Activity and tolerance of biweekly CapeOx-cetuximab in 1st line therapy of metastatic colorectal cancer (mCRC): Relation to K-ras mutation status

e15018 Background: This novel q2w schedule trial combined oxaliplatin (Ox), flat dose capecitabine (Cape) and cetuximab(C) in first line therapy of mCRC. C was given weekly initially and then q2w. We report the response rate, toxicity and influence of K-ras mutation status in first-line patients treated with biweekly CapeOx-C in this phase II trial. Methods: Pts with previously untreated, histologically confirmed, metastatic colon adenocarcinoma, ECOG PS 0–1, and adequate organ function were eligible. Pts were treated with C (initially 250mg/m2 q week and later amended to 500mg/m2 q2w) and Ox (85mg/m2) combined with flat dose Cape (2500mg po bid x 7days) q2w. Endpoints included response (RECIST), toxicity (CTCAE v3) and relationship to K-ras mutation status as determined in codons 12/13 of exon 2 in genomic tumor DNA by PCR, blinded to clinical data. Results: Between 8/04 and 8/08, 27 pts were enrolled. One pt failed screening, 1 withdrew prior to rx and 2 too early for assessment. 25 pts were treated: M/...