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342 citation(s) found for "Luo, Yi".

Abstract 4283: CD3-positive allogeneic CAR T-cells: A novel platform with persistence, BiTE-capture, and no alloreactivity
Hundal, Tanya , Luo, Yan, Qie, Yaqing, Guo, Siqi , Kharfan-Dabaja, M., Qin, Hong, Gadd, Martha E. , Kharfan‐Dabaja, Mohamed A. , Qin, Hong

Cancer Research | April 3, 2026 | Volume: 86 | Issue: 7_Supplement | Pages: 4283-4283

10.1158/1538-7445.am2026-4283 Get It

Abstract Several allogeneic CAR T-cell therapies are in clinical trials to evaluate safety, many of which rely on CRISPR/Cas-based genome editing. However, the Cas enzyme’s random repair mechanism elevates the risk of undesired, off-target effects, posing a challenge for safe allogeneic CAR T-cell generation. To mitigate the risk of therapy-related oncogenesis, we sought to pursue an alternative safe strategy to manufacture allogeneic CAR T-cells distinct from the preexisting ones in the clinic. We have developed a CRISPR RNA (crRNA) targeting T-cell receptor beta constant (TRBC) gene, which in conjunction with AsCas12a Ultra enzyme, causes site-specific editing by eliciting a predictable microhomology-mediated end joining (MMEJ) DNA repair pathway, which mitigates off-targeting risk. Targeted amplicon sequencing was employed to evaluate off-targeting and repair mechanisms. Graft versus host alloreactivity as well as CAR T persistence was evaluated using immunocompromised mice. In vivo tumor challenge study was conducted for over 3 months. Engraftment confirmation was done using immunohistochemistry and flow cytometry. Interestingly while evaluating the edited T-cells, we sequestered a unique T-cell population that showed TCR disruption yet remained CD3-positive and did not cause in vivo alloreactivity. These CD3-Retained, Allogeneically Functioning T-cells (CRAFT-cells) showed a similar growth rate as unedited T-cells and were then used as a platform to produce CD19-targeted CAR T-cells and BAFF-R-targeted CAR T-cells. When compared to the standard CD3-disrupted allogeneic CAR T-cells, CRAFT CAR T-cells displayed an equally robust cytotoxicity while possessing a safer genomic profile. CRAFT CAR T-cells could function as effector cells for bispecific T-cell engager (BiTE) and induce CD3-dependent cytotoxicity against tumor cells. Pertinently, CRAFT CAR T-cells as opposed to CD3-disrupted CAR T-cells, were present in mouse xenografts without alloreactivity. Having the onset of MMEJ-directed repair and minimal off-targeting, positions this CRAFT crRNA to generate safer allogeneic CAR T-cells with an overall reduced genotoxic profile in a clinical setting. This unique CRAFT CAR T-cell population displays in vivo persistence. Additionally, CRAFT CAR T can be combined with BiTE therapy, offering a promising and potentially more durable alternative to preexisting ex vivo allogeneic CAR T-cell therapies. Citation Format: Tanya Hundal, Yan Luo, Yaqing Qie, Martha E. Gadd, Shaohua Guo, Mohamed A. Kharfan-Dabaja, Hong Qin. CD3-positive allogeneic CAR T-cells: A novel platform with persistence, BiTE-capture, and no alloreactivity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 4283.
Abstract 539: Cholesterol triggers chromatin stress to drive senescence and inflammation.
Han, Yiqun, Ouyang, Yaobin, Xu, Hangcheng, Chen, Bin, Yin, Ping , Zhou, Qin , Huang, Jinzhou , Luo, Kuntian, Wu, Zheming , Xiao, Huaping, Tu, Xinyi , Jing, Jiajun, Huang, Xiaofeng, Welliver, M.X., Lou, Zhenkun, Mutter, Robert, Ouyang, Yaobin , Zhu, Shouhai , Xu, Hangcheng , Yin, Ping, Huang, Jinzhou, Kloeber, Jake A. , Lou, Zhenkun , Mutter, Robert W.

