Biotechnology companies shares down at 1 p.m.

Shares of some top biotechnology companies are down at 1 p.m.:

Amgen Inc. fell $1.94 or 1.6 percent, to $120.91.

Biogen Idec fell $5.32 or 1.6 percent, to $325.83.

Celgene Corp. fell $.90 or 1.0 percent, to $89.29.

Gilead Sciences Inc. fell $.26 or .3 percent, to $87.64.