Boardroom drama at Wegovy-maker Novo Nordisk has laid bare the company's biggest challenge: how to better tap into America's mass market for weight-loss drugs.

The Danish drugmaker that initially soared on the success of its obesity drug has lost its market lead to U.S. rival Eli Lilly and cheaper copycats, with pressure on prices from U.S. President Donald Trump and growing direct-to-consumer sales.

On Tuesday, Novo's top investor, the nonprofit Novo Nordisk Foundation, moved to take control of the company's board. It vowed a sharper focus on the key U.S. market to boost sales growth for Wegovy, and flagged a need to move faster on burgeoning mass-market channels.