Rapidly climbing sales of the new obesity drug Zepbound and its counterpart for diabetes, Mounjaro, pushed Eli Lilly to a better-than-expected first-quarter profit.

The drugmaker also hiked its sales and earnings forecast for 2024 beyond Wall Street’s expectations even as it hustles to boost manufacturing and catch up to surging demand for the drugs.

Lilly said it was still dealing with supply issues that also hampered the company in the fourth quarter. Company officials expect that to persist through this year, but they emphasized Tuesday that help was on the way.

They expect significant manufacturing increases to occur, starting in the back half of the year.

CEO David Ricks told analysts Tuesday that Lilly was undergoing “the most ambitious expansion plan in our company’s history.”

Indianapolis-based Eli Lilly and Co. recorded $517 million in sales from Zepbound, which received approval from U.S. regulators last November. Total Mounjaro sales more than tripled to $1.81 billion from $568 million in last year’s quarter.