Cancer Research | April 3, 2026 | Volume: 86 | Issue: 7_Supplement | Pages: 539-539

10.1158/1538-7445.am2026-539 Get It

Abstract Cholesterol has long been viewed as a structural component of cellular membranes, yet its role in DNA damage response remains poorly defined. Here, we show that ionizing radiation (IR) induces broad transcriptional upregulation of cholesterol biosynthesis, transport, and storage pathways, leading to sustained intracellular accumulation of cholesterol. BODIPY-cholesterol imaging, Filipin III staining, and quantitative subcellular fractionation confirmed selective nuclear enrichment of cholesterol following IR, coinciding with extensive chromatin remodeling. Proteomic profiling of cholesterol-interacting proteins revealed a strong enrichment of chromatin-associated factors, suggesting a previously unrecognized lipid-chromatin interface in irradiated cells. Functionally, cholesterol accumulation promoted chromatin compaction and repressive histone modification patterns, impairing DNA damage sensing and checkpoint activation despite increased underlying DNA lesions. These alterations facilitated aberrant mitotic entry, formation of cytoplasmic chromatin fragments (CCFs), and activation of cGAS-STING-NF-κB signaling. Cholesterol exposure ultimately diverted damaged cells toward a senescent fate, marked by Lamin B1 loss, p21 induction, and a robust senescence-associated secretory phenotype (SASP) enriched for IL-1 and TNF family cytokines. In vivo, dietary cholesterol exacerbated radiation-induced inflammation and weakened systemic anti-tumor immunity. Transcriptomic analyses of immunotherapy-treated patients revealed that tumors enriched for cholesterol import and senescence signatures were associated with poor response to PD-L1 blockade and worse survival. Together, these findings identify a cholesterol-chromatin-senescence axis that links metabolic remodeling to defective DNA damage signaling and immune suppression after radiation, highlighting cholesterol metabolism as a potential therapeutic vulnerability in cancer therapy. Citation Format: Yiqun Han, Yaobin Ouyang, Shouhai Zhu, Hangcheng Xu, Bin Chen, Ping Yin, Qin Zhou, Jinzhou Huang, Kuntian Luo, Zheming Wu, Huaping Xiao, Xinyi Tu, Jake A. Kloeber, Jiajun Jing, Xiaofeng Huang, Meng Xu Welliver, Zhenkun Lou, Robert Mutter. Cholesterol triggers chromatin stress to drive senescence and inflammation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 539.
NT-I7, a Long-Acting Interleukin 7, Increases Lymphocyte Counts and Induces CD8+ T-cell Clonotype Expansion in Patients with Newly Diagnosed High-Grade Gliomas
Butt, Omar H. , Singhal, Kartik , Luo, Jingqin , Rettig, Michael P. , Foltz, Jennifer A. , Huang, Jiayi , Zhou, Alice Y. , Tao, Yu , Griffith, Obi L., Griffith, Malachi, Johanns, Tanner M. , Ansstas, George , Zhang, Chaocai , Tang, Justin , Christ, Stephanie , Ferrando-Martinez, Sara , Lee, Byung Ha , Chheda, Milan G., Fehniger, Todd A. , Campian, Jian L., Griffith, Malachi , Griffith, Obi L. , Huang, Jiayi , Griffith, Obi L , Griffith, Malachi , DiPersio, John F , Chheda, Milan G , Fehniger, Todd A , Campian, Jian L , Luo, Jingqin , Ansstas, George , DiPersio, John F. , Chheda, Milan G. , Campian, Jian

Clinical Cancer Research | March 25, 2026 | Volume: 32 | Issue: 13 | Pages: 2581-2592

