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Abstract Introduction: Multiple myeloma (MM) accounts for nearly 20% of all hematologic cancers in the US and remains a substantial clinical burden, with patients (pts) requiring multiple lines of therapy (LOT). While advances such as BCMA-directed CAR T-cell therapy have improved outcomes, challenges persist, including disease relapse, treatment toxicities (CRS, ICANS, and non-ICANS neurotoxicities), and access. AZD0120 (formerly GC012F) is a first-in-class autologous BCMA/CD19 dual-targeting CAR T-cell therapy using the FasTCAR rapid manufacturing platform that preserves the naive and central memory T-cell phenotypes with marked in vivo proliferative capacity. Phase 1 investigator-initiated trials in China demonstrated deep, durable responses and a favorable safety profile following single-infusion AZD0120 in newly diagnosed and relapsed/refractory MM (RRMM) (Du J, et al. EHA 2024 and ASCO 2023). Here, we report for the first time preliminary phase 1b results from DURGA-1, an ongoing phase 1b/2 clinical trial evaluating the safety and efficacy of AZD0120 in pts with RRMM. Methods: This open-label, single-arm, US-based, multicenter study (NCT05850234) evaluated the safety/tolerability of 2 dose levels (DL) of AZD0120 in pts with RRMM along with preliminary efficacy. Eligible ptswere aged ≥18 y with RRMM (3+ prior LOT [pLOT] including a proteasome inhibitor, immunomodulatory drug, and anti-CD38 antibody), ECOG PS 0–1, and documented evidence of progressive disease. Exposure to BCMA-directed therapy ≥6 mo with best response of PR or better was permitted. Pts underwent lymphodepletion followed by a single infusion of AZD0120. Pts in DL1 received 1x105 cells/kg; DL2 received 3x105 cells/kg. Dose escalation and recommended phase 2 dose (RP2D) were determined by a safety review committee. Phase 1b primary objectives included safety/tolerability and RP2D determination; secondary objectives included efficacy, cellular kinetics (CK), and pharmacodynamics. Results: As of data cutoff (DCO) on 18 July 2025, a total of 25 pts received infusion of AZD0120 (n=12 DL1; n=13 DL2). The median age was 64 y (range 44–78), median pLOT was 4 (range 3–7), 72% were triple-class refractory, 20% had prior BCMA CAR T-cell therapy, 4% had prior teclistamab, 28% had high-risk cytogenetic features [del(13q), del(17p13), t(4;14), t(14;16), amp(1q)], and 8% had extramedullary plasmacytomas. The median time from apheresis to release was 14 d (range 10–30). Median time from apheresis to infusion was 28 d (range 19–44) with 5 pts receiving bridging therapy. Median follow-up was 1.4 mo (range 0–19.3). No dose-limiting toxicities were reported for either dose. The most common treatment-emergent AEs (TEAEs, any grade) were CRS (64%), neutrophil count decreased (56%), and anemia (32%). The most common grade ≥3 TEAEs were neutrophil count decreased (52%), lymphocyte count decreased (32%), and white blood cell count decreased (32%). CRS was reported in 75% of pts at DL1 (all grade 1) and 54% at DL2 (46% grade 1; 8% grade 2), with no cases of grade ≥3 CRS. Median time to CRS onset (DL1/DL2) was 9 d (range 2–11), with a median duration of 2 d (range 1–4); 12 pts (48%) received tocilizumab for CRS management and 12% received dexamethasone. No cases of ICANS, related non-ICANS neurotoxicity, IEC-colitis, or secondary primary malignancies have been reported. There have been no deaths. For efficacy-evaluable patients (n=15), ORR was 100% (33% sCR, 47% VGPR, 20% PR). CR rates in evaluable pts were 30% in DL1 (n=10) and 40% in DL2 (n=5); median time to response was 0.9 mo for both DLs (range 0.9–1.9 DL1; 0.6–1.8 DL2). All MRD-evaluable pts (n=5 DL1; n=3 DL2; DCO 01 July 2025) were MRD-negative by NGS at a sensitivity of 10-5. Three pts in DL1 with ≥12 mo follow-up maintained MRD negativity. Consistent with robust in vivo expansion, CK analysis from 16 evaluable pts (DCO 12 June 2025) demonstrated a median Tmax of 13 d post-infusion with a median Cmax of 85,266 copies/mg gDNA. Median persistence was 42 d (range 13–273). Updated clinical data with additional follow-up will be presented. Conclusion: Preliminary phase 1b results demonstrated AZD0120 was well tolerated, with a low incidence of serious AEs, no grade ≥3 CRS, and no ICANS. FasTCAR-manufactured AZD0120 had expectedin vivo expansion, which may have resulted in the predictable CRS profile. A single infusion of AZD0120 achieved early, deep responses with 100% MRD negativity from 4L+ triple-class‒exposed pts with RRMM.

