Lymphocyte Activation Gene-3 Blockade Research Articles

Inhibition of USP7 enhances CD8+ T cell activity in liver cancer by suppressing PRDM1-mediated FGL1 upregulation.

Lymphocyte activation gene 3 (LAG3), an immune checkpoint molecule expressed on activated T cells, functions as a negative regulator of immune responses. Persistent antigen exposure in the tumor microenvironment results in sustained LAG3 expression on T cells, contributing to T cell dysfunction. Fibrinogen-like protein 1 (FGL1) has been identified as a major ligand of LAG3, and FGL1/LAG3 interaction forms a novel immune checkpoint pathway that results in tumor immune evasion. In addition, ubiquitin-specific peptidase 7 (USP7) plays a crucial role in cancer development. In this study we investigated the role of USP7 in modulation of FGL1-mediated liver cancer immune evasion. We showed that knockdown of USP7 or treatment with USP7 inhibitor P5091 suppressed liver cancer growth by promoting CD8+ T cell activity in Hepa1-6 xenograft mice and in HepG2 or Huh7 cells co-cultured with T cells, whereas USP7 overexpression produced the opposite effect. We found that USP7 upregulated FGL1 in HepG2 and Huh7 cells by deubiquitination of transcriptional factor PR domain zinc finger protein 1 (PRDM1), which transcriptionally activated FGL1, and attenuated the CD8+ T cell activity, leading to the liver cancer growth. Interestingly, USP7 could be transcriptionally stimulated by PRDM1 as well in a positive feedback loop. P5091, an inhibitor of USP7, was able to downregulate FGL1 expression, thus enhancing CD8+ T cell activity. In an immunocompetent liver cancer mouse model, the dual blockade of USP7 and LAG3 resulted in a superior antitumor activity compared with anti-LAG3 therapy alone. We conclude that USP7 diminishes CD8+ T cell activity by a USP7/PRDM1 positive feedback loop on FGL1 production in liver cancer; USP7 might be a promising target for liver cancer immunotherapy.

Neoadjuvant nivolumab or nivolumab plus LAG-3 inhibitor relatlimab in resectable esophageal/gastroesophageal junction cancer: a phase Ib trial and ctDNA analyses

Gastroesophageal cancer dynamics and drivers of clinical responses with immune checkpoint inhibitors (ICI) remain poorly understood. Potential synergistic activity of dual programmed cell death protein 1 (PD-1) and lymphocyte-activation gene 3 (LAG-3) inhibition may help improve immunotherapy responses for these tumors. We report a phase Ib trial that evaluated neoadjuvant nivolumab (Arm A, n = 16) or nivolumab–relatlimab (Arm B, n = 16) in combination with chemoradiotherapy in 32 patients with resectable stage II/stage III gastroesophageal cancer together with an in-depth evaluation of pathological, molecular and functional immune responses. Primary endpoint was safety; the secondary endpoint was feasibility; exploratory endpoints included pathological complete (pCR) and major pathological response (MPR), recurrence-free survival (RFS) and overall survival (OS). The study met its primary safety endpoint in Arm A, although Arm B required modification to mitigate toxicity. pCR and MPR rates were 40% and 53.5% for Arm A and 21.4% and 57.1% for Arm B. Most common adverse events were fatigue, nausea, thrombocytopenia and dermatitis. Overall, 2-year RFS and OS rates were 72.5% and 82.6%, respectively. Higher baseline programmed cell death ligand 1 (PD-L1) and LAG-3 expression were associated with deeper pathological responses. Exploratory analyses of circulating tumor DNA (ctDNA) showed that patients with undetectable ctDNA post-ICI induction, preoperatively and postoperatively had a significantly longer RFS and OS; ctDNA clearance was reflective of neoantigen-specific T cell responses. Our findings provide insights into the safety profile of combined PD-1 and LAG-3 blockade in gastroesophageal cancer and highlight the potential of ctDNA analysis to dynamically assess systemic tumor burden during neoadjuvant ICI that may open a therapeutic window for future intervention. ClinicalTrials.gov registration: NCT03044613.

Favezelimab in Combination with Pembrolizumab in Patients with Heavily Pretreated Anti-PD-1-Refractory Classical Hodgkin Lymphoma: Updated Analysis of an Open-Label Phase 1/2 Study

