CTLA-4 Blockade Research Articles

Combined PD-1 and CTLA-4 Blockade in an International Cohort of Patients with Acral Lentiginous Melanoma.

Combination immune checkpoint blockade targeting PD-1 and CTLA-4 leads to high response rates and improved survival in advanced cutaneous melanoma (CM). Less is known about the efficacy of this combination in acral lentiginous melanoma (ALM). To determine the efficacy of combination immune checkpoint blockade targeting PD-1 and CTLA-4 in a real-world, diverse population of ALM. This multi-institutional retrospective study analyzed patients with histologically confirmed ALM treated with the combination of PD-1 and CTLA-4 inhibitors between 2010-2022. The primary objective of the study was objective response rate (ORR) per RECIST criteria. The secondary objectives were progression-free survival (PFS) and overall survival (OS). In total, 109 patients with advanced ALM treated with combined PD-1 and CTLA-4 blockade in any line of treatment were included. The majority of patients had stage IV disease (n=81, 74.2%). The ORR for the entire cohort was 18.3% (95% CI 11.6-26.9%), with 9 (8.3%) complete responses (CR) and 11 (10.1%) partial responses (PR). An additional 22 patients (20.2%) had stable disease (SD), and the disease control rate (DCR) was 38.5%. The median PFS was 4.2 months [95% CI 3.25-5.62], while the median OS was 17 months [95% CI 12.4%-23.1%]. A total of 95 patients (87.2%) had a treatment-related adverse event, with 40.4% (n=44/109) experiencing at least one grade 3 or 4 toxicity. Elevated LDH (p=.04), 2+ lines of prior therapy (p=.03), and Asian race/ethnicity (p=.04) were associated with worse OS, while Hispanic/Latino race/ethnicity was associated with better OS (p=.02). Combination of PD-1 and CTLA-4 blockade is less effective for ALM, as compared to CM, despite similar toxicity. Asian patients, in particular, appear to derive lower benefit from this regimen. Novel treatment approaches are needed for this rare melanoma subtype.

Overcoming tyrosine kinase inhibitor resistance in lung cancer brain metastasis with CTLA4 blockade.

Lung cancer brain metastasis (LCBM) poses a significant clinical challenge due to acquired resistance to tyrosine kinase inhibitor (TKI) treatment. To elucidate its underlying mechanisms, we employed single-cell RNA sequencing analysis on surgically obtained LCBM samples with diverse genetic backgrounds and TKI treatment histories. Our study uncovers that TKI treatment elevates the immune checkpoint CTLA4 expression in Tcells, promoting an immune-suppressive microenvironment. This immunomodulation is initiated by tumor-derived HMGB1 in response to TKIs. In LCBM syngeneic murine models with TKI-sensitive or TKI-resistant EGFR mutations, combining CTLA4 blockade with TKIs demonstrates enhanced efficacy over TKI monotherapy or TKIs with PD1 blockade. These findings provide insights into the TKI resistance mechanisms and highlight the potential of CTLA4 blockade in effectively overcoming TKI resistance in LCBM.

CTLA4 blockade abrogates KEAP1/STK11-related resistance to PD-(L)1 inhibitors.

For patients with advanced non-small-cell lung cancer (NSCLC), dual immune checkpoint blockade (ICB) with CTLA4 inhibitors and PD-1 or PD-L1 inhibitors (hereafter, PD-(L)1 inhibitors) is associated with higher rates of anti-tumour activity and immune-related toxicities, when compared with treatment with PD-(L)1 inhibitors alone. However, there are currently no validated biomarkers to identify which patients willbenefit from dual ICB1,2. Here we show that patients with NSCLC who have mutations in the STK11 and/or KEAP1 tumour suppressor genes derived clinical benefit from dual ICB with the PD-L1 inhibitor durvalumab and the CTLA4 inhibitor tremelimumab, but not from durvalumab alone, when added to chemotherapy in the randomized phase III POSEIDON trial3. Unbiased genetic screens identified loss of both of these tumour suppressor genes as independent drivers of resistance to PD-(L)1 inhibition, and showed that loss of Keap1 was the strongest genomic predictor of dual ICB efficacy-a finding that was confirmed in several mouse models of Kras-driven NSCLC. In both mouse models and patients, KEAP1 and STK11 alterations were associated with an adverse tumour microenvironment, which was characterized by a preponderance of suppressive myeloid cells and the depletion of CD8+ cytotoxic T cells, but relative sparing of CD4+ effector subsets. Dual ICB potently engaged CD4+ effector cells and reprogrammed the tumour myeloid cell compartment towards inducible nitric oxide synthase (iNOS)-expressing tumoricidal phenotypes that-together with CD4+ and CD8+ T cells-contributed to anti-tumour efficacy. These data support the use of chemo-immunotherapy with dual ICB to mitigate resistance to PD-(L)1 inhibition in patients with NSCLC who have STK11 and/or KEAP1 alterations.

