Agonistic Antibody Research Articles

Tumor reactive T cells from the cerebrospinal fluid of patients with leptomeningeal disease from melanoma.

2027 Background: Leptomeningeal disease (LMD) is a devastating complication from cancer, with a median survival of 6-8 weeks. The incidence of LMD is highest in melanoma (5-25%) carrying the worst prognosis. Adoptive cell therapy (ACT) using tumor-infiltrating lymphocytes (TILs) showed complete and durable responses in patients with advanced metastatic melanoma. CSF-derived T cell populations in LMD shift to more exhausted phenotypes compared to extracranial and brain metastases. Ex vivo large T cell expansion can overcome this shortfall, with adoptive T cell transfer representing a novel therapeutic approach to treat melanoma LMD (M-LMD). The goal of this study is to optimize rapid CSF-derived tumor reactive T cell expansion in M-LMD, and evaluate the immune microenvironment in CSF compared to peripheral immunity and anti-tumoral response. Methods: CSF was collected from M-LMD patients (n=6) via lumbar puncture or Ommaya. Cells were plated following established TIL culture protocols to determine optimal expansion conditions i.e.: 1) 6000 IU/mL IL-2, 2) IL-2+OKT3, 3) IL-2+anti-4-1BB agonistic antibody, 4) IL-2+IL-7+IL-15+IL-21, 5) IL-2+anti-CD3/CD28 human dynabeads, & 6) IL-2+anti-CD3/CD28/CD137 human dynabeads. After 4 weeks, T cells were propagated via rapid expansion protocol (REP) and phenotyped for CD4+ and CD8+ T cells with flow cytometry. T cells were co-cultured for 18-24 hours with HLA-matched melanoma cell lines to assess functionality, and IFN-y levels evaluated in supernatant. Ongoing studies are evaluating other biomarkers i.e., chemokines via Luminex. To examine the expanded TCR clonotypes, TCR beta seq was done in CSF-derived T cells at different times point of expansion and peripheral T cells. Results: Collected CSF yielded an average 8.12e4 viable cells for expansion (range 5e2-2.43e6). After initial culture in IL-2, 61.9% of samples showed increased cell yield with an average 101.68-fold expansion (range 2.35-1054). PreREP T cells were predominantly CD4+ (45.7%). REP was completed with a 100% success rate (mean 187.47-fold expansion). Post-REP flow cytometry analysis revealed similar results with further expansion of T cells. Additional culture supplements (Methods #2-6) produced similar expansion with a reduced T cell input requirement and demonstrated the potential to enrich for CD8+ T cells. M-LMD T cells were highly functional, producing substantial levels of IFN-y in response to HLA-matched melanoma cell lines. Anti-CD3/CD28 produced a larger expansion of T cells with higher levels of IFN-y. Preliminary TCR beta sequencing data revealed a distinct clonal distribution between peripheral and CSF-derived T cells. Conclusions: Therapies for LMD patients are desperately needed. Results demonstrate successful expansion of T cells ex vivo from CSF in M-LMD. Results raise potential to use autologous CSF-derived T cells as therapeutic strategy for patients with LMD.

Combining CD40 agonist mitazalimab with mFOLFIRINOX in previously untreated metastatic pancreatic ductal adenocarcinoma (OPTIMIZE-1): a single-arm, multicentre phase 1b/2 study

