Treatment options for patients with immunoglobulin light chain (AL) amyloidosis and advanced cardiac involvement remain limited. The prospective, phase 2 EMN22 trial included previously untreated patients with AL amyloidosis, measurable hematologic disease, and Mayo2004/European cardiac stage IIIB to receive daratumumab monotherapy at the standard dose and schedule for up to two years (28-day cycles); patients with inadequate response after three cycles could additionally receive bortezomib weekly and dexamethasone. The primary endpoint was 6-month overall survival (OS) rate. Of 40 enrolled patients, ten (25.0%) received additional treatment with bortezomib and dexamethasone. The 6-month OS rate was 65.0% (95% CI, 48.2-77.6) and median OS was 10.4 months. The best hematologic response rate (partial response or better) up to six months was 75.0% (very good partial response or better: 47.5%; complete response: 12.5%), the median time to the first and best hematologic response being one week and 2.3 months, respectively. The cardiac response rate at six months was 30.0%. Common serious adverse events were cardiac failure (25.0%), sudden cardiac death (10.0%), and acute kidney injury (7.5%). The patients' quality of life remained stable throughout the trial treatment and observation. In patients with high-risk, advanced (stage IIIB) AL amyloidosis, daratumumab monotherapy was feasible and well-tolerated, achieving rapid hematologic responses and associated with prolonged survival relative to historical cohorts. Cardiac response rates at 6 months were significant, considering the advanced cardiac disease. These findings support daratumumab as the backbone of anti-clonal therapy in advanced cardiac AL amyloidosis. This trial was registered at www.clinicaltrials.gov as #NCT04131309.

Targeting ACKR3/CXCR7 regulates enzymatic generation of pro-thrombotic, while favoring anti-thrombotic lipids that inhibit platelets through AC-cAMP-PKA pathway in coordination with prostacyclin-IP receptor. This investigation validated the impact of CXCR7 in modulating non-enzymatic lipid (per)oxidation, platelet response to lipoproteins-(LDL, oxLDL), mitochondrial metabolism and procoagulatory functions. Pharmacological CXCR7-agonist-(VUF11207) preserved mitochondrial membrane integrity-(Δψm), counteracted activation-induced mitochondrial superoxide generation-(MitoSOXRed), and nonenzymatic lipid (per)oxidation. Additionally, CXCR7-agonist regulated lipoprotein-induced platelet adhesion on thrombogenic matrices, degranulation, αIIbβIII-integrin activation, aggregation and thrombotic response, by reducing lipoprotein uptake through scavenger receptors-(CD36, ApoER2). CXCR7-ligation triggered activation of metabolic energy sensor Adenosine MonoPhosphate-dependent Kinase-(AMPKSer-172), prompted AMPK-mediated inhibitory phosphorylation of Acetyl-CoA-Carboxylase-(ACC)Ser-79, to foster lipolysis over lipogenesis. Consequently AMPKSer-172-ACCSer-79 pathway increased anticoagulatory FXa-inhibitory long-chain acylcarnitine-(LC-CARs)-(16:0, 18:1, 18:2) generation in platelets from healthy subjects and CAD patients. Increased intraplatelet LC-CARs was not due to dysregulated mitochondrial respiration; since CXCR7-agonist improved maximal respiration, spare respiratory capacity, and ATP-linked respiration in thrombin-activated platelets, suggesting sustained mitochondrial metabolism. Exerting a two-pronged effect on procoagulant function, CXCR7-agonist downregulated phosphatidylserine exposure on activated platelets, reducing FX/FXa binding, while platelet-derived anticoagulatory-LC-CARs regulated thrombin generation. CXCR7-agonist administration reduced thrombus formation, platelet degranulation, αIIbβIII-integrin activation, procoagulant activity, circulatory platelet-leukocyte aggregates in murine venous thrombosis model; besides, decreased plasma procoagulant lipids-(platelet COX-1, 12-LOX, and leukocyte 5/15-LOX-derived) and thrombo-inflammatory mediators-(IL-1β, IL-6, IFN-γ, TNF-α, MCP-1), and increased plasma LC-CAR levels. Therefore, pharmacological targeting of CXCR7 could regulate (non)enzymatic lipid processing, and promote anticoagulatory LC-CAR generation to check platelet-directed thrombotic propensity, and hypercoagulation, moreover, replenish reduced levels of circulatory anticoagulant-LC-CARs in STEMI and venous thromboembolism-(VTE) patients.

