(Reuters) - Eli Lilly ( LLY ) on Thursday posted better-than-expected quarterly results, although sales of its popular weight-loss drug, Zepbound, came in slightly below Wall Street estimates, sending its shares down 4% in premarket trading.

Separately, CVS Health said that its pharmacy benefit management unit would drop Lilly's Zepbound as a preferred product from its list of drugs eligible for reimbursement from July 1, but would retain rival Novo Nordisk's Wegovy.

The success of Lilly's diabetes and weight-loss treatments has led Eli Lilly ( LLY ) to become the world's most valuable healthcare company, with a market capitalization of more than $800 billion.

It competes with Danish drugmaker Novo Nordisk in the lucrative market for these treatments, known as GLP-1 agonists.

Zepbound posted sales of $2.31 billion for the first quarter, while analysts were expecting sales of $2.33 billion, according to LSEG data.

Lilly said lower prices for the drug impacted revenue, but demand remained strong. In February, Lilly had cut the price for vials of Zepbound by $50 or more and expanded the range of doses it sold online.

It now offers the two lowest doses of Zepbound for $349 and $499 for a month's supply.

The company cut its annual adjusted profit forecast to between $20.78 and $22.28 per share from its previous expectation of between $22.50 and $24.00 per share.

Sales of diabetes drug Mounjaro came in at $3.84 billion while analysts were expecting sales of $3.80 billion, according to data compiled by LSEG.

On an adjusted basis, Lilly earned $3.34 per share for the quarter, compared with analysts' estimates of $3.02 per share.

Total revenue was $12.73 billion for the quarter ended March 31, compared with expectations of $12.67 billion.

(Reporting by Bhanvi Satija in Bengaluru and Patrick Wingrove in New York; Editing by Anil D'Silva)