These findings argue against a rebound effect after stopping bevacizumab, according to Dr. de Gramont. A "more aggressive tumor could have more involved sites," he explained. And "if there was a rebound effect, survival after relapse would have been worse in these patients."
The types of drugs given after recurrence were generally similar, except that patients in the FOLFOX4-alone group were more likely to receive bevacizumab. The most commonly used agents were irinotecan and 5-fluorouracil.
"A big translational effort is [being] done in the AVANT trial to look at different biomarkers to [determine] if there is a subpopulation that could benefit from this approach, and also to try to have predictive markers," Dr. de Gramont concluded.
"Everybody has been waiting for the results from AVANT to be presented because it’s very eagerly anticipated, given the results that we have seen of NSABP C-08," commented session discussant Dr. Johanna C. Bendell, director of the GI cancer research program at the Sarah Cannon Research Institute in Nashville, Tenn.
Results for the new trial differ in that the hazard ratios for disease-free survival increased after year 1 and showed not only lack of benefit of bevacizumab thereafter, but also possibly harm.
The time from recurrence to death was somewhat longer with FOLFOX4 alone, she noted. "But in the FOLFOX4 arm, more of those patients received bevacizumab after recurrence than [did] the patients in the bevacizumab arms," which could be contributing to their longer survival.
"When you really start to see the difference [between arms] is after the patients had already recurred, suggesting that something happens in the metastatic setting and perhaps not in the adjuvant until-disease-recurrence setting," said Dr. Bendell.
Roche sponsored the trial. Dr. de Gramont reported that he is a consultant for and has received honoraria from Roche (manufacturer of bevacizumab) and Sanofi-Aventis (manufacturer of oxaliplatin). Dr. Bendell reported having no relevant conflicts of interest.