10.1158/1078-0432.ccr-25-2953 | PMID 41880597 Get It

Abstract Purpose: Standard care for high-grade gliomas (HGG) involves maximal surgical resection followed by radiation and temozolomide. Postoperative adjuvant therapy frequently causes lymphopenia, which is associated with poor prognosis. Interleukin 7 (IL7) is essential for lymphocyte development, homeostasis, and survival. NT-I7 (efineptakin alfa), a long-acting recombinant IL7, reverses lymphopenia and improves survival in murine glioma models. However, the safety, maximum tolerated dose (MTD), and impact of NT-I7 on immune cells in patients with HGG remain unknown. Patients and Methods: We conducted a phase I trial (NCT03687957) examining the MTD and effect of NT-I7 on lymphocytes in patients with newly diagnosed HGG. The primary endpoint was dose-limiting toxicity; secondary endpoints included absolute lymphocyte count (ALC) changes over time, overall response, progression-free survival, and overall survival. Exploratory endpoints included immune profiling at different time points using single-cell RNA sequencing (scRNA-seq) in a subset of patients. Results: NT-I7 was well tolerated with a MTD of 720 µg/kg. Moreover, NT-I7 significantly increased ALCs for more than 12 weeks in duration. Early elevations in CD4+, CD8+ T cells and NK cells further coincided with increased TNF and CXCL9 cytokine levels. Comprehensive immune profiling of peripheral blood T cells revealed selective clonotype expansion within CD8+, but not CD4+, T cells following NT-I7 administration. Finally, a subset of our patients with MGMT promoter–unmethylated glioblastoma, which are typically associated with a poorer prognosis, demonstrated promising clinical responses. Conclusions: NT-I7 has the potential to maintain and increase lymphocyte counts in patients with HGG and warrants further investigation, particularly in combination with immune-based therapies.
Angle-Free Ultrasound-assisted Technique for Difficult Lumbar Puncture to Enhance Precision and Success in Complex Spinal Anatomy: A Case Series with Longitudinal Learning Curve Analysis
Wang, Xuan, Luo, Yijun , Huang, Chanyan, Lu, Xiaolin , Diedrich, Daniel A. , Xiao, Ying , Wang, Xuan, Zhang, Xiaolong, Huang, Chanyan , Xiao, Ying

No container title available | March 20, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.21203/rs.3.rs-8901033/v1 Get It

