Shao, Zuoyi

Abstract Background: Hepatocellular carcinoma (HCC) is largely refractory to immune checkpoint blockade due to immune exclusion, stromal barriers, and aberrant vasculature. We evaluated whether multimodal therapy - external beam radiotherapy (EBRT) for antigen release, intratumoral dendritic cell (DC) vaccination for antigen presentation, PD-L1 blockade for immune activation, and VEGF inhibition for vascular normalization - could convert “cold” HCC tumors into sustained immune-inflamed states. Methods: Serial biopsies (baseline, post-EBRT, end-of-treatment [EOT], and progression [PD] when available) from three patients enrolled in an ongoing phase II trial (NCT03942328) underwent multiplex immunofluorescence, spatial neighborhood analysis, and transcriptomic profiling. Longitudinal changes in cellular composition, immune-stromal architecture, spatial contact networks, and pathway activity were compared. Results: Baseline tumor microenvironments (TMEs) were strongly immune-excluded, dominated by tumor (PanCK+60-70%) and stroma (SMA+/Vimentin+25-30%) with sparse immune infiltration (<10-15%). Post-therapy, immune complexity and spatial connectivity increased 2-3-fold in all patients. Patient 1 showed robust cold-to-hot conversion with CD8+(3x), CD4+(2.2x), and DC (2.3x) expansion, increased CD8-DC interactions (2.5x), and reduced tumor fraction (-40%). Transcriptomics showed marked upregulation of IFN-γ (↑3.4x), HLA-DRA (↑2.7x), and reductions in VEGFR2 (↓50%) and HIF1A (↓40%), consistent with vascular normalization. Patient 2 exhibited stromal/vascular remodeling and improved T-cell infiltration but restricted immune diversity, with CD4+/CD8+ dyads (↑2.2x) and B/NK cells(↓ 60%). Neighborhood diversity rose (3→7 communities) and immune-tumor proximity improved (distance ↓ 35%). Patient 3 showed transient inflaming with CD8+(↑3x), DC(↑2x), and new CD4-CD20/CD4-CD56 interactions, followed by relapse marked by stromal/myeloid re-expansion (SMA+↑1.8x, CD14+↑2.5x), angiogenic resurgence (VEGFR2/CD34+↑2.2x), contraction of immune networks, and genomic shift from activating CTNNB1 mutation loss to ATM gain. DCs accumulated but localized mainly to DC-DC or DC-myeloid niches, indicating non-productive antigen presentation. Conclusions: Multimodal EBRT+DC+PD-L1/VEGF blockade induces four-sided synergistic TME reprogramming - antigen release, immune priming, checkpoint release, and vascular normalization - promoting cold-to-hot conversion in HCC. Durable inflaming correlates with sustained T-cell/DC expansion and vascular remodeling, whereas relapse reflects stromal/myeloid reinforcement and genomic adaptation. These findings define mechanistic trajectories of TME remodeling and highlight actionable barriers to sustained immunotherapy response in HCC. Citation Format: Lionel Aurelien Kankeu Fonkoua, Christopher L. Hallemeier, Basim Salem, Arina Tkachuk, Kaitlynn McCay, Panwen Wang, Ying Li, Thomas D. Atwell, Krishan R. Jethwa, Caitlin Conboy, Nguyen H. Tran, Leslie A. Washburn, Melody Wu, Chen Wu, Andre De Menezes Silva Corraes, Rondell P. Graham, Jose Caetano Villasboas, Kevin Regan, Zuoyi Shao, Rayaan Kamal, Nathan R. Foster, Haidong Dong, Sean Park, Yi Lin, Lewis R. Roberts. Multimodal immunotherapy remodels the tumor microenvironment in hepatocellular carcinoma: Integrative spatial and transcriptomic profiling from a Phase II trial [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 7935.

