Some patients have impressive and long-lasting responses to immune checkpoint inhibitors, while for most patients, the benefits of immunotherapy prove elusive, although these patients are subject to potentially life-threatening immune-related adverse events. The identification of a biomarker for benefit from immunotherapy is, therefore, urgent.
A recent paper published in the Journal of Clinical Oncology analysed tumour samples from patients in the non-randomised phase 1b KEYNOTE-028 study, looking for three potential biomarkers; tumour mutational burden (TMB), a T-cell inflammation gene-expression signature, and PD-L1 expression.
The analyses found weak associations between the biomarkers and treatment outcomes, none of which were strong enough to act as predictive biomarkers. “Even combining the 3 markers, it’s not yet an accurate predictor,” said the researchers. “Not all patients with all 3 markers responded and likewise, there were responders with low inflammation and low TMB. It’s not 100% accurate.”