Photo Credit: Mohammed Haneefa Nizamudeen
Treating ctDNA-positive patients with stage II colon cancer adjuvant chemotherapy for 6 months did not lead to an improvement in ctDNA clearance.
In a low-risk population of patients with stage II colon cancer, treating ctDNA-positive patients with adjuvant chemotherapy for 6 months did not lead to an improvement in ctDNA clearance, results of a phase 2 study showed.
In the phase 2 NRG-GI005/COBRA study (NCT04068103), 635 patients with resected stage IIA colon cancer were randomized 1:1 to standard-of-care active surveillance (arm 1) or to assay-directed therapy (arm 2). In the latter arm, participants with detected ctDNA were treated with mFOLFOX6 or CAPOX chemotherapy for 6 months. Van Morris, MD, presented the findings.1
In total, ctDNA positivity was detected in 33 patients. The current analysis included 16 of them: 7 had been randomized to arm 1, and 9 had been randomized to arm 2. The ctDNA clearance rate was 43% in arm 1 and 11% in arm 2 (one-sided P=0.98). “Since the one-sided P-value exceeded 0.35, the null hypothesis could not be rejected, and we had to stop the trial due to futility,” said Dr Morris.
Despite the neutral trial results, Dr. Morris pleaded for more ctDNA trials. “Prospective trials assessing ctDNA as a surrogate for minimal residual disease are feasible and necessary to confirm clinically relevant hypotheses in oncology,” he reasoned. “Future clinical trial design should account for the evolution of ctDNA methodologies and assay performance in order to answer relevant questions in the field.”
Medical writing support was provided by Robert van den Heuvel.
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