The Opus study is a randomized first-line Phase II study of 337 patients comparing Erbitux plus Folfox to Folfox alone in epidermal growth factor receptor (EGFR)-expressing colorectal cancer (mCRC) patients who have not previously been treated.
Response rate, the Opus study’s primary endpoint, was found to be 46% in the Erbitux-plus-Folfox arm compared with 36% in the Folfox-only arm (P = .064). When the wild type K-Ras patients are selected from the population, the response rate in the wild type K-Ras group increased to 61% in the Erbitux-plus-Folfox arm compared with 37% in the Folfox-only arm (P = .01).
With regard to the progression-free survival endpoint, the risk of disease progression was reduced by 43% (hazard ratio = 0.57; P = .02) by the addition of Erbitux to Folfox chemotherapy in wild-type K-Ras patients. The Opus study was conducted by Merck KGaA, Darmstadt, Germany.
Erbitux is a monoclonal antibody to inhibit the function of a molecular structure expressed on the surface of normal and tumor cells called the epidermal growth factor receptor (EGFR, HER1, c-ErbB-1).