Fas-associated phosphatase-1 (FAP-1), a nonreceptor protein tyrosine phosphatase, has been implicated in multiple signaling pathways, but its in vivo role remains unclear. Here, we show that FAP-1-deficient (FAP-1ΔP/ΔP) mice develop early megakaryocyte hyperplasia with defective platelet function and occasional hemorrhagic manifestations, accompanied by myelofibrosis-like features in aged animals. Bone marrow analysis revealed impaired demarcation membrane system (DMS) development with pre-DMS arrest in megakaryocytes, leading to defective proplatelet formation and impaired platelet function, with prolonged bleeding partly associated with reduced clot retraction. Mechanistically, FAP-1 deficiency induces sustained Src activation and cofilin inactivation, impairing perinuclear actin remodeling required for DMS expansion and resulting in pre-DMS arrest. With aging, approximately half of mice develop a symptomatic phenotype characterized by extramedullary hematopoiesis, hepatosplenomegaly, anemia, and thrombocytopenia; among these, most remain in a prefibrotic state, while a subset progresses to fibrosis-like changes. Bone marrow transplantation demonstrates that megakaryocyte abnormalities and fibrosis-associated changes are hematopoietic cell-intrinsic and partially transferable. Pharmacologic inhibition of Src with dasatinib attenuates these defects in FAP-1-deficient mice, supporting pathway specificity. In patients with primary myelofibrosis, reduced FAP-1 expression is associated with pre-DMS megakaryocyte accumulation, abnormal DMS and actin organization, and Src activation, supporting clinical relevance. Collectively, we identify a FAP-1-dependent mechanism governing Src-cofilin-mediated actin remodeling required for megakaryocyte maturation and platelet function, and suggest this pathway as a potential therapeutic target for platelet dysfunction, hemorrhagic complications, and fibrosis-associated disease.

Anbalcabtagene autoleucel (Anbal-cel) is a CD19-directed CAR T-cell therapy incorporating dual PD-1 and TIGIT knockdown to enhance antitumor function and durability. We report the results of a Phase 1/2 study in patients with relapsed or refractory large B-cell lymphoma (LBCL). In Phase 2, 79 patients received Anbal-cel, and efficacy was evaluated in 73 patients. The complete response (CR) and partial response (PR) rates were 67.1% and 8.2%, respectively. Median progression-free survival (PFS) was 6.04 months (95% CI, 4.34-16.46), and the 6-, 12-, and 18-month PFS rates were 50.9%, 41.1%, and 35.2%, respectively. Median overall survival (OS) was not reached, with 12- and 18-month OS rates of 66.6% and 57.3%. CAR T-cell expansion was significantly greater in responders than in non-responders (median Cmax: 20,403 vs. 8,580 copies/μg). Patients were categorized into long-term response (LR) group or non-LR group based on sustained CR at 6 months. Reduced PD-1 and TIGIT expression on CAR-positive T cells was observed in LR group. Most patients (97.5%) experienced grade ≥3 adverse events, most commonly neutropenia (93.7%), followed by thrombocytopenia (41.8%) and anemia (30.4%). Cytokine release syndrome and neurologic events occurred in 57.0% and 13.9% of patients, respectively. Grade 3 CRS occurred in 8.9% of patients, with no grade 4 events reported, and grade ≥3 neurologic events occurred in 3.8%. Serious infections occurred in 25.3% of patients, and grade 5 infection was reported in 3 patients. This trial was registered at Clinicaltrials.gov (NCT04836507).