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.

Abstract Background. Uproleselan (GMI-1271) is an antagonist of E-selectin, an adhesion molecule expressed on endothelial cells in the vascular niche of the bone marrow. Engagement of E-selectin by acute myeloid leukemia (AML) blasts, which express E-selectin ligand, activates cell survival pathways and promotes resistance to chemotherapy. In multiple preclinical AML tumor models, blockade of E-selectin with uproleselan enhanced the efficacy of chemotherapy. Methods. We conducted a phase (P) 2/3 study in which subjects age ≥ 60 years with untreated, FLT3 unmutated AML were randomized to receive conventional chemotherapy with or without uproleselan. Induction chemotherapy consisted of 7+3 (cytarabine + daunorubicin) +/- uproleselan with a second induction cycle with 5+2 +/- uproleselan administered for residual AML. Uproleselan 800 mg IV was administered as a single dose 24 hours before the first dose of chemotherapy and then every 12 hours until 48 hours after the completion of chemotherapy. Post-remission therapy consisted of up to 3 cycles intermediate-dose cytarabine 2 gm/m2 IV d1-5 +/- uproleselan. Allogeneic transplant was performed at the discretion of the treating physician. The primary endpoint was event-free survival (EFS) for P2 and overall survival (OS) for P3. Results. The study enrolled 267 patients between March 2019 and November 2021, with a median age of 66.9 years (IQR 63.8-69.9). 32% were classified as 2017 ELN intermediate risk, 41% as adverse risk, with 62 (29%) having complex karyotype / mutated TP53. The P2 analysis was to be performed when at least 191 events were observed. However, as the required events had not been observed > 5 years after study initiation and 3 years after completion of P2 enrollment, an independent statistician was consulted, and the analysis plan was amended to conduct the P2 EFS analysis in November 2024. With a median follow-up of 53.1 months, the EFS was not significantly different between the two arms (HR 0.90, 95% CI 0.70-1.23, P=0.58). As the study did not meet its P2 EFS endpoint, enrollment in the P3 was not initiated. There was no significant difference in OS between the 2 arms (HR 0.99, p=0.94) with a median OS in the uproleselan arm of 23.6 months (95% CI 15.1-35.4 mo) vs 19.8 months (14.6-36.3) for the control arm. The overall rate of CR/CRi after induction was 65% (CR: 60%) in the uproleselan arm versus 63% (CR: 55%) in the control. MRD results by either local or central assessment in patients achieving a CR/CRi were available for 129 patients with the MRDneg rate of 81 % (95% CI 69.5-89.9%) in the uproleselan arm vs 67% (54.3-78.4%) in the control arm (p=0.053), The 30-day mortality was 5.3% for uproleselan vs 8.1% in the control. Forty-eight (36%) patients in the uproleselan arm and 55 (40%) in the control arm underwent alloHCT, including 37 (27%) and 29 (22%) in CR1, respectively (p = 0.34). In patients undergoing alloHCT in CR1, those randomized to uproleselan and allografted in CR1 had an HR 0.71 (95% CI 0.34-1.47; P=0.35) compared to the control arm. Expression of E-selectin ligand on AML blasts was performed by flow cytometry, with subjects having an E-selectin ligand expression above the median having a trend towards worse median OS 16.2 (95% CI 11.4-24.3) vs 32.2 (15.9-57.8) months, but was not affected by treatment arm. In both univariate and multivariate analyses, WBC at baseline, ELN genetic risk group, and TP53/complex karyotype were found to be associated with EFS. A subgroup analysis identified an improvement in EFS favoring uproleselan in patients with mutated ASXL1 (HR 0.25, 95% CI 0.08-0.78, p<0.017). Conclusions. Although the addition of uproleselan to intensive chemotherapy was associated with a higher rate of MRDneg CR/CRi in older adults with AML, uproleselan failed to improve EFS or OS and did not overcome the adverse outcomes associated with higher E-selectin expression on AML blasts. The median OS of 20-24 months with an overall 3-year OS of almost 40% for patients treated on this study exceeds previous CALGB / US Cooperative Group studies (median OS ~12 months, 3-year OS ~20%) and continues to support a role for intensive chemotherapy in the management of older adults with AML. Furthermore, this study suggests a potential benefit for uproleselan in patients harboring ASXL1 mutations, which may warrant further investigation. ClinicalTrials.gov Identifier: NCT03701308