Abstract Background Lumbar puncture is a routinely performed procedure, yet it presents significant challenges in patients with abnormal spinal anatomy, such as severe scoliosis or obesity. Conventional ultrasound-assisted neuraxial techniques, while superior to landmark-based methods, are constrained by two fundamental limitations: inaccurate projection of the probe’s geometric center onto the skin when the probe is tilted or rocked, and the difficulty of consistently replicating the exact probe angle during needle insertion. These limitations contribute to multiple needle passes, prolonged procedure time, and increased patient discomfort and complication risk. To address these issues, we developed a novel angle-free ultrasound-assisted technique designed to eliminate the need for replicating probe angulation during needle insertion. Case presentation: This angle-free approach was utilized for serial lumbar punctures in two patients with spinal muscular atrophy requiring repeated intrathecal nusinersen administration. Both patients presented with extreme anatomical complexity, including high body mass index (30 and 35.1 kg/m²) and severe scoliosis (Cobb angles 90° and 83°). The technique follows a three-step protocol: (1) Preprocedural imaging to select the optimal interlaminar space; (2) Ultrasound-guided postural adjustment until the probe could be held perpendicular to the bed edge and parallel to the floor while maintaining target visualization; (3) Needle insertion along this orthogonal trajectory. All 22 procedures (11 per patient) were completed successfully without persistent neurological complications. Procedural outcomes demonstrated a first-attempt success rate of 81.8% (Case 1) and 100% (Case 2), with first-pass success rates of 45.5% and 54.5%, respectively. Longitudinal analysis across sequential procedures revealed a consistent reduction in both the number of needle passes and needling time, reflecting a favorable learning curve. Conclusions The angle-free ultrasound-assisted neuraxial technique offers a valuable alternative for patients with complex spinal anatomy. By using real-time postural adjustments to achieve a needle trajectory, it enhances procedural precision and eliminates the technical hurdle of replicating probe angulation. The structured "4P" framework (Planning, Positioning, Perpendicular, Parallel) offers a practical guide for clinical adoption. The observed learning curve suggests that clinicians can readily acquire and apply this technique to manage such challenging cases.
Integrative screening identifies functional variants and VNTRs underlying GWAS signals at the 5p15.33 multi-cancer susceptibility locus
O’Brien, Aidan , Kong, Hyunkyung, Patel, Harsh , Ho, Michelle , Patel, Minal, Zhong, Jun , Xu, Mai, Papenberg, Brenen W. , Connelly, Katelyn E. , Collins, Irene , Hennessey, Rebecca C. , Thakur, Rohit , Sowards, Hayley , Funderburk, Karen, Luong, Thong Minh, Florez-Vargas, Oscar , Myers, Timothy , Jermusyk, Ashley , Gorman, Bryan, Das, Sudipto, (PanScan/PanC4), The Pancreatic Cancer Cohort and Case-Control Consortia, Lan, Qing, Rothman, Nathaniel , McKay, James , Hung, R., Iles, Mark M. , Landi, Maria Teresa , Stolzenberg-Solomon, Rachael Z, Wolpin, Brian M. , Hassan, Manal M. , Antwi, Samuel O. , Lindström, Sara , Stern, Marc-Henri, Andrésson, Þorkell , Shi, Jianxin , Choi, Jiyeon, Brown, Kevin M, Rabe, Kari G. , Patel, Minal B , Hennessey, Rebecca , Luong, Thong , Jones, Kristine , Das, Sudipto , McKay, James , Hung, Rayjean J , Amos, Christopher I , Iles, Mark M , Koutros, Stella , Landi, Maria T , Law, Matthew H , Hassan, Manal M , Klein, Alison P , Orr, Nick , Chanock, Stephen Jacob , Lindstrom, Sara , Hoskins, Jason W , Shi, Jianxin , Prokunina-Olsson, Ludmila , Choi, Jiyeon , Brown, Kevin M , Amundadottir, Laufey , Chaffee, Kari G. , Antwi, Samuel O , Zhong, Jun , Luo, Wen , Lan, Qing , Rothman, Nathaniel , Amos, Christopher I. , Koutros, Stella , Law, Matthew H. , Stolzenberg‐Solomon, Rachael Z. , Klein, Alison P. , Orr, Nick , Hoskins, Jason W. , Stern, Marc‐Henri , Choi, Jiyeon , Ámundadóttir, Laufey T.

No container title available | March 5, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.64898/2026.03.03.26347427 | PMID 41867231 Get It

Abstract Chromosome 5p15.33 harbors several independent association signals which demonstrate antagonistic pleiotropy across cancer types, with causal mechanisms largely unresolved. To identify functional variants and enhancer elements at this locus, we performed statistical fine-mapping followed by massively parallel reporter assays (MPRA) and proliferation based CRISPRi screens. This approach identified eight multi-cancer functional variants (MCFVs) across three GWAS signals. Targeting rs421629 (part of the CLPTM1L signal marked by rs465498) with CRISPRi revealed opposing effects on TERT expression in pancreatic versus lung cancer cells, consistent with the antagonistic pleiotropy observed for this signal. Furthermore, CRISPRi nominated an intronic CLPTM1L variable number tandem repeat (VNTR) as a potent enhancer. Long-read sequencing established VNTR polymorphisms as potential causal variants for the rs465498 signal. We showed that Hippo-pathway transcription factors mediate VNTR enhancer activity in lung and pancreatic cancer cells. Together, these findings indicate that cancer susceptibility at 5p15.33 may be mediated by both SNPs and VNTRs and provide an integrated framework for resolving complex pleiotropic loci.
Integrated Single-Cell Profiling Reveals Dichotomous NK Cell Populations Associated with Immunosuppression in Solid Tumors
Ali, Atef , Luo, Christine, Plagens, Rosemary N. , Zhang, Bin, Elliott, A., Boytim, Ella, Zorko, Nicholas, Heath, Elisabeth I. , Patnaik, Akash, VanderWalde, A., Antonarakis, Emmanuel S., Miller, Jeffrey S., Hwang, Justin H., Cichocki, Frank, Hwang, Justin H. , Patnaik, Akash , Elliott, Andrew , Zorko, Nicholas A. , Lozada, John R , Ali, Atef , Luo, Christine , Plagens, Rosemary N , Zhang, Bin , Elliott, Andrew , Boytim, Ella , Zorko, Nicholas A , Heath, Elisabeth I , Patnaik, Akash , VanderWalde, Ari , Antonarakis, Emmanuel S , Miller, Jeffrey S , Hwang, Justin H , Cichocki, Frank , Vanderwalde, Ari M. , Antonarakis, Emmanuel S. , Miller, Jeffrey S.

