Shares of some top biotechnology companies are down at 10 a.m.:
Amgen fell $.11 or .2 percent, to $54.51.
Biogen Idec fell $.28 or .4 percent, to $64.45.
Celgene fell $.42 or .7 percent, to $60.97.
Gilead Sciences fell $.37 or .9 percent, to $38.61.