Background: Programmed cell death protein 1 (PD-1) inhibitors are a standard of care for relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL), but better treatment options are needed for patients with anti-PD-1-refractory disease. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint receptor with a role in regulating T-cell function. Dual blockade of PD-1 and LAG-3 has demonstrated antitumor activity in patients with advanced melanoma. Combination therapy with favezelimab (anti-LAG-3) and pembrolizumab (anti-PD-1) is currently being investigated in a phase 1/2 study (NCT03598608) in patients with R/R hematologic malignancies. Prior analyses showed that the combination had antitumor activity and manageable safety in patients with heavily pretreated anti-PD-1-refractory cHL (cohort 2). Updated results for this cohort are presented. Methods: The study consisted of a safety lead-in (part 1) followed by a dose-expansion phase (part 2). Eligible patients were ≥18 y; had R/R cHL after autologous stem cell transplantation (ASCT), were ineligible for ASCT, or did not respond to salvage chemotherapy; had an ECOG performance status of 0 or 1; and had experienced disease progression after ≥2 doses of anti-PD-1-based therapy and within 12 weeks of the last dose of anti-PD-1 therapy. In part 1, patients received pembrolizumab 200 mg IV Q3W + favezelimab starting at 200 mg and escalating to 800 mg IV Q3W per a modified toxicity probability interval design. In part 2, patients received pembrolizumab + favezelimab at the established RP2D of 800 mg Q3W for ≤35 cycles (~2 y). The 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 end points. Results: 34 patients with anti-PD-1-refractory cHL were enrolled in cohort 2. The median age was 37.5 y (range, 25-79), 16 patients (47%) were male, 21 (62%) had an ECOG performance status of 0, and 94% had received ≥4 prior lines of therapy. Seventeen patients (50%) had received an anti-PD-1-based regimen as their most recent therapy. At database cutoff (March 2, 2023), 8 patients (24%) had completed 35 cycles of treatment and 26 (76%) had discontinued treatment (14 [41%] progressive disease, 7 [21%] AEs, 5 [15%] other reasons). The median time from first dose to data cutoff was 35.3 mo (range, 15.0-49.4). Treatment-related AEs occurred in 28 patients (82%), of which the most common (≥15%) were hypothyroidism (18%), nausea (18%), and fatigue (15%). Grade 3/4 treatment-related AEs occurred in 6 patients (18%). 6 patients (18%) discontinued treatment because of treatment-related AEs. No deaths due to treatment-related AEs were reported. AEs of clinical interest occurred in 17 patients (50%); 2 patients (6%) had grade 3 events (encephalitis, hepatitis) and 1 patient (3%) had a grade 4 event (type 1 diabetes mellitus). Of the 2 patients who underwent allogeneic hematopoietic stem cell transplantation after discontinuation or completion of study treatment, 1 had a grade 3 AE (acute graft versus host disease) unrelated to study treatment that resolved. The ORR in cohort 2 was 29% (10/34; 95% CI, 15-48), with 3 (9%) complete responses (CR) and 7 (21%) partial responses (PR). Of the 10 responders, 7 had received ≥5 prior lines of therapy (3 CR/4 PR). The ORR in patients with anti-PD-1 as their most recent therapy was 35% (6/17; 95% CI, 14-62; 1 CR/5 PR); the ORR in patients with non-anti-PD-1 as their most recent therapy was 24% (4/17; 95% CI, 7-50; 2 CR/2 PR). Of 28 patients with a baseline and postbaseline assessment available, 25 (89%) had any reduction in target lesion size from baseline, and 12 (43%) had ≥50% reduction. Median DOR was 21.9 mo (range, 0.0+ to 26.1+) and an estimated 17% of responders remained in response ≥24 mo. Median PFS was 9.7 mo (95% CI, 5.1-14.7); 24-mo PFS rate was 21%. Median OS was 34.3 mo (95% CI, 25.7-NR); 24-mo OS rate was 76%. Conclusion: After additional follow-up, the combination of favezelimab + pembrolizumab continued to demonstrate manageable safety and antitumor activity in patients with heavily pretreated anti-PD-1-refractory cHL. Analyses are underway to identify biomarkers predictive of response to the combination of favezelimab and pembrolizumab. The phase 3 KEYFORM-008 study (NCT05508867) is being conducted to evaluate a coformulation of favezelimab and pembrolizumab in patients with anti-PD-1-refractory cHL.

Favezelimab in Combination with Pembrolizumab in Patients with Anti-PD-1-Naive Relapsed or Refractory Classical Hodgkin Lymphoma: Updated Analysis of an Open-Label Phase 1/2 Study

