ISTANBUL, Turkey—Adding the targeted antibody cetuximab(Drug information on cetuximab) (Erbitux) to standard cytotoxic chemotherapy as first-line treatment for patients with advanced colorectal cancer improves response rates, two groups of researchers said at the 31st Congress of the European Society for Medical Oncology (ESMO).
At an ESMO press briefing, Volker Heinemann, MD, PhD, of Klinkum Grosshadern, Munich, Germany, described a phase II study (abstract 327 O) in which patients were randomly assigned to XELIRI—capecitabine (Xeloda) 800 mg/m2 twice daily orally on days 1 to 14 and irinotecan(Drug information on irinotecan) (Camptosar) 200 mg/m2 intravenously on day 1—or XELOX— capecitabine(Drug information on capecitabine) 1,000 mg/m2 twice daily on days 1 to 14 and oxaliplatin(Drug information on oxaliplatin) (Eloxatin) 130 mg/m2 intravenously on day 1. In both arms, cetuximab was given at a dose of 400 mg/m2 intravenously on day 1 of the first 3-week cycle and then at 250 mg/m2 for each subsequent cycle.
The overall response rate (complete and partial responses) in the XELIRI/ cetuximab arm was 42.4% (14 of 33 patients) and in the XELOX arm, 65.5% (19 of 29 patients). Disease control (responders plus patients with stable disease) was 91% for XELIRI/cetuximab and 93% for XELOX/cetuximab.
The most common grade 3–4 toxicities in both arms were skin toxicity, allergic reactions, diarrhea, neurotoxicity, and leukopenia. There were more hematological adverse events in the irinotecan arm and more nonhematological adverse events in the oxaliplatin arm.
“In summary,” Dr. Heinemann said, “cetuximab enhances the activity of cytotoxic chemotherapy. New agents like the monoclonal antibodies cetuximab or bevacizumab(Drug information on bevacizumab) [Avastin] hold promise to prolong survival among patients with metastatic colorectal cancer.”
Cetuximab Plus XELOX
Another study (abstract 328 O) compared XELOX with or without cetuximab. The study was conducted by Daniel Helbling, MD, of University Hospital Bern, and his colleagues through the Swiss Group for Clinical Cancer Research (SAKK). Compared with other colon cancer chemotherapy regimens, XELOX is easy to administer, Dr. Helbling said. Patients attend the clinic once every 3 weeks for an infusion of oxaliplatin and take capecitabine tablets for 14 days.
In the multicenter, randomized phase II trial, patients were given oxaliplatin 130 mg/m2 on day 1 and oral capecitabine 1,000 mg/m2 twice daily on days 1 to 14 every 21 days, with or without cetuximab 250 mg/m2 weekly following a loading dose of 400 mg/m2. Therapy was stopped after a maximum of six cycles.