Evaluation of the efficacy of combined immune checkpoint inhibitors in advanced melanoma treatment - Long term outcomes and emerging therapeutic perspectives: a narrative review

Combination therapy with immune checkpoint inhibitors, specifically CTLA-4 and PD-1 blockade, has shown promise in treating advanced melanoma. However, this approach often results in increased toxicity, necessitating a careful evaluation of both efficacy and safety. This review explores clinical outcomes, survival rates, and adverse events associated with these therapies. A systematic review of PubMed, Scopus, and clinical trial databases was conducted for studies published from 2014 to 2024. Studies assessing the combined use of CTLA-4 and PD-1 inhibitors in melanoma patients were included, focusing on overall survival (OS), progression-free survival (PFS), and treatment-related adverse events (AEs). The combination of CTLA-4 and PD-1 inhibitors significantly improved clinical outcomes in advanced melanoma. In trials like CheckMate 067, the five-year overall survival rate reached 52%, with a notable improvement in progression-free survival. However, these benefits came with substantial toxicity, as approximately 55% of patients experienced grade 3 or 4 treatment-related adverse events, including colitis, hepatitis, and pneumonitis. Despite these challenges, combination therapy led to durable responses in a subset of patients, underscoring its efficacy. The review emphasizes the need for balancing efficacy with toxicity management in clinical practice. While CTLA-4 and PD-1 inhibitor combinations improve survival in advanced melanoma, increased toxicity presents challenges. Further research is needed to optimize treatment strategies and enhance patient selection to balance efficacy and safety.

Unraveling the gut microbiome's contribution to pancreatic ductal adenocarcinoma: mechanistic insights and therapeutic perspectives.

The gut microbiome plays a significant role in the pathogenesis of pancreatic ductal adenocarcinoma (PDAC), influencing oncogenesis, immune responses, and treatment outcomes. Studies have identified microbial species like Porphyromonas gingivalis and Fusobacterium nucleatum, that promote PDAC progression through various mechanisms. Additionally, the gut microbiome affects immune cell activation and response to immunotherapy, including immune checkpoint inhibitors and CAR-T therapy. Specific microbes and their metabolites play a significant role in the effectiveness of immune checkpoint inhibitors (ICIs). Alterations in the gut microbiome can either enhance or diminish responses to PD-1/PD-L1 and CTLA-4 blockade therapy. Additionally, bacterial metabolites like trimethylamine N-oxide (TMAO) and lipopolysaccharide (LPS) impact antitumor immunity, offering potential targets to augment immunotherapy responses. Modulating the microbiome through fecal microbiota transplantation, probiotics, prebiotics, dietary changes, and antibiotics shows promise in PDAC treatment, although outcomes are highly variable. Dietary modifications, particularly high-fiber diets and specific fat consumption, influence microbiome composition and impact cancer risk. Combining microbiome-based therapies with existing treatments holds potential for improving PDAC therapy outcomes, but further research is needed to optimize their effectiveness.

Long-term survivals of immune checkpoint inhibitors as neoadjuvant and adjuvant therapy in dMMR/MSI-H colorectal and gastric cancers

BackgroundThe long-term survival benefit of immune checkpoint inhibitors (ICIs) in neoadjuvant and adjuvant settings is unclear for colorectal cancers (CRC) and gastric cancers (GC) with deficiency of mismatch repair (dMMR) or microsatellite instability-high (MSI-H).MethodsThis retrospective study enrolled patients with dMMR/MSI-H CRC and GC who received at least one dose of neoadjuvant ICIs (neoadjuvant cohort, NAC) or adjuvant ICIs (adjuvant cohort, AC) at 17 centers in China. Patients with stage IV disease were also eligible if all tumor lesions were radically resectable.ResultsIn NAC (n = 124), objective response rates were 75.7% and 55.4%, respectively, in CRC and GC, and pathological complete response rates were 73.4% and 47.7%, respectively. The 3-year disease-free survival (DFS) and overall survival (OS) rates were 96% (95%CI 90–100%) and 100% for CRC (median follow-up [mFU] 29.4 months), respectively, and were 84% (72–96%) and 93% (85–100%) for GC (mFU 33.0 months), respectively. In AC (n = 48), the 3-year DFS and OS rates were 94% (84–100%) and 100% for CRC (mFU 35.5 months), respectively, and were 92% (82–100%) and 96% (88–100%) for GC (mFU 40.4 months), respectively. Among the seven patients with distant relapse, four received dual blockade of PD1 and CTLA4 combined with or without chemo- and targeted drugs, with three partial response and one progressive disease.ConclusionWith a relatively long follow-up, this study demonstrated that neoadjuvant and adjuvant ICIs might be both associated with promising DFS and OS in dMMR/MSI-H CRC and GC, which should be confirmed in further randomized clinical trials.

Targeting exhausted cytotoxic T cells through CTLA-4 inhibition promotes elimination of neoplastic cells in human myelofibrosis xenografts.