Introduction: Programmed cell death protein 1 (PD-1) inhibitors such as pembrolizumab play an important role in the treatment of patients with relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL), but treatment failure remains a significant challenge. Lymphocyte-activation gene 3 (LAG-3) is an immune checkpoint receptor that downregulates T-cell activity and plays a role in regulating T-cell function. Dual blockade of PD-1 and LAG-3 demonstrated antitumor activity in patients with advanced melanoma in the RELATIVITY-047 trial, which led to FDA approval in this setting. Favezelimab is a humanized IgG4 monoclonal antibody directed against LAG-3 that is being investigated in combination with pembrolizumab in patients with R/R hematologic malignancies in a multicohort phase 1/2 study (NCT03598608). Prior analyses of this study demonstrated that pembrolizumab 200 mg plus favezelimab 800 mg every 3 weeks (Q3W) exhibited sustained antitumor activity and acceptable safety in the cohort of patients with anti-PD-1-naive R/R cHL (cohort 1). We present updated results from this cohort. Methods: A safety lead-in phase to determine the recommended phase 2 dose (RP2D) was followed by a dose-expansion phase. Eligible patients were ≥18 years of age; had R/R cHL after autologous stem cell transplantation (ASCT), were ineligible for ASCT, or did not respond to salvage chemotherapy; had not received prior anti-PD-1 therapy; and had an ECOG performance status of 0 or 1. In the safety lead-in, patients received pembrolizumab 200 mg IV Q3W and favezelimab at a starting dose of 200 mg that was escalated to 800 mg IV Q3W using a modified toxicity probability interval method. In the dose-expansion phase, patients received pembrolizumab 200 mg Q3W plus favezelimab at the established RP2D of 800 mg Q3W for up to 35 cycles (~2 years). CT was performed every 12 weeks and PET at weeks 12 and 24. The 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: Thirty patients with anti-PD-1-naive cHL were enrolled in cohort 1. The median age was 40.5 years (range, 19-82), 17 patients (57%) were male, 16 (53%) had an ECOG performance status of 0, and 24 (80%) had received 3 or fewer prior lines of therapy. At data cutoff (March 2, 2023), 13 patients (43%) had completed 35 cycles of study treatment, 16 (53%) had discontinued treatment (10 [33%] progressive disease, 5 [17%] adverse event [AE], 1 [3%] noncompliance with study drug), and 1 (3%) was ongoing on treatment. The median time from first dose to data cutoff was 31.5 months (range, 24.0-43.2). Treatment-related AEs occurred in 27 patients (90%), of which the most common (≥20%) were hypothyroidism (27%), infusion-related reaction (23%), and fatigue (20%). Grade 3/4 treatment related AEs occurred in 9 patients (30%). Five patients (17%) discontinued treatment because of treatment-related AEs. No deaths due to treatment-related AEs were reported. AEs of clinical interest occurred in 20 patients (67%); 3 patients (10%) had grade 3 events (colitis, pneumonitis, severe skin reaction) and 1 patient (3%) had a grade 4 event (hepatitis). Of 5 patients who received allogeneic stem cell transplantation after discontinuation or completion of study treatment, 1 had a grade 3/4 AE (increased blood bilirubin) that was unrelated to study treatment and resolved. The ORR was 80% (n = 24; 95% CI, 61-92); 10 patients (33%) had a complete response and 14 (47%) had a partial response. Twenty-nine patients (97%) had any reduction in target lesions size from baseline, and 25 (83%) had a reduction of ≥50%. Median DOR was 17.0 months (range, 2.6-30.2), and an estimated 47% of responders remained in response ≥24 months. Median PFS was 19.4 months (95% CI, 9.0-28.5), 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%. Conclusion: With additional follow-up, the combination of favezelimab and pembrolizumab continued to demonstrate sustained antitumor activity and manageable safety in patients with anti-PD-1-naive R/R cHL. Analyses are underway to identify biomarkers predictive of response to the combination of favezelimab and pembrolizumab. Further studies to investigate this combination are warranted.

Blockade of PD-1 and LAG-3 expression on CD8+ T cells promotes the tumoricidal effects of CD8+ T cells.

The diffuse large B-cell lymphoma (DLBCL) has the highest incidence of all lymphomas worldwide. To investigate the functions of lymphocyte activation gene 3 (LAG-3) and programmed cell death 1 (PD-1) in tissues and peripheral blood of patients with DLBCL, the expression of LAG-3 and PD-1 genes in DLBCL-TCGA were analyzed. LAG-3 and PD-1 mRNA levels in DLBCL were analyzed using data from The Cancer Genome Atlas (TCGA) database. Utilize the Genotype-Tissue Expression (GTEx) database for assessing the variance in the expression of LAG-3, PD-1, and other associated factors between the tissues of DLBCL patients and healthy individuals. Immunohistochemistry was applied to detect the expression of LAG-3 and PD-1 levels in 137 cases of DLBCL tissues and 20 cases of reactive lymphoid hyperplasia. The prognostic value of LAG-3 and PD-1 were assessed using the Kaplan-Meier curve. The Estimation of Stromal and Immune cells in Malignant Tumor tissues using Expression data (ESTIMATE) and ssGSEA algorithm were used to explore the immune microenvironment of DLBCL. Additionally, the expression and co-expression of LAG-3 and PD-1 were detected on CD4 and CD8 T cells in peripheral blood samples from 100 cases of DLBCL tissues and 30 cases of healthy individuals using flow cytometry. According to TCGA database, LAG-3 and PD-1 gene expression levels were significantly up-regulated in DLBCL tissues. LAG-3 and PD-1 levels were also strongly positively correlated with those of most infiltrating immune cells. Overall survival of patients with high LAG-3 and PD-1 co-expression was significantly shorter than that of patients with low co-expression. In DLBCL patients, LAG-3 and PD-1 were highly expressed in peripheral blood CD8+ T cells. In addition, LAG-3 was highly expressed in CD4+ T cells, while the expression of PD-1 in CD4+ T cells of DLBCL patients showed no significant difference compared to healthy individuals. Additionally, CD8+ T cells and SU-DHL6/OCI-LY3 from patients with DLBCL were co-cultured in vitro; after addition of LAG-3 and/or PD-1 inhibitors alone, an increased perforin and granzyme B secretion levels by CD8+ T cells were detected, as well as an increase in the overall proportion of tumor cells undergoing apoptosis. High LAG-3 and PD-1 levels significantly inhibit CD8+ T cell function, resulting in weakened ability to kill tumor cells. Combined LAG-3 and PD-1 blockade can restore CD8+ T cell function and provides a potential avenue for development of personalized cellular immunotherapy for DLBCL.

