Publication: CO26 Secondary Analysis

The CO26 sub-study: Circulating Tumor DNA Identifies Diverse Landscape of Acquired Resistance to Anti-Epidermal Growth Factor Receptor Therapy in Metastatic Colorectal Cancer has recently been published in Journal of Clinical Oncology.

Topham JT, O'Callaghan CJ, Feilotter H, Kennecke HF, Lee YS, Li W, Banks KC, Quinn K, Renouf DJ, Jonker DJ, Tu D, Chen EX, Loree JM. (ONLINE). J Clin Oncol JCO, 2022.

“Our study highlights how we can use circulating tumor DNA (ctDNA) in blood to identify the ways a cancer becomes resistant to treatment. We hope this will allow us to find new combinations that prevent or target this resistance to help patients with colorectal cancer.”  says Dr Jonathan Loree, CCTG Colon Cancer Disease Site Co-chair, and GI Medical Oncologist at BC Cancer in Vancouver, Canada & Assistant Professor at The University of British Columbia.

Paired tissue and ctDNA sequencing identified multiple novel mutations, copy gains, and fusions associated with anti-EGFR therapy that frequently co-occur as subclonal alterations in the same patient.


This is a correlative study from the CO26: A Phase II Randomized Study of Durvalumab and Tremelimumab and Best Supportive Care vs Best Supportive Care Alone in Patients with Advanced Colorectal Adenocarcinoma Refractory to Standard Therapies

CO26 was a phase II study of doublet immunotherapy (durvalumab + tremelimumab) and best supportive care versus best supportive care only in patients with advanced colorectal cancer who are refractory to all available therapy. The purpose of this study was to determine the effect on overall survival (OS) of the combination of durvalumab and tremelimumab and best supportive care versus best supportive care only in patients with refractory, advanced colorectal cancer.

For more information please visit the CO26 trial page.