AbbVie's second-quarter profit increased nearly 3 percent and beat analysts' expectations, as sales soared for the world's top-selling drug, Humira.

The North Chicago, Illinois company said Friday that earnings increased to $1.1 billion, or 68 cents per share, from $1.07 billion, or 66 cents per share, in the same quarter last year.

Earnings, adjusted for non-recurring costs and amortization costs, came to 82 cents per share. Analysts expected, on average, earnings of 76 cents per share, according to FactSet.

Revenue climbed 5 percent to $4.93 billion, which also trumped average analyst expectations of $4.7 billion.

Sales of the anti-inflammatory drug Humira jumped 26 percent to $3.29 billion in the quarter.

The data firm IMS Health ranks Humira, which brought in more than $10 billion in revenue last year, as the world's best-selling drug.

AbbVie announced last week that it had reached a deal worth roughly $55 billion to combine with fellow drugmaker Shire Plc and become the latest U.S. company to seek an overseas haven from tax rates back home. The drugmakers plan to create a new company that is incorporated on the British island of Jersey, where Shire currently is incorporated. But the new company will be controlled by AbbVie shareholders.

AbbVie executives have cited lower taxes as part of the reason for their move. They forecast a tax rate of about 13 percent by 2016 for the new company, compared to a current rate of about 22 percent.

The U.S. drugmaker said Friday its income tax expense climbed 12 percent in the quarter to $335 million.

AbbVie shares climbed 28 cents to $54.36 at the start of trading Friday. The stock had risen only about 2 percent from the beginning of the year until Thursday's close, while the Standard & Poor's 500 index advanced 7.6 percent.