Updated from 5:37 p.m. EDT

Who said drug makers are immune to economic disruption?

Cor Therapeutics ( CORR) warned late Wednesday that third-quarter profits will fall far short of estimates due to lower-than-expected September sales of its blood clot-fighting drug Integrilin.

The South San Francisco, Calif.-based biotech firm now expects to post a profit of 1 cent per share. Analysts were looking for a profit of 8 cents per share, according to consensus figures compiled by Thomson Financial/First Call.

Cor issued its warning about 30 minutes before the close of trading. Cor shares were in the red most of Wednesday, closing down $1.63, or 7%, to $20.60. They then slid sharply in after-hours trading, falling $3.62, or 17.5%, to $16.98.

The company said sluggish September sales of Integrilin pushed third-quarter revenue down to $53 million in the U.S. and $59 million worldwide. That compares with second-quarter sales of $61.3 million domestically and almost $70 million worldwide.

Integrilin is used primarily to prevent blood clots in patients undergoing angioplasty. On a conference call with analysts, Cor CEO Vaughn Kailian said in the wake of the Sept. 11 terrorist attacks, many nonemergency or elective surgeries were postponed.

Kailian said normal demand for Integrilin is coming back and that the drug's market share continues to grow. But the business interruption has forced the company to take down 2001 Integrilin sales forecasts to a range of $240 million to $250 million, as much as $10 million lower than previous forecasts.

"I really do think this is a blip," says Needham and Co. analyst Mark Monane, who rates Cor a buy. "The fourth quarter is typically strong for cardiovascular companies and Cor is expected to generate some positive news at the upcoming American Heart Association conference in November." Monane's firm has a banking relationship with Cor.

Cor now says it expects to report full-year earnings of between 11 cents and 13 cents per share, excluding a possible $10 million milestone payment the company is due to receive related to European approval of an angioplasty treatment. Earnings are also being hurt by lower interest income on investments, the company added.

Wall Street is expecting 2001 earnings of 36 cents per share, an estimate which includes the $10 million milestone payment, according to Thomson Financial/First Call.