Current systemic therapies for metastatic pancreatic ductal adenocarcinoma are associated with poor outcomes with a 5-year overall survival rate under 5%. We aimed to assess the safety and antitumour activity of mitazalimab, a human CD40 agonistic IgG1 antibody, with modified FOLFIRINOX (mFOLFIRINOX; fluorouracil, leucovorin, oxaliplatin, and irinotecan), in chemotherapy-naive patients with metastatic pancreatic ductal adenocarcinoma. OPTIMIZE-1 was a single-arm, multicentre, phase 1b/2 study which enrolled adults with histologically-confirmed metastatic pancreatic ductal adenocarcinoma and European Cooperative Oncology Group performance status 0 or 1 in 14 university hospitals in Belgium, France, and Spain. The primary endpoint of phase 1b was to determine the recommended phase 2 dose of intravenous mitazalimab (450 μg/kg or 900 μg/kg) when combined with intravenous mFOLFIRINOX (oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, irinotecan 150 mg/m2, fluorouracil 2400 mg/m2). In the first 21-day treatment cycle, mitazalimab was administered on days 1 and 10, and mFOLFIRINOX on day 8. In subsequent 14-day cycles mitazalimab was administered 2 days after mFOLFIRINOX. The phase 2 primary endpoint was objective response rate. Activity and safety analyses were conducted on the full analysis set (all patients who received the combination of mitazalimab at the recommended phase 2 dose and mFOLFIRINOX for at least two treatment cycles) and safety set (all patients who received any study treatment), respectively. Enrolment is complete, and data represents a primary analysis of the ongoing trial. The trial is registered at Clinicaltrials.gov (NCT04888312). Between Sept 29, 2021, and March 28, 2023, 88 patients were screened and 70 patients were enrolled (40 [57%] were female and 30 [43%] were male). In phase 1b, 900 μg/kg mitazalimab was determined as the recommended phase 2 dose. Overall, five patients received 450 μg/kg mitazalimab; 65 received 900 μg/kg mitazalimab. No dose-limiting toxicities were observed at 450 μg/kg, and one dose-limiting toxicity was observed at 900 μg/kg. 57 patients were evaluated for activity, and all 70 patients were included in the safety set. At data cutoff on Nov 14, 2023, median follow-up was 12·7 months (95% CI 11·1-15·7). Of the 57 patients, 29 (51%) remained on study and 18 (32%) remained on treatment. The primary endpoint (objective response rate >30%) was met (objective response rates in 23 [40%]; one-sided 90% CI ≥32 of 57 patients). The most common grade 3 or worse adverse events were neutropenia (18 [26%] of 70 patients), hypokalaemia (11 patients [16%]), and anaemia and thrombocytopenia (eight patients [11%]). Serious adverse events were reported in 29 (41%) of 70 patients, the most common being vomiting (five [7%] of 70 patients), decreased appetite (four [6%]), and diarrhoea and cholangitis (three [4%] of 70 patients for each), none considered related to mitazalimab. No treatment-related deaths were reported. Mitazalimab with mFOLFIRINOX demonstrated manageable safety and encouraging activity, warranting continued development in a phase 3, randomised, controlled trial. The results from OPTIMIZE-1 pave the way for further exploration and confirmation of a novel immunotherapy treatment regimen for metastatic pancreatic ductal adenocarcinoma, which is a complex and aggressive cancer with very low survival rates and restricted treatment options. Alligator Bioscience.

A phase II, multi-center, open-label study to evaluate the safety and efficacy of YH003 in combination with toripalimab (anti-PD-1 mAb) in patients with unresectable/metastatic pancreatic ductal adenocarcinoma (PDAC).

4146 Background: Pancreatic cancer therapy remains a formidable challenge. Although chemotherapy offers tumor control and clinical stabilization, both standard regimens are limited in response durability and incur toxicity. YH003, a humanized agonistic anti-CD40 monoclonal antibody specifically recognizes and agonizes CD40 to enhance immune responses, has demonstrated good safety and promising antitumor activity in Phase I clinical studies in patients with solid tumors. Here, we report the results of the phase II study of YH003 plus Toripalimab with/without chemotherapy, as 1L or 2L treatment in patients with metastatic PDAC. Methods: Patients with unresectable/metastatic (u/m) PDAC were enrolled into two Cohorts. In the second and plus line (2L+) Cohort, patients who had confirmed progressive disease during treatment with first line standard of therapy were enrolled and received 0.3 mg/kg YH003 plus 240 mg Toripalimab, iv, every 21 days. In the 1L Cohort, patients without any prior systemic treatment were enrolled and received 0.3 mg/kg YH003 plus 240 mg Toripalimab plus nab-paclitaxel + gemcitabine, iv, every 21 days. The treatment continued for 12 months if subject was deriving an ongoing clinic benefit. The primary endpoint was overall Response Rate (ORR) by investigator’s assessment per RECIST 1.1. The medium Progression-Free Survival (mPFS) and Overall Survival (mOS) were secondary endpoints. Results: A total of 92 patients were enrolled including 45 subjects for the 2L+ Cohort and 47 subjects for the 1L Cohort. In the 2L+ Cohort, 40 (including 14 Caucasians) of 45 patients had at least 1 evaluable post-treatment tumor assessment, the unconfirmed ORR was observed in 4 patients (10.0%) with 4 partial responses (PR). 10 patients (25.0%) had stable disease (SD), and the Disease Control Rate (DCR) was 35.0%. The mOS was 7.23 months. For the Caucasian subgroup (n = 14), the ORR was 7.1%, DCR was 50%, mPFS was 2.25 months and mOS 9.54 months. For the 1L Cohort, 43 (including 10 Caucasians) of 47 patients had at least 1 evaluable post-treatment tumor assessment, the unconfirmed ORR was observed in 12 patients (27.9%) with 1 CR and 11 PR. 23 patients (53.5%) had SD, and the DCR was 81.4%. The mOS time was 12.12 months. For the Caucasian subgroup (n = 10), the ORR was 50%, DCR was 100%, mPFS was 11.27 months and mOS 19.78 months. The grade 3 or above adverse events that occurred in the 92 patients were 57.8% (26/45) in 2L+ Cohort and 74.5% (35/47) in 1L Cohort. There is no significant safety signal from the study. Conclusions: The results of the phase II study have shown that YH003 plus Toripalimab with/without chemotherapy, as 1L or 2L treatment in patients with u/m PDAC have promising antitumor activity and response durability, especially in the Caucasian subgroups. Both treatment regimens are well tolerated. Clinical trial information: NCT05031494 .

