Nature Communications | Phase II Study Results of Ociperlimab Combined with Tislelizumab in Advanced Esophageal Squamous Cell Carcinoma

This study reveals the limitations of TIGIT inhibitors in the second-line treatment of esophageal squamous cell carcinoma, providing critical data support for the screening of biomarkers in subsequent immune checkpoint combination strategies.

 

Literature Overview

The article "Ociperlimab and tislelizumab in advanced esophageal squamous cell carcinoma (AdvanTIG-203): a phase II study," published in Nature Communications, systematically investigates whether adding the TIGIT inhibitor Ociperlimab significantly enhances the efficacy of Tislelizumab in patients with advanced esophageal squamous cell carcinoma (ESCC) with high PD-L1 expression. The results show that while the combination therapy demonstrated a good safety profile, it failed to meet the prespecified primary endpoint, suggesting that dual immune checkpoint blockade alone may face bottlenecks in specific populations.

Background Knowledge

Although PD-1 inhibitors have transformed the treatment landscape of esophageal cancer, long-term survival rates remain low, indicating a significant unmet clinical need. As a key immune checkpoint co-expressed with PD-1, TIGIT theoretically enhances the anti-tumor activity of CD8+ T cells and NK cells when combined with PD-1 blockade. However, the clinical benefits of TIGIT inhibitors in solid tumors remain controversial, with bottlenecks potentially arising from tumor microenvironment heterogeneity, compensatory mechanisms involving CD155, and a lack of precise biomarker guidance. This study aims to verify whether a dual blockade strategy can break through the efficacy ceiling of single PD-1 blockade in the second-line setting for patients with PD-L1 TAP ≥ 10% via the AdvanTIG-203 trial.

 

 

Research Methods and Core Experiments

This study is a multicenter, randomized, double-blind phase II clinical trial (NCT04732494) that enrolled 125 patients with unresectable, locally advanced, recurrent, or metastatic esophageal squamous cell carcinoma with PD-L1 TAP ≥ 10%. Patients were randomly assigned to either the combination therapy group (Ociperlimab + Tislelizumab) or the control group (placebo + Tislelizumab). The primary endpoint was the investigator-assessed objective response rate (ORR), while secondary endpoints included overall survival (OS), progression-free survival (PFS), and safety. The study also conducted exploratory biomarker analyses, including immunohistochemical detection of PD-L1 and TIGIT, as well as tumor microenvironment characterization based on RNA sequencing.

Key Conclusions and Perspectives

• Primary Endpoint Not Met: The ORR in the combination therapy group was 30.6%, compared to 20.6% in the control group, with no statistically significant difference (p=0.2114), indicating that adding Ociperlimab did not significantly improve tumor response rates.
• Limited Survival Benefit: Final analysis showed a median OS of 10.2 months in the combination group versus 9.3 months in the control group, with a hazard ratio (HR) of 0.92, demonstrating no significant survival advantage.
• Controllable Safety: The incidence of grade 3 or higher treatment-related adverse events in the combination group was 25.8%, comparable to the control group (20.6%), suggesting that dual blockade did not increase significant toxicity.
• Biomarker Exploration: Exploratory analysis revealed that patients with an inflammatory tumor microenvironment (characterized by enrichment of NK cells, T cells, macrophages, etc.) may benefit from combination therapy, with NK cell signature scores correlating with trends in OS and PFS improvement.
• Mechanistic Insights: The study suggests that TIGIT expression levels or alternative CD155 pathways may limit efficacy, indicating that relying solely on PD-L1 expression as a selection criterion may be insufficient to predict beneficiaries of TIGIT inhibitors.

Research Significance and Prospects

The results of this study carry important implications for immuno-oncology drug development, indicating that not all combinations of immune checkpoints yield clinical benefits, necessitating a deeper understanding of the complex interactions within the tumor microenvironment. For clinical monitoring in esophageal squamous cell carcinoma, future efforts should focus on NK cell infiltration levels and inflammatory microenvironment characteristics to screen for potential beneficiary populations. Furthermore, the study suggests that in disease modeling and subsequent trial designs, compensatory mechanisms between TIGIT and other immunosuppressive pathways must be considered, exploring potential applications in first-line settings or in combination with chemotherapy/radiotherapy.

 

 

Conclusion

Although the AdvanTIG-203 study did not meet its primary endpoint, it provided valuable negative data for immunotherapy strategies in esophageal squamous cell carcinoma. It revealed that simply adding a TIGIT inhibitor in populations with high PD-L1 expression may be insufficient to overcome tumor immune escape mechanisms. This finding underscores the importance of precision medicine; future drug development should shift towards biomarker-enriched population studies, particularly targeting patients with inflammatory tumor microenvironments and specific NK cell characteristics. In the translation from laboratory to clinic, deeply elucidating the synergistic mechanisms between TIGIT and PD-1 pathways, and exploring blockade strategies for alternative targets such as CD155, will be key to breaking through current treatment bottlenecks in esophageal cancer. This study lays a solid foundation for optimizing the design of clinical trials for immune combination therapies, helping to avoid resource waste and accelerate the emergence of effective treatments.

 

Feng Wang, Chen-Yuan Lin, Jong-Mu Sun, Jiadong Zhou, and Rui-Hua Xu. Ociperlimab and tislelizumab in advanced esophageal squamous cell carcinoma (AdvanTIG-203): a phase II study. Nature Communications.