Adjuvant therapy with bevacizumab (Avastin) plus chemotherapy did not improve disease-free survival in stage III colon cancer, according to Roche/Genentech. The AVANT trial compared the efficacy and safety of the combination regiment with chemotherapy alone.
The AVANT data are in line with the results of the NSABP C-08 study, which demonstrated a DFS of 77.4% in the bevacizumab arm and 75.5% in the control arm (American Society of Clinical Oncology [ASCO] 2009 LBA4).
However, preliminary data from AVANT numerically favored chemotherapy alone, according to the company. Adverse events in AVANT were consistent with those of previous studies of bevacizumab across tumor types for approved indications.
Roche is reviewing the data from these two studies to define the next steps for the bevacizumab in the adjuvant setting. The results from AVANT do not affect bevacizumab's approved indications in metastatic disease, according to the company.
AVANT was a randomized three-arm study in 3,451 patients that evaluated bevacizumab in combination with either capecitabine plus oxaliplatin (XELOX) or fluorouracil/leucovorin with oxaliplatin (FOLFOX-4) versus FOLFOX-4 alone as adjuvant chemotherapy in patients who had undergone surgery for high-risk stage II and stage III colon cancer. Data from the trial will be presented in 2011, the company stated.
When results from the NSABP C-08 trial were released, colon cancer experts looked to AVANT for the final word. "If AVANT is strongly positive, then you have to square it with a negative study [NSABP C-08]," said Alan P. Venook, MD, in a July 2009 Oncology News International article. "My suspicion is that AVANT will have similar findings," added Dr. Venook, from at the University of California, San Francisco.
Lee Ellis, MD, from Houson's M.D. Anderson Cancer Center said that if the AVANT results were not outright positive, then further trials of long-term anti-VEGF for the adjuvant treatment of colon cancer should not be conducted ("NSAPB chair admits 'failure' in C-08 trial, denies defeat," page 5).