Idecabtagene vicleucel (ide-cel) induces deep responses in relapsed/refractory multiple myeloma (RRMM), yet more than half of patients relapse within one year. The intrinsic features of CAR-T products that distinguish durable from non-durable responders are poorly defined, particularly at single-cell resolution, and defining drivers of durable response is critical to guide patient counseling and to inform strategies for optimizing CAR-T manufacturing and efficacy. To address this need, 40 ide-cel infusion products (184,398 cells) were profiled using single-cell RNA sequencing. These analyses revealed that a transcriptional program in CD4 CAR-T cells that led to durable responses is characterized by NF-κB signaling, pro-survival circuits, tonic/chemokine signaling, and elevated CAR transgene expression. These features were associated with prolonged progression-free and overall survival irrespective of baseline clinical characteristics. Further, analysis of paired apheresis and tumor microenvironment samples showed that elevated NF-κB activity is an intrinsic hallmark of T-cell fitness that is characterized by a central memory phenotype and the lack of checkpoint receptorligand expression, and that these features were manifest in marrow-derived and peripheral blood T cells prior to CAR-T manufacturing. Finally, validating functional relevance, pharmacologic inhibition of NF-κB abrogated CAR-T cytotoxicity and cytokine production in vitro. Our results support that NFKB in the ide-cel product marks a signaling axis impacting CAR-T function and NFKB activity represents a global marker of T cell fitness present prior to CAR-T manufacture.

Pharmacological plasminogen reduction enhanced liver regeneration experimentally and clinically. siRNA-induced plasminogen deficiency promoted hepatocyte proliferation after partial hepatectomy in mice, contrasting genetic deficiency models. In the HeLiX trial, tranexamic acid reduced post-hepatectomy liver failure odds, suggesting a novel therapeutic strategy.

Thrombosis is a major contributor to global morbidity and mortality. Current standards of care target the extrinsic and/or common pathways of coagulation, effectively inhibiting thrombosis but also increasing bleeding risk, highlighting the unmet need for additional treatment options. Genetic deficiency in factor XI (FXI), a component of the intrinsic pathway, reduces thrombosis risk without spontaneous bleeding. We generated 2 FXI monoclonal antibodies (mAbs) with distinct profiles to provide new approaches to anticoagulation. Cenvacibart (REGN7508Cat) targets the catalytic domain to completely block FXI activity (induced by FXIIa or FXIa in the intrinsic pathway or thrombin in an intrinsic/common pathway amplification loop), thereby maximizing anticoagulation; amrecibart (REGN9933A2) targets the apple 2 domain of FXI/FXIa to specifically prevent FXI activity induced by FXIIa-delivering perhaps less anticoagulation but with potentially lower bleeding risk. We evaluated the anticoagulant effects of both mAbs in vitro in human/non-human primate plasma, in vivo in non-human primates, and healthy volunteers. Both mAbs inhibited intrinsic pathway-triggered coagulation, assessed by activated partial thromboplastin time (aPTT); cenvacibart exhibited a greater increase in aPTT versus amrecibart or other FXI-targeted inhibitors. Neither amrecibart nor cenvacibart affected the extrinsic pathway, assessed by prothrombin time (PT). In non-human primates, both mAbs prevented thrombosis without increasing bleeding. In first-in-human studies, both mAbs were generally well tolerated and dose-dependently inhibited intrinsic pathway-triggered coagulation, with durable aPTT prolongation without affecting PT. Amrecibart and cenvacibart may offer tailored therapies for patients with different bleeding risk profiles. The trials are registered at www.clinicaltrials.gov as #NCT05102136 and #NCT05603195.

Host-versus-graft reaction (HvGR) is a major challenge in allogeneic chimeric antigen receptor (CAR) T cell therapy. To counter host natural killer (NK) cell attacks, we armored allogeneic, human leukocyte antigen (HLA)-I deficient, B-cell maturation antigen (BCMA)-targeting CAR T cells with an NKG2A CAR. In vitro and animal studies demonstrated that allogeneic CAR-NKG2A T cells effectively resisted host NK cell-mediated killing. BCMA and NKG2A dual-targeting allogeneic CAR T cells (CT0590) resisted killing by NK cells and showed robust antitumor activity in preclinical in vivo models. On the basis of these data, a first-in-human study (NCT05066022) enrolled five patients (four with relapsed and refractory multiple myeloma [RRMM] and one with primary plasma cell leukemia [pPCL]). CT0590 was well-tolerated and caused no dose-limiting toxicities, treatment-related death, or graft-versus-host disease. Three patients achieved confirmed responses, including two with stringent complete response (sCR). Notably, sCR in the patient with RRMM was still ongoing (duration of response > 23 months) at the time of data cutoff, and sCR in the patient with pPCL lasted for 20 months. Both patients showed robust expansion of universal CAR (uCAR) T cells (Cmax > 280,000 copies/µg gDNA) and higher baseline NKG2A expression on NK cells than nonresponders. These results suggest that CAR-NKG2A technology may overcome HvGR, especially in patients with elevated NKG2A expression on NK cells. Further studies of CT0590 in RRMM and pPCL are warranted.

