Lymphocyte Activation Gene-3 Research Articles

A phase 2 study evaluating response and biomarkers in patients with microsatellite stable (MSS) advanced colorectal cancer (CRC) treated with nivolumab/relatlimab.

3554 Background: Lymphocyte-activation gene 3 (LAG-3) is an immunosuppressive signal, impairing T effector (Teff) activation. Pre-clinical studies suggest LAG-3 inhibition promotes anti-tumor immunity by enhancing Teff function. Correlative studies linked increased LAG-3 levels with reduced overall survival (OS) in CRC. These data prompted optimism that combined LAG-3/PD-1 inhibition might promote anti-tumor responses in MSS CRC. Methods: We conducted a phase 2 study of nivolumab (Nivo) (aPD1)/relatlimab (Rela) (aLAG3) in patients with previously treated advanced MSS CRC. This study enrolled patients onto 1 of 3 arms. Arms A and B used a Composite PD-L1 and acellular Mucin (CPM) score to define patients as CPM(+) in Arm A (CPM≥ 15%) and CPM(-) in Arm B (CPM< 15%). Patients in Arm A and B received Nivo 480mg/Rela 160mg IV q4 weeks. Arm C enrolled patients without biomarker selection who received Nivo 480mg/Rela 960mg or Rela 480mg/Nivo 480mg. The primary endpoint was objective response, and each arm was powered to detect an objective response rate (ORR) of ≥20%. Results: Fifty nine evaluable patients were enrolled (Arm A: 12, Arm B: 15, Arm C: 32). Patient characteristics and responses are outlined. Treatment was well tolerated with no new safety signals over aPD1 alone. Three (5%) patients achieved a partial response (PR), 6 (10%) stable disease (SD), and 50 with progression of disease (PD) as best response. The median progression-free survival was (Arm A: 2.2 mo., Arm B: 2.8 mo., Arm C: 2.6 mo.) while median OS was (Arm A: 4.3 mo., Arm B: 14.2 mo., Arm C: 12.4 mo.). In N=6 patients with lung-only metastases, 2 (33%) experienced a PR, and 1 (17%) a SD, for a clinical benefit rate of 50%. The trial incorporated translational correlates. We will report mass cytometry on PBMCs, RNAseq on baseline biopsies, and imaging mass cytometry on pre- and on-treatment biopsies. Conclusions: This combination did not meet the primary endpoint of 20% ORR for any of the 3 cohorts, but there was intriguing possible activity in patients with lung only metastases, consistent with emerging data. Clinical trial information: NCT03642067 .

A phase 1/2 study of favezelimab in combination with pembrolizumab for heavily pretreated anti–PD-1–refractory classical Hodgkin lymphoma (cHL): An updated analysis.

7056 Background: PD-1 inhibitors are standard of care for relapsed or refractory (R/R) cHL, but patients (pts) often progress after anti–PD-1 therapy. The immune checkpoint receptor lymphocyte-activation gene 3 (LAG-3) is proposed to contribute to anti–PD-1 resistance. In a phase 1/2 study (NCT03598608) evaluating favezelimab (anti–LAG-3) plus pembrolizumab (anti–PD-1) for R/R hematologic malignancies, the combination provided antitumor activity and manageable safety in pts with heavily pretreated anti–PD-1–refractory cHL (cohort 2). Updated results after additional follow-up are presented. Methods: Eligible pts were aged ≥18 years with R/R cHL; prior treatment with or ineligibility for autologous stem cell transplantation or no response to salvage chemotherapy; an ECOG performance status of 0 or 1; and disease progression after ≥2 doses of anti–PD-1–based therapy and within 12 weeks of the last dose of anti–PD-1 therapy. The study comprised a safety lead-in (pembrolizumab 200 mg IV Q3W + favezelimab 200-mg starting dose, then dose escalation to 800 mg IV Q3W per a modified toxicity probability interval design) and a dose expansion phase (pembrolizumab + favezelimab at the established recommended phase 2 dose of 800 mg Q3W for ≤35 cycles). Primary end point was safety. ORR per IWG 2007 criteria by investigator review was a secondary end point. DOR and PFS per IWG 2007 criteria by investigator review and OS were exploratory. Results: Cohort 2 enrolled 34 pts. Median time from first dose to data cutoff (August 15, 2023) was 40.7 months (range, 20.4-54.8). Treatment-related AEs occurred in 28 pts (82%); the most common (≥15%) were hypothyroidism (18%), nausea (18%), and fatigue (15%). Grade 3 or 4 treatment-related AEs occurred in 6 pts (18%). Discontinuation due to treatment-related AEs occurred in 6 pts (18%). No deaths due to treatment-related AEs were reported. AEs of clinical interest occurred in 17 pts (50%); 2 pts (6%) had grade 3 events (encephalitis, hepatitis) and 1 pt (3%) had a grade 4 event (type 1 diabetes mellitus). ORR was 29% (10/34; 95% CI, 15-48), with 3 (9%) complete responses and 7 (21%) partial responses. ORR was 35% (6/17; 95% CI, 14-62) in pts with anti–PD-1 and 24% (4/17; 95% CI, 7-50) in pts with non–anti–PD-1 as most recent therapy. Median DOR was 21.9 months (range, 0.0+ to 26.1+) and an estimated 17% of responders remained in response at 24 months. Median PFS was 9.7 months (95% CI, 5.1-14.7); 24-month PFS rate was 21%. Median OS was 39.0 months (95% CI, 25.7-not reached); 24-month OS rate was 73%. Conclusions: After additional follow-up, favezelimab + pembrolizumab continued to demonstrate manageable safety and antitumor activity in pts with heavily pretreated anti–PD-1–refractory cHL. The phase 3 KEYFORM-008 study (NCT05508867) will evaluate a coformulation of favezelimab and pembrolizumab in pts with anti–PD-1–refractory cHL. Clinical trial information: NCT03598608 .