Abstract Background: Recent clinical trials of immune checkpoint inhibitors (ICI) in multiple myeloma (MM) demonstrated the need to prioritize patients most likely to benefit from this type of therapy (Richard, et al., Nat. Cancer, 2024). Immune checkpoints in MM function through receptor-ligand (RL) interactions between CD8+ T cells and malignant plasma cells. However, there is a gap in our understanding of the immune checkpoint landscape in newly diagnosed MM (NDMM). To explore this, we mapped known immune checkpoint RL pairs in subjects enrolled in the CoMMpass Study (NCT01454297), a prospective, longitudinal observational trial. Methods Bone marrow aspirates from study participants were collected and separated into CD138 positive and CD138 negative fractions for comprehensive molecular characterization of the tumor (using bulk RNA sequencing and whole genome sequencing) and tumor immune microenvironment (using 3' single cell RNA sequencing (scRNA-seq)). 191 patients had paired bulk tumor and single cell immune expression profiles. To evaluate the co-expression of receptor-ligand pairs, we developed two approaches that combine gene expression values across single cell and bulk RNA-seq. The first approach uses joint percentiles to identify patients with high expression (top 75%) of both receptor and ligand (referred to as high-high). The second approach uses a rank-based interaction score to create a single value for each patient within a distribution defined for each receptor-ligand pair; patients with extreme values have high expression of both receptor and ligand. The two methods identified similar sets of patients with high co-expression of receptor and ligand. We then compared progression free survival (PFS) across receptor-ligand co-expression groups (high-high vs. others) and tested for other clinical associations. From a pre-defined list of 17 receptor-ligand pairs (Liu, et al., Exp. Hematol. Oncol., 2023), we focused on the following receptors (from CD8+ T cells) and ligands (from tumor plasma cells): PD-1 with PD-L1; LAG-3 with MHC-II; TIGIT with CD115; and TIM-3 with phosphatidylserine. Results Overall, 91 patients (91/191, 47.6%) showed high-high co-expression for at least 1 out of 17 receptor-ligand pairs, and 100 patients were high-high for no receptor-ligand pairs. Among patients with at least one high-high pair, there was a median of 2.0 high-high pairs (range: 1-11). Hierarchical clustering of high-high status and rank-based interaction score correlations showed that for a given receptor, patients often showed high-high co-expression across multiple related ligands. For TIM-3 (receptor, CD8+ T cells) and phosphatidylserine (ligand, tumor plasma cells), we identified 16 patients (16/191, 8.4%) with high-high co-expression and significantly worse PFS (median survival 485 vs. 1503 days, log-rank p-value 0.043). For PD-1-PD-L1, we identified 7 patients with high-high co-expression; for LAG-3-MHC-II, 12 patients (6.3%); and for TIGIT-CD115, 13 patients (6.8%). Conclusion ICI therapy remains an emerging area of study in MM. Here, we developed methods to explore immune checkpoint receptor-ligand co-expression from paired immune microenvironment and tumor cell populations. Our approach demonstrates the value of data integration across gene expression modalities, especially when standard sample collection methodologies segregate tumor and immune populations. Co-expression analysis may be one factor in prioritizing patients for immune checkpoint inhibitor therapy.

