European shares closed half a percent lower.Drugmakers were the biggest losers. Sanofi-Aventis was down eight percent, extending the previous day’s losses on continuing concerns about the safety of its diabetes drug Lantus while Novo Nordisk fell 3.7 percent because of more general worries about modern insulins. Commodities retreated as oil and metal prices slid. Crude was affected by Nigeria saying it would halt a battle with rebels during a sixty day amnesty period for militants and release a suspected rebel leader if he accepted an amnesty offer. Energy stocks BP, Royal Dutch Shell and Tullow Oil were in the doldrums along with miners Anglo American, Antofagasta, BHP Billiton, Eurasian Natural Resources Corporation and Rio Tinto.