Here's the FDA's decision (70 page PDF). As I've said here many times, I think that this is the right decision. A key section:
. . .As noted, FDA may withdraw an accelerated approval when confirmatory trials fail to confirm clinical benefit, or when the evidence does not show that the drug is safe and effective. However, the agency also carefully considers the effect on current and future patients of such a decision, and there may be circumstances, in particular cases, that would lead the agency to conclude that it would be appropriate to exercise discretion and leave an approval in place pending further study. This is not such a case.
Accelerated approval was based on the results of E2100, which showed an effect on (progression-free survival) that would be large enough to constitute clinical benefit, despite the known risks of Avastin, which are serious. However, we now have five trials, and they have substantially changed our view of this drug. The current evidence no longer supports a determination that it has a strong effect in metastatic breast cancer, and it appears likely that its effects are very weak, while the risks associated with this drug remain serious and potentially life-threatening.
There's going to be a lot of commentary, not all of it very informed, to the effect that this decision is a price-driven attempt to bring down health care costs, an assault on medical progress, the opening salvo of Obamacare, and so on. Wrong.
Avastin doesn't work as well as we thought it did for this indication. If you're going to believe in medical progress at all, you have to believe in what multiple well-controlled clinical trials are telling you - trials carried out, keep in mind, by the drug company that has every interest in having them come out favorably. But they didn't. On medical grounds, on scientific grounds, this was the right decision.