Myeloproliferative neoplasms represent a group of clonal hematopoietic disorders of which myelofibrosis (MF) is the most aggressive. In the context of myeloid neoplasms, there is a growing recognition of the dysregulation of immune response and T-cell function as significant contributors to disease progression and immune evasion. We investigated cytotoxic T-cell exhaustion in MF to restore immune response against malignant cells. Increased expression of inhibitory receptors like CTLA-4 was observed on cytotoxic T cells from MF patients together with a reduced secretion of IFNɣ and TNFɑ. CTLA-4 ligands CD80 and CD86 were increased on MF granulocytes and monocytes highlighting a possible role for myeloid cells in suppressing T-cell activation in MF patients. Unlike healthy donors, the activation of cytotoxic T cells from MF patients was attenuated in the presence of myeloid cells and restored when T cells were cultured alone or treated with anti-CTLA-4. Moreover, anti-CTLA-4 treatment promoted elimination of neoplastic monocytes and granulocytes in a co-culture system with cytotoxic T cells. To test CTLA-4 inhibition in vivo, patient-derived xenografts were generated by transplanting MF CD34+ cells and by infusing homologous T cells in NSGS mice. CTLA-4 blockade reduced human myeloid chimerism and led to T-cell expansion in spleen and bone marrow. Overall, these findings shed light on T-cell dysfunction in MF and suggest that CTLA-4 blockade can boost the cytotoxic T cell-mediated immune response against tumor cells.

Establishment and validation of a novel CD8+ T cell-associated prognostic signature for predicting clinical outcomes and immunotherapy response in hepatocellular carcinoma via integrating single-cell RNA-seq and bulk RNA-seq

CD8+ T lymphocytes are critical in the immune response against neoplasms, yet the prognostic relevance of CD8+ T cell-associated genes in hepatocellular carcinoma (HCC) is not fully understood. We sourced single-cell RNA-sequencing (scRNA-seq) and bulk RNA-seq data for HCC from the GSE98638 dataset and The Cancer Genome Atlas (TCGA) repository. We utilized Weighted Gene Correlation Network Analysis (WGCNA) to identify CD8+ T cell-related genes. A clinical prognostic model for risk stratification was then constructed via Cox-Lasso regression analysis. The Immunophenotypic Score (IPS) was utilized to evaluate the potential of immunotherapeutic interventions in the categorized cohorts. Validation of the expression of CD8+ T cell-associated risk genes was performed using quantitative reverse transcription PCR (qRT-PCR). Integrating scRNA-seq with RNA-seq data, we identified five CD8+ T cell-related signature genes: IKBKE, ATP1B3, MSC, ADA, and BATF. Notably, HCC patients in the high-risk group had markedly decreased overall survival. Elevated infiltration levels of CD8+ T cells, B cells, and macrophages were observed in the high-risk group. Moreover, there was a positive correlation between the risk score and immune checkpoints (ICPs), including PDCD1, CD274, and CTLA4. Patients within the high-risk group subject to PD1 and CTLA4 blockade exhibited higher IPS levels. Additionally, the expression of the five risk genes was upregulated in HCC cell lines and tissues compared to normal cells and tissues. Our findings establish a prognostic signature based on CD8+ T cells, offering a potent predictive model for clinical outcomes and responsiveness to immunotherapy in HCC patients.

Intermittent MEK Inhibition with GITR Costimulation Rescues T-cell Function for Increased Efficacy with CTLA-4 Blockade in Solid Tumor Models.

MEK inhibitors (MEKi) have shown limited success as a treatment for MAPK/ERK pathway-dependent cancers due to various resistance mechanisms tumor cells can employ. CH5126766 (CKI27) is an inhibitor that binds to MEK and prevents release of RAF, reducing the relief of negative feedback commonly observed with other MEKis. We observed that CKI27 increased MHC expression in tumor cells and improved T cell-mediated killing. Yet, CKI27 also decreased T-cell proliferation, activation, and cytolytic activity by inhibiting the MAPK/ERK pathway that is activated downstream of T-cell receptor signaling. Therefore, we aimed to balance the positive and negative immunomodulatory effects of MEKis for optimal combination with immunotherapy. Intermittent administration of CKI27 allowed T cells to partially recover and costimulation via GITR and OX-40 agonist antibodies completely alleviated inhibition of function. In Kras mutant lung and colon tumor mouse models, intermittent CKI27 and anti-GITR significantly decreased tumor growth and prolonged survival when further combined with CTLA-4 immune checkpoint blockade. Moreover, this triple combination increased CD8+ and CD4+ T-cell proliferation, activation, and effector/memory subsets in the tumor-draining lymph nodes and tumors and led to intratumoral regulatory T-cell destabilization. These data, collectively, will allow for more informed decisions when optimizing combination regimens by overcoming resistance, reducing toxicity, and generating long-term immune responses.

Immunotherapy-based therapy versus chemotherapy for the neoadjuvant treatment of locally advanced dMMR/MSI-H gastric cancer.

