BERLIN – The potent oral multiple kinase inhibitor sorafenib (NexavarR) combined with the chemotherapy drug capecitabine (XelodaR) significantly improves progression-free survival (PFS) over capecitabine alone in patients with locally advanced or metastatic HER-2 negative breast cancer, according to phase 2b results released at the joint 15th European Cancer Organization (ECCO) and 34th European Society for Medical Oncology (ESMO) Multidisciplinary Congress.

In fact, the data showed a 74% higher median PFS in the sorafenib/capecitabine group than in the group receiving chemotherapy alone.

The study is the first, large-scale randomized investigation to document significant clinical activity for sorafenib in breast cancer when combined with chemotherapy, ESMO President Jose Baselga, MD, chairman of the oncology division at Vall d’Hebron Institute of Oncology in Barcelona, said.

Professor Baselga and colleagues elsewhere randomized 229 women to treatment with capecitabine (1000 mg/m2 taken twice daily for 14 of every 21 days) and a placebo OR capecitabine and sorafenib (400 mg taken twice daily continuously).

The study followed a phase 1 trial showing limited toxicity with sorafenib 400 mg BID and capecitabine 850 mg/m2 BID.

In the phase 2b trial, all women had locally advanced or metastatic HER-2 negative breast cancer and had received no more than one prior chemotherapy for advanced/metastatic breast cancer.

The primary endpoint was PFS.

Results demonstrated that the median PFS was significantly longer in the sorafenib/capecitabine combination group than the placebo/capecitabine alone group (6.4 months versus 4.1 months for the two groups, respectively). Further analysis revealed that first-line patients who received the sorafenib-capecitabine combination had a median PFS of 7.6 months. Patients who got the combination as second-line therapy had a median PFS of 5.7 months.

The combination treatment was well tolerated and produced no new or unexpected adverse side effects.

Overall survival data are not yet available.

“This is a very positive study, and the magnitude of the benefit is such that this agent will be an important addition to our therapeutic armoury [sic] in breast cancer,” Professor Baselga said.

He also noted that “the fact that this treatment can be taken orally may represent a unique and convenient “treatment option in breast cancer patients.

The study was co-sponsored by Onyx Pharmaceuticals Inc. and Bayer Health Care.

Written by Jill Stein
Jill Stein is a Paris-based freelance medical writer.