(Reuters) - Amgen ( AMGN ) posted a higher quarterly profit on Tuesday, driven by an 11% rise in product sales, and said late-stage studies of key obesity drug candidate MariTide will start before mid-year but regulators have placed a hold on an early-stage trial of a different experimental weight-loss drug.

The California-based biotech company said adjusted fourth-quarter earnings rose 13% from a year earlier to $5.31 per share, beating the $5.08 estimated by analysts, according to LSEG data.

Net earnings fell 18% to $1.16 per share, due mainly to losses on equity investments.

Quarterly revenue rose 11% to $9.1 billion, which exceeded analyst estimates of $8.52 billion.

For full-year 2025, Amgen ( AMGN ) said it expects adjusted earnings per share of $20.00 to $21.20 on revenue of $34.4 billion to $35.7 billion. Analysts have forecast EPS of $20.82 on revenue of $33 billion.

The outlook is "demonstrative of our confidence and conviction of being able to grow through the denosumab loss of exclusivity this year," Amgen CFO Peter Griffith said, referring to the expiration of patents on the company's drugs for bone diseases like osteoporosis. He expects biosimilar competition sometime in the middle of this year.

Amgen ( AMGN ) investors have been focused on prospects for MariTide, which activates the appetite- and blood sugar-reducing hormone known as GLP-1 while blocking a second gut hormone called GIP. The drug, given by injection once monthly or less often, was shown in a mid-stage trial to help overweight or obese patients shed up to 20% of their body weight.

Amgen ( AMGN ) on Tuesday said follow-up data from that study, and from a trial of the drug in people with diabetes, are expected in the second half of this year.

The company said the first studies in a broad Phase 3 program for MariTide, which could provide data enabling regulatory approval of the medicine, are expected to begin in the first half of this year.

It also said a Phase 1 study of a drug known as AMG 513 in people living with obesity was placed on clinical hold by the U.S. Food and Drug Administration. The regulatory agency issues holds to protect trial participants from unreasonable risk and to ensure that studies are conducted properly.

Amgen ( AMGN ), which has not disclosed a mechanism of action for AMG 513, said discussions are underway on a path forward to reopen the study.

The company's fourth-quarter sales of cholesterol-lowering medication Repatha rose 45% to $606 million, while sales of bone drug Prolia rose 5% to $1.2 billion and sales of arthritis drug Enbrel were flat at $1 billion.

In the rare disease space, Amgen's ( AMGN ) sales of thyroid eye disease drug Tepezza rose 3% to $460 million, and sales of gout treatment Krystexxa rose 27% to $346 million.