The effect of blocking immune checkpoints LAG-3 and PD-1 on human invariant Natural Killer T cell function

Invariant Natural Killer T (iNKT) cells undergo immune exhaustion during chronic activation caused by cancer and viral infections, such as HIV. Exhaustion is marked by cell dysfunction and increased expression of immune checkpoint proteins programmed cell-death-1 (PD-1) and lymphocyte-activation-gene-3 (LAG-3). We hypothesize that blockade of PD-1 and/or LAG-3 will enhance iNKT cell function. Utilizing peripheral blood mononuclear cells from healthy donors, LAG-3 and PD-1 expression on iNKT cells was assessed using flow cytometry following in vitro stimulation with iNKT-specific stimulant α-galactosylceramide (n = 4). Efficacy of anti-LAG-3 and/or anti-PD-1 antibody blockades in enhancing iNKT cell function was assessed by determining proliferative capacity and IFN-γ production (n = 9). LAG-3 and PD-1 expression on iNKT cells peaked at Day 4 (98.8%; p ≤ 0.0001 and 98.8%; p = 0.005, respectively), followed by steep decrease by Day 10, coinciding with peak iNKT cell proliferation. In a 10-day blocking assay, both the anti-PD-1 alone and dual anti-PD-1 and anti-LAG-3 significantly increased iNKT proliferation (6 and 6.29 log2 fold-change respectively) compared to the no blockade control (ANOVA-p = 0.0005) with the dual blockade system being more effective (t-test-p = 0.013). This provides proof-of-concept for LAG-3 and PD-1 as immunotherapeutic targets to enhance human iNKT cell function, with the long-term goal of addressing immune exhaustion.

Characterization of 405B8H3(D-E), a newly engineered high affinity chimeric LAG-3 antibody with potent antitumor activity.

Lymphocyte activation gene-3 (LAG-3) is a type I transmembrane protein with structural similarities to CD4. Overexpression of LAG-3 enables cancer cells to escape immune surveillance, while its blockade reinvigorates exhausted T cells and strengthens anti-infection immunity. Blockade of LAG-3 may have antitumor effects. Here, we generated a novel anti-LAG-3 chimeric antibody, 405B8H3(D-E), through hybridoma technology from monoclonal antibodies produced in mice. The heavy-chain variable region of the selected mouse antibody was grafted onto a human IgG4 scaffold, while a modified light-chain variable region was coupled to the human kappa light-chain constant region. 405B8H3(D-E) could effectively bind LAG-3-expressing HEK293 cells. Moreover, it could bind cynomolgus monkey (cyno) LAG-3 expressed on HEK293 cells with a higher affinity than the reference anti-LAG-3 antibody BMS-986016. Furthermore, 405B8H3(D-E) promoted interleukin-2 secretion and was able to block the interactions of LAG-3 with liver sinusoidal endothelial cell lectin and major histocompatibility complex II molecules. Finally, 405B8H3(D-E) combined with anti-mPD-1-antibody showed effective therapeutic potential in the MC38 tumor mouse model. Therefore, 405B8H3(D-E) is likely to be a promising candidate therapeutic antibody for immunotherapy.

Abstract 6371: Identification of a lymphocyte activation gene-3-binding peptides using phage displayed-peptide libraries for cancer immunotherapy

Abstract Treatment with immune checkpoint blockades against CTLA-4, PD-1, and PD-L1 is currently giving improved results to many cancer patients. Nevertheless, a significant proportion of cancer patients treated with immune checkpoint blockades are still largely unsatisfied with the benefits of these drugs. One of the reasons is that cancer cells also use other immune checkpoints such as lymphocyte activation gene-3 (LAG-3), T cell immunoreceptor with Ig and ITIM domains, and T-cell immunoglobulin and mucin-domain containing-3. In this study, we screened phage displayed-peptide libraries for peptides that selectively bind to LAG-3. After five rounds of screening, we selected a candidate peptide and named it LAG3Pep. LAG3Pep preferentially bound to human LAG-3-transfected HEK 293T cells over mock-transfected cells and phorbol myristate acetate/ionomycin/chloroquine-stimulated Jurkat T cells over unstimulated cells. LAG3Pep also bound to splenocytes isolated from tumor-bearing mice, suggesting the reactivity across human and mouse LAG-3. Pull-down assay of human recombinant LAG-3 protein using biotin-labeled LAG3Pep yielded a protein band of LAG-3. LAG3Pep showed a high-affinity binding to the LAG-3 protein in SPR assays. Pre-treatment of a LAG-3-blocking antibody competed the binding of LAG3Pep to stimulated Jurkat T cells. LAG3Pep inhibited the binding of the LAG-3 protein to THP-1 cells expressing HLA-DR, a well-known LAG-3 ligand. In addition, treatment of T-cells with LAG3Pep in combination with a PD-L1-blocking antibody recovered the secretion of IL-2 by T-cells which was suppressed by FGL-1, another ligand of LAG-3, secreted from HepG2 tumor cells in co-culture. Intravenous administration of LAG3Pep in combination with a PD-L1-blocking peptide showed an anti-tumor growth activity in the MC38 syngeneic mouse colon tumor model. These results show that LAG3Pep acts as LAG-3 blockade and, in combination with a PD-L1-blockade, could be a promising tool for cancer immunotherapy. Citation Format: Seok-Min Lee, Byungheon Lee. Identification of a lymphocyte activation gene-3-binding peptides using phage displayed-peptide libraries for cancer immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6371.

