Eli Lilly And Company's (NYSE: LLY) weight-loss drug, Zepbound (tirzepatide), is gaining traction in the U.S., rivaling Novo Nordisk A/S's (NYSE: NVO) Wegovy (semaglutide).
Due to ongoing supply issues, some doctors are prioritizing availability when prescribing these medications.
Reuters noted, citing IQVIA data, that Eli Lilly has captured roughly 40% of the market since Zepbound's December launch.
As of July 19, 130,000 prescriptions were filled weekly, compared to 200,000 for Wegovy.
Five U.S. obesity specialists revealed they prescribe whichever drug is more accessible, sometimes requiring patients to switch treatments to maintain continuity.
Investors are keenly awaiting updates from Novo Nordisk and Lilly during their quarterly earnings release this week.
"All doses of Mounjaro and Zepbound are listed as available on the FDA's website, consistent with our previous statements that supply would steadily improve toward the latter half of 2024," Reuters added, quoting an Eli Lilly spokesperson.
"While we will do our best to support those who want to start taking Wegovy, it is important to recognize that overall demand will continue to exceed supply, and some patients may still have difficulty filling Wegovy prescriptions," Novo Nordisk noted in an update on its website.
Meanwhile, Lilly's CEO recently assured that the Zepbound shortage would be resolved "very soon." The FDA updated its status on Friday, indicating that while Zepbound is available, it remains on the shortage list pending confirmation of stable supplies.
The FDA's website still lists shortages for the lowest three out of five dose strengths of Wegovy. Since Q2, Novo Nordisk has averaged nearly 170,000 weekly U.S. prescriptions for Wegovy, while Lilly has filled just under 100,000.
Analysts predict a roughly even market split by the end of 2024 as Lilly boosts its manufacturing capacity.