GSK warns profits to be hit by generic drugs competition

Pharmaceutical company GlaxoSmithKline saw sales and net earnings grow in the fourth quarter but warned that tougher competition from generic drugmakers this year could depress its earnings.

The London-based company said Wednesday its net income rose to 257 million pounds, from a loss of 354 million pounds a year earlier. Sales rose to 7.6 billion pounds, above both market expectations for 7.5 billion pounds and the previous year's figure of 6.3 billion pounds.

But GSK shares fell after CEO Andrew Witty said that "this year we face some uncertainty as to the level of our earnings performance."

He highlighted the risk that a generic version of GSK's asthma drug Advair could be introduced in the U.S. If that happens, core earnings would be flat, instead of up by 5-7 percent.