Sales of the Trimeris AIDS drug Fuzeon plunged 34 percent in the first quarter, the biopharmaceutical firm reported Wednesday.

Trimeris (Nasdaq: TRMS) cited sharp declines in sales in the U.S. and Canada as the primary reasons for the falloff.

Trimeris sells the drug worldwide in partnership with Roche. The company will report full quarterly financial results next month.

For the quarter, Fuzeon sales dropped to $42.7 million, compared with $64.3 million a year ago.

U.S. and Canada sales plummeted to $17 million, compared with $29.3 million for the same three months in 2007.

Other global sales were down to $25.7 million from $35 million a year earlier.