Phase I dose escalation trial of the first-in-class TNFR2 agonist monoclonal antibody, HFB200301, in monotherapy and in combination with tislelizumab, an anti-PD-1 monoclonal antibody, in adult patients with advanced solid tumors.

2526 Background: Tumor necrosis factor receptor-2 (TNFR2) is expressed on effector CD8+, CD4+, and regulatory T (Treg) cells, natural killer (NK) cells, and myeloid cells. Activation of TNFR2 is anticipated to yield effective anti-tumor immunity by stimulating T-cell and NK-cell activation and proliferation in the tumor microenvironment. HFB200301 is a first-in-class anti-TNFR2 agonistic monoclonal antibody that triggers both innate and adaptive immune stimulation by binding to a specific epitope on TNFR2. We report initial results of an ongoing Phase I dose escalation, multicenter study (NCT05238883) of HFB200301 in monotherapy and in combination with tislelizumab (TIS) in patients (pts) with advanced refractory solid tumors. Methods: A Phase I trial designed to evaluate the safety, pharmacokinetics (PK), pharmacodynamics (PD), and initial efficacy of HFB200301 in monotherapy and in combination with TIS. Eligible pts, ≥18 years with an ECOG PS 0-1 and advanced solid tumors, will be enrolled in dose escalation at 5 different dose cohorts in monotherapy (Q4W), 3 different dose cohorts in combination with TIS (Q4W), or in dose expansion following determination of safety. Radiographic response is assessed every 8 weeks. Results: A total of 39 pts have been enrolled, 27 pts in monotherapy and 12 pts in combination. All pts received prior systemic therapy (median 2, range 1-4); 23 pts (59%) had prior checkpoint inhibitor treatment. No dose limiting toxicities were observed in either the monotherapy or combination arms. Treatment-related adverse events (TRAEs) occurred in 44% of monotherapy and in 50% of combination pts, with pruritis (11%), tremor (7%), fatigue (7%), asthenia (7%) and nausea (7%) being the most common TRAEs. No ≥ Grade 3 TRAEs were reported, and there were no drug discontinuations due to TRAEs. Preliminary HFB200301 PK analysis demonstrated non-linear clearance of HFB200301, with dose-proportional maximum concentration [Cmax], achieving sufficient exposures for peripheral target engagement in all tested doses. Emerging PD data demonstrates evidence of immune activation and expansion of CD8+ T cells, but not Tregs, in the tumor microenvironment and peripheral blood. Single cell RNAseq analysis of peripheral blood mononuclear cells demonstrated PD modulation in TNFR2 positive immune cell types post-HFB200301 treatment. Early response evaluation reveals ongoing durable clinical responses (> 6 months) in a PD-L1+ pleural mesothelioma pt and an EBV+ gastric cancer pt from combination cohorts. Conclusions: HFB200301 demonstrates a favorable safety profile, dose-dependent PK, with PD and preliminary clinical activity in monotherapy and in combination with TIS in pts with heavily pre-treated refractory solid tumors. Clinical trial information: NCT05238883 .

A multicenter, single-arm, open-label phase II study to evaluate the efficacy and safety of YH003 in combination with pembrolizumab and nab-paclitaxel in the first-line treatment of patients with unresectable/metastatic mucosal melanoma.

e21520 Background: Mucosal melanoma therapy remains a formidable challenge especially in Asia. Although several therapies are available for skin type of melanoma, the efficacy of mucosal melanoma is not satisfactory. YH003, a humanized agonistic anti-CD40 monoclonal antibody specifically recognizes and agonizes CD40 to enhance immune responses, has demonstrated good safety and promising antitumor activity in Phase I clinical studies in patient with ocular melanoma. Here, we report the results of the phase II study of YH003 in combination with pembrolizumab and nab-paclitaxel in the first-line treatment of patients with unresectable/metastatic mucosal melanoma. Methods: Patients with unresectable/metastatic mucosal melanoma were enrolled and received 0.3 mg/kg YH003, 200 mg pembrolizumab and 200 mg/m2 of nab-paclitaxel iv, every 21 days. The treatment continued for 12 months if subject was deriving an ongoing clinic benefit. The primary endpoint was overall Response Rate (ORR) by investigator’s assessment per RECIST 1.1. Results: A total of 20 patients were enrolled and had at least 1 evaluable post-treatment tumor assessment, the unconfirmed ORR was observed in 7 patients (35.0%), with 7 partial responses (PR). 7 patients (35.0%) had stable disease (SD), and the Disease Control Rate (DCR) was 70.0%. The mOS was not reached, mPFS was 4.11 months. The grade 3 or above TEAE that occurred in the 20 patients were 30.0% (6/20). There is no significant safety signal from the study. Conclusions: The results of the phase II study have shown that YH003 in combination with pembrolizumab and nab-paclitaxel, as 1L treatment in patients with unresectable/metastatic mucosal melanoma have promising antitumor activity and response durability and well tolerated. Clinical trial information: NCT05420324 .

