A selection of injector pens for the Wegovy weight loss drug are shown in this photo illustration in Chicago, Illinois, U.S., March 31, 2023.
CNN  — 

Citing “unprecedented demand,” drugmaker Novo Nordisk said Thursday it expects supply restrictions on starter doses of the weight loss medicine Wegovy to persist into 2024, several months beyond its previous prediction.

The company is prioritizing higher, or so-called maintenance, doses of the medicine so that patients who have already started taking Wegovy can continue to access the drug, Doug Langa, executive vice president of North America Operations, told CNN. Novo Nordisk had said in May it expected supply restrictions on lower doses to continue through September.

“We are going to continue to supply the market, but it’s just going to be on a limited form so we can have that continuity of care,” Langa said.

He emphasized “we’re still producing all strengths and we’re still supplying all strengths to the market.”

Supply has been constrained for many forms of medicines in a class known as GLP-1 agonists, which have rocketed in popularity as they produce greater magnitudes of weight loss than previously seen with older medicines. And new results this week of a landmark trial in people with cardiovascular disease showed Wegovy can reduce the risk of heart attack, stroke, or heart-related death by 20%, bolstering expectations for wider use of the medicine and, potentially, broader insurance coverage.

Wegovy shares the same key ingredient, semaglutide, as Novo Nordisk’s Ozempic, approved for type 2 diabetes. Langa said total weekly prescriptions of Ozempic in the US are now almost 500,000 — 200,000 higher than they were a year earlier — meaning half a million Americans have prescriptions for the drug.

“This pace of demand is challenging to keep up with,” he said.

For Wegovy, the figure is around 80,000, and had been as high as 100,000.

“Part of that is because we’re restricting some of those lower doses,” Langa said.

Competitor Eli Lilly is also having trouble meeting demand for its drug Mounjaro, approved for type 2 diabetes and awaiting clearance from the US Food and Drug Administration for weight loss. Its key ingredient, tirzepatide, targets both the hormone GLP-1 and another, called GIP.

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“Supply will likely remain tight in the coming months and quarters due to significant demand,” Lilly’s chief financial officer, Anat Ashkenazi, said on the company’s quarterly earnings conference call Tuesday.

“Because we’re seeing really unprecedented demand, we do still expect to see tight supply and some spot outages on Mounjaro through the end of the year,” added Michael Mason, president of Lilly Diabetes.

Both Lilly and Novo Nordisk are investing heavily in increasing manufacturing to try to meet global demand for these medicines, contracting with outside manufacturers as well as building up their own plants.

“This is categorically the largest unmet need that I know of in life science,” Novo Nordisk’s Langa said, noting there are 120 million Americans who would qualify to take Wegovy based on having a body mass index of 30 or more, the category for obesity. The drug is also approved for people with BMI of 27, in the overweight category, and a weight-related health condition.

“We’re seeing this unprecedented demand,” Langa said. “We’re super happy to be able to be bringing something that is so meaningful.”