NPM1-mutated acute myeloid leukemia (AML) is genetically well-defined, but clinical outcomes remain heterogeneous, suggesting that quantitative clonal features may refine current risk stratification. We analyzed 688 intensively treated NPM1-mutated AML integrating variant allele frequency (VAF), mutation order, and clonal architecture inferred by PyClone and ClonEvol. Co-mutations were present in 97% of patients (median = 3 per case), dominated by DNMT3A (49%), FLT3-ITD (46%), TET2 (22%), and IDH2 (20%). Prognostic modelling of NPM1 VAF identified an optimal cut-off of 31.44%, defining NPM1high and NPM1low groups. NPM1low correlated with splicing-related alterations and independently predicted inferior overall (HR = 1.46; p = 0.037) and relapse-free survival (HR = 1.40; p = 0.036). Gene-specific VAF analyses revealed divergent effects across partners, high DNMT3A, FLT3-OTHER, KRAS, and PTPN11 burdens were adverse, whereas high IDH2 VAF was protective. Combined models showed that patients with NPM1high and favorable co-mutation VAFs had the best outcomes, while dual unfavorable burdens conferred the poorest survival. Mutation ordering inferred from VAFs positioned NPM1 after epigenetic and splicing lesions but before signaling and transcription-factor mutations. Non-canonical orders, such as early FLT3-OTHER/TKD or WT1 prior to NPM1, significantly stratified outcomes. Clonal reconstruction revealed predominantly linear evolutionary trajectories (84.3%), with increased mutational burden and clonal diversity associating with inferior survival. Notably, intra-clonal co-localization of NPM1 with IDH1 or TET2 was associated with improved outcomes, whereas co-localization with WT1 predicted dismal prognosis. These results demonstrate that quantitative and structural dimensions of clonality refine the biological and prognostic landscape of NPM1-mutated AML beyond mutational status alone.

N7-methylguanosine (m7G), a prevalent modification in tRNAs, is primarily catalyzed by the methyltransferase METTL1. While growing evidence supports a role for METTL1 in various tumors, its therapeutic potential and precise function in leukemia stem cell (LSC) homeostasis remain largely unexplored. Here, we identify METTL1 as a key regulator of LSC self-renewal and homing within bone marrow (BM) microenvironment through catalyzing m7G formation on a specific tRNA, tRNAPheGAA, thereby driving leukemogenesis. Mechanistically, METTL1 loss significantly reduces m7G abundance and steady-state levels of tRNAPheGAA, leading to translation suppression and degradation of transcripts enriched with tRNAPheGAA-related codons, such as tyrosine-protein kinase HCK. Decreased HCK expression disrupts CXCR4 signaling, impairing LSC self-renewal and BM homing. Therapeutically, we characterize a small-molecule METTL1 inhibitor (M1i; NSC137443), through high throughput screening. Pharmacological inhibition of METTL1 demonstrates potent anti-tumor efficacy by reduction of tRNA m7G levels and disrupting the tRNAPheGAA/HCK/CXCR4 cascade. Notably, targeting METTL1 significantly reduces LSC frequency, delays leukemogenesis, and prolongs survival in multiple acute myeloid leukemia models. Our findings establish a previously unrecognized role for METTL1 and its target tRNAPheGAA in LSC homeostasis and provide compelling proof-of-concept evidence that METTL1 is a druggable epitranscriptomic target for anti-leukemia therapy.