Cancer Immunology Research | February 27, 2026 | Volume: 14 | Issue: 6 | Pages: 1008-1021

10.1158/2326-6066.cir-25-1229 | PMID 41758966 Get It

Abstract Natural killer (NK) cells represent key effectors of antitumor immunity, yet emerging evidence highlights populations with distinct roles in cancer. Despite such expanded diversity within the NK cell repertoire, we lack an understanding of how this heterogeneity affects immune responses and downstream clinical outcomes. Using single-cell RNA sequencing, we systematically profiled NK cells across cancer and uncovered a dichotomous phenotypic and functional landscape of tumor-infiltrating NK cells shaped by opposing intrinsic signaling programs that drive the expression of IFNG or TGFB1. These divergent programs are associated with distinct transcription factor circuits that integrate cues within the tumor microenvironment and skew NK cells toward proinflammatory or suppressive functions. We found that the capacity for NK cells to engage in either functional direction is intrinsically linked to their phenotypic identity. Canonical NK cells recruited from circulation predominantly directed suppressive TGFB1 signals toward effector CD8+ T cells in tumors. Of note, these subsets exhibited higher TGFB1 expression than intratumoral myeloid cells across tumor types. In contrast, a tissue-resident (TR) adaptive subset exhibited exclusively proinflammatory IFNG-driven profiles and was associated with prolonged survival in both primary and metastatic tumor settings. Moreover, these TR adaptive NK cells, but not other subsets, were linked to response to immune checkpoint blockade. Collectively, our study reveals a previously unrecognized regulatory axis in NK cells that shapes NK cell diversity and augments broader antitumor immune responses.
Deep Learning Based on the Facial Color Images for Assisted Diagnosis of Chronic Renal Failure with Spleen–Kidney Qi Deficiency Syndrome
Yang, Luo , Tong, Tong , Lu, Yu , Wang, Wei, Wei, Changyun, Wang, R. , Ouyang, Yulin, Moossavi, Maryam , Liu, Hong-Xia, Ma, Xueling

World Journal of Traditional Chinese Medicine | February 24, 2026 | Volume: No volume available | Issue: No issue available | Pages: No page available

10.4103/wjtcm.wjtcm_74_25 Get It

Abstract Objective: This study aimed to develop a machine learning model for the diagnosis of chronic renal failure (CRF) with spleen–kidney qi deficiency (SKQD) syndrome by investigating facial chromatic biomarkers based on traditional Chinese medicine (TCM) theory. Materials and Methods: This cross-sectional study analyzed TCM-defined facial regions in 303 patients with CRF (166 SKQD and 137 non-SKQD) and 25 healthy controls using active appearance models and RGB/Lab color spaces. Key chromatic features were selected using Chi-square automatic interaction detection (CHAID) decision trees to construct a multibranch deep convolutional neural network (CNN), nomogram, and hybrid model. The model performances were compared using the DeLong test. Results: The SKQD group showed a higher glomerular filtration rate, albumin level, and facial R-value with a lower serum creatinine level (all P < 0.05), accompanied by a higher prevalence of shortness of breath with reluctance to speak, and cold extremities ( P < 0.05) compared with the non-SKQD group. Chromatic analysis revealed elevated R/a values in the kidney region using the natural facial color region method ( P < 0.05), and distinctively higher R -values in the bladder-uterus region and a -values in the right small intestine region using the Mingtang facial color region method ( P < 0.05). The CHAID algorithm selected four diagnostic determinants, including the overall facial R -values. The CNN achieved superior discriminative performance (test area under the receiver operating characteristic curve = 0.74 vs. nomogram 0.68, DeLong test P < 0.001) with no added benefit from model integration ( P > 0.05). Conclusions: Facial chromatic biomarkers effectively differentiated SKQD in patients with CRF when analyzed using TCM-defined regions. The superior performance of the CNN validates AI-driven TCM diagnostics as a clinically actionable tool for precise syndrome classification.
The Association Between the C-Reactive Protein-Albumin-Lymphocyte Index and Gallstone Disease: A Cross-Sectional Study
Liu, Xingxing , Li, Kang , Zeng, Yonghua , Ying, X.N. , Zhao, Yu , Zhou, Xiaodong , Chen, Youxiang , Zeng, Chunyan , Zhu, Liang , Luo, Yixing , Chen, Youxiang , Ying, Xiaolong

