The price surge follows the American low-cost competitor Hims & Hers' decision this weekend to halt plans to sell a low-cost copy of Novo Nordisk's new diet pill Wegovy.
Hims & Hers withdrew the plan after the US Food and Drug Administration (FDA) launched an investigation into the company's actions.
Novo Nordisk also said that despite the challenger's halt to the launch, it has sued Hims & Hers for damages over patent infringement.
Novo Nordisk's stock has been taking a beating for some time now in the wake of competitor Eli Lilly's strong gains. The stock is down 4 percent since the beginning of the year and down 49 percent compared with its price a year ago.
