After decades of failure, weight loss drugs seem finally poised to become big pharma’s newest blockbuster category. Bloomberg Intelligence sees the U.S. obesity drug market alone as worth $12 billion in 2028. Morgan Stanley Research recently made a far more bullish prediction, forecasting global sales of obesity drugs could reach $54 billion by 2030.
The enthusiasm is merited. These newer drugs offer more profound and sustained weight loss than any of the medicines that came before them, and there are many people who could benefit from them: According to the U.S. Government Accountability Office, between 2013 and 2016, only 3% of the people eligible for an obesity medication were taking one.
But those lofty sales goals will only be reached if the medical field can overcome the structural barriers to their use.
The new drugs are typically once-a-week injections that mimic gut hormones that regulate the feeling of satiety. The approach seems to be solving the field’s problems with safety and efficacy. Data on Novo Nordisk’s Wegovy, approved in June 2021, and Eli Lilly & Co.’s Mounjaro, expected to be approved next year, suggest these drugs can help people shed, on average, as much as 15-20% of their body weight. We have only a snippet of data on Amgen’s early-stage weight-loss drug, AMG 133, but it has already generated intense interest from investors based on hopes that it could offer similar or potentially higher weight loss as Mounjaro with a once-a-month shot. Amgen said this week that people taking a high dose of the drug had lost on average about 14.5% of their body weight about three months into its phase 1 trial. Full data from that study will be disclosed at a conference early next month.
Results like those would make the new drugs 2-3 times more effective than older diet drugs, which also carried a litany of side effects ranging from the unpleasant (leaky stools) to downright dangerous (increased risk of heart attacks or cancer).
People are eager to try the new treatments. At a conference on obesity last week, experts in the field traded stories of the long waits for new patients seeking an appointment with weight-loss specialists. The Massachusetts General Hospital Weight Center, for example, has over 4,000 people on its wait list, says Fatima Cody Stanford, an obesity medicine physician there.
“The demand is overwhelming the workforce,” says Robert Kushner, who specializes in obesity medicine at Northwestern Medicine.
Pharma companies are also struggling to keep up with demand. Lilly has had trouble keeping up its supply of Mounjaro, even though it’s currently only approved for diabetes. When it gets an expected nod from the Food and Drug Administration as an obesity treatment in the second half of 2023, at least one analyst believes it could swiftly become one of the best-selling drugs in the history of the industry. And although Novo Nordisk’s Wegovy has been on the market for more than a year, it has been in a constant state of short supply, first because of unexpectedly high demand, and later due to manufacturing issues.
Novo expects that supply constraint to be resolved by the end of this year, a situation that could finally provide some answers to key questions on the market. For one, the magnitude of demand could become clearer; currently, it’s complicated by people turning to diabetes treatments that use the same ingredients as weight-loss drugs. And once supply is steady, it should be easier to gauge how long people are sticking with these once-a-week injections, a factor that will affect just how big of a blockbuster drug they become.
But all of this enthusiasm assumes the field will work out some fundamental challenges that could hold back widespread use of these weight loss drugs.