Drug resistance is a major challenge in cancer therapy, especially in hematologic malignancies where kinase inhibitors have transformed treatment yet are frequently undermined by drug resistance. While targeted protein degradation (TPD) offers a mechanistically distinct mode of action compared to inhibition-based therapeutic therapies, the potential value of TPD in drug-resistant blood cancer remains unclear. Here, we report the discovery of cereblon-recruiting molecular glue degraders (MGDs) targeting LCK, an oncogenic kinase in T-cell acute lymphoblastic leukemia (T-ALL). By high-throughput screening and medicinal chemistry optimization, we developed a series of MGDs that induced CRBN-dependent degradation of LCK as well as potent cytotoxicity in T-ALL in vitro. Structure-activity relationship analysis and ternary complex modeling revealed a non-canonical degron at the LCK-CRBN interface involving the G-loop, whose mutation disrupts this interaction. Unlike inhibitors and inhibitor-based PROTACs, these MGDs engage LCK in regions distal to the ATP binding site and thus their activities in T-ALL are not affected by gate-keeper LCK mutations that drive resistance to inhibitor-based therapeutics. Taken together, our data highlights the potential of LCK-targeting MGDs as a strategy to overcome kinase inhibitor resistance in T-ALL, offering a framework for targeting kinase dependencies in drug-refractory hematologic malignancies more broadly.

Chimeric antigen receptor (CAR) T cells specific for myeloid-associated antigens expressed on the cell surface of acute myeloid leukemia (AML) can cause depletion of normal myeloid progenitor cells. We developed a CAR specific for a human Leucocyte Histocompatibility Antigen (HLA)-A*02:01-restricted peptide of the myeloid-restricted cathepsin-G protein. Cathepsin-G-specific CAR (CG1.CAR) T cells were further engineered to increase their functional avidity. Specifically, we developed CG1.CAR-T cells co-expressing the lymphocyte-specific protein tyrosine kinase (LCK) and duplicated CD3ζ chain, which allows the functional recognition of the CG1 peptide as low as 0.025 mM. Optimized CG1.CAR T cells displayed antileukemia effects in vitro and in vivo in AML patient-derived-xenotransplant (PDX) mouse models and did not cause hematopoietic toxicity in colony assays and humanized mice. Mechanistically, LCK overexpression in CG1.CAR-T cells caused transcriptional modifications characterized by the overexpression of mitochondrial-encoded electron transport chain components that were correlated with increased mitochondrial mass and improved respiratory capacity. Based on these data, CG1.CAR-T cells hold clinical potential for the treatment of AML.

Multiple Myeloma (MM), the second most prevalent hematologic malignancy, remains incurable, highlighting the need to identify molecular drivers of disease progression and new therapies. Using a CRISPR-Cas9 library screening approach in MM cells, we identified 22 essential transcription factors (TFs), including members of the interferon regulatory factor (IRF) family. Remarkably, in addition to the well-known IRF4, IRF2 emerged as a critical TF in MM. Cut&Run experiments demonstrated that IRF2 binds extensively to chromatin, both independently and in cooperation with IRF1 and IRF4. While IRF2-unique regions were predominantly associated with active promoters, regions bound by IRF2/1/4 were biased towards introns. Functionally, IRF2 contributes to MM cell survival by suppressing necroptosis and promoting cell migration. Notably, IRF2-dependent transcriptional dysregulation was evident in precursor conditions such as MGUS and SMM, suggesting a role in early disease evolution. In addition to its role as early factor, IRF2 levels also seem to influence disease progression, as MMs with higher expression showed worse progression-free survival (PFS) and overall survival (OS) in both univariate and multivariate analyses, even after adjusting for common MM genetic risk factors. In conclusion, IRF2 constitutes an underappreciated essential TF involved in the pathogenesis and clinical behavior of MM. Its inhibition leads to dysregulation of key signaling pathways in MM pathogenesis, highlighting its potential as a therapeutic target.

