Article Impact Level: HIGH Data Quality: STRONG Summary of Nature Cancer. https://doi.org/10.1038/s43018-025-01018-w Dr. Justin Huang et al.
Points
- This study investigated combining stereotactic radiation with pembrolizumab immunotherapy to treat metastatic non-small cell lung cancer.
- Patients with immunologically “cold” tumors had significantly longer progression-free survival when receiving radiation before immunotherapy.
- Radiation induces powerful immune-signaling pathways, including interferon and antigen presentation, in distant tumors that are not directly targeted.
- The therapy prompted the expansion of both new and existing tumor-fighting T cell clones throughout the body and within tumors.
- These findings confirm that radiation can create a therapeutic window to overcome immunotherapy resistance by activating a systemic immune response.
Summary
A phase 2 clinical trial (NCT02492568) investigated the effects of stereotactic body radiation therapy (SBRT) followed by pembrolizumab versus pembrolizumab alone in metastatic non-small cell lung cancer. Researchers conducted multiomic analyses on 293 serial tissue and blood biospecimens from 72 participants to characterize the systemic immunomodulatory effects of radioimmunotherapy. The study focused on whether SBRT could sensitize immunologically “cold” tumors—defined by low tumor mutation burden, null programmed death ligand 1 (PD-L1) expression, or Wnt pathway mutations—to immune checkpoint inhibition, thereby overcoming therapeutic resistance.
The findings demonstrate that SBRT induces significant systemic immune activation. In nonirradiated (abscopal) tumor sites, multiomic analysis revealed a significant enrichment of interferon-γ, interferon-α, and antigen processing and presentation gene sets following SBRT. This “warming up” of the tumor microenvironment was accompanied by significant on-therapy expansions of both new and pre-existing T cell clones. These clonal expansions were observed systemically in the blood and locally in abscopal tumor tissues, indicating a broad, radiation-induced anti-tumor immune response.
These molecular and cellular changes correlated directly with clinical benefit. Participants with immunologically cold tumors experienced significantly longer progression-free survival in the SBRT combination arm compared to the arm receiving immunotherapy only. Furthermore, functional analyses in participants who achieved long-term survival confirmed the presence of clonal, neoantigen-reactive autologous T cell responses. These results support a mechanism whereby SBRT overcomes immunotherapy resistance by inducing a systemic anti-tumor response, suggesting a potent therapeutic strategy for patients with tumors previously unresponsive to immune checkpoint inhibitors.
Link to the article: https://www.nature.com/articles/s43018-025-01018-w
References Huang, J., Theelen, W. S. M. E., Belcaid, Z., Najjar, M., Van Der Geest, D., Singh, D., Cherry, C., Balan, A., White, J. R., Wehr, J., Karchin, R., Niknafs, N., Van Den Heuvel, M. M., Velculescu, V. E., Smith, K. N., Baas, P., & Anagnostou, V. (2025). Combination of pembrolizumab and radiotherapy induces systemic antitumor immune responses in immunologically cold non-small cell lung cancer. Nature Cancer. https://doi.org/10.1038/s43018-025-01018-w