e16121 Background: Growing evidences have suggested that immunotherapy represents a promising treatment for the neoadjuvant treatment of mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) gastric cancer. The study aimed to compare the efficacy of neoadjuvant chemotherapy and immune checkpoint inhibitor (ICI)-based therapy in locally advanced, dMMR/MSI-H gastric cancer. Methods: Patients with MSI-H/dMMR locally advanced gastric cancer who received neoadjuvant chemotherapy, or ICI-based therapy between December 2018 and June 2023 at West China Hospital, Sichuan University were included. Patient data were collected from the prospectively database program of gastric cancer at our Hospital. Demographic and clinicopathologic data of patients were collected, including age, sex, ECOG performance status, primary tumor site, tumor staging, Lauren’s classification, tumor response, tumor regression grade (TRG), R0 resection, disease-free survival (DFS) and overall survival (OS). Results: A total of 21 patients treated with ICIs-based regimens and 18 patients treated with chemotherapy were included. In the ICI-based therapy group, 10 patients (47.6%) received dual PD-1 and CTLA-4 blockade, 1 patient (4.8%) received PD-1 blockade, and 10 patients (47.6%) received PD-1 blockade combined with chemotherapy. The median age of chemotherapy group and ICI-based group were 63 years (range, 36-76 years) and 59 years (range, 34-74 years), respectively. The rates of T4b and limited metastases were significantly higher in the ICI-based therapy group compared to chemotherapy group (T4b: 11.1% vs. 23.8%; limited metastases: 0% vs. 19.0%). 17 patients (94.4%) in the chemotherapy group and 20 patients (95.2%) in the ICI-based therapy group underwent R0 radical gastrectomy. One patient in the chemotherapy group did not undergo surgery due to disease progression. One patient in the ICI-based therapy group refused radical gastrectomy. For patients undergoing surgery, TRG 0-1 rate was obviously lower in patients receiving chemotherapy compared to those treated with ICI-based regimen (0.0% vs. 78.9%). The pCR rates in the chemotherapy group and ICI-based group were 0.0% and 57.9%, respectively. The pCR rates in patients treated with dual PD-1/CTLA-4 blockade and PD-1 blockade with chemotherapy were 66.6% and 50.0% (P = 0.65). Median DFS and OS have not yet been achieved due to the short follow-up time. Conclusions: Improvements in TRG 0-1 rate and pCR rate suggested that ICI-based treatments are favorable in the neoadjuvant setting of locally advanced, dMMR/MSI-H gastric cancer compared to chemotherapy. However, within the overall favorable group, there was no differences between dual PD-1/CTLA-4 blockade and PD-1 blockade with chemotherapy in term of pCR rate. Whether high pCR rates can translate into long-term survival benefits requires longer follow-up time.

Mathematical modeling of routine biological parameters kinetics in order to predict durable benefit for first-line immunotherapy in metastatic or unresectable melanoma.

e21549 Background: PD1, CTLA4 and LAG3 blockade have shown remarkable efficacy in melanoma patients. Predictive biomarkers are needed to predict response, prevent unneeded toxicity and reduce costs. Despite collective efforts, no biomarker is robust or accessible enough for routine use. Our objective was to evaluate mathematical modeling-based kinetic markers derived from routine biological parameters as early predictors of durable benefit for first-line immunotherapy in advanced melanoma. Our secondary objective was to assess if these modeling could predict progression-free survival (PFS). Methods: We retrospectively included all consecutive, treatment-naïve, metastatic or unresectable melanoma patients treated with PD1 blockade alone or in combination with CTLA4 or LAG3 blockade between April 2020 and 2022 in our department. Clinical, biological and radiological data were collected. The primary endpoint was durable clinical benefit (DCB) defined as partial or complete response at 6 months or stable disease of at least 6 months. 11 simple blood markers and their on-treatment kinetics were considered. 4 empirical mathematical models (constant, linear, double exponential and hyperbolic) were fitted to the data, allowing to reject the constant null hypothesis for all of them. The association of the best-models coefficients with DCB and PFS was assessed using logistic and Cox regression. To do so, the data was truncated at 1, 2 and 3 months and the model coefficients were retrieved using Bayesian estimation with a population prior identified on the full-kinetics dataset. This study was approved by our local IRB. Results: 61 patients were included with 24 months median follow-up. DCB was observed for 57% of them. A low model-based value at baseline using 1 month truncated data was significantly associated with DCB for neutrophils (OR = 4.54[1.69-12.5], p < 0.0001) and - neutrophils/lymphocytes ratio (NLR) (OR = 3.03 [1.47-6.67], p = 0.003). Model-based results increased AUC versus baseline raw data: 0.755 versus 0.699 for neutrophils and 0.76 versus 0.7 for NLR. An elevated model-based at baseline using 1 month truncated data was significantly associated with PFS for neutrophils (HR = 1.56 [1.25-1.96], p < 0.0001), AST (HR = 1.71 [1.24-2.35], p < 0.0001), LDH (HR = 2.0 [1.44-2.77], p < 0.0001), CPR (HR = 1.75 [1.14-2.67], p = 0.01) and ALT (HR = 1.37 [1.05-1.78], p = 0.02). At 1 month, the kinetics parameters on creatinine (HR = 1.38 [1.05-1.82], p = 0.02), albumin (HR = 0.68 [0.48-0.97], p = 0.03) and monocytes (HR = 1.49 [1.02-2.18], p = 0.04) were significantly associated with PFS. Conclusions: Modeling the kinetics of routine biological parameters shows potential ability to predict DCB. Perspectives include model improvement, kinetics machine learning integrative model development as well as a toxicity prediction.

High dose bolus (HDB) interleukin-2 (IL2) and concurrent low dose ipilimumab followed sequentially by nivolumab in patients with advanced melanoma after failure of anti-PD1-based immunotherapy and BRAF-MEK inhibition.

