(Reuters) - Amgen ( AMGN ) reported a slightly lower first-quarter profit on Thursday, citing higher operating and interest expense from its recent acquisition of rare disease drugmaker Horizon Therapeutics, partially offset by double-digit revenue growth.

The biotechnology company's adjusted profit fell 1% to $3.96 per share, which still beat the average analyst estimate of $3.88 per share, according to LSEG data.

Revenue rose 22% to $7.45 billion, in line with analysts' estimates of $7.44 billion.

Including one-time items, Amgen ( AMGN ) posted a first-quarter net loss of 21 cents a share.

Quarterly product sales were led by an 8% jump for osteoporosis drug Prolia to $999 million, and a 33% increase to $517 million for cholesterol drug Repatha. Sales of rheumatoid arthritis drug Enbrel fell 2% to $567 million.

Sales of eye drug Tepezza, which Amgen ( AMGN ) acquired through its Horizon purchase, rose about 5% to $424 million.

Excluding Horizon's medications, Amgen ( AMGN ) said year-over-year product sales grew 6%.

Investors are focused on Amgen's ( AMGN ) pipeline of experimental weight-loss drugs, and the company said it has completed a Phase 1 study of oral drug candidate AMG786.

Amgen ( AMGN ) said it anticipates data from a Phase 2 trial of its lead injectable weight-loss drug, MariTide, late this year and is planning "for a comprehensive Phase 3 program across multiple indications."

For full-year 2024, the company nudged up the lower end of its revenue outlook to between $32.5 billion and $33.8 billion from a previous view of $32.4 billion to $33.8 billion.

Amgen ( AMGN ) narrowed its 2024 adjusted earnings estimate and now expects a profit of $19.00 to $20.20 per share, from a previous view of $18.90 to $20.30.

Analysts have forecast 2024 earnings per share of $19.50 on revenue of $33 billion.