Novo Nordisk A/S (NVO) is having one of its best days in more than two months, with shares popping 2.58% -- their highest percentage gain since May 2 -- shortly after the market opened Thursday. NOV added $1.18 to $46.83 after Novo Nordisk released positive late-stage test results for two drugs designed to treat diabetes.

The drugs, PIONEER 4 and PIONEER 7, both met analyst expectations for reducing the amount of a protein that affects people's blood-sugar levels, but "demonstrated statistically significant and superior reductions in body weight" when compared to competitors, Nova Nordisk said in a statement.

Jefferies analysts estimate the drugs could enjoy $4.5 billion in peak sales if the substances win U.S. Food and Drug Administration approval, according to Bloomberg data.