Imclone Systems

(IMCL)

was dropping 15.8% to $46.50 in premarket Instinet trading on the heels of news that the Food and Drug Administration refused to accept the application for approval of Erbitux, which the company filed with

Bristol-Myers Squibb

(BMY) - Get Report

on Oct. 31.

The biotech company was easily the volume leader on the Instinet platform before regular trading opened, with more than 260,000 shares changing hands.

The FDA's decision

raises serious questions about when the companies could actually get the cancer drug to the marketplace.