Purpose: Mechanisms of primary resistance to inhibitors of the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) signaling axis in non–small cell lung cancer (NSCLC) are still poorly understood. While some studies suggest the involvement of trophoblast cell surface antigen 2 (TROP2) in modulating tumor cell resistance to therapeutic drugs, its specific role in the context of PD-1/PD-L1 axis blockade is not definitively established. Experimental Design: We performed high-throughput analysis of transcriptomic data from 891 NSCLC tumors from patients treated with either the PD-L1 inhibitor atezolizumab or chemotherapy in two large randomized clinical trials. To confirm our results at the protein level, we complemented this transcriptional approach by performing a multiplex immunofluorescence analysis of tumor tissue samples as well as a proteomic profiling of plasma. Results: We observed a significant association of TROP2 overexpression with worse progression-free survival and overall survival on PD-L1 blockade, independent of other prognostic factors. Importantly, we found increased TROP2 expression to be predictive of survival in patients treated with atezolizumab but not chemotherapy. TROP2 overexpression was associated with decreased T-cell infiltration. We confirmed these results at the proteomic level both on tumor tissue and in plasma. Conclusions: Our results suggest an important contribution of TROP2 expression to the primary resistance to PD-L1 blockade in NSCLC. TROP2-biomarker–based strategy may be relevant in selecting patients with NSCLC who are more likely to benefit from a combination of immunotherapy and an anti-TROP2 agent.

Anti-angiogenic agents elicit considerable immune modulatory effects within the tumor microenvironment, underscoring the rationale for synergistic clinical development of VEGF and immune checkpoint inhibitors in advanced gastric cancer (AGC). Early phase studies involving Asian patients demonstrated encouraging anti-tumor efficacies. We report the results of the REGOMUNE phase II study, in which Caucasian patients were administered regorafenib, a multi-tyrosine kinase inhibitor, in combination with avelumab, a PD-L1-targeting monoclonal antibody. This therapeutic regimen resulted in deep and durable responses in 19% of patients, with the median duration of response not yet reached. Notwithstanding, a significant proportion of AGC patients exhibited no therapeutic advantage, prompting investigations into mechanisms of inherent resistance. Comprehensive biomarker profiling elucidated that non-responders predominantly exhibited an augmented presence of M2 macrophages within the tumor microenvironment and a marked overexpression of S100A10 by neoplastic cells, a protein previously implicated in macrophage chemotaxis. Additionally, peripheral biomarker assessments identified elevated levels of cytokines, including CSF-1, IL-4, IL-8, and TWEAK, correlating with adverse clinical outcomes, thereby accentuating the role of macrophage infiltration in mediating resistance. These insights furnish an invaluable foundation for elucidating, and potentially circumventing, resistance mechanisms in current AGC therapeutic paradigms, emphasizing the integral role of tumor microenvironmental dynamics and immune modulation.

Most soft-tissue sarcomas (STS) exhibit an immunosuppressive tumor microenvironment (TME), leading to resistance against immune checkpoint inhibitors (ICIs) and limited therapeutic response. Preclinical data suggest that oncolytic viral therapy can remodel the TME, facilitating T cell accumulation and enhancing the immunogenicity of these tumors.We conducted the METROMAJX, a phase II clinical trial, to investigate the combination of JX-594, an oncolytic vaccinia virus engineered for selective tumor cell replication, with metronomic cyclophosphamide and the PD-L1 inhibitor avelumab in patients with advanced, ‘cold’ STS, characterized by an absence of tertiary lymphoid structures. The trial employed a two-stage Simon design. JX-594 was administered intratumorally at a dose of 1.10⁹ pfu every 2 weeks for up to 4 intra-tumoral administrations. Cyclophosphamide was given orally at 50 mg twice daily in a week-on, week-off schedule, and avelumab was administered at 10 mg/kg biweekly. The primary endpoint was the 6-month non-progression rate.Fifteen patients were enrolled, with the most frequent toxicities being grade 1 fatigue and fever. Fourteen patients were assessable for efficacy analysis. At 6 months, only one patient remained progression-free, indicating that the trial did not meet the first stage endpoint of Simon’s design. Analysis of sequential tissue biopsies and plasma samples revealed an increase in CD8 density and upregulation of immune-related protein biomarkers, including CXCL10.Intra-tumoral administration of JX-594 in combination with cyclophosphamide and avelumab is safe and capable of modulating the TME in cold STS. However, the limited efficacy observed warrants further research to define the therapeutic potential of oncolytic viruses, particularly in relation to specific histological subtypes of STS.

The majority of sarcomas are under the influence of a tumor microenvironment that dampens immune activity, resulting in resistance to monoclonal antibodies targeting immune checkpoints and reduced clinical effectiveness. Preclinical studies indicate that targeting abnormal neoangiogenesis by inhibiting vascular endothelial growth factor receptor (VEGFR) can alter the TME, thereby promoting T cell infiltration and increasing tumor immunogenicity. The REGOMUNE study, a phase II clinical trial, assessed the therapeutic combination of regorafenib, a multityrosine kinase inhibitor that targets VEGFR2 and the PD-L1 blocker avelumab, in individuals with advanced “cold” STS characterized by a lack of mature tertiary lymphoid structures (mTLS). Forty-nine mTLS-negative STS patients were enrolled, including leiomyosarcoma (45%), synovial sarcoma (18%), and other subtypes. The objective response rate was 11.0% (95% CI: 4.0% - 22.0%), with median progression-free survival and overall survival of 1.8 months (95% CI, 1.7–3.5 months) and 15.1 months, respectively. Frequent adverse events included grade 1 or 2 palmar-plantar erythrodysesthesia, fatigue, and diarrhea. On-treatment multiplex immunofluorescence analysis revealed significant increases in CD8 + T cell and B cell infiltration and PD1 expression on immune cells. Plasma analysis indicated significant upregulation of soluble PD-L1 (sPD-L1) levels and tryptophan consumption. Overall, these results indicate that anti-angiogenic therapy modulates the tumor microenvironment in patients with cold STS and highlight the need for complementary strategies to enhance the functional activity of immune cells in this particular setting. Clinical trial registration number: NCT03475953