LONDON/COPENHAGEN (Reuters) -Danish drugmaker Novo Nordisk is facing a major challenge to its blockbuster weight-loss drug Wegovy.

Booming sales of Wegovy powered the firm to become Europe's most valuable, but it has lost over $400 billion in market capitalisation since the middle of 2024 as competition from U.S. rival Eli Lilly and Co ( LLY ) and copycat rivals has hardened.

The firm, which reported third-quarter results on Wednesday and trimmed its annual outlook for the fourth time, is battling to turn around its fortunes under new CEO Mike Doustdar.

Doustdar, who has made 9,000 job cuts globally to reduce costs and refocus the firm, faces a more assertive new board and is locked in a bidding war with Pfizer ( PFE ).

Here are some of the challenges facing Novo as it looks to bolster sales and fend off challengers.

WEGOVY VS ZEPBOUND

Novo has seen Eli Lilly's ( LLY ) rival drug Zepbound overtake it in terms of prescriptions in the key U.S. market this year. With Wegovy, Novo was first-to-market with a highly effective obesity treatment, which was approved in the U.S. in 2021. Lilly launched Zepbound in late 2023.

LOSING GROUND

Novo has seen its share price fall steeply versus rivals over the last year.

VALUE PREMIUM SLIPPING

That has brought the company's price-earnings ratio back in line with peers. It had previously commanded a wide premium.

RISING COSTS

The drugmaker has seen costs rise as it has spent billions to expand manufacturing and sales capacity.

NO LONGER TOP DOG

Novo, valued at $650 billion in June last year, has shed over two-thirds of its value since. Its latest market cap is around $219 billion.

($1 = 6.4029 Danish crowns)