Abstract Introduction: Waldenström macroglobulinemia (WM) is characterized by the presence of a MYD88 mutation in >90% and a CXCR4 mutation in 30-40% of cases. The impact of these mutations on treatment responses and disease outcomes is well known. TP53 alterations (TP53ALT) have more recently been described in WM and are reported to occur in up to 25% of patients, with a higher frequency in patients with previously treated WM, especially those with prior alkylator or nucleoside analogue exposure (Tam et al Blood Adv 2024; Poulain et al CCR 2017; Tsakmaklis et al, ASH 2025). TP53 ALT WM is associated with a shorter time to disease progression, as well as worse overall survival (Poulain et al CCR 2017; Gustine et al, BJH 2019). Depth of response to BTK inhibitors is affected by TP53 status, with recent data reporting a very good partial response (VGPR) rate of 34% v. 25% and major response rates of 84% v. 73% in patients without or with a TP53 ALT (Tam et al Blood Adv 2024). No complete responses were reported and median PFS was shorter in those with a TP53ALT compared with wild-type (TP53WT). Loncastuximab tesirine is a humanized IgG1 anti-CD19 antibody that is conjugated to a pyrrolobenzodiazepine (PBD) dimer. Following internalization, the PBD dimer is released via proteolytic cleavage and binds to the DNA minor groove forming highly cytotoxic DNA inter-strand crosslinks. Cells deficient in DNA repair including TP53 alterations are vulnerable to the cytotoxic effects of loncastuximab tesirine (Tarantelli et al, Haematologica 2024). Methods: In an ongoing investigator-initiated, prospective phase II study in symptomatic patients with relapsed or refractory WM (NCT05190705), patients are receiving single agent loncastuximab tesirine. Loncastuximab tesirine is administered at 150 ug/kg in cycles 1 and 2 and 75 ug/kg in cycles 3 to 6. Each cycle is 28 days. The primary outcome measure of this study is attainment of VGPR or complete (VGPR/CR) response. The accrual goal of this trial is 20 patients, based on an alternative VGPR/CR rate ≥40% versus a null of ≤10%, with a double-sided alpha of 0.037 and a power of 87%. The study would meet its endpoint if ≥6 patients attained a VGPR/CR. Results: Of the 14 patients who have completed therapy on this trial to date, the median age is 71 years (range 53-81), 9 (64%) are male, and the median prior number of therapies is 4 (range 2-10). Median baseline hemoglobin is 9.5 g/dL (range 8.2-12.6), serum IgM is 2146 mg/dL (range 723-5955), and bone marrow involvement is 53% (range <5-90). Four patients had extramedullary disease. Twelve patients (86%) are MYD88 mutated; 8 patients (57%) are CXCR4 mutated, and 8 (57%) are TP53 altered. Nine patients completed all 6 cycles of therapy. Of the 5 other patients, treatment was stopped early due to GGT elevation (n=2), disease progression (n=1), patient decision (n=1), and skin toxicity (n=1). No IgM flare and no infusion reactions have occurred. For all patients, the median time to minor response, major response, and deepest response was 28, 55, and 172 days, respectively. The response rates include 1 (7%) CR; 9 (64%) VGPRs; 2 (14%) partial responses (PR); 1 (7%) minor response; and 1 (7%) progressive disease, for an overall response rate of 93% and a VGPR/CR rate of 71%. For the 8 patients with TP53ALT, the baseline characteristics were as follows: 50% male; median age of 70 years (range 53-77), median prior therapies is 4 (range 2-10); median IgM is 1877 mg/dL (range 723-5639); and median hemoglobin is 9.2 g/dL (range 8.2-11.6). All TP53ALT patients had an MYD88 mutation, and 6 (75%) carried a CXCR4 mutation. For those with TP53 ALT, the median time to minor response, major response, and deepest response was 28, 49, and 235 days, respectively. All TP53ALT patients attained a major response; 1 patient (13%) with a CR, 6 (75%) with a VGPR, and 1 (13%) with a PR, for an overall response rate of 100% and a VGPR/CR rate of 89%. One patient had splenomegaly and one had adenopathy, both of which resolved after treatment. Conclusion: Our findings from this ongoing, prospective trial demonstrate a high VGPR/CR rate of 71% in heavily pre-treated WM. Notable, is the VGPR/CR rate of 89% in high-risk patients with TP53ALT WM. No unexpected toxicities have been seen in this trial. Our findings identify a potentially novel time-limited therapy in relapsed or refractory WM, including patients with high-risk TP53ALT WM.

