(Reuters) - Amgen ( AMGN ) reported higher quarterly earnings on Wednesday, driven by a 24% rise in sales of products including cholesterol drug Repatha and Prolia for osteoporosis, and said results of a mid-stage trial of a potentially lucrative obesity medicine will be unveiled late this year.

The U.S. biotech company said adjusted third-quarter earnings rose 13% from a year earlier to $5.58 per share, beating the $5.11 estimate by analysts, according to LSEG data.

Third-quarter revenue of $8.5 billion was in line with analyst estimates of $8.52 billion.

Amgen ( AMGN ) said a Phase 2 study of its experimental weight-loss drug Maritide, part of a class known as GLP-1s, is ongoing with initial results expected in late 2024. The company has already set up a broad Phase 3 clinical program that could provide data that would be the basis for getting the medicine approved.

Some analysts have forecast annual sales of new weight-loss medicines reaching $150 billion in the next decade.

Amgen ( AMGN ) has begun studying a different weight-loss drug, known as AMG513, but few details have been disclosed.

The company also announced plans for late-stage testing of experimental immunotherapy xaluritamig in men with advanced prostate cancer.

"We continue to invest in research and development spending," Chief Financial Officer Peter Griffith told Reuters, noting that spending this year is expected to increase 25%.

Quarterly sales of Repatha rose 40% to $567 million, while sales of Prolia increased 6% to $1.05 billion.

Sales of arthritis drug Enbrel fell 20% to $825 million as revenue from outside of the U.S. nearly disappeared due to competition from less expensive biosimilar versions of the drug.

Sales of thyroid eye disease drug Tepezza, acquired with Amgen's ( AMGN ) buyout last year of Horizon Therapeutics, totaled $488 million for the quarter.

For the full year, Amgen ( AMGN ) narrowed its earnings outlook to between $19.20 and $20.00 per share, from $19.10 to $20.10. It also raised the midpoint of its revenue forecast to a range of $33 billion to $33.8 billion from a previous $32.8 billion to $33.8 billion.

Analysts, on average, had forecast earnings per share of $19.49 on revenue of $31.8 billion.