Clinical and Translational Gastroenterology | January 26, 2026 | Volume: 17 | Issue: 3 | Pages: e00979

10.14309/ctg.0000000000000979 | PMID 41586504 Get It

INTRODUCTION: This study used the novel C-reactive protein-albumin-lymphocyte (CALLY) index to explore its relationship with the risk of developing gallstones. METHODS: This study conducted a cross-sectional analysis of the National Health and Nutrition Examination Survey data from 2017 to 2020; multivariable logistic regression examined the CALLY-gallstone association. Restricted cubic splines tested nonlinearity. Subgroup and mediation analyses explored population variations and mediating effects (Conicity, lipid accumulation product, and a body shape index). Receiver operating characteristic curves compared CALLY, systemic immune inflammation index, systemic inflammatory response index, and aggregate index of systemic inflammation predictive performance. RESULTS: After comprehensive adjustments, the highest CALLY quartile had significantly lower gallstone risk vs the lowest (odds ratio 0.56, 95% confidence interval 0.34–0.94). Restricted cubic splines revealed a linear inverse correlation. Subgroup analyses generally supported this inverse relationship. Mediation analysis identified the Conicity index as the strongest mediator (21.47%, P < 0.001), followed by lipid accumulation product and a body shape index (10.72% each, P < 0.001). Receiver operating characteristic analysis showed CALLY (area under the curve = 0.604) outperformed systemic immune inflammation index (0.540), systemic inflammatory response index (0.550), and aggregate index of systemic inflammation (0.546). DISCUSSION: A significant inverse association exists between the CALLY index and gallstone prevalence. The CALLY index demonstrates superior predictive ability compared with other indices, suggesting its potential utility as an objective biomarker for early gallstone risk identification.
Multiscale Segmentation-Guided Diffusion Model for CBCT-to-CT Synthesis
Guo, Yike, Luo, Yi , Hooshangnejad, Hamed , Zhang, Rui , Feng, Xue , Chen, Quan , Ngwa, Wilfred , Ding, Kai , Chen, Quan , Feng, Xue , Ding, Kai , Guo, Yike

Life | December 8, 2025 | Volume: 15 | Issue: 12 | Pages: 1871

10.3390/life15121871 | PMID 41465810 Get It

To improve synthetic CT (sCT) generation from cone-beam CT (CBCT) in radiotherapy, we propose a multiscale segmentation-guided diffusion framework. The proposed model integrates anatomical priors across multiple spatial resolutions through a segmentation mask pyramid and introduces a scale-specific loss function to guide learning at each level. When evaluated on the SynthRAD2023 brain dataset, our model achieves a mean absolute error (MAE) of 61.82 HU, a peak signal-to-noise ratio (PSNR) of 32.05 dB, and a structural similarity index (SSIM) of 0.90, outperforming baseline models. These results suggest that multiscale anatomical guidance can improve the fidelity and anatomical consistency of sCT images, thus facilitating high-quality CBCT-to-CT translation in radiotherapy applications.
Ultra-sensitive detection of clonal m-protein by mass spectrometry enhances detection of residual disease: Results from A phase 1 study of etentamig monotherapy in patients with relapsed or refractory multiple myeloma
Ahsan, Aarif, Luo, Adam , Valdes, Cesar Rodriguez , Voorhees, Peter M. , Safah, Hana, McKay, John, Korde, Neha , Vij, Ravi, Kumar, Shaji , Doerr, Thomas, Pothacamury, Rajvineeth Kumar, Chyla, Brenda , D’Souza, Anita , Chung, Alfred , Tuchman, Sascha Alexander , Weisel, Katja C , Teipel, Raphael , Talati, Chetasi , Ross, Jeremy A.

