Abbott Laboratories (NYSE: ABT - News) on Wednesday beat Wall Street expectations with second-quarter earnings bolstered by strong sales of Humira, its rheumatoid-arthritis treatment, and other medical products.

The US drug company reported net income of $1.32bn, or 85 cents a share, compared with $988.7m, or 63 cents a share, in the same quarter last year.

Analysts had on average expected the company to report earnings of 79 cents a share on revenue of $7.23bn, according to a poll by Thomson Reuters.

The company's sales benefited in part from favourable exchange rates.

Net sales increased 15 per cent to $7.31bn as the weak dollar, which has fallen in recent years against most leading currencies, contributed 5.9 percentage points of the growth.

Domestic sales increased 5.7 per cent, while international sales rose 24 per cent.

The company's flagship arthritis medication, Humira, posted sales revenue of over $1bn, a 48 per cent rise from last year. Abbott raised full-year sales expectations for the drug, also used to treat autoimmune disorders, to $4.3bn.

The company also reported robust sales growth for its cholesterol pill Niaspan and HIV therapy Kaletra.

Abbott raised its full-year 2008 guidance to between $3.24 and $3.28 from between $3.20 and $3.25.

Earlier this month, Abbott gained approval to begin selling its Xience drug-coated stent in the US.

Coated stents hold open clogged heart arteries and use medication to stop vessels from closing as they heal.

The heart device is seen as a potential leader in a domestic market, according to Jan David Wald, an analyst at Stanford Group.

"We expect that the recent US approval and launch of Xience will drive growth in the coming quarters and years," he wrote in a research note.

Shares of Abbot edged 12 cents higher to $57.97 in morning trading. They have risen about 10 per cent in the past 52 weeks, as Humira and Xience have bolstered investor confidence.