Two new studies suggest that Avastin may have some additional benefit for small groups of patients with metastatic breast cancer. In particular, patients with HER-2 negative metastatic breast cancer showed "signifificantly higher rates of pathologic complete response when [Avastin] was added to neoadjuvant chemotherapy."
Translation: when given to women with localized breast cancer prior to surgery, Avastin helped produce a "pathological complete response" or pCR (so that the tumor was no longer detectable) somewhat more often (about 20%) than with chemotherapy alone.
The question that will obsess researchers now is whether or not the surrogate marker will translate into an overall survival benefit - and thus might lead the FDA to put metastatic breast cancer back on Avastin's label in this particular subgroup.
But the most interesting story is what is - or isn't happening at the molecular level that makes the drug more potent in these subgroups. If we can identify that marker, doctors can target the drug at patients who are most likely to benefit, especially since both studies also showed that Avastin produced some serious side effects in patients who used it.