Phase 1 study of CTX-471, a novel CD137 agonist antibody, in patients with progressive disease following PD-1/PD-L1 inhibitors in metastatic or locally advanced malignancies.

Phase 1 study of CTX-471, a novel CD137 agonist antibody, in patients with progressive disease following PD-1/PD-L1 inhibitors in metastatic or locally advanced malignancies.

Phase 1 trial safety and efficacy of ragistomig, a bispecific antibody targeting PD-L1 and 4-1BB, in advanced solid tumors.

2529 Background: Activation of T cells in the tumor microenvironment by 4-1BB agonist antibodies is a promising approach to augment PD-(L)1 inhibitor efficacy. Ragistomig(ABL503/TJ-L14B) is a bispecific antibody combining PD-L1 antagonist with 4-1BB agonistic activity, designed to induce 4-1BB signaling only when bound to the PD-L1 tumor antigen on cancer cells, which may overcome resistance to PD-(L)1 inhibition and avoid hepatoxicity seen with traditional 4-1BB mAbs. Methods: ABL503 was investigated at doses ranging from 0.7 mg (flat dose) to 10 mg/kg (weight-based dose) IV every 2 weeks (Q2W) in patients with advanced or relapsed/refractory solid tumors, to assess safety, preliminary anti-tumor effect and pharmacokinetic (PK)/pharmacodynamic (Pd) activity. The BOIN design was utilized during dose escalation (regardless of CPS/TPS score). Additional patients were enrolled in dose expansion cohorts at 3 and 5 mg/kg (CPS/TPS>=1 required). Results: As of Jan 2024, the study enrolled 49 patients (30 dose escalation, 19 dose expansion). At least 1 treatment related adverse event (TRAE) occurred in 37 patients (75.5%); most common TRAE (≥ 10%, any grade/grade 3-4) were elevated AST (30.6%/18.4%), elevated ALT (26.5%/18.4%), rash (14.3%/4.1%), nausea (12.2%/0%), pyrexia (12.2%/2.0%) and fatigue (10.2%/0%). Dose limiting toxicities occurred in 5 patients and were observed at dose levels of 1, 5, and 10 mg/kg. All DLTs were recovered/recovering. MTD was not reached. Based on the safety, efficacy, PK and Pd analysis, the optimal dose was determined to be 5 mg/kg Q2W. Objective responses were observed in 6 out of 39 efficacy-evaluable patients, and all responses were observed at 3 and 5 mg/kg, including 1 complete response (CR) in a patient with ovarian cancer who received 6 prior lines of treatment and 5 partial responses (PRs) in patients with ovarian (n=1), melanoma (n=1), gastric (n=1), head and neck squamous cell (n=1), and esophageal cancer (n=1). Overall response rate (ORR) for all dose levels was 15.3%, and ORR at 5 mg/kg was 30% (3/10). Clinical benefit rate (CBR) for all dose levels was 61.5%, and CBR at 5 mg/kg was 80% (8/10). 66.7% of responders received prior PD-(L)1 inhibitors. One patient achieved sustained tumor regression over 6 months, even after treatment discontinuation. PK was dose proportional, and half-life was ~5 days. Dose-dependent increase of Pd marker s4-1BB was observed, demonstrating target engagement. Conclusions: ABL503 had a manageable safety profile and demonstrated promising anti-tumor activity, with objective responses in 6 out of 39 efficacy-evaluable patients across multiple tumor types in heavily pre-treated patients, including patients previously treated with checkpoint inhibitors. The data support continued development of ABL503 alone and in combination with other compounds, as a potential therapeutic option for patients with solid tumor cancers. Clinical trial information: NCT04762641 .

Efficacy, safety, and PK/PD of LVGN6051, 4-1BB agonistic antibody, with pembrolizumab in a phase Ib dose expansion in resistant NSCLC, melanoma, and GI malignancy.

Efficacy, safety, and PK/PD of LVGN6051, 4-1BB agonistic antibody, with pembrolizumab in a phase Ib dose expansion in resistant NSCLC, melanoma, and GI malignancy.

