Worldwide sales of Fuzeon were $42.7 million, down from $64.3 million during the same three months a year ago. First-quarter sales in the U.S. and Canada were $17 million, down 42 percent.

Other drugs to treat HIV and AIDS have eclipsed Fuzeon, including new products from Pfizer and Merck that became available last year.

Gilead Sciences, a California company with a campus in Durham, last year passed GlaxoSmithKline for the first time as the world's largest maker of AIDS medicines. Gilead generated $3.14 billion in sales of AIDS drugs for the year, including the best-selling Truvada, compared with $2.88 billion for GSK, according to company reports.

As competition increases, Trimeris is also facing mounting pressure from its largest investor, a New York investment firm that wants the company sold. In response, Trimeris has slashed jobs, brought in new management and is considering strategic options for its future. That could include a sale of the company, which once employed 150 workers and was one of the Triangle's most-promising young drug companies.

Trimeris now has 10 workers.

The company, which plans to report its full first-quarter financial results in May, released its preliminary sales data on Fuzeon late Wednesday.

On Thursday, the shares fell 26 cents to $5.84. The stock is down 13 percent in the past year.

The stock began trading publicly in 1997 and soared above $70 in 2000, largely on the potential of the company's revolutionary medicine to treat AIDS. But patients and physicians balked at the drug's high cost and painful daily injections.

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