FDA approves pill for aggressive breast cancer that’s spread

AP – United States (US) 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 is especially tough to treat.

The Food and Drug Administration (FDA) said Tukysa, a twice-daily pill developed by Seattle Genetics, is for people with what is 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 US are diagnosed with HER2-positive breast cancer. It is usually curable, but when it spreads it kills most patients. In up to half of them, the cancer reaches the brain, giving that group such a poor prognosis that they have rarely been included in tests of new drugs.

Tukysa, also known as tucatinib, works by attacking cancer cells from inside and outside to block production of the HER2 protein.

“This is basically taking the ammunition out of that weapon,” said Dr Eric Winer, a Dana-Farber Cancer Institute researcher who helped lead the key patient study and consults for Seattle Genetics and other drugmakers.

Breast cancer drug Tukysa, developed by Seattle Genetics. PHOTO: AP

In that company-funded study, half the 612 participants got Tukysa along with standard cancer drugs Herceptin and Xeloda. The other half got the two standard drugs and a dummy pill.

In the group getting Tukysa, 45 per cent survived at least two years, compared with 27 per cent in the placebo group.

Among the participants whose cancer spread to the brain, 25 per cent were alive after a year versus none in the placebo group. “It’s a significant advance,” said Winer.

Common side effects included diarrhea, fatigue, vomiting and liver function changes.

Tukysa has a list price of USD18,500 per month, or roughly USD111,000 for an average course of treatment, without insurance. Most patients do not pay that, and Seattle Genetics plans to offer financial aid.

Tukysa should be available almost immediately.