The rationale of reprogramming TREM2+ macrophages for overcoming the resistance to immune checkpoint inhibitors in pancreatic adenocarcinoma.

e14649 Background: Pancreatic ductal adenocarcinoma (PDAC) resists to immune checkpoint inhibitors as single agents. TAMs expressing the triggering receptor expressed on myeloid cells (TREM2) protein were found to be a dominant macrophage population in PDAC; targeting TREM2 has been found to enhance the efficacy of immune checkpoint inhibitor-based therapies in preclinical studies of other malignancies. Here, we studied the role of targeting TREM2 in PDAC by testing the combination of non-depleting anti-TREM2 antibody and anti-PD-1 antibody in a mouse model of PDAC. We also examined the relationship between TREM2 expression and effector T cells in surgically resected human PDAC collected from a previous clinical trial treated with the neoadjuvant combination therapy of nivolumab (anti-PD-1 antibody), urelumab (anti-CD137 agonist antibody), and the pancreatic cancer GVAX vaccine. Methods: C57BL/6 mice were orthotopically implanted with KPC tumors. Anti-TREM2 was injected intraperitoneally (i.p.) once a week and anti-PD-1 was injected i.p. twice a week. Tumor volume was measured by ultrasound. TREM2 was stained on slides which were previously obtained from surgically resected PDACs following the neoadjuvant combination treatment of nivolumab, urelumab, and GVAX and stained for multiple immune cell markers with a multiplex staining-striping immunohistochemistry (IHC) technique. Results: Tumor growth post-tumor implantation was found to be significantly decreased by the anti-PD-1 and anti-TREM2 combination compared with anti-PD-1 alone, anti-TREM2 alone, or control treatment (p < 0.0001). Survival of tumor-bearing mice was significantly prolonged by the anti-PD-1 and anti-TREM2 combination when compared to anti-PD-1(p < 0.05), anti-TREM2(p < 0.05), and control (p < 0.01). Multiplex IHC analysis of human PDACs following neoadjuvant immunotherapy showed a higher density of granzyme B+CD8+ effector T cells correlated with higher density of TREM2+ cells (p = 0.0357). Conclusions: Our study demonstrates the anti-tumor efficacy of anti-TREM2 antibody in combination with an immune checkpoint inhibitor in mouse PDAC. However, the analysis of human PDAC following neoadjuvant immunotherapy suggests that TREM2 on TAMs may be activated following the activation of effector T cells. Taken together, our results suggest that TREM2+ TAMs should be reprogrammed instead of being depleted in the design of anti-TREM2-based therapy for PDAC.

An open label, phase 1b/2 trial of LVGN6051 (4-1BB agonistic antibody) combined with anlotinib for refractory soft tissue sarcoma (STS).

An open label, phase 1b/2 trial of LVGN6051 (4-1BB agonistic antibody) combined with anlotinib for refractory soft tissue sarcoma (STS).

Agonistic anti-DCIR antibody inhibits ITAM-mediated inflammatory signaling and promotes immune resolution.

DC inhibitory receptor (DCIR) is a C-type lectin receptor selectively expressed on myeloid cells, including monocytes, macrophages, DCs, and neutrophils. Its role in immune regulation has been implicated in murine models and human genome-wide association studies, suggesting defective DCIR function associates with increased susceptibility to autoimmune diseases such as rheumatoid arthritis, lupus, and Sjögren's syndrome. However, little is known about the mechanisms underlying DCIR activation to dampen inflammation. Here, we developed anti-DCIR agonistic antibodies that promote phosphorylation on DCIR's immunoreceptor tyrosine-based inhibitory motifs and recruitment of SH2 containing protein tyrosine phosphatase-2 for reducing inflammation. We also explored the inflammation resolution by depleting DCIR+ cells with antibodies. Utilizing a human DCIR-knock-in mouse model, we validated the antiinflammatory properties of the agonistic anti-DCIR antibody in experimental peritonitis and colitis. These findings provide critical evidence for targeting DCIR to develop transformative therapies for inflammatory diseases.

Microglia, Trem2, and Neurodegeneration.

Microglia are a specialized type of neuroimmune cells that undergo morphological and molecular changes through multiple signaling pathways in response to pathological protein aggregates, neuronal death, tissue injury, or infections. Microglia express Trem2, which serves as a receptor for a multitude of ligands enhancing their phagocytic activity. Trem2 has emerged as a critical modulator of microglial activity, especially in many neurodegenerative disorders. Human TREM2 mutations are associated with an increased risk of developing Alzheimer disease (AD) and other neurodegenerative diseases. Trem2 plays dual roles in neuroinflammation and more specifically in disease-associated microglia. Most recent developments on the molecular mechanisms of Trem2, emphasizing its role in uptake and clearance of amyloid β (Aβ) aggregates and other tissue debris to help protect and preserve the brain, are encouraging. Although Trem2 normally stimulates defense mechanisms, its dysregulation can intensify inflammation, which poses major therapeutic challenges. Recent therapeutic approaches targeting Trem2 via agonistic antibodies and gene therapy methodologies present possible avenues for reducing the burden of neurodegenerative diseases. This review highlights the promise of Trem2 as a therapeutic target, especially for Aβ-associated AD, and calls for more mechanistic investigations to understand the context-specific role of microglial Trem2 in developing effective therapies against neurodegenerative diseases.

