U.S. regulators have approved a new drug as an initial treatment for postmenopausal women with a type of advanced breast cancer.

The drug, called Kisqali, is a pill that works to slow the spread of cancer by blocking two proteins that can stimulate growth and division of cancer cells.

It’s for women who have what’s known as HR+/HER2- breast cancer.

Developed by Swiss drugmaker Novartis, Kisqali is taken along with an older cancer drug called letrozole.

A study funded by Novartis of 668 women found that the two drugs together reduced the risk of death or the cancer worsening by 44 percent, compared to those receiving only letrozole.