Abstract GS5-03: Evaluation of anti-PD-1 Cemiplimab plus anti-LAG-3 REGN3767 in early-stage, high-risk HER2-negative breast cancer: Results from the neoadjuvant I-SPY 2 TRIAL

Abstract Background: I-SPY2 is a multicenter, phase 2 trial using response-adaptive randomization within biomarker subtypes defined by hormone-receptor (HR), HER2, and MammaPrint (MP) status to evaluate novel agents as neoadjuvant therapy for high-risk breast cancer. The primary endpoint is pathologic complete response (pCR). Cemiplimab is an anti-PD-1 inhibitor approved for the treatment of NSCLC and cutaneous basal and squamous cell CA. Lymphocyte activation gene 3 (LAG-3) binds MHC class II leading to inhibition of T-cell proliferation and activation and is often co-expressed with PD-1. REGN3767 is a fully humanized mAb that binds to LAG-3 and blocks inhibitory T-cell signaling. Concurrent blockade of LAG-3 with an anti-PD-1 may enhance efficacy of an anti-PD-1. Methods: Women with tumors ≥ 2.5cm were eligible for screening. Only HER2 negative (HER2-) patients were eligible for this treatment; HR positive (HR+) patients had to be MP high risk. Treatment included Paclitaxel 80 mg/m2 IV weekly x 12 and Cemiplimab 350 mg and REGN3767 1600 mg both given q3weeks x 4, followed by doxorubicin/cyclophosphamide (AC) every 2 weeks x 4. The control arm was weekly paclitaxel x 12 followed by AC every 2-3 weeks x 4. Cemiplimab/REGN3767 was eligible to graduate in 3 of 10 pre-defined signatures: HER2-, HR-HER2-, and HR+HER2-. The statistical methods for evaluating I-SPY 2 agents has been previously described. To adapt to changing standard of care, we constructed “dynamic controls” comprising ‘best’ alternative therapies using I-SPY 2 and external data and estimated the probability of Cemiplimab/REGN3767 being superior to the dynamic control. Response predictive subtypes (Immune+ vs Immune-) were assessed using pre-treatment gene expression data and the ImPrint signature. Results: 73 HER2- patients (40 HR+ and 33 HR-) received Cemiplimab/REGN3767 treatment. The control group included [357 patients with HER2- tumors (201 HR+ and 156 HR-) enrolled since March 2010. Cemiplimab/REGN3767 graduated in both HR-/HER2- and HR+/HER2- groups; estimated pCR rates (as of June 2022) are summarized in the table. Safety events of note for Cemiplimab/REGN3767 include hypothyroidism 30.8%, adrenal insufficiency (AI) 19.2%, hyperthyroidism 14.1%, pneumonitis 1.3%, and hepatitis 3.8%. All were G1/2 except for 6 (7.7%) G3 AI and 3 (3.8%) G3 colitis. Rash occurred in 62.8%, 9% G3 and 2 pts (2.6%) had pulmonary embolism. X% of adrenal insufficiency cases required replacement therapy. 40 patients (11 HR+ and 29 HR-) in Cemiplimab/REGN3767 were predicted Immune+; 32 (29 HR+ and 3 HR-) were predicted Immune-. In the HR+ group pCR was achieved in 10/11 (91%) patients with Immune+ subtype compared with 8/29 (28%) with Immune- subtype. Additional biomarker analyses are ongoing and will be presented at the meeting. Conclusion: The I-SPY 2 study aims to assess the probability that investigational regimens will be successful in a phase 3 neoadjuvant trial. Dual immune blockade with a LAG-3 inhibitor and anti-PD1 therapy resulted in a high predicted pCR rate both in HR-/HER2- (60%) and HR+/HER2- (37%) disease. The novel Imprint signature identified a group of HR+ patients most likely to benefit from this active regimen. Table 1: Estimated pCR rates Citation Format: Claudine Isaacs, Rita Nanda, Jo Chien, Meghna S. Trivedi, Erica Stringer-Reasor, Christos Vaklavas, Judy C. Boughey, Amy Sanford, Anne Wallace, Amy S. Clark, Alexandra Thomas, Kathy S. Albain, Laura C. Kennedy, Tara B. Sanft, Kevin Kalinsky, Hyo S. Han, Nicole Williams, Mili Arora, Anthony Elias, Carla Falkson, Smita Asare, Ruixiao Lu, Maria Pitsouni, Amy Wilson, Jane Perlmutter, Hope Rugo, Richard Schwab, W. Fraser Symmans, Nola M. Hylton, Laura Van’t Veer, Douglas Yee, Angela DeMichele, Donald Berry, Laura J. Esserman, I-SPY Investigators. Evaluation of anti-PD-1 Cemiplimab plus anti-LAG-3 REGN3767 in early-stage, high-risk HER2-negative breast cancer: Results from the neoadjuvant I-SPY 2 TRIAL [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr GS5-03.

