In April 2023, Guardant Health and the Parker Institute for Cancer Immunotherapy (PICI) announced a research collaboration agreement to study the correlation between molecular cancer biomarkers and patient response to immunotherapy treatment across more than 14 different types of cancer.

Under the agreement, Guardant Health will analyze patient blood samples from PICI’s RADIOHEAD (Resistance Drivers for Immuno-Oncology Patients Interrogated by Harmonized Molecular Datasets) prospective study of 1,200 individuals on standard-of-care immune checkpoint inhibitor (ICI) treatment regimens in community hospitals. The testing, conducted with GuardantINFINITY, will provide a multi-dimensional analysis of each patient’s tumor response based on genomic and epigenomic profiling. The study will use blood samples drawn at multiple points during the treatment regimen and will assess the connection between the presence of specific cancer biomarkers and real-world clinical outcomes, including survival and immune-related adverse events.

Interim data readout from this collaboration was released in ASCO 2024. 

Key Findings: 

• Guardant Infinity was successful in 96% of advanced cancer patients before starting an ICI, with 70% having ctDNA detected via methylation TF at C1D1. Baseline detection increases to 81% for Stage IV alone. 

• At each time point, a higher tumor fraction level is associated with worse outcomes in patients with solid tumors treated with immunotherapy.

• Increases and relative decreases ≥95% in tumor fraction while on ICI treatment are associated with shorter and longer real-world PFS and real-world OS, respectively.

KOL insights

“The study has generated deeper insights about the tumor microenvironment and its response to therapy” – Expert Opinion.

Conclusion

To conclude, monitoring advanced solid tumor patients using tumor fraction may help predict patient response or progression on immunotherapy and help facilitate treatment decisions.