A phase 1/2 study of favezelimab in combination with pembrolizumab for anti–PD-1–naive relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL): An updated analysis.

7055 Background: PD-1 inhibitors such as pembrolizumab are an important treatment option for patients (pts) with R/R cHL, but treatment failure remains a significant challenge. Dual immune checkpoint blockade with a PD-1 inhibitor and a lymphocyte-activation gene 3 (LAG-3) inhibitor shows promise as a treatment option for R/R cHL. In a multicohort phase 1/2 study (NCT03598608) evaluating the anti–LAG-3 monoclonal antibody favezelimab in combination with pembrolizumab for R/R hematologic malignancies, pembrolizumab plus favezelimab demonstrated sustained antitumor activity and acceptable safety in the cohort of pts with anti–PD-1–naive R/R cHL (cohort 1). We present updated results from this cohort after additional follow-up. Methods: Eligible pts were aged ≥18 years with R/R cHL; prior treatment with or ineligibility for autologous stem cell transplantation or no response to salvage chemotherapy; no prior PD-1 inhibitor; and an ECOG PS of 0 or 1. The study comprised a safety lead-in (pembrolizumab 200 mg IV Q3W plus favezelimab 200-mg starting dose, then dose escalation to 800 mg IV Q3W using a modified toxicity probability interval method) and a dose expansion phase (pembrolizumab 200 mg Q3W plus favezelimab at the established recommended phase 2 dose of 800 mg Q3W for up to 35 cycles). Primary end point was safety. Objective response rate (ORR) per IWG 2007 criteria by investigator review was a secondary end point. Duration of response (DOR) and progression-free survival (PFS) per IWG 2007 criteria by investigator review and overall survival (OS) were exploratory. Results: Cohort 1 enrolled 30 pts. The median time from first dose to data cutoff (August 15, 2023) was 36.9 months (range, 29.4-48.6). Treatment-related adverse events (AEs) occurred in 27 pts (90%), of which the most common (≥20%) were hypothyroidism (27%), infusion-related reaction (23%), and fatigue (20%). Grade 3 or 4 treatment-related AEs occurred in 7 pts (23%). Five pts (17%) discontinued treatment due to treatment-related AEs. No deaths due to treatment-related AEs were reported. AEs of clinical interest occurred in 20 pts (67%); 3 pts (10%) had grade 3 events (colitis, pneumonitis, severe skin reaction) and 1 pt (3%) had a grade 4 event (hepatitis). The ORR was 83% (n = 25; 95% CI, 65-94); 11 pts (37%) had a complete response and 14 (47%) had a partial response. Median DOR was 17.0 months (range, 2.6-30.5), and an estimated 47% of responders remained in response at 24 months. Median PFS was 19.4 months (95% CI, 9.5-28.5), and the 24-month PFS rate was 46%. Median OS was not reached (NR; 95% CI, NR-NR), and the 24-month OS rate was 93%. Conclusions: With additional follow-up, favezelimab plus pembrolizumab continued to demonstrate sustained antitumor activity and manageable safety in pts with anti–PD-1–naive R/R cHL. Further studies to investigate this combination are warranted. Clinical trial information: NCT03598608 .

Effect of combinatorial immune checkpoint blockade on myocardial expression of NLRP-3 and secretion of H-FABP, NT-Pro-BNP, interleukin-1β, and interleukin-6: Biochemical implications in cardio-immuno-oncology.