The MuSK agonist antibody protects the neuromuscular junction and extends the lifespan in C9orf72-ALS mice

The disassembly of the neuromuscular junction (NMJ) is an early event in amyotrophic lateral sclerosis (ALS), ultimately leading to motor dysfunction and lethal respiratory paralysis. The hexanucleotide GGGGCC repeat expansion in the C9orf72 gene is the most common genetic mutation, and the dipeptide repeat (DPR) proteins have been shown to cause neurodegeneration. While no drugs can treat ALS patients efficiently, new treatment strategies are urgently needed. Here, we report that a MuSK agonist antibody alleviates poly-PR-induced NMJ deficits in C9orf72-ALS mice. The HB9-PRF/F mice, which express poly-PR proteins in motor neurons, exhibited impaired motor behavior and NMJ deficits. Mechanistically, poly-PR proteins interacted with Agrin to disrupt the interaction between Agrin and Lrp4, leading to attenuated activation of MuSK. Treatment with a MuSK agonist antibody rescued NMJ deficits, and extended the lifespan of C9orf72-ALS mice. Moreover, impaired NMJ transmission was observed in C9orf72-ALS patients. These findings identify the mechanism by which poly-PR proteins attenuate MuSK activation and NMJ transmission, highlighting the potential of promoting MuSK activation with an agonist antibody as a therapeutic strategy to protect NMJ function and prolong the lifespan of ALS patients.

Increased co-expression of 4-1BB with PD-1 on CD8+ tumor-infiltrating lymphocytes is associated with improved prognosis and immunotherapy response in cervical cancer.

The combination of agonistic antibodies with immune checkpoint inhibitors presents a promising avenue for cancer immunotherapy. Our objective is to explore the co-expression of 4-1BB, ICOS, CD28, with PD-1 on CD8+ T cells in the peripheral blood and tumor tissue of cervical cancer(CC) patients, with a specific focus on the association between the co-expression levels of 4-1BB with PD-1 and clinical features, prognosis as well as immunotherapy response. The goal is to offer valuable insights into cervical cancer immunotherapy. In this study, 50 treatment-naive patients diagnosed with CC were enrolled. Flow cytometry was used to detect PD-1/4-1BB, PD-1/ICOS and PD-1/CD28 co-expression on CD8+ T cells. Subsequent analysis aimed to investigate the differential co-expression between peripheral blood and cancer tissue, and also the correlation between co-expression and clinical features in these patients. Gene Expression Omnibus (GEO) datasets, The Cancer Genome Atlas (TCGA) cohort, The IMvigor210 cohort, The BMS038cohort and Immunophenoscores were utilized to investigate the correlation between PD-1/4-1BB and the immune microenvironment, prognosis, immunotherapy, and drug sensitivity in cervical cancer. The co-expression levels of PD-1/4-1BB, PD-1/ICOS, and PD-1/CD28 on CD8+ tumor-infiltrating lymphocytes (TILs) were significantly higher in cervical cancer patients compared to those in peripheral blood. Clinical feature analysis reveals that on CD8+ TILs, the co-expression of PD-1/4-1BB is more closely correlated with clinical characteristics compared to PD-1/ICOS, PD-1/CD28, PD-1, and 4-1BB. Pseudo-time analysis and cell communication profiling reveal close associations between the subgroups harboring 4-1BB and PD-1. The prognosis, tumor mutation burden, immune landscape, and immunotherapy response exhibit statistically significant variations between the high and low co-expression groups of PD-1/4-1BB. The high co-expression group of PD-1/4-1BB is more likely to benefit from immunotherapy. PD-1/4-1BB, PD-1/ICOS, and PD-1/CD28 exhibit elevated co-expression on CD8+TILs of cervical cancer, while demonstrating lower expression in circulating T cells. The co-expression patterns of PD-1/4-1BB significantly contributed to the prediction of immune cell infiltration characteristics, prognosis, and tailored immunotherapy tactics. PD-1/4-1BB exhibits potential as a target for combination immunotherapy in cervical cancer.

Trem2 Agonist Reprograms Foamy Macrophages to Promote Atherosclerotic Plaque Stability-Brief Report.

