A single biomarker is not adequate to identify patients with gastric cancer (GC) who have the potential to benefit from anti-PD-1/PD-L1 therapy, presumably owing to the complexity of the tumour microenvironment. The predictive value of tumour-infiltrating immune cells (TIICs) has not been definitively established with regard to their density and spatial organisation. Here, multiplex immunohistochemistry is used to quantify in situ biomarkers at sub-cellular resolution in 80 patients with GC. To predict the response to immunotherapy, we establish a multi-dimensional TIIC signature by considering the density of CD4⁺FoxP3⁻PD-L1⁺, CD8⁺PD-1⁻LAG3⁻, and CD68⁺STING⁺ cells and the spatial organisation of CD8⁺PD-1⁺LAG3⁻ T cells. The TIIC signature enables prediction of the response of patients with GC to anti-PD-1/PD-L1 immunotherapy and patient survival. Our findings demonstrate that a multi-dimensional TIIC signature may be relevant for the selection of patients who could benefit the most from anti-PD-1/PD-L1 immunotherapy.

Research on patients with advanced esophageal squamous cell carcinoma (ESCC) who have progressed on immunotherapy remains limited. BL-B01D1 is a first-in-class antibody–drug conjugate consisting of an EGFR–HER3 bispecific antibody bound to a topoisomerase I inhibitor (Ed-04) payload via a cleavable linker. Here, we present safety and efficacy data from a phase 1 study of BL-B01D1, in 82 patients previously treated for ESCC. The primary endpoint was the recommended phase 2 dose. Administered doses were 2.0 (n = 22) and 2.5 (n = 60) mg kg⁻¹ D1D8 infusion every 3 weeks (Q3W). The confirmed objective response rate (cORR) was 29.3% (24 of 82) in all patients and 32.9% (24 of 73) among evaluable patients. For patients dosed at 2.5 mg kg⁻¹, cORR was 39.6% (21 of 53) and disease control rate was 79.2% (42 of 53). In the 2.0 mg kg⁻¹ group, cORR was 15.0% (3 of 20), and the disease control rate was 50.0% (10 of 20). The phase 2 dose was established at 2.5 mg kg⁻¹ D1D8 Q3W. The incidence of G3 treatment-related adverse events at 2.5 mg kg⁻¹ was 63.3%; most common adverse events were anemia (28.3%), leukopenia and thrombocytopenia (18.3%, each), and neutropenia (16.7%). Two cases of ≥G3 interstitial lung disease were observed. Overall, BL-B01D1 demonstrated promising efficacy and manageable safety in patients with metastatic ESCC. A further phase 3 clinical trial has already been initiated. ClinicalTrials.gov registration: NCT05262491.

The tumor microenvironment plays a vital role in tumor progression and treatment response. However, the association between immune cell concentrations in primary tumor and blood indexes remains unknown. Thus, we enrolled patients with gastric cancer (GC) in two cohorts. We used multiplexed immunohistochemistry to quantify in situ proteins covering rare cell types at sub-cellular resolution in 80 patients with GC in the first cohort. A high correlation between the LMR (lymphocyte-to-monocyte ratio)/NLR (neutrophil-to-lymphocyte ratio) and tumor immune microenvironment was found. The density of exhausted CD8 T cells including CD8⁺PD1⁻TIM3⁺, CD8⁺LAG3⁺PD1⁺, CD8⁺LAG3⁺PD1⁻, CD8⁺LAG3⁺PD1⁺TIM3⁻ was negatively associated with LMR and positively associated with NLR (p < 0.05). Additionally, the higher density of macrophages in tumor core was associated with a higher platelet-to-lymphocyte ratio and systemic immune-inflammation index. Furthermore, we validated the prognostic value of LMR and NLR in an independent cohort of 357 gastric cancer patients receiving immunotherapy. Higher LMR at baseline was significantly associated with superior immune-related PFS (irPFS) and a trend of superior immune-related OS (irOS). Higher NLR was associated with inferior irOS. In conclusion, blood indexes were associated with immune cells infiltrating in primary tumors of GC. NLR and LMR are associated with the density of exhausted CD8⁺ T immune cells, which leads to prognostic values of immunotherapy.

Purpose: The aim of the study was to evaluate the safety, pharmacokinetics, and preliminary clinical activity of UTAA06, an “off-the-shelf” allogeneic B7-H3–targeted chimeric antigen receptor (CAR) Vδ1T-cell therapy, in patients with pretreated, advanced B7-H3–positive solid tumors. Patients and Methods: In this first-in-human, phase I, dose-escalation study (NCT06372236), 10 patients with advanced solid tumors (including gastric, colorectal, hepatocellular, ovarian, and neuroendocrine cancers) were enrolled. Following lymphodepletion chemotherapy (cyclophosphamide and fludarabine), patients received UTAA06 infusion across three dose levels (5 × 108, 8 × 108, or 1 × 109 cells). The primary endpoint was safety. Secondary endpoints included pharmacokinetics and antitumor efficacy. Results: UTAA06 demonstrated a manageable safety profile; no GVHD was observed, and cytokine release syndrome was limited to two transient grade 1 events. A single dose-limiting toxicity (grade 3 pneumonitis) was reported in one patient at the 5 × 108 cell dose level. Although UTAA06 demonstrated signals of biological activity, including transient reductions in serum tumor markers in 50% of patients, no objective response by RECIST v1.1 criteria was observed. Further analysis identified that the limited CAR T-cell persistence was likely driven by subclinical host-versus-graft rejection. Conclusions: This study provides clinical proof of concept for allogeneic B7-H3–targeted CAR-Vδ1T cells as a safe platform with low risk of GVHD and demonstrable biological activity in solid tumors. However, clinical efficacy was constrained by limited cellular persistence caused by host immune rejection. Future strategies are required to enhance the durability and therapeutic potential of this allogeneic approach.