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 5813-5813

10.1182/blood-2025-5813 Get It

Abstract Background: Clonotypic peptide detection by mass spectrometry (MS) leverages monoclonal protein (M-protein) de novo sequencing and peptide quantification to enable ultra-sensitive blood-based monitoring of multiple myeloma (MM) patient M-protein kinetics. Etentamig is a 2nd generation BCMA x CD3 bispecific antibody that has shown promising efficacy and a favorable safety profile in heavily pre-treated patients with relapsed or refractory (RR) MM (Journal of Clinical Oncology, 43;16:suppl.7527). In the current study, we explored the depth and kinetics of MS M-protein response to etentamig monotherapy in serum samples from Phase 1 M22-466 (NCT03933735) study patients. The correlation between blood-based MS M-protein levels and bone marrow minimal residual disease (MRD) negativity as determined by next generation sequencing (NGS) was also evaluated. Method: Clonotypic peptide MS using M-Insight (Sebia/Corgenix) was performed on serum samples from a subset of MRD evaluable patients enrolled into the Phase 1 (NCT03933735) clinical trial of etentamig monotherapy in patients with RRMM. Bone marrow MRD negativity (&lt;10-5 and 10-6) analysis was determined by NGS (clonoSEQ, Adaptive Biotechnologies). Patient pre-treatment (Cycle [C] 1 Day [D] 1) serum samples were digested with proteolytic enzymes to permit sequencing of the M-protein heavy and light chain. Clonotypic peptides specific to the patient's complementarity-determining regions were selected for quantification by MS. Clonotypic peptide quantification by MS was performed on available tracking peripheral blood samples at C2D1, C3D1, C4D1, and C5D1 time points post etentamig monotherapy treatment. Results: Twenty patients who were MRD evaluable and treated with 40 mg and 60 mg doses of etentamig with available serum samples collected from C1D1–C5D1 time points were selected for M-Insight evaluation. Of the 20 patients, 16 (80%) had at least one clonotypic peptide identified prior to etentamig treatment that was utilized for tracking at subsequent time points. Rapid decline in MS M-protein levels was observed in patients treated with etentamig, which strongly correlated with the patients' best International Myeloma Working Group (IMWG) response. At C3D1 post etentamig treatment, patients with complete response (CR)/stringent CR (n=9) demonstrated a significant decline from MS M-protein levels (median: 1.8±0.9 g/dL at C1D1 to 0.03±0.2 g/dL at C3D1) (P&lt;0.001). All evaluable subjects (n=16) had detectable MS M-protein at all time points (n=80). The lowest detectable M-protein level observed in the current dataset was 44 mg/dL (lower limit of quantitation of assay: 10 mg/dL). Subsequent analysis of differences in kinetics between MRD-negative (&lt;10-5) (n=8) and MRD-positive (n=8) patients revealed a deeper reduction in M-protein levels for MRD-negative patients (median 0.02±0.2 g/dL at C3D1 compared with 0.4±0.3 g/dL at C3D1 for MRD-positive patients). Among the 8 patients who achieved MRD negativity at 10-5 threshold, 5 patients also achieved &lt;10-6 threshold, and serum MS M-protein levels remained detectable in these patients (0.07±0.2 g/dL). Conclusions: Using MS-based clonotypic peptide detection, rapid and deep decline in serum M-protein levels was observed in RRMM patients treated with etentamig. Strong concordance was observed between MS M-protein levels and IMWG response, including in patients achieving MRD-negative CR at &lt;10-5 and 10-6thresholds. Non-invasive and ultra-sensitive M-protein detection is feasible in MM and may serve as a key biomarker for enhancing the detection of residual disease in the future.