Polyploidization resulted from massive DNA synthesis is crucial for megakaryocyte maturation, while the regulatory mechanisms of cell fitness upon this special cellular process remain poorly understood. Here, we reveal that glutamine synthetase (GLUL) facilitates thrombocytopoiesis by restricting ammonia accumulation during polyploidization. GLUL is found to be distinctly expressed in platelet-producing megakaryocytes and increasingly elevated with the progression of polyploidization, and GLUL deficiency impairs megakaryocyte maturation and platelet production. Mechanistically, GLUL detoxifies ammonia derived from adenosine deaminase acting on RNA 1 (ADAR1)-mediated double-stranded RNA (dsRNA) editing in megakaryocytes undergoing polyploidization. Ammonia accumulation is observed in megakaryocytes defective in GLUL, leading to lysosomal and mitochondrial damage and even cell death. Fulvotomentoside A (FtA) is identified as a potential GLUL agonist with the capacity to promote thrombocytopoiesis in mice after radiation and chemotherapy injury. Our findings uncover the biological significance of GLUL in megakaryocyte maturation and provide a new avenue for regulating thrombocytopoiesis.

FLT3-ITD measurable residual disease (MRD) testing for patients in remission from acute myeloid leukemia (AML) is now recommended by the recently updated clinical standard of care guidelines. This companion technical note provides important laboratory and clinical recommendations regarding such testing.

We present 5-year survival results in patients with R/R LBCL from TRANSCEND NHL 001 (TRANSCEND), including data from the separate long-term follow-up (LTFU) study. Overall, 345 patients were leukapheresed, 270 received liso-cel, and 257 were efficacy evaluable. Among efficacy-evaluable patients, median overall survival (OS) was 27.5 months (95% confidence interval [CI], 16.2‒47.3; leukapheresed set, 15.2 months [95% CI, 11.5‒23.4]) with estimated 5-year OS rate of 38% (95% CI, 32‒45; leukapheresed set, 33% [95% CI, 28‒39]). Median disease-specific survival (DSS; excludes deaths unrelated to disease progression) was 67.8 months (95% CI, 23.5‒not reached [NR]; leukapheresed set, 27.4 months [95% CI, 14.4‒69.7]) with estimated 5-year DSS rate of 52% (95% CI, 45‒59; leukapheresed set, 47% [95% CI, 41‒52]). Among efficacy-evaluable patients from TRANSCEND who were alive at end-of-study and enrolled in the LTFU (n=84), median OS and DSS were NR (95% CI, NR‒NR) and estimated 5-year OS and DSS rates were 78% (95% CI, 67‒86) and 92% (95% CI, 84‒97), respectively. Most deaths occurred ≤2 years after infusion; no new safety signals were observed with low rates of late severe infections and second primary malignancies. These data support the curative potential of liso-cel in patients with R/R LBCL. Clinicaltrials.gov: NCT02631044, NCT03435796.

Deletion of 17p is among the most adverse cytogenetic abnormalities in multiple myeloma (MM). By integrating RNA-seq data from patient MM cells with genetic dependency data from MM cell lines, we identified the protein kinase membrane-associated tyrosine/threonine 1 (PKMYT1) kinase, a member of the Wee family, as a potential therapeutic target in MM cells harboring del(17p). Genetic suppression or pharmacological inhibition of PKMYT1 activity with the selective inhibitor RP-6306 triggered accumulation of DNA damage, micronucleus formation and mitotic catastrophe, resulting in preferential cell death in del(17p) MM cells while largely sparing del(17p)-negative MM cells and healthy cells. RP-6306 also reduced tumor burden and extended survival in vivo in both xenograft and TP53-deficient syngeneic models. Collectively, our findings nominate PKMYT1 as an actionable target and support PKMYT1 inhibition as a biomarker-driven therapeutic strategy for patients with del(17p)/TP53-deficient MM.