e24016 Background: Immune checkpoint blockade in monotherapy or combinatorial regimens with chemotherapy or radiotherapy have become an integral part of oncology in recent years. Monoclonal antibodies against CTLA-4 or PD-1 or PDL-1 are the most studied ICIs in randomized clinical trials, however, more recently, an anti-LAG3 (Lymphocyte activation gene-3) antibody, Relatlimab, has been approved by FDA in combination with Nivolumab for metastatic melanoma therapy. Moreover, Atezolizumab is actually under study in association with Ipilimumab for therapy of metastatic lung cancer. Myocarditis, vasculitis and endothelitis are rarely observed in these patients on monotherapy, however new combination therapies could expose patients to more adverse cardiovascular events. Methods: human cardiomyocytes, human peripheral blood lymphocytes (hPBMCs) and combinatorial ICIs (PD-L1 and CTLA-4 or PD-1 and LAG-3 blocking agents, at 100 nM) for 48 h. After treatments, cardiac cell lysis and secretion of biomarkers of cardiotoxicity (H-FABP, troponin-T, BNP, NT-Pro-BNP), NLRP3-inflammasome and Interleukin 1 and 6 were determined through colorimetric and enzymatic assays. Mitochondrial functions were studied in cardiomyocyte cell lysates through quantification of intracellular Ca++, ATP content and NADH:ubiquinone oxidoreductase core subunit S1 (Ndufs1) levels. Histone deacetylases type 4 (HDAC-4) protein levels were also determined in cardiomyocyte cell lysates to study potential epigenetic changes induced by immunotherapy regimens. Results: Both combinations of immune checkpoint inhibitors exert more potent cardiotoxic side effects compared to monotherapies against human cardiac cells co-cultured with human lymphocytes. LDH release from cardiac cells was 43% higher in PD-L1/CTLA-4 blocking agents, and 35.7% higher in PD-1/LAG-3 blocking agents compared to monotherapies. HDAC4 and intracellular Ca++ levels were increased, instead ATP content and Ndufs1 were reduced in myocardial cell lysates (p < 0.001 vs untreated cells). Troponin-T, BNP, NT-Pro-BNP and H-FABP, were also strongly increased in combination therapy compared to monotherapy regimen. NLRP3 expression, IL-6 and IL-1β levels were also increased by PDL-1/CTLA-4 and PD-1/LAG-3 combined blocking agents compared to untreated cells and monotherapies. Conclusions: Data of the present study, although in vitro, indicate that combinatorial immune checkpoint blockade, induce a pro- inflammatory phenotype, thus indicating that these therapies should be closely monitored by the multidisciplinary team consisting of oncologists, cardiologists and immunologists.

A phase 3 trial of fixed dose combinations of fianlimab (anti–LAG-3) + cemiplimab (anti–PD-1) versus relatlimab + nivolumab in patients with unresectable or metastatic melanoma.

TPS9611 Background: Fianlimab (anti–lymphocyte activation gene 3 [LAG-3]) and cemiplimab (anti–programmed cell death-1 [PD-1]) are high-affinity, fully human, immunoglobulin G4 monoclonal antibodies. Concurrent LAG-3 blockade may enhance the efficacy of anti–PD-1 therapies. Relatlimab (anti–LAG-3) + nivolumab (anti–PD-1) monoclonal antibodies demonstrated benefit in progression-free survival (PFS) in advanced melanoma (Mel) patients compared with nivolumab alone in the RELATIVITY-047 study. In a multicohort Phase 1 study (NCT03005782), fianlimab + cemiplimab demonstrated reproducibly high clinical activity (objective response rate [ORR]: 61%, N=98) in three independent cohorts of advanced PD-(L)1–naïve metastatic Mel patients with an acceptable safety profile. Methods: This is a randomized, open-label, multicenter Phase 3 study (NCT06246916) comparing the fixed dose combination (FDC) of fianlimab + cemiplimab to the FDC of relatlimab + nivolumab in patients with unresectable or metastatic Mel. The primary objective is to demonstrate superiority of fianlimab + cemiplimab compared with relatlimab + nivolumab as measured by ORR assessed by blinded independent central review (BICR). This study will be conducted at approximately 80 sites across North America. Key inclusion criteria are: (1) aged ≥18 years; (2) histologically confirmed unresectable stage III or IV (metastatic) Mel; (3) no prior systemic therapy for unresectable or metastatic Mel; patients with adjuvant and/or neoadjuvant systemic therapies are eligible with a treatment-free and disease-free interval of >6 months; (4) measurable disease per Response Evaluation Criteria in Solid Tumors version 1.1; (5) Eastern Cooperative Oncology Group performance status of ≤1; (6) adequate bone marrow, hepatic, and kidney function. Approximately 560 patients will be randomized in a 1:1 ratio to two treatment arms: Arm A: FDC of fianlimab (Dose 1) + cemiplimab (Dose 2) every 3 weeks intravenously (IV); Arm B: FDC of relatlimab 160 mg + nivolumab 480 mg every 4 weeks IV. All patients will be stratified based on metastatic stage (stage III vs M1a–b vs M1c–d), baseline lactate dehydrogenase level (≤ vs > upper limit of normal), and prior adjuvant and/or neoadjuvant systemic therapy. Patients will receive treatment until disease progression, unacceptable toxicity, withdrawal of consent, a study withdrawal criterion is met, or the sponsor terminates the study. The primary endpoint is ORR and key secondary endpoints are PFS and overall survival. Additional secondary endpoints are duration of response, disease control rate, investigator-assessed ORR and PFS, safety, pharmacokinetics, and immunogenicity. Clinical trial information: NCT06246916 .

A phase 2/3 study of fianlimab, cemiplimab, plus chemotherapy versus cemiplimab plus chemotherapy in first-line treatment of advanced non-small cell lung cancer.

