New drug combination for Advanced Breast Cancer delays disease progression

A new combination of cancer drugs delayed disease progression for patients with hormone-receptor-positive metastatic breast cancer, according to a multi-center phase II trial.
The trial enrolled 118 post-menopausal women with metastatic hormone-receptor-positive breast cancer whose cancer continued to progress after being treated with an aromatase inhibitor. The study, based on work done by Doris Germain of Mt. Sinai Hospital, found that the combination of the drugs bortezomib and fulvestrant, versus fulvestrant alone, doubled the rate of survival at 12 months and reduced the chance of cancer progression overall.
Bortezomib, used most commonly in treating multiple myeloma, is a proteasome inhibitor that prevents cancer cells from clearing toxic material. Fulvestrant causes clumping of the estrogen-receptor protein. When bortezomib blocks the ability of the cell to clear these protein clumps, they grow larger and become toxic to the cancer cells. This, in turn, amplifies the effectiveness of fulvestrant, a drug commonly used in this subset of patients.
The drug combination doubled the number of patients whose cancer had not progressed after one year from 14% to 28%.