Eli Lilly And Co's (LLY  ) much-in-demand weight-loss drug Zepbound (tirzepatide) surged ahead with 77,590 new prescriptions in the U.S. for the week ending March 8, surpassing Novo Nordisk A/S's (NVO  ) rival obesity medicine Wegovy (semglutide) for the first time since its launch.

Despite filling 6,000 fewer prescriptions than Wegovy that week, Lilly's Zepbound managed to claim the top spot, according to data from IQVIA.

Since its U.S. launch in December, Zepbound has been gaining momentum, closing the gap with Novo's Wegovy, which was approved over two years earlier.

However, Novo still holds the lead in total weekly prescriptions over Zepbound by 25,307, Reuters reported, citing JPMorgan's weekly note.

According to a data analytics firm GlobalData report, GLP-1 drugs, including Zepbound and Wegovy, are on track to surpass cancer immunotherapies as the best-selling medicines, fueled by their efficacy in treating various health conditions and celebrity endorsements.

Merck & Co Inc's (MRK  ) cancer drug Keytruda currently holds the title of the world's top-selling prescription medicine, with over $25 billion in annual sales.

GlobalData forecasts the GLP-1 market to reach $105 billion by 2029, with Novo Nordisk expected to capture more than half of it with its portfolio of drugs.

Last week, Amazon.com's (AMZN  ) Amazon Pharmacy announced the integration of Eli Lilly's LillyDirect into its services, enabling home delivery of select medications for diabetes, obesity, and migraine.

The partnership with Lilly signifies a significant step in expanding access to vital medications, as Amazon Pharmacy becomes a third-party dispensing provider for LillyDirect Pharmacy Solutions.

In a report, Eli Lilly revealed that it has identified bacteria and elevated impurity levels in products falsely claiming to be compounded versions of tirzepatide.

The U.S. pharmaceutical giant has taken legal action against numerous medical spas, weight-loss clinics, and compounding pharmacies to halt the sale of these fraudulent products.

Price Action: LLY shares are up 1.19% at $763.18 on the last check Monday.