TPS8660 Background: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. Anti–programmed cell death-1 (PD-1) therapies have improved outcomes in patients with NSCLC; however, most patients do not respond or only respond for a limited time. The combination of cemiplimab (anti–PD-1) and chemotherapy has been studied for the first-line treatment of advanced NSCLC (aNSCLC), regardless of programmed cell death-ligand 1 (PD-L1) status. While the standard of care continues to evolve for NSCLC, one approach to potentially improve outcomes is the combination of checkpoint inhibitors (IO) with chemotherapy. Fianlimab (anti–lymphocyte activation gene 3 [LAG-3]) and cemiplimab are both high-affinity, fully human IgG4 monoclonal antibody IO therapies that have shown promising clinical activity when combined in patients with aNSCLC in a Phase 1 study (NCT03005782). This ongoing study will further investigate the combination of fianlimab + cemiplimab + chemotherapy. Methods: This is a randomized, multicenter, Phase 2/3 study of fianlimab + cemiplimab + platinum-doublet chemotherapy (chemo) versus cemiplimab + chemo in patients with unresectable stage IIIB/IIIC or stage IV NSCLC irrespective of PD-L1 expression levels (NCT05800015). This study will be conducted globally at approximately 210 sites. Patient eligibility criteria: ≥18 years old; squamous or non-squamous histology with stage IIIB, IIIC, or IV disease; valid PD-L1 result; ≥1 radiographically measurable lesion by computed tomography/magnetic resonance imaging; Eastern Cooperative Oncology Group performance status ≤1; adequate organ and bone marrow function. The Phase 2 portion will be used to determine the fianlimab dose selected for the Phase 3 portion: patients will be randomized 1:1:1 to receive fianlimab high dose + cemiplimab 350 mg + chemo (Arm A), fianlimab low dose + cemiplimab 350 mg + chemo (Arm B), or cemiplimab 350 mg + chemo + placebo (Arm C), Q3W IV. In Phase 3, patients will be randomized 1:1 into one of two treatment arms (either Arm A or Arm B, and Arm C) based on findings from Phase 2. The primary endpoint of Phase 2 is objective response rate (ORR) per blinded independent central review. The primary endpoint of Phase 3 is overall survival. The secondary endpoints include efficacy (ORR, disease control rate, time to tumor response, duration of response, progression-free survival, and overall survival), safety and tolerability, immunogenicity (anti-drug antibodies and neutralizing antibodies against fianlimab or cemiplimab in serum), patient-reported outcomes, and pharmacokinetics. This study and a parallel study of fianlimab + cemiplimab in patients with aNSCLC with tumors expressing PD-L1 ≥50% (NCT05785767) are currently open for enrollment. Clinical trial information: NCT05800015 .

A phase 2/3 study of fianlimab plus cemiplimab versus cemiplimab in patients with advanced non-small cell lung cancer with tumors expressing PD-L1 ≥50%.

TPS8663 Background: Fianlimab (anti–lymphocyte activation gene 3 [LAG-3]) and cemiplimab (anti–programmed cell death-1 [PD-1]) are high-affinity, fully human, IgG4 monoclonal antibodies. In patients (pts) with advanced non-small cell lung cancer (aNSCLC) and programmed cell death-ligand 1 (PD-L1) expression ≥50% with no actionable mutations, first-line cemiplimab monotherapy showed significantly prolonged overall survival (OS) and progression-free survival (PFS) versus chemotherapy, with a safety profile consistent with previous reports for cemiplimab monotherapy. Despite pts’ selection by PD-L1 expression, only ~50% of pts respond to PD-1 therapy, thus there is a need for immune-oncology combinations like anti–LAG-3 plus anti–PD-1 to potentially improve outcomes. Methods: This is a randomized, double-blind, Phase 2/3 study (NCT05785767) to evaluate fianlimab + cemiplimab versus cemiplimab monotherapy as first-line treatment in pts with aNSCLC and tumors expressing PD-L1 ≥50%. The study will be conducted globally at ~210 sites. Key inclusion criteria: ≥18 years old; histologically confirmed squamous or non-squamous stage IIIB/C (not candidates for surgical resection or definitive chemoradiation) or stage IV NSCLC (no prior systemic treatment for recurrent or metastatic NSCLC); PD-L1 expression in ≥50% of tumor cells; ≥1 radiographically measurable lesion per Response Evaluation Criteria in Solid Tumors v1.1; Eastern Cooperative Oncology Group performance status ≤1; adequate organ and bone marrow function. This study has Phase 2 and Phase 3 parts and is expected to enroll ~850 pts. Pts will be treated for up to 108 weeks. In Phase 2, 150 patients will be randomized 1:1:1 into three treatment arms (Q3W IV): Arm A, fianlimab high dose + cemiplimab 350 mg; Arm B, fianlimab low dose + cemiplimab 350 mg; Arm C, cemiplimab 350 mg + saline/dextrose placebo. Based on findings from Phase 2, the dose of fianlimab (low or high) will be selected for Phase 3. In Phase 3, 700 patients will be randomized 1:1 into either experimental Arm A or B, and comparator Arm C (cemiplimab + placebo). In Phase 2, the primary endpoint is objective response rate (ORR) per blinded independent central review (BICR). The secondary endpoints are safety, ORR per investigator assessment, disease control rate (DCR), time to tumor response (TTR), duration of response (DOR), PFS, OS, patient-reported outcomes, pharmacokinetics, and immunogenicity. In Phase 3, the primary endpoint is OS in patients receiving fianlimab + cemiplimab versus cemiplimab monotherapy. Secondary endpoints are safety, ORR, DCR, TTR, DOR, and PFS, per BICR and investigator assessment, patient-reported outcomes, pharmacokinetics, and immunogenicity. This study is open for enrollment along with a second study of fianlimab + cemiplimab + chemotherapy in aNSCLC. Clinical trial information: NCT05785767 .

