Eli Lilly plans to invest an additional $5.3B to manufacture more of its blockbuster weight-loss and diabetes treatments at its Indiana plant, the pharma giant announced Friday.

The expansion is the company’s largest-ever manufacturing investment and a sign of the rapidly expanding market for GLP-1 drugs.

The Indianapolis-based firm is looking to boost its capacity to make Zepbound and Mounjaro at its Lebanon facility after a $3.7B investment announced last April. The new expansion will manufacture tirzepatide, the main ingredient for both drugs, which generated more than $2B in revenue in just the first quarter of 2024 alone for Lilly.

"Today's announcement tops the largest manufacturing investment in our company's history and, we believe, represents the single largest investment in synthetic medicine API manufacturing in U.S. history," Eli Lill Chairman and CEO David Ricks said in a statement.

Lilly and its competitors have struggled to keep up with the demand for this new generation of weight loss treatments. Novo Nordisk spent $16.5B in February to acquire Catalent, a significant contract drug manufacturer that has three manufacturing plants it can set up to make its GLP-1 drug, Wegovy.

Eli Lilly Chief Financial Officer Anat Ashkenazi specifically addressed the tirzepatide shortage during the firms Q1 earnings call and the lengths the company is going to address the issue.

“While we are working tirelessly to ramp supply and expect meaningful increases in shipment volumes in the second half of the year, demand continues to outstrip even increased supply,” Ashkenazi said.

Big Pharma firms like Eli Lilly face a pivotal moment, raking in substantial revenue from the runaway success of weight-loss drugs like Ozempic, all while facing a patent cliff over the next five years that will lead to the loss of patents and revenue from many of their biggest sellers. Many predict a wave of investments in research and development, mergers and acquisitions of promising new treatments, and biomanufacturing expansion will help these firms overcome the loss of patents.

The LEAP Lebanon Innovation and Research District, a 600-acre development in Boone County roughly 30 miles northwest of Lilly's headquarters, has been the epicenter of its recent investments, many of which have been focused on growing their home state’s biotech industry. The plant is projected to create 5,000 construction jobs and employ 900 full-time workers when it comes online, expected to start in 2026.

Lilly has made a number of other significant investments in research and manufacturing spaces across the country in recent years, announcing a $450M investment in a Research Triangle manufacturing plant last year as well as spending $700M for a new Boston Seaport research facility focused on mRNA technology. The firm has spent a total of $16B on manufacturing sites in the U.S. and Europe since 2020.