WASHINGTON – U.S. regulators on Friday approved a new drug for an aggressive type of breast cancer that’s spread in the body — including into the brain, where it’s especially tough to treat. The Food and Drug Administration said Tukysa, a twice-daily pill developed by Seattle Genetics, is for people with what's known as HER2-positive breast cancer that has spread and resisted multiple other medicines. This type of cancer is driven by an overactive gene that makes too much of the HER2 protein, which promotes cancer growth. Each year, about 50,000 people in the U.S. are diagnosed with HER2-positive breast cancer. Among the participants whose cancer spread to the brain, 25% were alive after a year versus none in the placebo group.