Nivolumab plus relatlimab in patients with previously treated microsatellite instability-high/mismatch repair-deficient metastatic colorectal cancer: the phase II CheckMate 142 study

BackgroundProgrammed death-1 (PD-1) inhibitors, including nivolumab, have demonstrated long-term survival benefit in previously treated patients with microsatellite instability-high/mismatch repair-deficient (MSI-H/dMMR) metastatic colorectal cancer (CRC). PD-1 and lymphocyte-activation gene 3 (LAG-3)...

Aplp1 interacts with Lag3 to facilitate transmission of pathologic α-synuclein

Pathologic α-synuclein (α-syn) spreads from cell-to-cell, in part, through binding to the lymphocyte-activation gene 3 (Lag3). Here we report that amyloid β precursor-like protein 1 (Aplp1) interacts with Lag3 that facilitates the binding, internalization, transmission, and toxicity of pathologic α-syn. Deletion of both Aplp1 and Lag3 eliminates the loss of dopaminergic neurons and the accompanying behavioral deficits induced by α-syn preformed fibrils (PFF). Anti-Lag3 prevents the internalization of α-syn PFF by disrupting the interaction of Aplp1 and Lag3, and blocks the neurodegeneration induced by α-syn PFF in vivo. The identification of Aplp1 and the interplay with Lag3 for α-syn PFF induced pathology deepens our insight about molecular mechanisms of cell-to-cell transmission of pathologic α-syn and provides additional targets for therapeutic strategies aimed at preventing neurodegeneration in Parkinson’s disease and related α-synucleinopathies.

Progesterone receptor impairs immune respond and down-regulates sensitivity to anti-LAG3 in breast cancer

BackgroundProgesterone receptor (PR) serves as a crucial prognostic and predictive marker in breast cancer. Nonetheless, the interplay between PR and the tumor immune microenvironment remains inadequately understood. This investigation employs bioinformatics analyses, mouse models, and clinical specimens to elucidate the impact of PR on immune microenvironment and identify potential targets for immunotherapy, furnishing valuable guidance for clinical practice. MethodsAnalysis of immune infiltration score by Xcell between PR-positive and PR-negative breast cancer tumors. Construction of overexpression mouse progesterone receptor (mPgr) EMT-6 cell was to explore the tumor immune microenvironment. Furthermore, anti- Lymphocyte-activation gene 3 (LAG3) therapy aimed to investigate whether PR could influence the effectiveness of immune treatments. ResultsOverexpression mPgr inhibited tumor growth in vitro, but promoted tumor growth in Balb/c mouse. Flow cytometry showed that the proportion and cytotoxicity of CD8+T cells in tumor of overexpressing mPgr group were significantly reduced. The significant reduction in overexpressing mPgr group was found in the proportions of LAG3+CD8+ T cells and LAG3+ Treg T cells. Anti-LAG3 treatment resulted in reduced tumor growth in EV group mouse rather than in overexpressing mPgr group. Patents derived tumor fragment (PDTF) also showed higher anti-tumor ability of CD3+T cell in patents’ tumor with PR <20% after anti-human LAG3 treatment in vitro. ConclusionsThe mPgr promotes tumor growth by downregulating the infiltration and function of cytotoxic cell. LAG3 may be a target of ER-positive breast cancer immunotherapy. The high expression of PR hinders the sensitivity to anti-LAG3 treatment.

Immune checkpoint inhibitors: breakthroughs in cancer treatment.

Over the past two decades, immunotherapies have increasingly been considered as first-line treatments for most cancers. One such treatment is immune checkpoint blockade (ICB), which has demonstrated promising results against various solid tumors in clinical trials. Monoclonal antibodies (mAbs) are currently available as immune checkpoint inhibitors (ICIs). These ICIs target specific immune checkpoints, including cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein 1 (PD-1). Clinical trial results strongly support the feasibility of this immunotherapeutic approach. However, a substantial proportion of patients with cancer develop resistance or tolerance to treatment, owing to tumor immune evasion mechanisms that counteract the host immune response. Consequently, substantial research focus has been aimed at identifying additional ICIs or synergistic inhibitory receptors to enhance the effectiveness of anti-PD-1, anti-programmed cell death ligand 1 (anti-PD-L1), and anti-CTLA-4 treatments. Recently, several immune checkpoint molecular targets have been identified, such as T cell immunoreceptor with Ig and ITIM domains (TIGIT), mucin domain containing-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), V-domain immunoglobulin suppressor of T cell activation (VISTA), B and T lymphocyte attenuator (BTLA), and signal-regulatory protein α (SIRPα). Functional mAbs targeting these molecules are under development. CTLA-4, PD-1/PD-L1, and other recently discovered immune checkpoint proteins with distinct structures are at the forefront of research. This review discusses these structures, as well as clinical progress in mAbs targeting these immune checkpoint molecules and their potential applications.