The introduction of LAG-3 checkpoint blockade in melanoma: immunotherapy landscape beyond PD-1 and CTLA-4 inhibition.

Despite major advances with immunotherapy and targeted therapy in the past decade, metastatic melanoma continues to be a deadly disease for close to half of all patients. Over the past decade, advancement in immune profiling and a deeper understanding of the immune tumor microenvironment (TME) have enabled the development of novel approaches targeting and a multitude of targets being investigated for the immunotherapy of melanoma. However, to date, immune checkpoint blockade has remained the most successful with programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors, alone or in combination, yielding the most robust and durable clinical outcome in patients with metastatic melanoma. The highest rate of durable responses is achieved with the combination with PD-1 and CTLA-4 inhibition, and is effective in a variety of settings including brain metastases; however, it comes at the expense of a multitude of life-threatening toxicities occurring in up to 60% of patients. This has also established melanoma as the forefront of immuno-oncology (IO) drug development, and the search for novel checkpoints has been ongoing with multiple relevant targets including T-cell immunoglobulin and mucinodomain containing-3 (TIM-3), LAG-3, V-domain immunoglobulin suppressor T-cell activation (VISTA), T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif (ITIM) domain (TIGIT), among others. Lymphocyte activation gene-3 (LAG-3), which is a co-inhibitory receptor on T cells that suppress their activation, has revolutionized immunomodulation in melanoma. The 'game changing' results from the RELATIVITY-047 trial validated LAG-3 blockade as a relevant biological target and established it as the third clinically relevant immune checkpoint. Importantly, LAG-3 inhibition in combination with PD-1 inhibition offered impressive efficacy with modest increases in toxicity over single agent PD-1 inhibitor and has been U.S. Food and Drug Administration approved for the first-line therapy of patients with metastatic melanoma. The efficacy of this combination in patients with untreated brain or leptomeningeal metastases or with rare melanoma types, such as uveal melanoma, remains to be established. The challenge remains to elucidate specific mechanisms of response and resistance to LAG-3 blockade and to extend its benefits to other malignancies. Ongoing trials are studying the combination of LAG-3 antibodies with PD-1 inhibitors in multiple cancers and settings. The low toxicity of the combination may also allow for further layering of additional therapeutic approaches such as chemotherapy, oncolytic viruses, cellular therapies, and possibly novel cytokines, among others.

150P Phase I study of fianlimab: A human lymphocyte activation gene-3 (LAG-3) monoclonal antibody, in combination with cemiplimab in advanced melanoma (mel) - Subgroup analysis

Concurrent blockade of LAG-3 may enhance efficacy of anti-programmed cell death-1 (PD-1) therapies. We previously presented safety and efficacy data from the phase 1 study in patients (pts) with advanced mel treated with anti-LAG-3 (fianlimab) in combination with anti-PD-1 (cemiplimab). We demonstrated high clinical activity among pts with anti–PD-1/PD-ligand (L)1-naive (expansion cohort [EC] 6 and 15) advanced mel. Among pts in EC6+EC15 (N=80), the objective response rate (ORR) was 63.8%, the disease control rate (DCR) was 80.0%, and the median duration of response (mDOR) was not reached (NR).

127P Phase I study of fianlimab: A human lymphocyte activation gene-3 (LAG-3) monoclonal antibody, in combination with cemiplimab in advanced NSCLC

Concurrent blockade of LAG-3 may enhance efficacy of anti–programmed cell death-1 (anti–PD-1) therapies. We present safety and clinical activity data from a phase 1 study in patients (pts) with NSCLC treated with anti–LAG-3 (fianlimab) + anti–PD-1 (cemiplimab).

Updated Results from an Open-Label Phase 1/2 Study of Favezelimab (anti-LAG-3) Plus Pembrolizumab in Relapsed or Refractory Classical Hodgkin Lymphoma

