Non-small cell lung cancer (NSCLC) patients with higher measures of tumor mutations which show up in a blood test generally have a better clinical response to PD-1-based immunotherapy treatments than patients with a lower measure of mutations. A clinical trial led by researchers from the Perelman School of Medicine and the Abramson Cancer Center shows that in cases where the liquid biopsy detects higher volumes of mutations, patients with cancers that have spread are more likely to see a clinical benefit at 6 months, as well as to survive longer without seeing their disease progress. The findings were published in Clinical Cancer Research, a journal of the American Association for Cancer Research.

NSCLC is the most common form of lung cancer, accounting for about 84% of all lung cancer cases. In patients with metastatic disease—meaning the tumor has spread from the lungs to distant parts of the body—the 5-year survival rate is just 6%. Immunotherapy with a PD-1 inhibitor, either alone or in combination with chemotherapy, is the standard first-line treatment in these cases when cancers do not have a targetable mutation. Historically, doctors have used a tissue sample to look for a protein called PD-L1, which can predict response. However, it’s an imperfect biomarker and requires the availability of tissue. Instead, the Penn trial focused on biomarkers found in more easily-obtained blood samples.

“While some people see a benefit from these therapies, unfortunately not everyone does. There is an important clinical need to identify new, non-invasive biomarkers to help us guide each patient to the treatments that have the best chance of success for them, and our findings show we may now have a tool to help us do that,” says the study’s lead author Charu Aggarwal, the Leslye M. Heisler assistant professor for Lung Cancer Excellence at Penn.