Pharmaceutical executives from Amgen to Pfizer are plotting to break into the lucrative obesity market by developing or cutting deals to acquire better drugs that will compete with Novo Nordisk’s Wegovy and Zepbound from Eli Lilly.

At stake is a market that is now estimated to reach $100 billion at a minimum by the end of the decade, as consumers flock to the new treatments that have been shown to reduce weight by as much as 20%. Drugmakers are also testing these drugs for other health benefits such as lowering cardiovascular disease risk and obstructive sleep apnea.

Shares Eli Lilly and Novo Nordisk are up around 75% and 60%, respectively, over the last year, far outpacing the broader pharmaceutical sector. The NYSE’s Arca Pharmaceutical Index, which includes both companies, is up just 10% over the same period.

Amgen has an experimental dual mechanism obesity drug in mid-stage trials it hopes will have fewer side effects with less frequent dosing than Wegovy or Zepbound, Chief Scientific Officer Jay Bradner told Reuters at the annual JPMorgan health conference in San Francisco this week.