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 Aims BMT CTN 1506 (“MORPHO”) was a global phase 3 study of post-hematopoietic cell transplantation (HCT) maintenance with gilteritinib versus placebo for patients with FLT3-ITD-mutated AML in CR1. The study did not meet its primary endpoint of improved relapse-free survival (RFS) for post-HCT gilteritinib, but subgroup analysis indicated a benefit for participants with pre-HCT measurable residual disease (MRD). Subgroup analysis also indicated a statistically significant benefit of post-HCT gilteritinib for participants in North America, but no benefit for those in Europe or Asia. RFS for the control arms in Europe and Asia was higher than anticipated, suggesting that participants with different disease biology may have accrued to the study in these different geographic regions. In the primary analysis of the study, pre-HCT FLT3 inhibitor use and MRD across the entire study population were both found to have impacted outcomes. Time from diagnosis to HCT, a reflection of local practice patterns, is also known to impact outcomes for FLT3-ITD AML. We hypothesized that local practice patterns of pre-HCT FLT3 inhibitor use and time from AML diagnosis to HCT could have influenced the disease biology of study pts at the time of enrollment. This would be predicted to result in pre-HCT MRD levels and could provide an explanation for the regional differences observed in the study outcome. Methods We conducted a post-hoc analysis of the data focusing on days from AML diagnosis to HCT, pre-HCT FLT3 inhibitor use, and FLT3-ITD MRD assessed by a high-sensitivity assay. Eligibility requirements included FLT3-ITD-mutated AML in first remission after intensive chemotherapy and HCT occurring within 12 months of achieving remission. Patients refractory to induction therapy, or those with a history of relapse, were ineligible. Results Accrual took place in 16 different countries, with 5 countries accounting for 79.7% of the total accrual: USA 42.7%; Japan 15.7%; Korea 8.4%; UK 6.7%; Germany 6.2%; other countries 20.2%. In two countries, USA and Germany (48.9% of total enrollment), participants underwent HCT a median of 119 days after AML diagnosis, and 90.2% were treated with a FLT3 inhibitor pre-HCT. In contrast, in Japan, Korea, the UK and the other 11 countries all combined, participants underwent HCT a median of 152.5 days after AML diagnosis, and only 30.8% received any FLT3 inhibitor pre-HCT. Amongst all participants, those transplanted < 120 days from AML diagnosis and/or those treated with FLT3 inhibition pre-HCT were more likely to have improved RFS from post-HCT gilteritinib. RFS was improved with post-HCT gilteritinib in the US and Germany (HR 0.397; CI 0.220-0.718), whereas no benefit was evident in all other countries combined (HR 1.184; CI 0.685-2.048). Pre-HCT MRD levels were significantly higher (P = 0.011) in participants transplanted within 120 days from diagnosis as well as in those treated with a FLT3 inhibitor pre-HCT and also transplanted within 120 days (P = 0.019). Pre-HCT MRD was dependent on both FLT3 inhibitor use and time to HCT, as participants treated with successive courses of chemotherapy + FLT3 inhibition had successively lower MRD by the time of HCT. Conclusions The time from AML diagnosis to HCT and FLT3 inhibitor use pre-HCT both appeared to impact MRD levels immediately prior to HCT, and geographic differences in these two practice patterns likely accounted for the regional differences in benefit from post-HCT gilteritinib observed in BMT CTN 1506. Successive courses of chemotherapy without FLT3 inhibition appears to have selected a more favorable risk (e.g., MRD-lower) population for enrollment. Successive courses of chemotherapy combined with FLT3 inhibition progressively eradicated MRD, such that a majority of participants undergoing HCT after 3 or 4 courses were MRD negative and therefore unlikely to benefit from post-HCT gilteritinib. These findings have implications for clinical practice. Increasing the number of courses of chemotherapy combined with FLT3 inhibition before HCT may lower MRD sufficiently to eliminate the need for post-HCT inhibition for some patients but, alternatively, the additional delay could increase the risk of pre-HCT relapse, preventing patients from receiving HCT in first remission.

