ImClone Systems Inc. (IMCL) fell more than 11 percent Wednesday after the drugmaker and Bristol-Myers Squibb Co. (BMY) said they will delay applying to sell their Erbitux drug as a treatment for certain types of head and neck cancer while they further review study data.

Imclone and Bristol-Myers said Tuesday they now plan to file an application with the Food and Drug Administration (search) by year-end, instead of in the second quarter as previously forecast.

Erbitux is currently approved by the FDA to treat advanced colorectal cancer that has spread to other parts of the body. ImClone and Bristol-Myers said they plan to take the extra time to strengthen the review process for results from the study of squamous cell carcinoma.

The domestic lifestyle diva Martha Stewart (search) was convicted last year of lying to the government about her sale of Imclone stock. She served five months in prison in West Virginia, then in early March began five months of house arrest.

ImClone shares fell $3.87 to $31.44 in morning trading on the Nasdaq Stock Market, sinking below its 52-week closing low of $33.08. Bristol-Myers shares slipped 7 cents to $25.25 in morning trading on the New York Stock Exchange.