9543 Background: Options are limited for patients with advanced metastatic melanoma who have disease progression following anti-PD1-based immunotherapy and BRAF-MEK inhibition (if BRAF V600 mutant). Evidence supports synergism between IL2 and CTLA4 blockade in enhancing the immunogenicity of the tumor microenvironment and therapeutic susceptibility to PD1 blockade. Methods: We conducted a phase II study of HDB IL2 in combination with LD ipilimumab followed sequentially by nivolumab in patients with advanced inoperable stage III or stage IV melanoma with progression after anti-PD1-based immunotherapy and BRAF-MEK inhibitors. Treatment consisted of up to 3 courses (One cycle is 21 days and one course is 4 cycles). HDB IL2 and concurrent ipilimumab 1 mg/kg were given during week 1 of the initial 2 cycles of each course. Nivolumab was given during week one of the 3rd cycle of each course. Patients without evidence of disease progression (RECIST v.1.1) or limiting toxicities (CTCAE v.5) were offered additional courses of treatment. A Simon two-stage minimax design (Simon, 1989) was followed. We report the outcomes for Stage I. Results: 12 pts (5 female, 7 male) with metastatic melanoma (2M1a, 1M1b, 6M1c, 3M1d) were treated. Median age 53 years (33 – 69), 11 cutaneous (including 1 acral) and 1 mucosal primary. Tumor mutation status: 4BRAF (V600E), 2NRAS (p.Q61K), 1NF1. The median number of prior regimens for metastatic melanoma was 3 (range 1 - 5). Eight patients previously received ipilimumab as monotherapy or in combination with anti-PD1. On study, the median number of doses of IL2 was 9 during cycle 1 and 7 during cycle 2. A median of 2 doses of ipilimumab and 1 dose of nivolumab were given as part of the combination regimen. Among the 11 evaluable patients (completed 1 course of systemic therapy), the response rate was 2/11 (18.2 %; 95% CI: 2.3% – 51.8%); 1CR, 1 PR, 5 SD, 4 PD and 1 NE as best response. After a median follow up of 39 months, both responses are ongoing (at 10+ and 37+ months), median progression free survival (PFS) was 3 months and median overall survival (OS) was 18.8 months. One-year PFS and OS were 17% (95% CI: 4.7% - 59%) and 83% (95% CI: 65% - 100%), respectively. The adverse event profile was consistent with the expected toxicity profile for each agent with no increase in frequency with the combination. Conclusions: Our combination regimen was relatively safe and well tolerated and demonstrated promising efficacy in a heavily pretreated patient population passing the prespecified efficacy criteria for Simon Stage I. The study has moved into Stage II testing. Clinical trial information: NCT04562129 .

EVOLVE-HNSCC: A global phase 3 study of volrustomig as sequential therapy for unresected locally advanced head and neck squamous cell carcinoma (LA-HNSCC) following definitive concurrent chemoradiotherapy (cCRT).

TPS6120 Background: Currently there are no approved maintenance therapies for patients (pts) with unresected LA-HNSCC following definitive cCRT. The PD-1 inhibitors pembrolizumab and nivolumab are licensed for treatment of pts with recurrent or metastatic HNSCC who have progressed on or after a platinum-based therapy. Dual inhibition of CTLA-4 and PD-L1 is approved in solid tumors including renal cell carcinoma (RCC), NSCLC, and melanoma, and has shown a numerical trend towards improved survival in first-line pts with recurrent/metastatic HNSCC whose tumors express PD-L1. Volrustomig (MEDI5752) is a monovalent, PD-1/CTLA-4 bispecific, humanized IgG1 monoclonal antibody engineered to specifically inhibit PD-1, with increased CTLA-4 blockade on PD-1+ activated T cells compared to PD-1– resting peripheral T cells. In a first-in-human phase 1/2 study (NCT03530397), volrustomig monotherapy showed promising efficacy with acceptable tolerability in advanced clear cell RCC and in combination with chemotherapy in advanced NSCLC. The phase 3, randomized, open-label, multicenter, eVOLVE-HNSCC study will evaluate the efficacy and safety of sequential therapy with volrustomig compared with observation in pts with unresected LA-HNSCC who have not progressed after receiving definitive cCRT (NCT06129864). Methods: Key eligibility criteria include histologically or cytologically confirmed, unresected LA-HNSCC with no evidence of metastatic disease, i.e. AJCC 8th edition (TNM staging system) stage IVA/B cancers of the hypopharynx, oral cavity, larynx or HPV-negative oropharynx, or stage III HPV-positive oropharynx cancer; age ≥18 years; WHO/ECOG performance score of 0 or 1; and adequate organ and bone marrow function. Key exclusion criteria include requiring further treatment with curative intent after definitive cCRT, resected LA-HNSCC, recurrent/metastatic disease, and >1 primary tumor. Following initial screening and definitive cCRT (cisplatin or carboplatin + paclitaxel or carboplatin + 5-FU, plus concomitant radiotherapy), approximately 1145 pts whose disease has not progressed within 12 weeks of the last dose of cCRT will be randomized 1:1 to Arm A or B. Arm A will receive volrustomig intravenously every 3 weeks for a maximum of 12 months or 18 cycles, or until RECIST v1.1-defined radiological progressive disease (PD) or unacceptable toxicity. Arm B will undergo observation for a maximum of 12 months or until PD. The primary endpoint is PFS in pts with PD-L1-expressing tumors. Secondary endpoints include PFS in all randomized pts, OS in pts with PD-L1-expressing tumors and in all randomized pts, PFS2, safety, patient-reported outcomes, pharmacokinetics, and immunogenicity. Exploratory biomarker analyses will also be conducted. Enrollment began in December 2023. Clinical trial information: NCT06129864 .