Abstract Introduction Defining the epidemiology of myelodysplastic syndromes/neoplasms (MDS) and precursor conditions, such as clonal cytopenia of undetermined significance (CCUS), is challenging due to inconsistent reporting, complex diagnostics, and evolving criteria. The National MDS Natural History Study (NHS) overcomes these challenges through central pathology review, prospective follow-up, and a nationally representative cohort enrolled at the time of suspected MDS, enabling robust analysis across the myeloid disease spectrum. We analyzed clinical, genetic, and pathologic features in NHS participants by race, ethnicity, and sex to characterize disease variation across populations. Methods The NHS (NCT02775383) enrolled individuals undergoing evaluation for suspected MDS from June 2016–July 2024 at 102 US sites. Participants underwent bone marrow assessment with centralized, adjudicated histopathology review. Those meeting WHO 2016 criteria for MDS, MDS/myeloproliferative neoplasm (MPN), CCUS, idiopathic cytopenia/dysplasia of undetermined significance (ICUS/IDUS), or oligoblastic AML were followed longitudinally. Demographics, comorbidities, exposures, and clinical data were collected at baseline and every 6 months. Deep DNA sequencing was performed on baseline marrow, with pathogenic variants manually curated (53 genes). Statistical analyses assessed associations using chi-squared, Fisher's exact, Kruskal-Wallis, logistic regression, and Cox models. A p-value <0.05 was considered significant. Results Among 2,021 participants, 1,174 (58%) were diagnosed with MDS or precursor conditions. Median age was 74 years (yrs) and 66% were male. Most identified as Non-Hispanic White (NHW, 92%), with 4% Black and 4% Hispanic. The most common diagnoses were MDS (42%) and CCUS (37%). Pathogenic somatic mutations were identified in 84% (774/918) of MDS/CCUS, with TET2 (26% of 918), DNMT3A (21%), and ASXL1 (16%) most frequent. Median follow-up was 1.8yrs and consistent across race, ethnicity, and sex (p≥0.6). Black, compared to NHW, participants were younger (69 vs 74 yrs, p=0.006) and trended toward more females (47% vs 34%, p=0.09) and more MDS diagnoses (51% vs 41%, p=0.07). Black participants showed more advanced disease (e.g., lower hemoglobin, higher peripheral blood blasts, higher variant allele frequencies (VAFs) of pathogenic mutations), yet received less MDS-directed treatment (14% vs 41%, p=0.01). Black, compared to NHW, participants had more mutations in RUNX1, TP53, BCOR, and DNMT3A, but fewer in TET2 and ASXL1. Hispanic, compared to Non-Hispanic, participants had fewer known pathogenic mutations, leading to more ICUS (19% vs 5%, p=0.02). Females, compared to males, were younger at diagnosis (72 vs 75yrs, p<0.001), had more ICUS/IDUS (20% vs 10%, p<0.001), fewer pathogenic mutations, especially in splicing/chromatin modifier genes (U2AF1, SRSF2, ASXL1, ZRSR2), more DNMT3A mutations, and lower VAFs (0.27 vs 0.33, p<0.001). Median overall survival (OS) was 6.4yrs, and shorter in MDS (4.2yrs) than CCUS (not reached). Worse OS was associated with age (adjusted hazard ratio (aHR) 1.06), MDS (vs CCUS; aHR 1.89), higher-risk disease by IPSS-R/CCRS (aHR 2.15), and TP53 mutations (aHR 2.17) (all p<0.001). A trend toward improved OS in Black participants was attenuated after adjustment (aHR 0.79, p=0.6). Progression (e.g., worsening of disease, increase in transfusion dependency, death) occurred in 53% of participants. Worse progression-free survival (PFS) was associated with MDS diagnosis (aHR 2.59), higher-risk disease by IPSS-R/CCRS (aHR 2.17), and TP53 mutations (aHR 1.86) (all p<0.001). Despite more advanced disease and less MDS therapy, Black participants trended toward improved PFS (aHR 0.62, p=0.14), while age was borderline significant (aHR 1.01, p=0.05). Conclusions For the first time, we show that among individuals evaluated for suspected MDS at sites across the US, 58% had MDS or precursor conditions. Differences across demographics underscore the heterogeneity of MDS. Black participants presented with more advanced MDS, received less treatment, but trended toward improved outcomes, particularly PFS, even after adjustment, suggesting biological rather than access-to-care differences driving disparities. These findings highlight the complex interplay of sex, race, and genetics in shaping MDS outcomes and reinforce the need for diverse, large-scale studies to improve risk stratification and personalized care.

