Novo Nordisk shares jumped on Friday as the Danish drugmaker said an experimental drug was able to reduce weight by as much as 22%.

Novo Nordisk's U.S.-listed shares are surging 9% Friday morning after the Danish drugmaker reported early stage results for its amycretin weight-loss drug.

Some outcomes, like reduced risk of cardiovascular disease and increased chance of nausea, were expected. But others took researchers by surprise.