EVOLVE-Lung02: A phase 3 study of first-line (1L) volrustomig plus chemotherapy (CT) versus pembrolizumab plus CT in metastatic non-small-cell lung cancer (mNSCLC) with PD-L1 tumor cell (TC) expression <50%.

TPS8652 Background: Immunotherapies targetingprogrammed cell death-1 (PD-1) and its ligand PD-L1 have transformed 1L mNSCLC. However, in a subset of patients (pts) with PD-L1-low or PD-L1-negative disease (i.e. PD-L1 TC expression <50% or <1%, respectively), anti-PD-(L)1 therapies, with or without CT, are associated with shorter overall survival (OS) than in pts with PD-L1-high disease. Dual inhibition of PD-1 and CTLA-4 is often undertaken in PD-L1-low, and especially PD-L1-negative, mNSCLC to address the poorer prognosis in these pts. Although combination therapy using lower doses of CTLA-4 inhibitors has shown benefit in this setting, toxicity at higher doses has limited the clinical utility of this approach. Volrustomig (MEDI5752) is a monovalent, PD-1/CTLA-4 bispecific, humanized IgG1 monoclonal antibody engineered to specifically inhibit PD-1, with increased CTLA-4 blockade on PD-1+ activated T cells compared to PD-1– resting peripheral T cells. This mode of action may facilitate enhanced CTLA-4 inhibition at tolerable doses beyond those achievable with current PD-1/CTLA-4 combinations. Data from the first-in-human phase 1/2 study (NCT03530397) showed encouraging antitumor activity and acceptable tolerability with 1L volrustomig plus carboplatin/pemetrexed (CP) in NSCLC, particularly in pts with PD-L1 TC <1%. The phase 3, two-arm, parallel-group, randomized, multicenter, open-label eVOLVE-Lung02 study (NCT05984277) is designed to evaluate the efficacy of 1L volrustomig plus CT versus pembrolizumab plus CT in mNSCLC pts with PD-L1 TC <50%. Methods: Eligibility criteria include age ≥18 years; ECOG performance status 0 or 1; histologically or cytologically documented squamous (sq) or non-squamous (non-sq) stage IV NSCLC with PD-L1 TC expression <50%; wild-type EGFR, ALK, or ROS1; and no prior systemic therapy for mNSCLC. Approximately 900 pts will be randomized 1:1 to receive histology-specific CT (sq, paclitaxel plus carboplatin; non-sq, CP with pemetrexed maintenance at investigator discretion) in combination with either volrustomig or pembrolizumab (200 mg) every 3 weeks (Q3W) for 4 cycles; after this volrustomig or pembrolizumab will be administered Q3W until completion of 24 months of treatment or disease progression, or other discontinuation criteria are met. Randomization will be stratified according to histology (sq vs non-sq), PD-L1 (<1% vs 1–49%), smoking (never vs former/current), and region (Asia vs rest of world). Primary endpoints are progression-free survival (PFS) per RECIST v1.1 and OS in the PD-L1 TC <1% population. Secondary endpoints include PFS and OS in all randomized pts (PD-L1 TC <50%), overall response rate, duration of response, PFS2, safety and tolerability, patient-reported outcomes, pharmacokinetics, and immunogenicity. Enrollment is ongoing. Clinical trial information: NCT05984277 .

Novel RNA-nanoparticle vaccine for the treatment of early melanoma recurrence following adjuvant anti-PD-1 antibody therapy.

TPS9609 Background: Melanoma is a major public health concern with an anticipated increase in prevalence and incidence in the coming years. Early detection and surgical management remain the mainstay of treatment of early-stage disease and use of adjuvant immunotherapy has improved outcomes for patients with more aggressive (IIB-IIC) local disease or those with lymph node involvement (IIIA-IIID). Based on the tolerability and efficacy across subjects with both BRAF mutated and wildtype melanoma anti-PD1 (aPD1) therapy with either nivolumab or pembrolizumab are considered first line treatment in this setting. Adjuvant aPD1 therapy has significant improvement in relapse free survival (RFS) yet 25-30% of subjects will have disease recurrence within 1 year of surgery. When disease recurs, the response rate to immunotherapy is significantly reduced, re-challenged with aPD1 therapy has shown an Objective Response Rate (ORR) of zero and a marginally better response to CTLA-4 blockade. Novel strategies are needed for this at-risk population with early aPD1 resistance. To address this need we have developed a novel multi-lamellar lipid-nanoparticle complexed with total-tumor derived mRNA administered intravenously to restore responsiveness to aPD1 through reprogramming the tumor microenvironment (TME) bridging an innate and adaptive immune response. We have designed a clinical trial in which patients who progress on while on aPD1 therapy or within 6 months of therapy will have tumor sampled and a personalized lipid-nanoparticle vaccine generated. This vaccine is then administered IV for a total of 3 doses spanning 6 weeks to reprogram the TME and restore response to aPD1 which will be resumed on completion of vaccine series. This phase I study will assess initial feasibility and safety of vaccine generation, utilize ctDNA surveillance as early detection of adjuvant failure, and provide essential biologic information on immunotherapy resistance to aPD1 therapy. Methods: We have designed a modified 3+3 phase I clinical trial that will enroll subjects who have evidence of progressive disease (PD) by ctDNA and/or RECIST 1.1 criteria while receiving adjuvant aPD1 therapy, or those who progress within 6 months of completion of treatment for stage IIB-IIID melanoma. The goal of this study is to assess safety, tolerability, and feasibility of tumor specific RNA-LPs. Important biological correlates will also be collected and analyzed including tumor tissue sampling at initial time of checkpoint resistance and following vaccination series to identify key changes to the TME and tumor induced by lipid-nanoparticle vaccine administration. Clinical trial information: NCT05264974 .