Abstract Introduction: Standardized reporting of clinical trials results for MDS is essential to improve clinical interpretation and cross-study comparison. However, reporting of patient characteristics, response criteria, and endpoints in publications is often inconsistent; there is no systemic analysis of MDS trial reporting available. We conducted a systematic review of published MDS trial manuscripts on behalf of the international consortium for MDS (icMDS) to assess variability in reporting practices. Methods We searched ClinicalTrials.gov to identify all clinical trials registered for adults (≥18 years) with MDS that reported results between 2015-2024. Clinical trials that included acute myeloid leukemia (AML) or MDS/myeloproliferative neoplasms (MPN) were included if they enrolled ≥5 MDS patients. We excluded trials without an MDS cohort; non-therapeutic trials; trials focused on transplant interventions; or those which enrolled solid malignancies or other hematologic malignancies (chronic myeloid leukemia or lymphoid diseases). Finally, trials were required to have a manuscript available on Larvol, PubMed, or Google Scholar. Trials were categorized by disease risk (lower-risk [LR] vs. higher-risk [HR]) and trial phase (early phase [EP] vs. late phase [LP]). Results We identified 502 MDS trials on ClinicalTrials.gov, of which 351 did not meet inclusion criteria and 79 lacked a manuscript. A total of 72 trials (32 EP, 40 LP) with 80 publications (34 EP, 46 LP) were analyzed. Frequently reported baseline characteristics included age (100% EP, 100% LP), disease risk (74% EP, 74% LP), Eastern Cooperative Oncology Group performance status (85% EP, 72% LP), prior treatments (71% EP, 67% LP), and RBC transfusion dependency (32% EP, 70% LP). Less frequently reported characteristics included blood counts (hemoglobin [Hb; 38% EP, 54% LP], platelet count [38% EP, 54% LP], neutrophil count [24% EP and LP]) and bone marrow blasts (29% EP, 43% LP). Although disease risk was widely reported, definitions varied: IPSS and IPSS-R were each reported in 54% of manuscripts, while IPSS-M appeared in only 3%. Cytogenetic risk was separately reported in 39% of manuscripts (38% EP, 39% LP), and mutational data in 45% (47% EP, 43% LP). Responses per IWG 2006 criteria were reported in 84% of manuscripts. The primary endpoint involved safety/tolerability in 85% of EP manuscripts, though definitions were variable; recommended phase 2 dose was the most common (26% of EP manuscripts). In LP trials, primary endpoints were risk-specific: transfusion independence (TI) in 77% of LR, overall response rate (ORR) in 28% of HR, and complete remission (CR) or overall survival (OS) in 22% of HR. In HR manuscripts, CR was reported in 100%, ORR in 73%, hematologic improvement (HI) in 48%, RBC-TI in 23%, and OS in 80%. However, seven different definitions were used for ORR: CR + marrow CR + partial remission + HI per IWG 2006 was most common (35%). Event-free survival was reported in 25%; progression-free survival and relapse-free survival in 13%; and leukemia-free survival in 5%. Early mortality rate was reported in 35% (18% EP, 56% LP) and transplant rate in 58% (50% EP, 67% LP). Only 47% of HR and 90% of LR manuscripts identified HI-eligible patients. In LR-MDS, RBC-TI was reported in 72% of manuscripts but used six definitions. The most common were RBC-TI ≥8 weeks at any time during treatment (24%), ≥8 weeks within 28 weeks of treatment (13%), ≥8 weeks with Hb increase ≥1.0 (4%), ≥12 weeks with Hb increase ≥1.5 (4%), and ≥16 weeks within 24 weeks of treatment (12%). The remainder did not report RBC-TI, did not define it, or used a custom definition not used in another trial. HI was reported in 80% of LR papers with most of those reporting HI using IWG 2006 criteria (90%). Conclusion Reporting of baseline characteristics, response criteria, and outcomes is inconsistent in MDS clinical trials, with wide variability in response definitions, including ORR and TI. This heterogeneity limits interpretability, hampers historical comparisons and may obscure efficacy signals. Our findings highlight the need for standardized reporting guidelines to ensure clarity and consistency in MDS trial publications. As a next phase of this effort, we will conduct a formal Delphi process among icMDS experts to establish consensus recommendations for minimal and optimal MDS clinical trial reporting in manuscripts by disease risk (LR/HR) and trial phase (EP/LP).