Hepatocyte-derived FGL1 accelerates liver metastasis and tumor growth by inhibiting CD8+ T and NK cells.

Fibrinogen-like protein 1 (FGL1) contributes to the proliferation and metabolism of hepatocytes; however, as a major ligand of the immune checkpoint, its role in the liver regional immune microenvironment is poorly understood. Hepatocytes specifically and highly expressed FGL1 under normal physiological conditions. Increases in hepatic CD8+ T and NK cell numbers and functions were found in Fgl1-deficient (Fgl1-/-) mice, but not in the spleen or lymph node, similar to findings in anti-FGL1 mAb-treated wild-type mice. Furthermore, Fgl1 deficiency or anti-FGL1 mAb blockade restrained liver metastasis and slowed the growth of orthotopic tumors, with significantly prolonged survival of tumor-bearing mice. Tumor-infiltrating hepatic CD8+ T and NK cells upregulated the expression of lymphocyte activation gene-3 (LAG-3) and exhibited stronger antitumor activities after anti-FGL1 treatment. The antitumor efficacy of FGL1 blockade depended on cytotoxic T lymphocytes and NK cells, demonstrated by using a cell-deficient mouse model and cell transfer in vivo. In vitro, FGL1 directly inhibited hepatic T and NK cells related to the receptor LAG-3. In conclusion, hepatocyte-derived FGL1 played critical immunoregulatory roles in the liver and contributed to liver metastasis and tumor growth by inhibiting CD8+ T and NK cell functions via the receptor LAG-3, providing a new strategy for liver cancer immunotherapy.

Cutting Edge: LAG3 Dimerization Is Required for TCR/CD3 Interaction and Inhibition of Antitumor Immunity.

Lymphocyte activation gene 3 (LAG3) is an inhibitory receptor that plays a critical role in controlling T cell tolerance and autoimmunity and is a major immunotherapeutic target. LAG3 is expressed on the cell surface as a homodimer but the functional relevance of this is unknown. In this study, we show that the association between the TCR/CD3 complex and a murine LAG3 mutant that cannot dimerize is perturbed in CD8+ T cells. We also show that LAG3 dimerization is required for optimal inhibitory function in a B16-gp100 tumor model. Finally, we demonstrate that a therapeutic LAG3 Ab, C9B7W, which does not block LAG3 interaction with its cognate ligand MHC class II, disrupts LAG3 dimerization and its association with the TCR/CD3 complex. These studies highlight the functional importance of LAG3 dimerization and offer additional approaches to therapeutically target LAG3.

O05 Single-cell transcriptomic signature of paradoxical eczema in patients with psoriasis treated with biologics

Abstract Introduction and aims Biologics targeting the tumour necrosis factor (TNF) and the interleukin (IL)-17/23 axis are highly effective treatments for psoriasis but can result in cutaneous adverse events. The pathogenesis of paradoxical eczema, an atopic dermatitis (AD) phenotype occurring after biologic initiation in people with psoriasis, is unknown. This study explored the systemic disease signature of paradoxical eczema. Methods We used single-cell RNA-Seq on peripheral blood mononuclear cells (PBMCs) from three patients with psoriasis with paradoxical eczema, and three matched, biologic-treated controls who had psoriasis. Differential gene expression, gene network expression and cell–cell interaction (using MultiNicheNet) analyses allowed comparison of cases and controls. We assessed overlap between paradoxical eczema and AD using six AD transcriptome datasets. Results Overall, 32 827 PBMCs (14 521 from cases, 18 306 from controls) were included and categorized into 27 clusters. Between cases and controls, there were 727 differentially expressed genes (DEGs) (log fold-change &amp;gt; 0.25, adjusted P &amp;lt; 0.05). A total of 94 of the top 100 DEGs were from monocytes. Significant DEG networks (P &amp;lt; 0.05) mostly mapped to T-cell and monocyte clusters, with commonly enriched pathways in cases including interferon (IFN)-γ, IFN-α, TNF, IL-2/signal transducer and activator of transcription 5 and T-cell differentiation pathways. Cell–cell interaction analysis revealed that the most prioritized interactions in controls, based on differential expression data and known ligand-receptor interactions, included immune regulatory interactions (including ligands such as transforming growth factor β1 and lymphocyte-activation gene 3). In cases, functions of prioritized interactions included chemotaxis, leucocyte activation, T-cell priming and IFN-γ signalling. There was significant enrichment of concordance in the direction of effect of DEGs (65%, P = 5.39 × 10−6) and enriched pathways (85%, P = 3.62 × 10−13) between AD and paradoxical eczema. Conclusions Patients with paradoxical eczema have reduced immune regulatory mechanisms and evidence of monocyte and T-cell activation systemically, with increased production IFN-γ, IFN-α and TNF. There is a significant overlap with the AD transcriptome.

