LONDON -- GlaxoSmithKline PLC is reporting that first-quarter profit fell 13.7 percent compared with a year ago as drug sales were hit hard by competition from generics in the United States.

Profit for the period was 1.3 billion pounds ($2.58 billion) compared with 1.5 billion pounds a year earlier.

Revenue for Glaxo, the world's second-largest drug maker after Pfizer Inc., rose 1.6 percent to 5.69 billion pounds ($11.3 billion).