The departure of Mary Szela follows her firm's decision to work on non-alcoholic steatohepatitis (NASH), or fatty liver, a Novo company spokeswoman said. NASH is a growing focus for the Danish group as it seeks to diversify beyond diabetes.

The progressive liver disease is increasingly common in nations with fatty diets and is linked to rising rates of obesity and diabetes.

As such, it is an attractive adjacent market opportunity for Novo, which faces pricing pressure in its core insulin business. Novo hopes to use its next-generation GLP-1 drug semaglutide to fight diabetes, obesity and NASH.

Diversifying into disease areas connected to diabetes, like obesity and NASH, is a strategic goal for Novo's new CEO Lars Fruergaard Jorgensen, who has said he would consider acquisitions in the "low single-digit billions of dollars".

The market for NASH drugs is forecast to eventually be worth more than $20 billion in annual sales as populations with fatty diets increasingly fall victim to a condition with no approved treatment.

(Reporting by Ben Hirschler; Editing by Susan Fenton)