Valrubicin-loaded immunoliposomes for specific vesicle-mediated cell death in the treatment of hematological cancers

We created valrubicin-loaded immunoliposomes (Val-ILs) using the antitumor prodrug valrubicin, a hydrophobic analog of daunorubicin. Being lipophilic, valrubicin readily incorporated Val-lLs that were loaded with specific antibodies. Val-ILs injected intravenously rapidly reached the bone marrow and spleen, indicating their potential to effectively target cancer cells in these areas. Following the transplantation of human pediatric B-cell acute lymphoblastic leukemia (B-ALL), T-cell acute lymphoblastic leukemia (T-ALL), or acute myeloid leukemia (AML) in immunodeficient NSG mice, we generated patient-derived xenograft (PDX) models, which were treated with Val-ILs loaded with antibodies to target CD19, CD7 or CD33. Only a small amount of valrubicin incorporated into Val-ILs was needed to induce leukemia cell death in vivo, suggesting that this approach could be used to efficiently treat acute leukemia cells. We also demonstrated that Val-ILs could reduce the risk of contamination of CD34+ hematopoietic stem cells by acute leukemia cells during autologous peripheral blood stem cell transplantation, which is a significant advantage for clinical applications. Using EL4 lymphoma cells on immunocompetent C57BL/6 mice, we also highlighted the potential of Val-ILs to target immunosuppressive cell populations in the spleen, which could be valuable in impairing cancer cell expansion, particularly in lymphoma cases. The most efficient Val-ILs were found to be those loaded with CD11b or CD223 antibodies, which, respectively, target the myeloid-derived suppressor cells (MDSC) or the lymphocyte-activation gene 3 (LAG-3 or CD223) on T4 lymphocytes. This study provides a promising preclinical demonstration of the effectiveness and ease of preparation of Val-ILs as a novel nanoparticle technology. In the context of hematological cancers, Val-ILs have the potential to be used as a precise and effective therapy based on targeted vesicle-mediated cell death.

First-Line Nivolumab and Relatlimab Plus Chemotherapy for Gastric or Gastroesophageal Junction Adenocarcinoma: The Phase II RELATIVITY-060 Study.

Open-label phase II study (RELATIVITY-060) to investigate the efficacy and safety of first-line nivolumab, a PD-1-blocking antibody, plus relatlimab, a lymphocyte-activation gene 3 (LAG-3)-blocking antibody, plus chemotherapy in patients with previously untreated advanced gastric cancer (GC) or gastroesophageal junction cancer (GEJC). Patients with unresectable, locally advanced or metastatic GC/GEJC were randomly assigned 1:1 to nivolumab + relatlimab (fixed-dose combination) + chemotherapy or nivolumab + chemotherapy. The primary end point was objective response rate (ORR; per RECIST v1.1 by blinded independent central review [BICR]) in patients whose tumors had LAG-3 expression ≥1%. Of 274 patients, 138 were randomly assigned to nivolumab + relatlimab + chemotherapy and 136 to nivolumab + chemotherapy. Median follow-up was 11.9 months. In patients with LAG-3 expression ≥1%, BICR-assessed ORR (95% CI) was 48% (38 to 59) in the nivolumab + relatlimab + chemotherapy arm and 61% (51 to 71) in the nivolumab + chemotherapy arm; median progression-free survival (95% CI) by BICR was 7.0 months (5.8 to 8.4) versus 8.3 months (6.9 to 12.1; hazard ratio [HR], 1.41 [95% CI, 0.97 to 2.05]), and median overall survival (95% CI) was 13.5 months (11.9 to 19.1) versus 16.0 months (10.9 to not estimable; HR, 1.04 [95% CI, 0.70 to 1.54]), respectively. Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 69% and 61% of all treated patients, and 42% and 36% of patients discontinued because of any-grade TRAEs in the nivolumab + relatlimab + chemotherapy and nivolumab + chemotherapy arms, respectively. RELATIVITY-060 did not meet its primary end point of improved ORR in patients with LAG-3 expression ≥1% when relatlimab was added to nivolumab + chemotherapy compared with nivolumab + chemotherapy. Further studies are needed to address whether adding anti-LAG-3 to anti-PD-1 plus chemotherapy can benefit specific GC/GEJC patient subgroups.

LAG-3 : recent developments in combinational therapies in cancer.

The study of anticancer immune responses and in particular the action of immune checkpoint inhibitors that overcome T cell inhibition has revolutionized metastatic patients' care. Unfortunately, many patients are resistant to these innovative immunotherapies. Over the last decade, several immune checkpoint inhibitors, currently available in the clinic, have been developed, such as anti-PD-1/PD-L1 or anti-CTLA-4. More recently, other immune checkpoints have been characterized, among them lymphocyte activation gene 3 (LAG-3). LAG-3 has been the subject of numerous therapeutic studies and may be involved in cancer-associated immune resistance phenomena. This review summarizes the latest knowledge on LAG-3 as an immunotherapeutic target, particularly in combination with standard or innovative therapies. Indeed, many studies are looking at combining LAG-3 inhibitors with chemotherapeutic, immunotherapeutic, radiotherapeutic treatments, or adoptive cell therapies to potentiate their antitumor effects and/or to overcome patients' resistance. We will particularly focus on the association therapies that are currently in phase III clinical trials and innovative combinations in preclinical phase. These new discoveries highlight the possibility of developing other types of therapeutic combinations currently unavailable in the clinic, which could broaden the therapeutic spectrum of personalized medicine.