Abstract Background: Cellular immunotherapy has transformed cancer treatment, but success in solid tumors remains limited by long manufacturing times, high costs, and the need for viral vectors that permanently modify DNA. To address this, we examined electroporation (EP) and mechanoporation (MP) approach to transfect T cells with mRNA to enable the development of a bedside immune cell editing platform. NKG7, natural killer cell granule-7, was previously demonstrated to play key function in activating T-cell cytotoxicity function. mRNA transfection of T cells with NKG-7 can increase these cells’ anti-tumor cell killing. We examine EP and MP methods for NKG7 transfection in primary peripheral blood mononuclear cells (PBMCs) from healthy donors. Method: Synthetic Clean Cap mRNAs encoding NKG7 or NKG7 with membrane-bound cRNA IL-2 were introduced into PBMCs by electroporation (MaxCyte) or mechanoporation (Portal Bio). T cell expression of NKG7 and IL-2 were analyzed by CytoFlex flow and Kaluza. Result: The yield at EP and MP were comparable at 0.615+/-0.09% and 0.597+/-0.16%, respectively. Viability were high at above 80% for 3 days after EP and MP. NKG7 and NKG7+cIL-2 mRNA transfection led to different NKG7 expression kinetics in T-cells and between EP and MP. With EP, CD4 T-cells showed an increase in NKG7 expressions with the highest MFI ratio (NKG7 MFI/ IgG MFI) compared to mock EP at Day 1 for the NKG7 -only EP (1.25 ± 0.38) and at Day 2 for NKG7+cIL-2 EP (1.20 ± 0.27). CD8+ T cells displayed a similar trend, with peak NKG7 expression at Day 1 for NKG7 EP (1.22 ± 0.76) and Day 2 for NKG7+cIL-2 EP (1.21 ± 0.90). However, MP did not enhance NKG7 expression in CD4+ T cells. NKG7 expression peaked at Day 1 for both NKG7 (1.28 ± 0.42) and NKG7 + cIL-2 (1.24 ± 0.20). IL2 expression peaked at Day 1 for both EP and MP: EP, CD4+ T (91.5% ± 4.4), CD8+ T (92.7% ± 12.8); MP, CD4+ T (88.9% ± 31.7), CD8+ T (84.7% ± 9.6). Functional assays for anti-tumor cell killing of these transfected cells are currently ongoing. Conclusions: We report that EP of PBMC can transfect all cell populations. MP may yield comparable yield, viability and NKG7 expression in CD8 T cells compared to EP, but without the need to isolate CD8 T cells from PBMC. EP and MP method can be used for bedside immune cell transfection depending on the target and cell populations of interest. Citation Format: Chen Wu, Christoph Schaefers, Malvika Gupta, Kevin Regan, Zuoyi Shao, Andre De Menezes Silva Corraes, Virginia Van Keulen, Jacob Hirdler, Tobias Peikert, Timothy D. Wiltshire, Haidong Dong, Yi Lin. A non-viral mRNA engineering platform for rapid, same-day immune-cell therapies [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 5198.

Abstract Background: Patients (pts) with myeloma (MM) receiving CAR-T therapy have usually been exposed to many prior therapies. Melphalan (HDM) and other chemotherapies can induce cellular senescence. It has recently been shown that MM cells can also exhibit features of therapy-induced senescence (TIS). TIS tumor cells are associated with resistance to therapy and relapse. To investigate the presence of TIS MM cells prior to CAR-T and association with response, we examined the transcriptome and phenotype of MM prior to CAR-T. Method: We used scRNA-seq data from bone marrow (BM) MM cells: Boiarsky, et al. (GSE193531, dbGaP: phs001323.v3.p1) newly diagnosed MM (NDMM) pts; Dhodapkar, et al. (GSE210079), pre- and post CAR-T; pts who received CAR-T at Mayo Clinic, pre- (N=10) and post- (N=2). To evaluate TIS, single-cell gene set enrichment analysis (scGSEA) for several gene sets (PMID: 40164720): SenUp (Senescence Upregulated), SenGA (Senescence Growth Arrest), and SCAPs (Senescent Cell Anti-apoptosis Pathways); and a Plasma Cell Senescence (PCSen) gene set (GSE5900, GSE47552). To assess TIS and myeloid phenotype, BM MM cells (CD138+) were stained for CD14, CD16, KLRG1 and GPNMB and analyzed by CytoFlex and Kaluza. Results: In the integrated dataset, scGSEA showed significantly higher enrichment of