Gilead Sciences Inc. on Wednesday reported profit that more than quadrupled in its second quarter, topping analysts' expectations on sales of its new breakthrough drug for hepatitis C.

The company's performance was driven by explosive growth of the blockbuster Sovaldi, which rose to $3.48 billion in sales for the quarter, up from $2.3 billion in the first quarter. Despite attracting heavy criticism over its $1,000-per-pill price tag, doctors in the U.S. and Europe have apparently embraced the drug. Gilead says the drug has been prescribed to more than 80,000 people since winning approval in December.

The Foster City, California-based company said earnings increased to $3.66 billion, or $2.20 per share, from $772.6 million, or 46 cents per share, in the same quarter a year ago.

Earnings, adjusted for costs related to mergers and acquisitions and stock option expense, came to $2.36 per share. The average per-share estimate of analysts surveyed by Zacks Investment Research was for profit of $1.80.

The HIV and hepatitis C drugmaker said revenue more than doubled to $6.53 billion from $2.77 billion in the same quarter a year ago, and beat Wall Street forecasts. Analysts expected $5.78 billion, according to Zacks.

Looking ahead, Gilead now expects annual sales of $21 billion to $23 billion. That's up from its prior range of $11.3 billion to $11.5 billion, and the revision reflects the impact of Sovaldi sales. Analysts forecast revenue of $22.49 billion, according to FactSet.

In after-hours trading, Gilead shares dipped 59 cents to $89.75. The stock has gained more than 20 percent in the year to date.