Given that the majority of GI events occurred during initial chemotherapy treatment, Dr. O’Malley asked whether bevacizumab should be included in future trials only as maintenance therapy.
"Point well taken," Dr. Burger replied. "We really do not know the absolute importance of combining [antiangiogenic and cytotoxic therapies] in the front-line setting at all."
"We can safely say we should inform our patients ... of the risk factors that may increase the probability of a severe gastrointestinal event," Dr. Burger said. "I don’t think we can come to a conclusion that patients should be excluded based on bowel resection or history of IBD," because confidence limits were fairly large for some of these relatively rare risks.
Dr. Burger said he would be more cautious, however, with prescription of bevacizumab in a patient who has other risk factors. "If a patient has two independent risk factors, those risks need to be multiplied," he said.
Strengths of the study include a large patient population and being the first prospective evaluation of GI adverse events associated with bevacizumab in advanced gynecologic cancer, Dr. O’Malley said. However, there was less than 1 month’s difference in progression-free survival between the control arm and treatment arm 1, he said. "When looking at bevacizumab as adjuvant therapy during these first six cycles, we need to keep this in mind."
The Gynecologic Oncology Group, National Cancer Institute, and Genentech supported this trial. Dr. Burger disclosed that he has served on advisory boards for Genentech and Roche but did not receive honoraria. Dr. O’Malley said he receives research support from Genentech.