In the plenary session at ASCO this year there was a presentation of a large NASBP trial which tested whether the addition of Avastin® (bevacizumab) to 6 months of FOLFOX would decrease tumor recurrence.
The data suggested that there was no benefit with the addition of Avastin, which was given not only for 6 months along with chemotherapy but 6 months in addition to FOLFOX for a total of 12 months.
Despite showing this was a negative clinical trial, when the investigators and Genentech looked at the 1 year disease free survival it appeared there was a potential transient benefit which lasted longer than the 1 year Avastin was given. Whether this is real or a fluke no one knows. However even considering that this is a real benefit, it would be very small may be 5 percent in 3 years. That means a 5% decrease of recurrence with one year of Avastin, but also means that many patients will be treated with no benefit.
Recent data have suggested that when Avastin was given 6 months longer some concerning side effects have been see in up to 10% of patients such as body pain interfering with daily function, dizziness, and central nervous system symptoms raising questions of the safety of Avastin given for a long time, particularly compared to little benefit at all (that benefit would be possible only under the best conditions). It became clear that studies using even longer administration of Avastin would be not indicated.
Fortunately there is a similar trial which was completed in Europe. The data will be hopefully available next year at ASCO and will answer whether this “transient” change is real which is more exciting for the tumor biology than clinical benefit or all a fluke.
Another question, of course, is will the clinical trials using Erbitux become effective in the adjuvant setting. In the US N0147 is again open and only enrolling wild-type KRAS for this trial.