Data from GALAXY Study Shows Ability of Natera to Predict Outcomes and Benefit of Adjuvant Chemotherapy in Resectable Colorectal Cancer

Natera, Inc. unveiled new data from the GALAXY arm of the CIRCULATE-Japan trial, demonstrating the effectiveness of the Signatera™ molecular residual disease (MRD) test in identifying patients with resectable colorectal cancer (CRC) who face an elevated risk of recurrence and predicting who is most likely to benefit from adjuvant chemotherapy.

The presentation was made during the 2023 European Society for Medical Oncology (ESMO) Congress in Madrid. Natera, along with its collaborators, provided an extended GALAXY analysis, building upon earlier results published in Nature Medicine in January 2023. This larger dataset includes 2,625 CRC patients and assesses disease-free survival (DFS) at 24 months, offering over twice the number of patients and significantly longer follow-up compared to the previously published 18-month findings.

The data showed that patients who tested negative for circulating tumor DNA (ctDNA) continued to exhibit high disease free survival (DFS) regardless of receiving adjuvant chemotherapy (ACT). There was no significant discrepancy in DFS at 24 months between ctDNA-negative patients who received ACT and those who didn’t (88.3% DFS vs. 89.9%, p-value 0.156). However, the presence of post-surgical ctDNA proved to be the most critical prognostic factor for disease recurrence and was predictive of the benefits of chemotherapy. ctDNA-positive patients who received ACT demonstrated significantly higher DFS at 24 months compared to those who did not (38.6% DFS vs. 16.1%, p-value <0.01). Patients with ctDNA-positive results had notably lower DFS at 24 months than ctDNA-negative patients (31% vs. 89%, p-value <0.01). Furthermore, in a multivariate analysis, ctDNA status remained the most prognostic factor for cancer recurrence (HR 10.44) and changes in ctDNA status at 3 months post-surgery were significantly linked to DFS at 24 months.

Principal investigator of the study, Dr. Takayuki Yoshino of the National Cancer Center Hospital East, Kashiwa, Chiba, Japan, commented on the results, saying, “The latest data from one of the largest prospective studies of MRD testing in colorectal cancer provides further evidence that Signatera can help clinicians determine which patients are most likely to benefit from adjuvant chemotherapy, while also showing that postoperative ctDNA status is a highly prognostic factor for cancer recurrence. With a larger cohort of patients and longer-term follow up, this updated analysis builds upon previously published findings and shows how ctDNA can play a critical role in monitoring disease progression and guiding adjuvant treatment.”