WASHINGTON (AP) — Federal health officials have approved a new combination drug for the most common form of cystic fibrosis, the debilitating inherited disease that causes internal mucus buildup, lung infections and early death.

The Food and Drug Administration approved the twice-a-day pill from Vertex Pharmaceuticals for a variation of cystic fibrosis that affects about 8,500 people in the U.S. who are 12 years and older. The approval notice was posted to the agency’s website.

The new drug, to be sold as Orkambi, is Vertex’s follow-up to its breakthrough pill Kalydeco, which became the first drug to treat the underlying cause of cystic fibrosis in 2012. Orkambi combines Kalydeco with another new drug ingredient.

Kalydeco is only approved for a cluster of rare forms of cystic fibrosis.