LONDON - Pharmaceutical company GlaxoSmithKline PLC said today that its first-quarter profit was virtually flat as the company faced greater competition from generic versions of its drugs in the United States.

Glaxo, with a U.S. headquarters in Philadelphia, said earnings, which were slightly better than the market consensus, were also dented by the weakness of the U.S. dollar.

Net income in the three months through March 31 came to 1.51 billion pounds ($3.01 billion), compared with 1.50 billion pounds in the same period a year earlier, the company said in a statement.

Sales rose 3 percent to 4.8 billion pounds ($9.59 billion).

Glaxo shares fell 0.3 percent to 1,467 pence ($29.33) on the London Stock Exchange.

Sales in the United States were up 3 percent to 2.4 billion pounds ($4.8 billion), the company said. It said sales were muted by generic competition to the antidepressant Wellbutrin XL, the anti-nausea drug Zofran and anti-inflammatory nasal steroid spray Flonase.

Excluding those drugs, U.S. sales were up 16 percent, the company said.

Sales of Seretide/Advair for asthma were up 11 percent, including a 12 percent gain in the United States. Sales of the Avandia drugs for type 2 diabetes rose 19 percent, the company said.

"This good start to 2007 is very encouraging and further evidence that GSK's broad portfolio, underpinned with effective cost control, will continue to deliver strong earnings performance at constant exchange rates," said Chief Executive Jean-Pierre Garnier.

He said the company had also strengthened its business, with more than 10 products filed, approved or launched since the start of 2007.