Background: PD-1 inhibitors play a key role in the treatment of relapsed or refractory (R/R) classical Hodgkin lymphoma (cHL) but improving upon current treatment responses remain of clinical interest. Lymphocyte-activation gene 3 (LAG-3) is involved in T-cell regulation and is commonly coexpressed with PD-1 on anergic T cells. Dual blockade of PD-1 and LAG-3 has demonstrated antitumor activity leading to US Food and Drug Administration approval for the treatment of patients with unresectable or metastatic melanoma. Favezelimab (MK-4280), a humanized IgG4 LAG-3 inhibitor, plus pembrolizumab (anti-PD-1) is being investigated in the multicohort phase 1/2 MK-4280-003 efficacy and safety study (NCT03598608) in patients with R/R hematologic malignancies. Initial results from the MK-4280-003 study demonstrated promising antitumor activity and acceptable safety in anti-PD-1-naive patients with R/R cHL (cohort 1) (Johnson NA, et al. J Clin Oncol. 2022;40(16_suppl):7516). Updated results from cohort 1 after additional follow-up are presented. Methods: Part 1 was the safety lead-in phase to determine the recommended phase 2 dose (RP2D) followed by a dose-expansion phase (part 2). Eligible patients in cohort 1 had R/R cHL after autologous stem cell transplantation (ASCT) or were ineligible for ASCT, and had no prior anti-PD-1 therapy. Part 1 included patients from all cohorts who received escalating doses (per modified toxicity probability index interval design) of pembrolizumab IV 200 mg Q3W and favezelimab IV 200 mg or 800 mg Q3W. In part 2, patients received pembrolizumab plus favezelimab at the established RP2D (800 mg Q3W) for ≤35 cycles (~2 years). CT scans were performed every Q12W and PET scans at Weeks 12 and 24 to assess response by investigator review per the IWG 2007 criteria. Adverse events (AE) were graded per the NCI CTCAE, v4.0. The primary end points were safety and RP2D. Objective response rate (ORR) was a secondary end point. Duration of response (DOR), progression-free survival (PFS), and overall survival (OS) were exploratory end points. Results: Among the 30 patients enrolled in cohort 1, the median age was 40.5 years, 53% had ECOG PS 0, and 80% had ≤3 prior lines of therapy. At database cutoff (May 03, 2022), 6 (20%) patients had completed 2 years of study treatment and 13 (43%) patients had discontinued (9 progressive disease; 4 AEs); 4 (13%) patients discontinued due to treatment-related adverse events [TRAEs]); 11 (37%) patients had treatment ongoing at the time of database cutoff. No deaths were treatment-related. Among the 26 patients (87%) who had TRAEs; the most common (≥10%) were hypothyroidism (27%); infusion-related reaction (23%), fatigue (20%); pruritus and headache (17% each), chills (13%); arthralgia, hyperthyroidism, maculopapular rash, myalgia, nausea and pyrexia (10%, each). Grade 3 or 4 TRAEs occurred in 7 patients (23%); including 1 (3%) event each of thrombocytopenia, enterocolitis, fatigue, autoimmune hepatitis, increased blood creatine phosphokinase, increased amylase, increased lipase, organizing pneumonia, and maculopapular rash. Of 3 patients who received hematopoietic stem cell transplantation after completion of study treatment, 1 had a grade 3 or 4 AE unrelated to study treatment (increased blood bilirubin) that resolved. After a median follow-up of 15.5 months, 22 patients had objective response (ORR, 73% [95% CI, 54-88]; complete response, 9 [30%]; partial response, 13 [43%]). Of 29 patients (97%) who received a postdose scan, 28 had a baseline reduction in target lesions and 23 (79%) had ≥50% reduction from baseline (Figure). Median DOR was not reached (NR; range, 2.6-28.8+ months); 7 patients (56%) had response ≥12 months. Median PFS was 19.4 months (95% CI, 8.5-NR); 12-month PFS rate was 62%. Median OS was NR (95% CI, NR-NR); 12-month OS rate was 96%. Conclusion: After additional follow-up, favezelimab plus pembrolizumab combination therapy continued to demonstrate sustained antitumor activity and acceptable safety in anti-PD-1-naive patients with R/R cHL. Further studies comparing the activity of this combination to that of single-agent pembrolizumab would be of clinical benefit. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

400P Phase I study of fianlimab, a human lymphocyte activation gene-3 (LAG-3) monoclonal antibody, in combination with cemiplimab in advanced melanoma (mel)

Concurrent blockade of LAG-3 may enhance efficacy of anti-programmed cell death-1 (PD-1) therapies. We present updated safety and clinical activity data from patients (pts) with advanced mel treated with concurrent anti-LAG-3 (fianlimab) and anti-PD-1 (cemiplimab).

790MO Phase I study of fianlimab, a human lymphocyte activation gene-3 (LAG-3) monoclonal antibody, in combination with cemiplimab in advanced melanoma (mel)

Concurrent blockade of LAG-3 may enhance efficacy of anti-programmed cell death-1 (PD-1) therapies. We present updated safety and clinical activity data from patients (pts) with advanced mel treated with concurrent anti-LAG-3 (fianlimab) and anti-PD-1 (cemiplimab).

Preclinical Characterization of Relatlimab, a Human LAG-3-Blocking Antibody, Alone or in Combination with Nivolumab.

