Hiromichi Shirasu, MD, of the Shizuoka Cancer Center in Shizuoka, Japan, discusses the clinical implications of the GALAXY trial (UMIN000039205) as part of the CIRCULATE-Japan project, which is investigating circulating tumor DNA (ctDNA) status in patients with resectable colorectal cancer (CRC).

The GALAXY study provides interesting data, comprising a large-scale patient screening registry, according to Shirasu. The data collected in the GALAXY study could serve as a reference, specifically in new molecularly stratified treatments, which will be further investigated in the minimal residual disease (MRD) space, Shirasu explains.

For example, in patients who are MRD positive and harbor 

 mutations, a BRAF inhibitor may be utilized as adjuvant therapy, and the bigger trial is evaluating whether to eliminate an immediate adjuvant chemotherapy for patients who are less likely to benefit from it, Shirasu continues. The goal of the GALAXY trial is to establish the clinical significance of early inhibition in patients who are MRD-positive at an early stage by monitoring ctDNA status, Shirasu concludes. 

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Hiromichi Shirasu, MD, discusses the clinical implications of the GALAXY trial as part of the CIRCULATE-Japan project, which is investigating circulating tumor DNA status in patients with resectable colorectal cancer.

Dr. Shirasu on the Clinical Implications of ctDNA in CRC 

Hiromichi Shirasu, MD, senior staff member, Division of Clinical Oncology, Shizuoka Cancer Center, Shizuoka, Japan, discusses the utilization of circulating tumor DNA (ctDNA) testing in colorectal cancer (CRC). 

The GALAXY trial (UMIN000039205), part of the CIRCULATE-Japan project, is an ongoingstudy monitoring ctDNA in patients with resectable CRC, Shirasu says. The Signatera™ assay is a novel, patient-specific, custom-built ctDNA test that detects minimal residual disease in the plasma, Shirasu explains. The assay tests for 16 patient-specific, somatic, single-nucleotide variants, Shirasu continues.

Via whole-exome sequencing of the tumor tissue, the assay is highly specific and sensitive based on a variant-allele frequency of 0.01%, Shirasu concludes. 

Hiromichi Shirasu, MD, discusses the utilization of circulating tumor DNA testing in colorectal cancer.  

Dr. Shirasu on the Utilization of ctDNA Testing in CRC

Hiromichi Shirasu, MD, of the Shizuoka Cancer Center in Shizuoka, Japan, discusses the design of the GALAXY trial (UMIN000039205), part of the CIRCULATE-Japan project, which is examining circulating tumor DNA (ctDNA) in patients with resectable colorectal cancer (CRC).

GALAXY is a prospectively-conducted, large-scale, registry designed to monitor ctDNA status in patients with stage II to stage IV CRC who are undergoing surgical resection, according to Shirasu. Blood samples will be collected from patients before they undergo surgery, as well as at 4, 12, 24, 36, 48, 72, and 96 weeks after resection, Shirasu says. Additionally, computed tomography scans will be conducted every 6 months after surgery for 7 years, Shirasu adds.

Once results from the assay are received, patients can then be considered for enrollment to the phase 3 VEGA trial, which will assess observation vs adjuvant capecitabine plus oxaliplatin in patients from the GALAXY study who have high-risk stage II disease or low-risk stage III disease; or the phase 3 ALTAIR trial (NCT02305238), which will evaluate the superiority of trifluridine/tipiracil vs placebo in GALAXY participants with ctDNA status that remains positive after the standard therapy, Shirasu explains. Additional samples will also be collected for assessment, and a total of 2500 patients will be enrolled to the study, Shirasu concludes.

Hiromichi Shirasu, MD, discusses the design of the GALAXY trial, part of the CIRCULATE-Japan project, which is examining circulating tumor DNA in patients with resectable colorectal cancer. 

Hiromichi Shirasu, MD

Articles

Dr. Shirasu on the Clinical Implications of ctDNA in CRC

Dr. Shirasu on the Utilization of ctDNA Testing in CRC

Dr. Shirasu on the Design for the GALAXY Trial Examining ctDNA in CRC