By Deena Beasley

LOS ANGELES (Reuters) - Gilead Sciences Inc (GILD.O: Quote, Profile, Research) said on Wednesday its first-quarter profit rose a better-than-expected 22 percent as its AIDS drugs continued to take market share.

But the company did not change its outlook for full-year sales, saying some U.S. states stockpiled the drugs in the first quarter. Shares fell slightly in after-hours trading.

Foster City, California-based Gilead said quarterly net profit increased to $496.1 million, or 51 cents per share, from $407.4 million, or 43 cents per share, a year ago.

Analysts, on average, expected 47 cents per share, according to Reuters Estimates.

"It's a very strong quarter. They beat on the top line, and they beat on the EPS line ... very strong all around," said Rodman & Renshaw analyst Mike King.

First-quarter revenue jumped 22 percent to $1.26 billion, beating the $1.22 billion expected by Wall Street analysts. Product sales increased 36 percent to $1.14 billion during the quarter.

Gilead has benefited from the emergence of AIDS trial data earlier this year showing that regimens containing Epzicom, a two-drug combination pill sold by GlaxoSmithKline Plc (GSK.L: Quote, Profile, Research), were less effective at controlling the HIV virus for some patients than regimens containing Truvada, which combines Gilead's Viread and Emtriva. Glaxo's drug was also associated with a higher risk of heart attack.

Gilead's first-quarter sales of HIV drugs rose 37 percent to $964.7 million, which included a 39 percent jump in sales of Truvada to $479.4 million.