LAG3 regulates antibody responses following kidney transplantation

Abstract Lymphocyte activation gene-3 (LAG3) is a coinhibitory receptor expressed by a range of immune cells. The immunomodulatory potential of LAG3 is being explored in cancer and autoimmunity fields but not in transplantation. Using our mouse kidney transplant models we sought to address the role of LAG3 in graft rejection. Untransplanted LAG3-/- mice have elevated heterologous immunity against a panel of alloantigens. Recipient LAG3 deficiency results in rapid rejection of MHC-mismatched renal allografts that are spontaneously accepted by WT recipients, with graft histology characteristic of antibody mediated rejection (ABMR). Antagonistic LAG3 antibody treatment of WT recipients enhanced anti-donor immune responses and induced kidney damage typical of chronic rejection, indicating that LAG3 regulates de novo alloresponses. Recipient B cell depletion, but not CD8+ T cells, prevented kidney allograft rejection in LAG3-/- recipients further supporting ABMR as the mechanism of graft loss. Posttransplant, follicular T cells and plasma cells are among LAG3 expressing immune cells. To identify the mechanism we used T or B cell conditional LAG3 knockout recipients, neither reject the allograft but both had elevated levels of donor specific antibodies (DSA), indicating LAG3 expression on either T or B cells is sufficient to regulate anti-donor humoral immunity. Our results identify LAG3 as a regulator of DSA following kidney transplantation and a potential therapeutic target for ABMR.

Chronic intermittent hypoxia alters CD8+ expression in the bone marrow of C57BL/6 mice

Cytotoxic CD8+ cells are critical in anticancer immune response and have become prevalent in immunotherapies over the past decade. Anti-LAG3/anti-PD1 combined immunotherapies increase the number of CD8+ cells. Moderate to severe sleep apnea increases the risk of cancer-related mortality. Chronic intermittent hypoxia, a feature of sleep apnea, decreases the percentage of perforin-expressing CD8+ cells, impairing cytotoxicity. Our objective is to determine the distribution of Prf1(perforin), LAG3(lymphocyte-activation gene 3), and PDCD1(programmed cell death 1) in C57BL/6 mice exposed to chronic intermittent hypoxia (CIH). We hypothesize that Prf1, PDCD1, and LAG3 will be expressed on three discrete clusters with a higher expression of LAG3 and PDCD1 and lower expression of Prf1 between C57BL/6 mice exposed to chronic intermittent hypoxia and normoxia. Bone marrow from the femur of C57BL/6 mice exposed to chronic intermittent hypoxia or normoxia was harvested. Bone marrow mononuclear cells were isolated, RNA was extracted, and single-cell RNA sequencing was performed. Loupe browser was used to re-cluster and quantify expression for genes of interest. Prf1 and PDCD1 are expressed in CD3+CD8−CD4− cluster and LAG3 is expressed in CD3−CD8+CD4+ cluster. LAG3 and Prf1 are present among the top ten genes, while PDCD1 is not in those clusters. Further analysis of the top ten genes of CD3+CD8−CD4− has demonstrated they are a group of natural killer cells. Contradictory to our expectation, Prf1 and PDCD1 are present in CD3+CD8−CD4− cluster while LAG3 is present in CD3−CD8+CD4+ cluster. Further analysis is necessary to determine the underlying mechanisms causing these changes. 5R01CA244271-02. 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.

Shedding light on the role of LAG-3 in hepatocellular carcinoma: unraveling immunomodulatory pathways

Hepatocellular carcinoma (HCC) stands as a primary malignant liver tumor characterized by chronic inflammation and complex alterations within the tumor microenvironment (TME). Lymphocyte activation gene 3 (LAG-3), also known as CD223, has gained prominence as a potential next-generation immune checkpoint, maintaining continuous expression in response to persistent antigen exposure within the TME, warranting our attention. In patients with HCC, LAG-3 expression on T cells, regulatory T cells (Tregs), and natural killer (NK) cells contributes to immune evasion, while high expression of LAG-3 leads to increased angiogenesis and poor prognosis. By interacting with major histocompatibility complex class II molecules, LAG-3 promotes T cell exhaustion and suppresses antitumor responses, often in collaboration with other immune checkpoints like programmed cell death protein 1 (PD-1), while on Tregs and NK cells, LAG-3 modulates their suppressive functions, indirectly facilitating tumor immune escape. LAG-3 expression may offer prognostic insights, correlating with disease progression and outcomes in HCC patients, while various preclinical studies highlight the potential of LAG-3-targeted therapies in reinvigorating immune responses against HCC, with a few combination approaches targeting LAG-3 alongside other checkpoints demonstrating synergistic effects in restoring T cell function. Therefore, harnessing LAG-3 as a therapeutic target holds promise for enhancing antitumor immunity and potentially improving HCC treatment outcomes. Our narrative review aims to delve into the full spectrum of LAG-3 signaling in HCC, with the goal of a better understanding of the pathophysiological and immunological basis of its use to arrest HCC growth and development.