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Beyond TIGIT: Lessons from a failed immune checkpoint for rational target discovery
Jiatong Ding1, Shuhang Wang1, Ning Li1
1Clinical Trial Center, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100021, China.
Abstract:
The clinical failure of TIGIT inhibitors resulted from an incomplete mechanistic understanding, lack of predictive biomarkers, and functional redundancy with PD-1. Future success requires a focus on PD-1-refractory tumors, improved humanized models, and co-developed diagnostics, emphasizing rigorous science over rapid commercial development.
Insights
Clinical trials for TIGIT inhibitors failed due to poor understanding and biomarker issues. Future success in cancer immunotherapy depends on targeting PD-1-refractory tumors and using better models.
Area of Science:
- Immunology
- Oncology
- Pharmacology
Background:
- TIGIT (T cell immunoreceptor with Ig and ITIM domains) inhibitors have shown limited clinical success.
- Understanding the mechanisms of TIGIT action and its relationship with PD-1 (programmed cell death protein 1) is crucial for improving cancer immunotherapy.
- Lack of predictive biomarkers has hindered patient selection for TIGIT-targeted therapies.
Purpose of the Study:
- To analyze the reasons behind the clinical failure of TIGIT inhibitors.
- To propose strategies for future development of TIGIT-based cancer immunotherapies.
- To highlight the importance of rigorous scientific investigation over accelerated commercialization.
Main Methods:
- Review of existing clinical trial data for TIGIT inhibitors.
- Analysis of preclinical research on TIGIT and PD-1 pathways.
- Comparative assessment of TIGIT and PD-1 functions in cancer immunology.
Main Results:
- Clinical failures were attributed to incomplete mechanistic insights, absence of predictive biomarkers, and functional overlap with PD-1.
- TIGIT inhibitors may be less effective in unselected patient populations or when PD-1 is already targeted.
- Significant redundancy exists between TIGIT and PD-1 pathways in regulating T cell responses.
Conclusions:
- Future TIGIT inhibitor development should prioritize PD-1-refractory tumors.
- Enhanced humanized models are needed to better predict clinical efficacy.
- Co-development of diagnostics and therapeutics is essential for advancing TIGIT-based immunotherapy.
- A focus on fundamental science is critical for overcoming current limitations and achieving clinical success.
