Pfizer has increased the survival rate of breast cancer patients by 63 percent with their latest drug compared to the standard regimes available . The clinical trial strengthens the case for administering the newer drug, exemestane, as a first option. A study showed that women recovering from breast cancer lowered their chance of developing another tumor by 32 percent if they switched to exemestane after two or three years of tamoxifen treatment.
According to the research presented this week at a breast cancer conference , the median survival for patients taking exemestane was 10.9 months, compared with 6.7 months for patients on tamoxifen. About 44.2 percent of patients in the study had tumors that responded either partially or fully to exemestane , compared with 29.2 percent on tamoxifen. The difference was statistically significant. These reports have been substantiated by specialists in the field who began trying the drug in patients in 1989, well before it was approved.
Tamoxifen is sold under the brand name Nolvadex by AstraZeneca Plc and is usually taken for five years. Tamoxifen works by blocking the hormone estrogen, which can stimulate and feed the growth of breast cancer.
By contrast, exemestane was the first approved oral therapy that binds to an enzyme known as aromatase, which normally converts the hormone androgen into estrogen in postmenopausal women. The drug thereby curtails the actual supply of estrogen to the cancerous tumors that are dependent on it, rather than blocking estrogen after it is already produced. Pfizer markets exemestane under the brand name Aromasin.
Researchers say ,"These (studies) are pieces of the puzzle, and the puzzle is becoming clearer now."