Oct 27 (Reuters) - AbbVie on Friday raised its annual profit forecast after beating quarterly earnings estimates, helped by a lower-than-feared drop in sales of its blockbuster arthritis drug, Humira, and strong demand for newer drugs.

Investors have been closely scrutinizing the erosion of Humira's sales following the entry of over half a dozen biosimilars this year, including those from Sandoz, Amgen and German drugmaker Boehringer Ingelheim.

Despite those biosimilars, Humira has maintained favorable positions on insurance drug coverage lists. AbbVie in July trimmed its 2023 view for Humira sales erosion to 35%, from 37% earlier.

Unlike chemical drugs that can be copied and sold as generics at a huge discount once patents lapse, complex biologic medicines like Humira are made from living cells that cannot be exactly duplicated. Their close alternatives are called biosimilars.

Humira's global sales fell 36.2% to $3.55 billion in the third quarter, but exceeded Wall Street estimates of $3.48 billion, according to LSEG data.

AbbVie has been seeking to expand the use of newer immunology drugs Skyrizi and Rinvoq as it banks on them to make up for the expected drop in Humira sales.

Skyrizi and Rinvoq generated global sales of $2.13 billion and $1.11 billion respectively, ahead of analyst expectations of $2.10 billion and $1.02 billion.

Cancer drug Imbruvica's sales of $908 million also beat estimates of $863 million.

AbbVie reported $13.93 billion in quarterly revenue, beating estimates of $13.71 billion.

It reported an adjusted profit of $2.95 per share, versus estimates of $2.86 per share.

The company now expects 2023 adjusted profit per share of between $11.19 and $11.23, compared with $10.86 and $11.06 it forecast earlier this month.

AbbVie also raised its 2024 adjusted earnings per share outlook to a minimum of $11 from at least $10.70. (Reporting by Leroy Leo and Christy Santhosh in Bengaluru; Editing by Maju Samuel)