PCSen, SenUp, SenGA, and SCAPs in late-stage MM cells (both pre- and post-CAR-T) compared to NDMM and healthy donors (p<0.05, Kruskal-Wallis with Dunn’s posttest). Conversely, the Normal gene set was significantly enriched in healthy plasma cells relative to MM (p<0.05). Expression of CDKN2A, which encodes the senescence marker p16, was also increased in late-stage MM relative to NDMM or healthy plasma cells. Notably, in our newly generated scRNA-seq samples collected within 6 months before CAR-T, a significant inverse correlation between senescence marker expression and progression free survival (PFS) post-CAR-T was seen, suggesting that MM cells exhibiting TIS may be more resistant to T cell mediated cytotoxicity. We found that 62.5% (25/40) of pts had >1% MM cells that were CD14+. Among them, the median CD14+ MM cells were 5.5% (1-71%); and median CD14+CD16+ MM cells were 2.14% (0.4-67%). Among 7 pts with available samples for KLRG1 and GPNMB assessment, 100% (7/7) had KLRG+ MM cells (median: 59% (24-99%)) and 57% (4/7) had GPNMB+ MM cells (median: 15% (3.9-30%)), and KLRG1+GPNMB+ MM cells (median: 9.6% (3.8-17%)). Conclusion: Our study shows that late-line MM cells exhibit transcriptional and phenotype profiles consistent with TIS. This senescent phenotype may contribute to resistance to immunotherapies, including CAR-T. Additional phenotype data is collected and will be presented. A phase II clinical trial is ongoing (NCT06940297) to assess for the combined treatment with senolytic drugs dasatinib and quercetin peri-CART to deepen clinical response. Citation Format: Sofia Arbelaez, Andre De Menezes Silva Corraes, Gabriel Alvares Borges, Chen Wu, Christoph Schaefers, Malvika Gupta, Zuoyi Shao, Kevin Regan, Rayaan Kamal, Angelo Jose Guilatco, Neal I. Sannuli, Ying Li, Taxiarchis Kourelis, Wilson Gonsalves, Moritz Binder, Melinda Tan, Nadine Abdallah, Megan Weivoda, Yi Lin. Myeloma cells with therapy-induced senescence-like phenotype are associated with resistance to CAR-T therapy [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 6467.

Abstract Background: Therapy-induced senescence (TIS), a tumor cell state associated with distinct gene expression patterns and implicated in therapy resistance, may be activated in Multiple Myeloma (MM) patients (pt) by genotoxic chemotherapies, such as high-dose melphalan (HDM). We investigated whether TIS is activated in MM cells following chemotherapy and linked to resistance to T-cell directed therapies. Method: We integrated scRNA-seq data from healthy donors (CNTRL) and MM pts (newly-diagnosed (NDMM), pre/post-CAR-T) bone marrow plasma cells (PCs) using two public datasets (Boiarsky, et al.; Dhodapkar, et al.) and a newly generated pt dataset. Senescence was evaluated using scGSEA with published gene sets (SenUp, SenGA, and SCAPs). For in vitro MM cytotoxicity assay, human H929 MM cells were treated with vehicle (Veh) or HDM (3µM, IC90) for 6h and examined for TIS features. H929VEH or H929HDM were co-cultured with CNTRL T cells with or without teclistamab (Tec, 10 nM) or with day 14 PBMCs from MM pts post-CAR-T (E:T 5:1). CAR+ T cells were high among the day 14 PBMC (median±SD: 93.4±7.2% of CD3+ cells, n=6). Results: scGSEA revealed significantly higher enrichment of SenUp, SenGA, and SCAPs in late-stage MM cells compared to NDMM and CNTRL (p<0.05). Expression of CDKN2A, encoding the senescence marker p16, was also increased in late-stage MM relative to NDMM/CNTRL PCs. Of interest, cells enriched for senescence also exhibited enrichment for myeloid markers (TET2, CEBP family). Notably, in pre-CAR-T, increased baseline senescence or myeloid marker expression showed an inverse association with CAR-T progression-free survival (PFS), suggesting TIS confers resistance to T cell mediated cytotoxicity. This may be due to myeloid plasticity. TIS MM cells generated in vitro, H929HDM, exhibited a distinct morphology characterized by increased cell size and enhanced cytoplasmic granularity. Increased CD14 expression was seen in 4 of the 6 experiments (median, range % increase: 11.2%, 2.5%-21%), consistent with myeloid plasticity; Increased KLRG1 expression was seen in 5 of the 7 experiments (median MFI ratio, range: 3.7, 1.3-471). No significant change was seen in GPNMB expression. Compared to H929VEH, H929HDM had a reduction in killing by CAR-T cells (median±SD: 22.8±32.94% n=6, p=0.016, Wilcoxon paired test). Similarly, H929HDM had a 10.69% decrease in Tec-mediated T-cell killing compared to H929VEH (n=8, p=0.02, Wilcoxon paired test). Conclusions: Late-stage MM cells exhibit transcriptional signatures consistent with TIS, which can be associated with decreased PFS to CAR-T. We report an in vitro model of TIS MM cells for testing of resistance to T cell killing. Based on these findings, a phase II trial (NCT06940297) is underway to test the hypothesis that peri-CAR-T senolytic therapy with dasatinib and quercetin will deepen responses by targeting this resistant TIS MM population. Citation Format: Christoph Schaefers, Angelo Jose Guilatco, Sofia Arbelaez, Gabriel Alvares Borges, Chen Wu, Andre de Menezes Silva Corraes, Malvika Gupta, Zuoyi Shao, Kevin Regan, Rayaan Kamal, Neal I. Sannuli, Ying Li, Taxiarchis Kourelis, Wilson Gonsalves, Melinda Tan, Nadine Abdallah, Yi Lin, Megan Weivoda. Myeloma cells with therapy-induced senescence-like phenotype have increased resistance to killing by T cell directed therapies [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 6475.

Abstract Introduction: Liver cancer remains a leading cause of cancer mortality globally with limited treatment options for patients (pts) with unresectable hepatocellular carcinoma [HCC] and intrahepatic cholangiocarcinoma [iCCA][1,2,3,4]. We hypothesize that combining the intratumoral dendritic cell (DC) vaccination after external beam radiotherapy (EBRT) without (phase I) and with (phase II) systemic atezolizumab and bevacizumab (atezo/bev for HCC) would enhance tumor-specific immunity and improve clinical outcomes, and present preliminary results from our phase I/II trial (NCT03942328). Methods: Peripheral blood mononuclear cells (PBMCs) were collected at baseline (PRE), after radiation (EBRT), and after completion of DC without or with atezo/bev (POST). Single-cell RNA sequencing with TCR sequencing were analyzed using CellRanger v7.0.1, Immunopipe, Seurat v5.3.0, & Gene-set enrichment analysis (GSEA). Long EFS (EFS-L) is defined as >=12 months (mo) for phase I and >=18mo for phase II, and short EFS (EFS-S) below that. Results: Seventeen patients have been analyzed to date (Phase I: n=8 [4 HCC, 4 iCCA]; Phase II: n=9 HCC). 674,106 cells were sequenced (146,843 PRE; 168,838 EBRT; 114,437 POST). GSEA for EFS-L vs EFS-S were comparable at PRE, EBRT and POST between phase I and phase II. EFS-S was associated with enrichment of interferon alpha (IFNα; B naïve, monocytes, pDC, cDC2, NK, Treg, CD8 Tcm and Tem at PRE and POST; B intermediate, CD4 Tem and NK at EBRT) and reactive oxygen species (ROS; PRE: pDC, CD8 Tcm, Tem. EBRT: CD4 Tem. POST: CD8 T naïve Tem, CD4 Tcm & Tem, cDC2) pathways. In contrast, EFS-L was associated with enrichment of WNT-β-catenin (WNT; CD14 mono at EBRT & POST, B intermediate at EBRT), TGFb (PRE: NK; EBRT: B intermed, CD4 Tem; POST: monocytes, CD4 naïve & Tem, pDC, cDC2), and angiogenesis (EBRT: NK; POST: monocytes, cDC2) pathways. Interestingly, enrichment of protein secretion pathway in NK cells was associated with EFS-L, but among other cells were associated with EFS-S (PRE: CD16 mono, Treg; POST: CD16 mono, CD4 & D8 Tem). Compared to phase I, addition of atezo/bev in phase II pts was associated with a significant increase in Gini coefficient (p<0.0001), suggesting expansion of certain TCR clones, along with a trend for increased Gini coefficient from Pre to Post in both phase I and II. Conclusions: Preliminary analysis of this study combining EBRT with intratumoral DC vaccination +/- PD-L1/VEGF blockade identified distinct treatment-related changes in systemic cellular immune profiles. Enhanced TCR clonal diversity in phase II suggests added immunologic benefit