Enhanced CTLA-4 blockade anti-tumor immunity with APG-157 combination in a murine head and neck cancer.

A phase I clinical study for patients with locally advanced H&N cancer with a new class of botanical drug APG-157 provided hints of potential synergy with immunotherapy. We sought to evaluate the efficacy of the combination of APG-157 and immune checkpoint inhibitors. CCL23, UM-SCC1 (human), and SCCVII (HPV-), MEER (HPV+) (murine) H&N cancer cell lines were utilized for invitro and invivo studies. We measured tumor growth by treating the mice with APG-157, anti-PD-1, and anti-CTLA-4 antibody combinations (8 groups). The tumor microenvironments were assessed by multi-color flow cytometry, immunohistochemistry, and RNA-seq analysis. Fecal microbiome was analyzed by 16S rRNA sequence. Among the eight treatment groups, APG-157 + anti-CTLA-4 demonstrated the best tumor growth suppression (p = 0.0065 compared to the control), followed by anti-PD-1 + anti-CTLA-4 treatment group (p = 0.48 compared to the control). Immunophenotype showed over 30% of CD8+ T cells in APG-157 + anti-CTLA-4 group compared to 4%-5% of CD8+ T cells for the control group. Differential gene expression analysis revealed that APG-157 + anti-CTLA-4 group showed an enriched set of genes for inflammatory response and apoptotic signaling pathways. The fecal microbiome analysis showed a substantial difference of lactobacillus genus among groups, highest for APG-157 + anti-CTLA-4 treatment group. We were unable to perform correlative studies for MEER model as there was tumor growth suppression with all treatment conditions, except for the untreated control group. The results indicate that APG-157 and immune checkpoint inhibitor combination treatment could potentially lead to improved tumor control.

Mitigating gut immune adverse effects in CTLA-4 blockade for antitumor efficacy.

Mitigating gut immune adverse effects in CTLA-4 blockade for antitumor efficacy.

494 Evaluating ERK1 2 Phosphorylation as a Predictive Biomarker for Survival in Recurrent Glioblastoma Patients: A REMARK Criteria-guided Analysis of a Clinical Trial Cohort Treated With Intracerebral PD-1 and CTLA-4 Blockade

INTRODUCTION: Glioblastoma patients exhibit variable clinical responses to anti-PD-1 immunotherapy. Our previous work identified ERK1/2 phosphorylation (p-ERK) in pre-treatment tumor samples as a predictive biomarker of overall survival in two independent cohorts of recurrent glioblastoma patients undergoing adjuvant anti-PD-1 therapy (Arrieta et al, Nat Cancer, 2021). This biomarker, however, has not yet been explored with alternative immune checkpoint blockade strategies nor assessed using REMARK criteria. METHODS: Adhering to REMARK criteria for biomarker validation, we investigated p-ERK as a predictor of survival in 24 evaluable recurrent glioblastoma patients from a clinical trial (NCT03233152; Duerinck J, et al, JITC, 2021). Patients underwent intracerebral administration of immune checkpoint inhibitors within a phase I clinical trial, receiving either ipilimumab (10 mg), or a combination of ipilimumab (5 mg) and nivolumab (10 mg), followed by postsurgical intravenous nivolumab (10 mg). We quantified p-ERK+ cell density in tumor regions and conducted a double-blinded statistical analysis of p-ERK’s association with survival outcomes, performed by an independent statistical team. RESULTS: Although analysis of the entire cohort revealed no statistically significant survival difference between patients with high and low p-ERK tumors (p = 0.29), a focused examination of wild-type IDH GBM patients demonstrated a significantly prolonged survival for those with high p-ERK tumors (median survival = 55.6 weeks, 95% CI 33.86-NA) compared to those with low p-ERK tumors (median OS of 30 weeks, 95% CI 16.14-NA; p = 0.036). CONCLUSIONS: Despite the limited sample size, this study highlights the promising predictive potential of p-ERK as a biomarker in a third independent prospective glioblastoma cohort treated with a novel immune checkpoint blockade administration approach, emphasizing the need for further investigation and validation in larger cohorts.

