In a study of more than 200 patients, those given Nexavar plus the chemotherapy drug Xeloda lived 2.3 months longer before their disease progressed than those given Xeloda alone.
"The magnitude of the benefit is such that it suggests that this agent will be an important addition to our therapeutic armory in breast cancer," says study researcher Jose Baselga, MD, head of oncology at Barcelona's Vall d'Hebron University Hospital and president of the European Society of Medical Oncology (ESMO).
Because it's a pill, Nexavar "is a unique and convenient treatment option," Baselga tells WebMD.
The findings were presented at a meeting of the European Cancer Organization and ESMO.
Nexavar attacks tumors on multiple fronts, starving them of their blood supply, interfering with cell signaling that spurs tumor growth, and preventing cell division. It's already approved to treat liver and kidney cancers.
Cancer progressed in a median of 6.4 months in those given Nexavar, compared with 4.1 months for those on placebo.
It's too early to tell if the drug extends lives, but Chris Twelves, MD, co-chairman of the committee that chose which studies to highlight at the meeting, tells WebMD that he expects it will. Twelves, professor of clinical cancer pharmacology at the Leeds Institute of Molecular Medicine in Leeds, England, was not involved with the work.
"This is a very important study," he says.
The Nexavar-Xeloda cocktail was relatively safe, with the most common side effects being diarrhea and hand-foot syndrome.
The side effects can usually be reversed if patients take "a drug holiday," Twelves says.
"Hand-foot syndrome is not something that develops overnight. If your hands or feet start getting red or sore, see your doctor, who can lower the dose or stop the medication for a short time," he says.
Baselga notes that three other large trials worldwide are looking at Nexavar in combination with other cancer drugs for the treatment of breast cancer.
The study was funded by Bayer and Onyx, which make and distribute Nexavar.