Trem2 (triggering receptor on myeloid cells 2), a surface lipid receptor, is expressed on foamy macrophages within atherosclerotic lesions and regulates cell survival, proliferation, and anti-inflammatory responses. Studies examining the role of Trem2 in atherosclerosis have shown that deletion of Trem2 leads to impaired foamy macrophage lipid uptake, proliferation, survival, and cholesterol efflux. Thus, we tested the hypothesis that administration of a Trem2 agonist antibody (AL002a) to atherogenic mice would enhance macrophage survival and decrease necrotic core formation to improve plaque stability. To model a therapeutic intervention approach, atherosclerosis-prone mice (Ldlr [low-density lipoprotein receptor]-/-) were fed a high-fat diet for 8 weeks, then transitioned to treatment with AL002a or isotype control for an additional 8 weeks while continuing on a high-fat diet. AL002a-treated mice had increased lesion size in both the aortic root and whole mount aorta, which correlated with an expansion of plaque macrophage area. This expansion was due to increased macrophage survival and proliferation in plaques. Importantly, plaques from AL002a-treated mice showed improved features of plaque stability, including smaller necrotic cores, increased fibrous caps, and greater collagen deposition. Single-cell RNA sequencing of whole aorta suspensions from isotype- and AL002a-treated atherosclerotic mice revealed that Trem2 agonism dramatically altered foamy macrophage transcriptome. This included upregulation of oxidative phosphorylation and increased expression of collagen genes. In vitro studies validated that Trem2 agonism with AL002a promoted foamy macrophage oxidized low-density lipoprotein uptake, survival, and cholesterol efflux. Trem2 agonism expands atherosclerotic plaque macrophages by promoting cell survival and proliferation but improves features of plaque stability by rewiring foamy macrophage function to enhance cholesterol efflux and collagen deposition.

CD4+ T Cells from Women with Preeclampsia During Pregnancy Contribute to Hypertension, AT1-AA, and Neurovascular Dysfunction in a Pregnant Rat Model of PE

Objective: Preeclampsia (PE) is characterized by new onset hypertension (HTN) during pregnancy and is associated with activated CD4+ T cells and agonistic antibodies against the angiotensin II type 1 receptor (AT1-AA). Interestingly, having had COVID-19 during pregnancy is associated with increased incidence of a PE-like phenotype. Both PE and CV have long lasting neurological implications. We sought examine a role for CD4+ T cells from PE with or without a CV Hx to contribute to a PE phenotype and neurovascular dysfunction postpartum (PP). Methods: We utilized adoptive transfer of one million placental CD4+ T cells from PE and normotensive (NT) patients with or without a CV (Hx) during pregnancy injected i.p. into gestational day (GD) 12 nude athymic rats athymic and determined neurological consequences at 12 weeks PP. At GD19, blood pressure (MAP) and AT1-AA were measured. At 3 months PP, memory and error in navigation were assessed by Barnes maze consecutively for 5 days. CBF was measured by laser Doppler flowmetry. A two-way ANOVA was used for statistical analysis. Results: In pregnant recipient rats, MAP increased in CV Hx PE (113±2, n=8) and PE (115±2 mmHg, n=10) compared to CV Hx NT (104±4, n=7) and NT (98±2 mmHg, n=7 p<0.05). AT1-AA increased in PE (8±2 ΔBPM, n=4) and CV Hx PE (4±2 ΔBPM, n=4) compared to NT (-3±2 ΔBPM, n=4, p<0.05) and CV Hx NT (2±2 ΔBPM, n=2) respectively. At 3 months PP, PE and CV Hx PE had impaired CBF autoregulation compared to CV Hx NT and NT rats, and both PE groups exhibited greater mistakes and latency in maze navigation, however, the scores were worse in those receiving T cells from PE patients without a Hx of CV compared to all other groups. Conclusion: Our findings indicate that pregnant recipients of CD4+ T cells from PE with or without a CV Hx during pregnancy cause HTN and increased AT1-AA compared to recipients of NT or NT Hx CV-19 CD4 + T cells. Interestingly, recipients of T cells from PE patients without a Hx of CV had worse CBF and cognitive function at 3 months PP, demonstrating the importance of CD4+ T cells in HTN and impaired neurological function during pregnancy PP in patients with previous PE. This study was supported by NIH grants RO1HD067541 (BL), F31HD110230 (NC), P20GM121334 (BL, LMA), and American heart association (AHA) early career award 19CDA34670055 (LMA). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 133: Trem2 Agonist Promotes Atherosclerotic Plaque Stability

