Addition of bevacizumab to oxaliplatin-based chemotherapy as first-line treatment for advanced metastatic colorectal cancer improves progression-free survival, according to a presentation at the 2007 Gastrointestinal Cancers Symposium.

The phase III trial, one of the largest ever conducted with metastatic colorectal cancer, involved 1,401 patients receiving chemotherapy with either capecitabine plus oxaliplatin (Eloxatin) (a regimen known as XELOX) or 5-fluorouracil and leucovorin plus oxaliplatin (a regimen known as FOLFOX4), who were randomized to receive either bevacizumab or placebo in addition to the chemotherapy.

Progression-free survival was 8.0 months in the chemotherapy plus placebo group compared with 9.4 months in patients who received chemotherapy plus bevacizumab.

Overall side effects for the groups were similar. These effects were due primarily to oxaliplatin-based therapy and included neuropathy, lowered resistance to infection, fatigue, and diarrhea. The only side effect that was clearly increased by bevacizumab was elevated blood pressure, which was easily controlled with medication.

“Although previous studies have not examined its use in the first-line setting, oxaliplatin-based chemotherapy plus bevacizumab is nonetheless currently a widely used first-line treatment regimen in standard practice in the United States for advanced colorectal cancer,” said Leonard Saltz, MD, Professor of Medicine and member of the Gastrointestinal Oncology Service at Memorial Sloan-Kettering Cancer Center, and the study’s lead author.

“This is the first study to examine this regimen’s use as first-line treatment. These data validate its continued use in standard practice.” Dr. Saltz is the U.S. principal investigator for this trial; the European principal investigator is James Cassidy, MD, MSc, Cancer Research UK Professor of Oncology at Glasgow University in Scotland.

Although the protocol specified study drug treatment until disease progression (PD), only 56 percent of patients were treated in this manner, and 50 percent of patients discontinued for reasons unrelated to disease progression.