Liquid Biopsy Assay Expands Offerings to Include MRD, Disease Recurrence Detection in Early-Stage Breast and Lung Cancer

Helmy Eltoukhy

The Guardant Reveal assay has been expanded for the detection of minimal residual disease (MRD) and disease recurrence in patients with early-stage breast cancer and lung cancer, according to an announcement from Guardant Health Inc.¹

Previously, the Guardant Reveal assay was the only tissue-free test for MRD and disease recurrence detection in early-stage colorectal cancer (CRC). The assay may be used as early as 3 weeks following surgery.

“We are very pleased to be able to make the Guardant Reveal test available to patients with breast and lung cancer, where obtaining a tissue biopsy can be a challenge,” Helmy Eltoukhy, co-chief executive officer of Guardant Health, stated in a news release. “With a simple blood draw, this test allows oncologists to confidently assess risk for their breast and lung cancer patients so they can quickly identify those patients who may benefit from therapy after surgery, as well as detect cancer recurrence earlier.”

The assay is designed for use in patients with stage II or III CRC, breast cancer, or lung cancer. The test combines genomic and epigenomic signals to detect circulating tumor DNA (ctDNA) in blood after surgery to identify patients with MRD who may benefit most from adjuvant therapy and to monitor for recurrence of disease in previously diagnosed patients.

The assay has also been shown to better predict disease recurrence than current standard-of-care tools, such carcinoembryonic antigen (CEA) tests.²

In a study published in Clinical Cancer Research, investigators collected ctDNA samples from 84 patients with CRC who underwent surgery only (n = 39) or who completed adjuvant therapy (n = 45). In landmark plasma drawn at a median of 31.5 days after definitive therapy and after 1 year of follow-up, 15 patients had detectable ctDNA according to data from Guardant Reveal, and all 15 recurred (positive predictive value [PPV], 100%; HR, 11.28; P < .0001).

Furthermore, of the 49 patients who did not have detectable ctDNA according to the assay, 24.5% recurred. Landmark recurrence sensitivity and specificity were 55.6% and 100%, respectively.

By including serial longitudinal and surveillance samples drawn within 4 months of recurrence, sensitivity improved to 69% and 91%. By integrating epigenomic signatures vs genomic alterations alone, sensitivity increased by 25%-36%.

Standard serum CEA levels did not predict recurrence (PPV, 53.9%; HR, 1.84; P = .18).

References

1. Guardant Health expands use of Guardant Reveal™ liquid biopsy test for residual disease detection and recurrence monitoring to include early-stage breast and lung cancers. News release. Guardant Health. August 15, 2022. Accessed August 16, 2022. https://bit.ly/3PrtxiP
2. Parikh AR, Van Seventer EE, Siravegna G, et al. Minimal residual disease detection using a plasma-only circulating tumor DNA assay in patients with colorectal cancer. Clin Cancer Res. 2021;27(20):5586-5594. doi: 10.1158/1078-0432.CCR-21-0410