Atherosclerosis is an inflammatory disease of the arteries that is a major cause of cardiovascular disease (CVD). Atherosclerotic plaque progression is driven by the deposition of low-density lipoprotein (LDL) within the intima, which is internalized by macrophages, forming lipid-engorged foamy cells. Importantly, the accumulation of excess LDL within foamy macrophages is cytotoxic, driving apoptosis, which ultimately promotes necrotic core formation and increased potential for plaque rupture. Recently, our lab identified the lipid receptor Trem2 to be highly expressed by foamy macrophages and regulate cell survival, proliferation, and cholesterol efflux. Thus, we tested whether agonizing Trem2 could drive macrophage survival to promote plaque stability. Using a Trem2 agonist antibody (AL002a, Alector Inc.), we treated Ldlr -/- mice that had preexisting atherosclerotic plaque with either isotype control or AL002a antibody for 8 weeks. AL002a treated mice showed an increase in plaque size in the aortic arch and aortic sinus. Plaque analysis determined that this was primarily due to an expansion of macrophage cellularity, through promotion of cell survival and proliferation. Furthermore, we found that plaques from AL002a treated mice had decreased necrotic core formation, increased fibrous cap size, and increased collagen deposition, consistent with improved stability. Single cell RNA-sequencing of atherosclerotic aortae from isotype and AL002a treated mice found that Trem2-agonism dramatically reshaped transcriptomes of both foamy macrophages and smooth muscle cells, including upregulation of oxidative phosphorylation (OXPHOS), cholesterol efflux, collagen, and pro-survival genes while downregulating inflammatory pathways. In vitro studies using bone marrow derived macrophages confirmed AL002a’s ability to drive cell survival, proliferation, OXPHOS, and cholesterol efflux in culture. Finally, we determined that AL002a’s ability to reshape aspects of foamy macrophage function was dependent on its ability to activate the kinase SYK downstream of Trem2. Overall, this data identifies Trem2 as a viable therapeutic target for promoting atherosclerotic plaque stability and improving outcomes in CVD.

CD3 aptamers promote expansion and persistence of tumor-reactive T cells for adoptive T cell therapy in cancer

The CD3/TCR complex is responsible for antigen-specific pathogen recognition by T cells, and initiates the signaling cascade necessary for activation of effector functions. CD3 agonistic antibodies are commonly used to expand T lymphocytes in a wide range of clinical applications, including in adoptive T-cell therapy for cancer patients. A major drawback of expanding T-cell populations ex vivo using CD3 agonistic antibodies is that they expand and activate T cells independent of their TCR antigen specificity. Therapeutic agents that facilitate expansion of T cells in an antigen-specific manner and reduce their threshold of T-cell activation, are therefore of great interest for adoptive T-cell therapy protocols. To identify CD3-specific T-cell agonists, several RNA aptamers were selected against CD3 using SELEX combined with high-throughput sequencing. The extent and specificity of aptamer binding to target CD3 were assessed through SPR, P32 double filter assays and flow cytometry. Aptamer-mediated modulation of the threshold of T-cell activation was observed in vitro and in pre-clinical transgenic TCR mouse models. The aptamers improved efficacy and persistence of adoptive T-cell therapy by low affinity TCR-reactive T lymphocytes in melanoma-bearing mice. Thus, CD3-specific aptamers can be applied as therapeutic agents which facilitate the expansion of tumor-reactive T lymphocytes while conserving their tumor specificity. Furthermore, selected CD3 aptamers also exhibit cross-reactivity to human CD3, expanding their potential for clinical translation and application in the future.

Facile generation of biepitopic antibodies with intrinsic agonism for activating tumor necrosis factor receptors

Agonist antibodies are being pursued for therapeutic applications ranging from neurodegenerative diseases to cancer. For the tumor necrosis factor (TNF) receptor superfamily, higher-order clustering of three or more receptors is key to their activation, which can be achieved using antibodies that recognize two unique epitopes. However, the generation of biepitopic (i.e., biparatopic) antibodies typically requires animal immunization and is laborious and unpredictable. Here, we report a simple method for identifying biepitopic antibodies that potently activate TNF receptors without the need for additional animal immunization. Our approach uses existing, receptor-specific IgGs, which lack intrinsic agonist activity, to block their corresponding epitopes, then selects single-chain antibodies that bind accessible epitopes. The selected antibodies are fused to the light chains of IgGs to generate human tetravalent antibodies. We highlight the broad utility of this approach by converting several clinical-stage antibodies against OX40 and CD137 (4-1BB) into biepitopic antibodies with potent agonist activity.

Dynamic Hybrid Module-Driven NK Cell Stimulation and Release for Tumor Immunotherapy.

Natural killer (NK) cells have become a powerful candidate for adoptive tumor immunotherapy, while their therapeutic efficacy in solid tumors remains unsatisfactory. Here, we developed a hybrid module with an injectable hydrogel and hydroxyapatite (HAp) nanobelts for the controlled delivery of NK cells to enhance the therapy of solid tumors. Surface-functionalized HAp nanobelts modified with agonistic antibodies against NKG2D and 4-1BB and cytokines IL-2 and IL-21 support survival and dynamic activation. Thus, the HAp-modified chitosan (CS) thermos-sensitive hydrogel not only improved the retention of NK cells for more than 20 days in vivo but also increased NK cell function by more than one-fold. The unique architecture of this biomaterial complex protects NK cells from the hostile tumor environment and improves antitumor efficacy. The generation of a transient inflammatory niche for NK cells through a biocompatible hydrogel reservoir may be a conversion pathway to prevent cancer recurrence of resectable tumors.