The global downturn and generic competition depressed sales and earnings at Merck, the US pharmaceutical group, even as it talked up full-year prospects following its planned takeover of Schering-Plough.

The company said net income was down 56 per cent to $1.5bn, while diluted earnings per share more than halved to 67 cents. Merck added it was delaying regulatory filing of a new migraine drug indefinitely after identifying unexpected side effects.