from PD-L1/VEGF blockade. As accrual continues, integrated analyses will identify systemic immune correlates of clinical benefit and resistance to this multimodal immunotherapy approach. Citation Format: Melody Wu, Panwen Wang, Chen Wu, Ying Li, Christopher L. Hallemeier, Thomas D. Atwell, Nguyen H. Tran, Andre de Menezes Silva Corraes, Kevin Regan, Zuoyi Shao, Rayaan Kamal, Haidong Dong, Lewis R. Roberts, Sean Park, Yi Lin, Lionel Aurelien Kankeu Fonkoua. Radiation-dendritic cell combination therapy drives systemic cellular immune shifts in liver cancer [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 3741.

Abstract Chimeric antigen receptor (CAR) T-cell therapy achieves high response rates in relapsed/refractory aggressive B-cell non-Hodgkin lymphoma, yet only 40% of patients achieve durable remission. Identifying biological programs linked to long-term response remains critical. As metabolic fitness underlies T-cell persistence and effector function, we profiled metabolic pathways associated with clinical outcomes following commercial CD19 CAR T-cell therapy. Single-cell RNA sequencing of peripheral blood mononuclear cells collected at baseline (BL), peak CAR-T expansion (PK), and one-month post-infusion (M1) was analyzed using CellRanger v7.0.1, immunopipe. Seurat v4.3.0 was applied for unsupervised clustering to delineate cell subsets based on top differentially expressed genes. Patients were categorized as durable complete remission (CR ≥6 months; n = 16), primary refractory (PD1; n = 4), or relapse after initial response (PD2; n = 12). Gene-set enrichment analysis defined metabolic pathway activity across T-cell, monocyte, dendritic cell (DC), and natural killer (NK) subsets. Oxidative phosphorylation (OXPHOS) emerged as the dominant metabolic program distinguishing clinical outcomes. At BL and PK, OXPHOS was consistently enriched in PD1 relative to CR across T-cell, monocyte, and DC subsets, suggesting early oxidative activation in non-responders. By M1, this pattern inverted, with higher OXPHOS activity in CR. PD2 largely paralleled PD1, but several subsets including CD8 T central memory, classical monocytes TGFβ, intermediate monocytes CD38, monocytic myeloid-derived suppressor cell (mMDSC) HIF1A, and mMDSC SIRPA, showed OXPHOS enrichment in CR at BL and/or PK that persisted through M1. In contrast, DC and NK subsets exhibited the opposite pattern: OXPHOS was enriched in CR at PK (conventional DC 2 (cDC2), plasmacytoid DC (pDC), NK, proliferating NK), but shifted toward enrichment in PD2 at M1 (cDC2, NK, NK CD56bright). Glycolysis (GLY) followed a similar trajectory in monocytes and NK cells, with enrichment in PD1/PD2 at BL and PK, followed by enrichment in CR at M1. In T-cells, PD1 maintained GLY enrichment from BL through PK, with no significant differences observed at M1. The inositol-phosphate metabolism pathway showed a more static pattern and was consistently enriched in multiple PD2 effector and memory T-cell subsets without reversal at M1. Taken together, these data reveal distinct, lineage-specific metabolic signatures that differentiate durable remission from early and late progression. Dynamic OXPHOS and GLY programming, characterized by lower activity early and enhanced activity at M1 in CR, may reflect adaptive metabolic programming that supports sustained antitumor immunity. Immune-metabolic profiling may therefore serve as a biomarker of response and highlight actionable metabolic pathways to enhance CAR T-cell durability. Citation Format: Melinda S.Y. Tan, Panwen Wang, Patrizia Mondello, Jacqueline Turner, Andre de Menezes Silva Corraes, Chen Wu, Zuoyi Shao, Kevin Regan, Ma Audrey, Arushi Khurana, Nora N. Benanni, Yucai Wang, Paul Hampel, Jonas Paludo, Saad J. Kenderian, Urshila Durani, Patrick B. Johnston, Jose Caetano Villasboas, Stephen M. Ansell, Ying Li, Haidong Dong, Hu Zeng, Yi Lin. Metabolic pathway signatures defining response to CD19 CAR T-Cell therapy in aggressive B-cell non-hodgkin lymphoma [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 3278.