Histidine-rich glycoprotein (HRG) is a 75-kDa plasma protein produced by the liver and circulating at about 2 µM, with an additional pool in platelets that is released upon activation. Previously, we demonstrated that HRG downregulates the contact system by binding polyanions and reducing their capacity to activate factor (F) XII. Although HRG localizes on the platelet surface, its role in platelet biology remains uncertain. Accordingly, we investigated whether HRG directly engages platelet receptors to regulate adhesion and aggregation. Using human and murine platelets, we show that HRG (a) binds to glycoprotein (GP)Ibα on resting and activated platelets and to GPIIb/IIIa on activated platelets, (b) competes with von Willebrand factor (VWF) for binding to GPIbα on resting platelets and with fibrinogen for binding to GPIIb/IIIa on activated platelets, and (c) attenuates platelet agglutination, aggregation, and platelet-mediated thrombus growth. Furthermore, in an endothelial-platelet flow system or a collagen-coated microperfusion chamber, HRG reduced VWF-mediated platelet string formation and attenuated platelet deposition under high-shear conditions. Plasma HRG levels in patients with sepsis or COVID-19 were about half those of healthy controls, and reducing HRG to these levels in vitro promoted a hyperreactive platelet phenotype. Therefore, HRG not only modulates coagulation but also platelet adhesion and aggregation by competing with VWF and fibrinogen for binding to GPIbα and GPIIb/IIIa.

Sickle cell disease (SCD) is characterized by chronic hemolysis, painful vaso-occlusive episodes (VOE) and end organ damage. High levels of fetal hemoglobin (HbF) attenuate the disease phenotype. We used a lentivirus vector (LVV) expressing an shRNA embedded in a microRNA (shmiR) targeting BCL11A in erythrocytes to induce HbF in a first-in-human pilot study in SCD. The purpose of the study was to assess hematopoietic stem/progenitor cells (HSPCs) collection, transduction parameters, safety, HbF induction and durability. Eleven eligible patients with SCD had HSC collection. Plerixafor-mobilized peripheral blood HSCs required for manufacturing were obtained in one mobilization cycle for 10/11 subjects and 11/11 patient products were successfully manufactured with a median time to release of product of 39 days. Ten patients were infused with autologous HSCs transduced with the shmiR vector. Engraftment occurred in all 10 patients. With a median follow-up of 58 months (range: 35-82) after infusion, no adverse events attributed to the gene vector have occurred. Transduction efficiency was 93.1%. One patient demonstrated low engraftment of transduced cells and had suboptimal HbF induction. In the remaining 9 patients, at 2 years post-treatment peripheral blood demonstrated 71% F cells with 11.9 pg HbF/F cells, both stable in 9 patients with ≥48 months follow-up. All patients who had VOEs prior to gene therapy demonstrated sustained mitigation of pain events. These data demonstrate excellent manufacturing efficiency and safety, with efficacy of targeting BCL11A using a shmiR LVV, and long-term durability of the shmiR vector, leading to a pivotal multi-site phase 2 trial currently underway (NCT05353647).

Patients with relapsed/refractory multiple myeloma (RRMM) have limited treatment options. Arlocabtagene autoleucel (arlo-cel, BMS-986393) is an autologous chimeric antigen receptor (CAR) T-cell therapy targeting G protein-coupled receptor class C group 5 member D (GPRC5D). This phase 1, dose-escalation/expansion study (NCT04674813) enrolled adult patients with RRMM and ≥3 prior antimyeloma treatment regimens, including an immunomodulatory drug (IMiD), a proteasome inhibitor, and an anti-CD38 antibody. At baseline, patients (N=84) had a median of 5 prior regimens and 49% had previously received BCMA-targeted therapy, of whom 38% received CAR T-cell therapy. Arlo-cel was administered as a one-time intravenous infusion of 25×106-450×106 CAR T cells. Primary endpoints were safety and maximum tolerated dose (MTD); secondary endpoints included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Data cutoff was 23August2024. Cytokine release syndrome (CRS) occurred in 82% of patients, immune effector cell-associated neurotoxicity syndrome in 10%, and other select neurotoxicities in 12%; most were grade 1/2 and frequency appeared dose-dependent. One death occurred from CRS at highest dose level. On-target/off-tumor skin (30%), nail (19%), and oral (32%) adverse events were transient, grade 1/2; most resolved without intervention. MTD was not reached. With median follow-up of 16.1 months, ORR=87% (complete response rate=53%), median duration of response=18.0 months, and median PFS=18.3 months (95% CI, 11.8-21.9) (n=79). The 1-year OS rate was 90% (N=84). In conclusion, arlo-cel had a safety profile supportive of future study and demonstrated deep and durable responses, with promising PFS and OS in patients with heavily pretreated RRMM.