* North America head Riis leaves Novo Nordisk
* To become CEO of emergency services group Falck
* Disappointed to have missed out on top job at Novo (Recasts with comments from Riis)
By Jacob Gronholt-Pedersen
COPENHAGEN, March 1 (Reuters) - The head of Novo Nordisk's North American operations will take charge of Danish emergency services group Falck after quitting the healthcare company in frustration at missing out on the top job.
Jakob Riis had been with Novo Nordisk since 1996 but moved to his current role only six months ago as part of broader management changes at the world's largest insulin maker.
His departure raises questions about Novo Nordisk's strategy in a market that accounts for more than half of its sales.
Doug Langa, who is currently senior vice president for market access and has been with the company since 2011, will assume the North America role, the company said.
Riis said his departure stemmed from his desire to head a company. He will become CEO of Falck, a Danish-based group which runs the world's largest ambulance fleet.
"This is a consequence of the fact that in recent years I have prepared myself for the possibility of taking over the role as CEO in Novo Nordisk," Riis said in a phone interview.
"I am ambitious, and the urge to lead a company - more specifically the motivation to lead Novo Nordisk - was very, very big. It's no secret it was a disappointment, when I was told that wasn't going to happen," he said.
Riis had been regarded as heir apparent to long-serving Lars Rebien Sorensen, who stepped down as Novo Nordisk CEO last September.
Instead, Sorensen was replaced by Lars Fruergaard, while Riis was given responsibility for the North American operations after previously being in charge of marketing and head of the China and Pacific sales regions.
The timing of the departure is sensitive for Novo Nordisk which last month disappointed investors with a lower 2017 sales and profit growth forecast, citing price pressure and political uncertainty in the United States.
"Given the evolving payer pressures faced by the company over insulin pricing in the United States, Jakob's departure after such a short period of time may raise some eyebrows," Jefferies analysts said in a note.
His successor Langa joined Novo Nordisk from GlaxoSmithKline and was previously at Johnson & Johnson.
"Doug's experience in the U.S. pharmaceutical market, his leadership skills and expertise in the area of market access make him the natural successor to Jakob Riis," Goran Ando, chairman of Novo Nordisk board, said in a statement.
U.S. President Donald Trump has called on pharmaceuticals companies to make more of their drugs in the United States and to cut "astronomical" prices, while vowing to speed approval of new medicines and ease regulation.
Since September, Riis has worked to address the challenges Novo Nordisk has regarding prices and affordability in the U.S. market.
"I have worked closely with my successor, who has been part of making plans and foundation for future growth in the United States," Riis said.
"Doug has already communicated to the team here that there will be no changes to our plan (for the North American market)," Riis said.
Novo Nordisk shares were 0.9 percent lower at 246.90 Danish crowns at 1050 GMT.
Reporting by Jacob Gronholt-Pedersen; Editing by Keith Weir