Abstract Background: Mutations in ethanolamine kinase-1 (ETNK1) have been identified in a wide range of myeloid neoplasms (MN), but their clinical significance remains poorly defined. Key gaps remain, including the true prevalence, variant- and disease-specific co-mutation patterns, cytogenetic patterns, and prognostic impact, highlighting the need for broader multi-institutional studies to refine our understanding and risk stratification. We present findings from an ongoing multi-institutional study of ETNK1-mutated (ETNK1mut) MN. Methods We analyzed 106 patients with ETNK1mut MN across the Mayo Clinic Comprehensive Cancer Center (Minnesota, Arizona, and Florida), H. Lee Moffitt Cancer Center (Tampa, FL), Massachusetts General Hospital (Boston, MA), and University of Milano-Bicocca (Monza, Italy), integrating clinical, hematologic, cytogenetic, and next-generation sequencing (NGS) data. Appropriate IRB approval was obtained. Diagnoses were assigned by the 5th edition of the World Health Organization and 2022 European LeukemiaNet criteria. A clone was considered dominant if it had the highest variant allele frequency (VAF) or VAF within 5% of the highest co-mutation. Overall survival (OS) was assessed by Kaplan-Meier. Comparison cohorts for OS included 83 ETNK1 wild-type (ETNK1wt) myelodysplastic syndrome (MDS) and 415 ETNK1wt acute myeloid leukemia (AML) patients without TP53 mutations. GraphPad Prism v10 was used for statistical analysis. Results Median age at diagnosis was 70 years (range 30.4-90), with a male predominance of 72.6% (n=77). ETNK1mut were identified in MDS (n=47, 44.3%), myelodysplastic/myeloproliferative neoplasms (MDS/MPN; n=23, 21.7%), myeloproliferative neoplasms (MPN; n=13, 12.3%), AML (n=12, 11.3%), clonal cytopenia of undetermined significance (CCUS; n=5, 4.7%), and other entities (n=6, 5.7%) including atypical chronic myeloid leukemia (n=1) and systemic mastocytosis (n=1). Over a median follow-up of 33.6 months (IQR 15-91.8), 49.1% (n=52) patients died and 19.4% (n=18 of 93 at risk) progressed to AML. Cytogenetics were available in 103 patients; 57.3% (n=59) had a normal karyotype, while 30.1% (n=31) had abnormal and 12.6% (n=13) had complex karyotypes. None harbored classical MDS-associated deletions such as del(5q), del(7q), or del(20q). The most frequent cytogenetic abnormalities included translocations (n=17), monosomy 7 (n=9), and trisomy 8 (n=8). Of 17 translocations, 8 (47%) involved chromosome 1, two of which (11.8%) involved der(1;7)(q10;p10). The most common ETNK1 mutation was N244S (n=70, 66.0%), followed by K378N (n=12, 11.3%) and G245 variants (n=9, 8.5%), including G245V and G245D. VAF data were available for 103 patients; the median ETNK1 VAF was 31.4% (range 2.0-54.8%). High VAF (≥40%) was observed in 27.2% (n=28) of patients. ETNK1 was the dominant mutation in 33% (n=34) of cases, shared equal dominance with a co-mutation in 13% (n=14), and was a subclone in 56% (n=58). Co-mutations were detected in 77% (n=82) of patients, with a median of 4 (range 0-13) co-mutated genes. A third of patients (n=37, 35%) had ≥5 co-mutations. The most frequently co-mutated genes were epigenetic regulators including ASXL1 (n=29, 27%), TET2 (n=17, 16%), EZH2 (n=12, 11%), and DNMT3A (n=12, 11%), followed by splicing factor genes including U2AF1 (n=13, 12%), SRSF2 (n=10, 9%), and ZRSR2 (n=10, 9%). Mutations in signaling genes (JAK2, NRAS, SETBP1) and transcription factors (RUNX1, BCOR) were also observed. High VAFs were seen in co-mutations of EZH2 (median 49%), TET2 (46%), and NRAS (46%). ASXL1 was most enriched in MDS/MPN (n=8, 35%) and MPN (n=3, 23%). Survival analysis showed better survival in ETNK1mut compared to ETNK1wt within AML (65 vs 19 months; p=0.2002) and MDS (107 vs 61 months; p=0.1993), although statistical significance was not reached. Conclusion ETNK1 mut frequently co-occur with mutations in epigenetic and splicing regulators, and demonstrate distinct molecular and cytogenetic features, including the absence of classic MDS-associated deletions and a high prevalence of translocations involving chromosome 1. ETNK1 was the dominant clone in a third of cases with a high co-mutation burden. Overall survival was better in ETNK1mut AML and MDS, but the difference was not statistically significant. These findings highlight the need for larger collaborative studies.