Study Shows Guardant360 Liquid Biopsy Predicts Response to Pembrolizumab-Based Immunotherapy in Patients with Metastatic Non-Small Cell Lung Cancer

For patients with metastatic non-small cell lung cancer (mNSCLC), not harboring an actionable mutation, immunotherapy is often recommended for first-line treatment. A new study in JCO Precision Oncology shows the Guardant360 liquid biopsy test provides an early indication of treatment response to pembrolizumab-based immunotherapy by detecting molecular response or changes in circulating tumor DNA (ctDNA) levels early on.¹⁰ The study was led by researchers at the Perelman School of Medicine at the University of Pennsylvania.

The single-center, prospective, observational study evaluated molecular response in patients with mNSCLC (n=51) receiving pembrolizumab-based therapy, as monotherapy or with chemotherapy, as first- or second-line treatment. Changes in ctDNA were evaluated from baseline to nine weeks post-therapy initiation, and correlated with clinical and radiographic response.

In the study, the Guardant360 test showed that molecular responders achieved improved durable clinic benefit (log mean 49.4% vs. 3.5%) and significantly longer progression-free survival (median 14.1 vs. 4.4 months) and overall survival (median 22.1 vs. 12.0 months) compared to non-molecular responders. Molecular response was also associated with radiologic response as assessed by Response Evaluation Criteria in Solid Tumors (RECIST) .

“Unfortunately, only a subset of patients with metastatic non-small cell lung cancer will respond to pembrolizumab-based therapy, and their failure to achieve clinical benefit becomes evident after their disease has progressed,” said Helmy Eltoukhy, Guardant Health CEO. “This study adds to the growing body of evidence showing that our Guardant360 test can effectively measure molecular response, giving clinicians an earlier indication whether to continue or stop treatment, explore other therapeutic regimens, or enroll the patient in a clinical trial.”

The Guardant360 test is used to guide treatment in metastatic non-small cell lung cancer as the number of treatment-relevant genomic alterations continues to grow. Using next-generation sequencing, Guardant360 analyzes 83 genes using cell-free tumor DNA from blood samples. The Guardant360 test is broadly covered by Medicare for use across the vast majority of advanced solid tumors, including patients with metastatic non-small cell lung cancer. Last year, the FDA approved the Guardant360 CDx for tumor mutation profiling, also known as comprehensive genomic profiling (CGP), in patients with any solid malignant neoplasm (cancerous tumor).