MONOCLONAL ANTIBODIES AGAINST CTLA-4 AND PD-L1 RECEPTORS OF THE CATTLE IMMUNE SYSTEM

With the progression of bovine leukemia virus (BLV), the concentration of T-cells, as well as CTLA-4 and PD-1 receptors on their cytoplasmic membrane increases. Elevated concentrations of regulatory T-cells lead to increased production of transforming growth factor-β (TGF β), suppression of interferon-γ (IFN-γ) expression, tumor necrosis factor-α (TNF-α), and inhibition of natural killer (NK) cells. Effector and cytotoxic T-lymphocytes, as well as the production of cytokines IFN-γ and TNF-α, play a crucial role in immune response against viral infections. However, at late subclinical stages, T-lymphocyte activity decreases due to the activity of regulatory T-lymphocytes, contributing to infection growth and progression to clinical disease. Blockade of CTLA-4 and PD-1/PD-L1 receptors with specific antibodies restores the immune response against BLV. Monoclonal antibodies (mAbs) against recombinant bovine CTLA-4 and PD-L1 were obtained using hybridoma technology methods. The obtained mAbs were analyzed using enzyme-linked immunosorbent assay (ELISA) and western blotting methods. As a result of the study, hybridoma cell lines producing mAbs to recombinant bovine CTLA-4 and PD-L1 receptors were obtained. The hybridomas produced IgG1 class mAbs that specifically reacted with standard proteins and had a binding constant: 3b3 - 2.9×108 M-1, 4h10 - 1.9×108 M-1. The obtained mAbs effectively blocked the reaction of commercial bovine CTLA 4 and PD-L1 proteins with specific polyclonal antibodies in an indirect fluorescent antibody assay (IFA).

Abstract 2712: Development of GB268, a tri-specific antibody targeting PD-1/CTLA-4/VEGF, with enhanced anti-tumor efficacy and reduced toxicity in pre-clinical studies

Abstract Background: Immunotherapy using immune checkpoint modulators such as anti-PD1/PD-L1 have been widely used in cancer therapy. Combination of checkpoint inhibition using anti-PD1 and anti-CTLA4 has improved therapeutic efficacy but is also accompanied by severe immune related adverse events (irAEs) which limited their clinical use. Bi-specific antibody targeting PD-1/CTLA-4 such as cadonilimab has shown improved clinical benefits with reduced irAEs in cervical cancer. Vascular endothelial growth factor (VEGF) is overexpressed in various solid tumors and anti-VEGF agents inhibit neovascularization and shrink tumor with time. Combined application of bevacizumab and PD-1/PD-L1 blockade displays durable and improved anti-tumor effects. We have recently developed a novel tri-specific antibody GB268, specifically targeting PD-1, CTLA-4 and VEGF with fine-tuned activity & potency for each arm to simultaneously block PD-1/CTLA-4 mediated immune-suppression and VEGF mediated tumor angiogenesis. Methods: GB268 is a hexavalent antibody with symmetrical structure, composed of anti-PD-1 VHH antibody, anti-CTLA-4 VHH antibody, and anti-VEGF conventional antibody. The Fc part is silenced by introducing L234A/L235A mutations. Comprehensive in vitro and in vivo characterization of GB268 have been carried out. Along with in vivo efficacy studies, toxicity has also been evaluated with a murine arthritis model in hPD1/hCTLA4 double-KI mice to assess immune related AEs. Results: GB268 specifically bound to PD-1, VEGF, and CTLA-4 with high affinity and completely blocked PD-1 and VEGF pathways in reporter systems. To reduce the CTLA4 inhibition-induced AEs, the CTLA-4 arm was intentionally designed to only partially block the interaction of CTLA4 to its ligands CD80/CD86, and furthermore, the blockade of CTLA-4 was highly dependent on PD-1 expression. GB268 displayed robust anti-tumor efficacy with attenuated toxicity in murine models. In multiple PBMC-humanized models including A375 melanoma model, HT29 colorectal cancer model, and NCI-H460 NSCLC model, etc., GB268 exhibited significantly better anti-tumor efficacy, compared to PD-1/CTLA-4 bsAb and PD-1/VEGF bsAb, or in the combination of monoclonal antibodies to PD-1, CTLA-4 or VEGF. In arthritis induction model using hPD1/hCTLA4 double KI mice, GB268 had improved tolerance than cadonilimab and at least 20-fold better safety profile than ipilimumab combined with nivolumab. Conclusions: GB268 is a first-in-class anti-PD-1/CTLA-4/VEGF tri-specific antibody with innovative design. Preclinical data demonstrated GB268 is very effective in provoking anti-tumor responses. At the meantime, immune-related AEs is alleviated. Thus, GB268 may emerge as a promising novel therapeutics for cancer treatment. Citation Format: Qinglin Du, Yaxua Lv, Juehua Xu, Fei Peng, Huanhuan Cao, Xueyan Yang, Zhen Qian, Xueqin Li, Yiqi Cao, Qian Ding, Yongcong Tan, Shuhua Han. Development of GB268, a tri-specific antibody targeting PD-1/CTLA-4/VEGF, with enhanced anti-tumor efficacy and reduced toxicity in pre-clinical studies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2712.