-related AE leading to dose reductions, and 6 (3.6%) had treatment-related AE leading to pirtobrutinib discontinuation. Conclusion: Pirtobrutinib continues to demonstrate efficacy in pts with heavily pre-treated R/R MCL including both those who previously received a cBTKi and those who were BTKi-naïve. The safety profile of pirtobrutinib remained favorable with a low-rate of dose reductions/discontinuations due to drug-related toxicity. No new safety signals were identified after up to 5 yrs of follow-up.

Abstract Background & aim: Myelodysplastic syndromes with isolated deletion of chromosome 5q (MDS-del(5q)) are associated with low-risk features and favorable prognosis. In contrast, TP53 multihit alterations, typically reflecting biallelic inactivation, are associated with high-risk features and adverse outcomes across MDS subtypes. Although current classification systems exclude MDS-del(5q) cases with TP53 multihit from low-risk categories, the prognostic significance of these alterations in this specific context remains unclear. Methods: We conducted an international, multicenter, retrospective study comparing MDS-del(5q) per 2017 WHO criteria with TP53 multihit alterations (MDS-del(5q) TP53 multihit) from 21 international institutions, to MDS with low blast counts with TP53 multihit alterations without isolated del(5q) (MDS-LB TP53 multihit) from the public data from the study of Bernard et al., Nat Med 2020. Clinical and biological data were collected at diagnosis. Genetic profiling included G-banding and NGS of myeloid genes. TP53 multihit was defined as >1 TP53 mutation or a single mutation with 17p deletion, copy-neutral loss of heterozygosity (LOH), or variant allele frequency (VAF) ≥50%. Patients were stratified as lower- or higher-risk based on IPSS-R and IPSS-M scores. Lower-risk included those with IPSS-R ≤3.5 points or very-low, low, or moderate-low IPSS-M, while higher-risk included those with IPSS-R >3.5 points or moderate-high, high, or very-high IPSS-M. Clinical, molecular features, overall survival (OS), and AML progression were compared between MDS-del(5q) TP53 multihit and MDS-LB TP53 multihit groups. Finally, outcomes between patients with likely biallelic TP53 multihit status, defined as harboring a single TP53 mutation accompanied by a co-occurring deletion/LOH of 17p or a TP53 VAF ≥50%, versus those considered less likely to be biallelic, thus still classified as multihit, defined as having >1 TP53 mutation but a combined VAF <50%, were compared in both MDS-del(5q) and MDS-LB groups. Statistical analysis was performed using R (version 4.2.2). Results: We included 113 patients with a median follow-up of 81.1 months (95% CI 74.9–NR). A total of 45 (39.8%) were MDS-del(5q) TP53 multihit, and 68 (60.2%) MDS-LB TP53 multihit. Compared to MDS-LB TP53 multihit, patients with MDS-del(5q) TP53 multihit had significantly higher platelet counts (209 ×10⁹/L vs. 77 ×10⁹/L) and were more frequently classified as lower-risk by both IPSS-R (75.4% vs. 9.8%) and IPSS-M (90.2% vs. 24.6%). The median number of mutations per patient, excluding TP53, was 1 in both groups, and only SF3B1 mutations were significantly more frequent in the MDS-del(5q) TP53 multihit group compared to MDS-LB TP53 multihit (20.5% vs. 2.9%; p<0.01). Regarding survival, MDS-del(5q) TP53 multihit patients showed an improved OS compared to MDS-LB TP53 multihit (median OS of 57.0 months (95%CI, 43.0–112.0) vs 14.0 months (95%CI, 8.6–19.0); p<0.01). Moreover, while the risk of progression to AML at 48 months were comparable between groups (34.9% for MDS-del(5q) TP53 multihit and 33.0% for MDS-LB TP53 multihit; p=0.8), a significant difference was observed in the timing of AML progression: median time to AML evolution of 31.7 months (IQR 23.4–55.3) in the MDS-del(5q) TP53 multihit group and 7.2 months (IQR 4.1–12.9) in the MDS-LB TP53 multihit group (p<0.01). Notably, no significant differences in outcomes were found between TP53 multihit and most likely biallelic cases in both MDS-del(5q) and MDS-LB cohorts. The impact of complex karyotype (CK) in MDS-LB TP53 multihit was also explored. MDS-LB TP53 multihitwith CK showed a significantly worse OS compared to MDS-LB TP53 multihitwithout CK (median OS of 10.0 months (95% CI 7.5–17.0) vs 40.0 months (95% CI 14.0–NA); respectively; p<0.001. However, the incidence of AML and median time to AML evolution were comparable between both groups. Finally, OS between MDS-LB TP53 multihit patients without CK and the MDS-del(5q) TP53 multihit cohort was compared. Median OS was significantly shorter in the former group (median of 40 months) compared to the latter (median of 61 months) (p <0.01) Conclusions: These findings underscore that, in contrast to other TP53-multihit MDS subtypes, MDS-del(5q) with TP53 multihit alterations constitute a clinically distinct entity with better outcomes, thereby warranting reconsideration of its place in current classification systems.

Abstract Background: Cryoprecipitate is indicated for bleeding patients with hypofibrinogenemia, typically when fibrinogen levels fall below 100–150 mg/dL. Despite established national transfusion guidelines, inappropriate use remains a persistent issue in clinical practice, especially in community hospitals where formal transfusion oversight may be limited. Unnecessary transfusions can expose patients to avoidable risks and contribute to increased healthcare costs. As part of a hospital-wide quality improvement initiative, we conducted a retrospective review of cryoprecipitate use at our institution to assess adherence to transfusion guidelines and identify areas for improvement. Methods: We performed a retrospective review of all cryoprecipitate transfusions at Landmark Medical Center, a 214-bed community hospital in Rhode Island, between January 2021 and June 2025. Transfusion episodes were identified through blood bank records. For each episode, we extracted the number of units ordered and administered, pre-transfusion fibrinogen levels, documented clinical indication in the electronic medical record (EMR), and any product wastage. Each transfusion was assessed based on institutional criteria aligned with national guidelines, which recommend cryoprecipitate only in cases of active bleeding with fibrinogen <100–150 mg/dL. Results: Twenty patients received cryoprecipitate in 23 transfusion episodes involving 32 units. Of these, 28 units were administered and 4 were wasted. The majority of patients were female (65%), and 40% were between ages 61 and 75. Only 10 of 23 episodes (43%) met established transfusion criteria. Nine episodes (39%) were given when fibrinogen levels ranged between 100–200 mg/dL, and two episodes (9%) occurred with levels >200 mg/dL. One transfusion was administered without a documented fibrinogen level. Additionally, 8 episodes (35%) lacked a clearly documented indication in the EMR. Three episodes (13%) involved product wastage, including one with no documentation and another where an order was placed but the unit was not administered. Conclusion: This review revealed that more than half of cryoprecipitate transfusions did not meet guideline-based criteria. The findings point to deficiencies in provider knowledge, inconsistent documentation, and limited transfusion oversight contributing to inappropriate use. These results highlight the need for targeted interventions, including: (1) provider education on transfusion thresholds, (2) EMR-based decision support requiring lab values prior to ordering, and (3) routine audits with feedback. Strengthening transfusion practices through structured quality improvement efforts can reduce unnecessary use, improve patient safety, and preserve limited blood product supplies for those who truly need them.