Abstract Introduction: Therapeutic outcomes in B-cell non-Hodgkin’s lymphoma (B-NHL) have substantially improved with the introduction of chimeric antigen receptor T-cell (CAR-T) therapy. Yet, persistent immune dysfunction and underlying metabolic dysregulation remain major obstacles to achieving durable clinical responses in B-NHL. We hypothesize that mitochondrial pathways play a critical role in mediating anti-tumor immunity during CAR-T therapy. Methods: Peripheral blood mononuclear cells were collected from healthy controls (CNTRL, n=5) and patients with advanced stage lymphoma (LYM) who received FDA approved CAR-T (n=32). Samples were collected before lymphodepletion (BL), at peak CAR-T expansion (PK) and one-month post-infusion (M1). Single-cell RNA sequencing was used to interrogate differential mitochondrial gene expression. Samples were obtained from LYM patients with complete remission for >6 months (CR), primary refractory (PD1), or relapsed (PD2) disease. Results: Compared to CNTRLs, LYM patients exhibited reduced expression of cytochrome c oxidase. At BL, CR patients demonstrated broader mitochondrial differential gene expression across all T-cell subsets relative to PD1 and PD2 and showed higher expression of MT-ATP-6, MT-ATP-8, and MT-CO3. Following CAR-T infusion, global mitochondrial gene expression increased across patients corresponding with expansion of CD8 effector T cells (Tem tumor circulating) and activated peripheral memory T cells (Tpm). Certain mitochondrial genes, such as MT-CO1, were durably expressed across LYM patients at BL, PK, and M1 in peripheral and central memory T cells (Tpm, Tcm). At PK, cytochrome c oxidase and ATP synthase genes were upregulated in CR Tpm and Tcm. At M1, MT-ATP-6, MT-ATP-8, MT-CO3 were significantly upregulated in CD8 memory precursor effector T-cells (MPECs) of CR patients compared to both PD1 and PD2. While CR and PD2 patients appeared clinically responsive at M1, CR samples maintained significantly higher MT-ATP-8 expression across T cell subsets (CD8 MPECS, Tpm, Tcm) compared to PD2 (p values 0.008; <0.0001; <0.0001). Conclusions: We report a temporal shift in immunometabolism with CAR-T therapy in LYM. Clinical responders exhibited sustained mitochondrial activity characterized by persistent expression of ATP synthase in CD8 MPECs and cytochrome c oxidase in Tpm and Tcm. In sum, mitochondrial programming may distinguish effective versus dysfunctional T cells and identify targets for therapeutic development. Citation Format: Jacqueline Turner, Panwen Wang, Patrizia Mondello, Melinda Tan, Christoph Schaefers, Chen Wu, Andre de Menezes Silva Corraes, Kevin Regan, Zuoyi Shao, Ma Audrey, Arushi Khurana, Nora N. Benanni, Yucai Wang, Paul Hampel, Saad J. Kenderian, Jonas Paludo, Urshila Durani, Patrick B. Johnston, Jose Caetano Villasboas, Stephen M. Ansell, Haidong Dong, Ying Li, Zeng Hu, Yi Lin. Mitochondrial transcriptome profiles associated with clinical responses to CAR-T therapy in aggressive lymphoma [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 1213.

