(Reuters) -AbbVie (ABBV) forecast 2025 profit above estimates on Friday, as strong sales of its newer immunology drugs Skyrizi and Rinvoq make up for a steep decline in those of Humira, its flagship rheumatoid arthritis drug that is now facing stiff competition.

The drugmaker's shares rose 4.2% in premarket trading.

Quarterly sales of Humira declined 49% to $1.68 billion, a steeper fall than the $1.99 billion analysts expected, according to data compiled by LSEG.

Once the world's best-selling drug, Humira must now beat competition from numerous less-expensive biosimilars that began hitting the U.S. market in 2023.

AbbVie is pushing Skyrizi and Rinvoq to counter the drop in Humira sales and said the two newer drugs would generate more than $31 billion in 2027, up $4 billion from its previous estimate.

The drugmaker forecast Skyrizi revenues of more than $20 billion and Rinvoq revenues of more than $11 billion in 2027.

"We are entering 2025 with significant momentum and expect net revenues to exceed their previous peak in just the second full year following the U.S. Humira loss of exclusivity," AbbVie CEO Robert Michael said in a statement.

Despite the competition, AbbVie has maintained Humira's market share with industry middlemen, known as pharmacy benefit managers, in the past year by reducing the drug's net price.

Pharmacy benefit managers, who negotiate volume discounts and fees with drug manufacturers on behalf of employers and health plans, have begun to remove Humira from their preferred drugs lists for reimbursement.

AbbVie is also bolstering its pipeline of drugs through acquisitions, especially in neuroscience, like its $8.7 billion deal for Cerevel Therapeutics.

The company now expects annual adjusted profit of $12.12 to $12.32 per share, compared to analysts' average estimate of $12.18 per share.

On an adjusted basis, AbbVie earned $2.16 per share in the fourth quarter, compared with an estimate of $2.12.

(Reporting by Puyaan Singh and Christy Santhosh in Bengaluru)