The tablet version of its diabetes drug, known as semaglutide, is an important growth prospect for the Danish drugmaker, which faces pressure on prices from competitors and US lawmakers, who have been critical of rising drug costs.

Novo, the world's biggest producer of diabetes drugs, said the new plant near Durham would receive shipments of the active pharmaceutical ingredient needed to produce the pill from another factory under construction in North Carolina.

"We want to build manufacturing capacity in the United States so that we can establish a local US supply chain for oral semaglutide and other future oral products," Novo Nordisk vice president Henrik Steen Jensen told Reuters.

Novo submitted its oral semaglutide drug for approval in the United States in March and hopes to begin local production in 2021, Jensen said.

The tablet, which Novo currently produces only in Denmark, belongs to a blockbuster class of treatments known as GLP-1s that stimulate insulin production.

So far, all have been via injection and a pill would make it quicker and easier for diabetics to take their medication.

Novo said it bought the plant in Durham from Purdue Pharma but did not disclose the price or capacity.