Abstract Background: Tarlatamab, a Delta-like ligand (DLL3)/CD3-targeted bispecific T-cell engager (TCE) is FDA approved in patients (pts) with extensive stage small cell lung cancer (ES-SCLC), after progression on frontline chemoimmunotherapy. We aimed to evaluate the immune cell profile in pts who received this therapy in standard-of-care (SOC) practice with progression free survival (PFS) less than and greater than two months (mo). Methods: Patients who received tarlatamab at Mayo Clinic Rochester and consented to immuno phenotyping of blood are included in the present study. Immune phenotyping was performed on whole blood by flow cytometry and analyzed by Kaluza. Data analysis was performed with Microsoft Excel and PRISM. Results: Eighteen patients with median age 64 (range 37-79) were included in the study. 66% of our cohort were women and 83% had present or past history of smoking, with an average of 40 pack years (range 26-60). With a median follow-up of 2 months, the median PFS for the cohort was 1.5 mo (range 0.33-2.76 months). 61% (13/18) of patients had PFS <2mo. 39% (5/18) had PFS>2mo and of which, three patients had partial response with one maintaining stable disease and one patient with mixed response. At baseline (BL), there were no difference in T cell, CD4 or CD8 cell count between patients in the PFS<2mo and PFS>2mo groups. Patients with PFS<2mo had higher exhausted CD8 T cells compared to those in the PFS>2mo group (CD8+PD1+TIGIT+CD57+, PFS<3mo vs >3mo, cells/mL: 7.14±4.28, 1.58±1.37, p=0.009). Additionally, when analyzing the B-cell population, the PFS<2mo group had lower percentage of B cells compared to the group with PFS>2mo at baseline (6.0±7.5, 10.4±14, p=0.02). At day 7, the group with PFS<2mo had lower Treg compared to the group with PFS>2mo (2.88±1.38, 4.60±1.47, p=0.02). Also, the PFS<2mo group had an increase of B cells compared to the group with PFS>2mo at day 7(<2mo vs >2mo: 10.0±14, 4.37±3.07, p=0.04). Finally, the group with PFS>2mo had decrease in total monocytes (mono), classical mono, and immunosuppressive cells (PFS<2mo vs >2mo, Mono: 340±347, 253±106, p=0.04. Classical mono: 305±283, 155±109, p=0.02. CD14+HLA-DRneg: 105.8±96, 12±39, p=0.03) compared to the group with PFS<2mo by day 7. While no changes were seen between BL and day 7 for intermediate mono in PFS<2mo group, PFS>2mo group had decreased post treatment intermediate monocytes (BL vs day 7, cells/mL, intermed mono: 32.5±15,17.7±6.2, p=0.03). Conclusion: In this study investigating the SOC outcomes of tarlatamab, early progression was associated with higher presence of exhausted CD8 T cells, B cells, and immunosuppressive monocytes. Analysis of additional patients will be shared at AACR meeting. Citation Format: Dhauna Karam Prasad, Andre De Menezes Silva Corraes, Malvika Gupta, Audrey Ma, Chen Wu, Zuoyi Shao, Kevin Reagan, Rayaan Kamal, Ashley Potter, Abdullah Al-Ajmi, Syeda Mina, Sykler J. Taylor, Antonious Hazim, Anastasios Dimou, Kaushal Parikh, Mohammed Shanshal, Ailsa Luce, Anna Schwecke, Julian Molina, Aaron Mansfield, Katherine Smith, Lucy Holmes, Haidong Dong, Yi Lin, Konstantinos Leventakos. Immune cell profile changes in patients treated with tarlatamab for extensive stage small cell lung cancer in real world practice [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 3931.