Novel therapeutic approaches combining immune-checkpoint inhibitors are needed to improve clinical outcomes for patients with cancer. Lymphocyte-activation gene 3 (LAG-3) is an immune-checkpoint molecule that inhibits T-cell activity and antitumor immune responses, acting through an independent mechanism from that of programmed death-1 (PD-1) and cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4). Here, we describe the development and preclinical characterization of relatlimab, a human antibody that binds to human LAG-3 with high affinity and specificity to block the interaction of LAG-3 with the ligands MHC II and fibrinogen-like protein-1, and to reverse LAG-3-mediated inhibition of T-cell function in vitro. Consistent with previous reports, in mouse models, the combined blockade of LAG-3 and PD-1 with surrogate antibodies resulted in enhanced antitumor activity greater than the individual blockade of either receptor. In toxicity studies in cynomolgus monkeys, relatlimab was generally well tolerated when combined with nivolumab. These results are consistent with findings from the RELATIVITY-047 phase II/III trial showing that relatlimab combined with nivolumab is a well-tolerated regimen that demonstrates superior progression-free survival compared with nivolumab monotherapy in patients with unresectable or metastatic melanoma.

LAG3-PD-1 Combo Overcome the Disadvantage of Drug Resistance.

Although PD-1 blockade therapy has been promising in cancer treatment, only 4% (pancreatic cancer) to 70% (melanoma) of patients have a positive response to this blockade therapy, which is one of its important disadvantages. Therefore, it is important to seek out new targets for cancer immunotherapy to improve the overall response rate in patients. Lymphocyte activation gene-3 (LAG-3), an immune checkpoint receptor, is mainly expressed in activated immune cells. LAG-3 maintains the body’s immune homeostasis under physiological conditions while mediating tumour immune escape. Several preclinical and clinical examinations have shown that LAG-3 blockade effectively alleviates the patient’s tolerance to PD-1 immune checkpoint inhibitors. Moreover, the combination of LAG-3 and PD-1 blockade has good clinical efficacy in cancers. Hence, synchronous LAG-3 and PD-1 inhibition may be a potential new strategy for tumour immunotherapy.

Update on lymphocyte-activation gene 3 (LAG-3) in cancers: from biological properties to clinical applications.

Immunotherapy that targets checkpoints, especially programmed cell death protein 1 and programmed cell death ligand 1, has revolutionized cancer therapy regimens. The overall response rate to mono-immunotherapy, however, is limited, emphasizing the need to potentiate the efficacy of these regimens. The functions of immune cells are modulated by multiple stimulatory and inhibitory molecules, including lymphocyte activation gene 3 (LAG-3). LAG-3 is co-expressed together with other inhibitory checkpoints and plays key roles in immune suppression. Increasing evidence, particularly in the last 5 years, has shown the potential of LAG-3 blockade in anti-tumor immunity. This review provides an update on the biological properties and clinical applications of LAG-3 in cancers.

Fewer LAG-3+ T Cells in Relapsing-Remitting Multiple Sclerosis and Type 1 Diabetes.

The coinhibitory receptor lymphocyte activation gene 3 (LAG-3) is an immune checkpoint molecule that negatively regulates T cell activation, proliferation, and homeostasis. Blockade or deletion of LAG-3 in autoimmune-prone backgrounds or induced-disease models has been shown to exacerbate disease. We observed significantly fewer LAG-3+ CD4 and CD8 T cells from subjects with relapsing-remitting multiple sclerosis (RRMS) and type 1 diabetes. Low LAG-3 protein expression was linked to alterations in mRNA expression and not cell surface cleavage. Functional studies inhibiting LAG-3 suggest that in subjects with RRMS, LAG-3 retains its ability to suppress T cell proliferation. However, LAG-3 expression was associated with the expression of markers of apoptosis, indicating a role for low LAG-3 in T cell resistance to cell death. In T cells from subjects with RRMS, we observed a global dysregulation of LAG-3 expression stemming from decreased transcription and persisting after T cell stimulation. These findings further support the potential clinical benefits of a LAG-3 agonist in the treatment of human autoimmunity.

Lag3: From Bench to Bedside.

The introduction of immune checkpoint inhibitors represented a breakthrough treatment for metastatic melanoma, but the effect of these agents is not limited to a single cancer type. Promising results have been reported in various solid tumors, for example, lung cancer. The success of these drugs depends on the activation of tumor-infiltrating lymphocytes and primary and acquired resistance have been reported alongside a high rate of immune-related adverse events when agents targeting different immune checkpoints are given in combination. Numerous other targets have been investigated to overcome the resistance, improve the activity, and reduce the toxicity of checkpoint inhibitor therapy. Among these, the most promising is Lymphocyte-activation gene 3 (LAG-3), a transmembrane protein involved in cytokine release and inhibitory signaling in T cells. Preclinical data showed that LAG-3 is a negative regulator of both CD4+ T cell and CD8+ T cell and the activity on CD8+ T cell is independent of CD4+ activation. On the CD8+ T cell, LAG-3 activation abrogates the antigen presentation whereas on the CD4+ T cell, arrests the S phase of the cell cycle. The blockade of LAG-3 has been tested in several combination therapies, and recent clinical data showed a good safety profile and a synergistic effect with anti-PD-1, suggesting that this combination could become a standard treatment for metastatic melanoma. In this review, we report the available preclinical data and the new clinical data on LAG-3 blockade in different solid tumors, and we discuss LAG-3 as potential prognostic and predictive factor, together with possible future applications.